IJSPT v13n3

IJSPT

INTERNATIONAL JOURNAL OF SPORTS PHYSICAL THERAPY

VOLUME THIRTEEN issue THREE JUNE 2018

IJSPT

INTERNATIONAL JOURNAL OF SPORTS PHYSICAL THERAPY

Editor in Chief Michael L. Voight, PT, DHSc, OCS, SCS, ATC, CSCS Belmont University Nashville, Tennessee – USA

Associate Editors: John Dewitt PT, DPT, SCS, ATC The Ohio State University Sports Medicine Columbus, Ohio - USA

Senior Associate Editor Barbara Hoogenboom, PT, EdD, SCS, ATC Grand Valley State University Grand Rapids, Michigan - USA

Terry Grindstaff PhD, PT, ATC Creighton University Omaha, Nebraska - USA

Associate Editor, Manuscript Coordinator Ashley Campbell, PT, DPT, SCS, CSCS Nashville Hip Institute Nashville, Tennessee – USA Associate Editor, Thematic Issues Robert Manske, PT, DPT, Med, SCS, ATC, CSCS Wichita State University Wichita, Kansas – USA Associate Review Editor Phil Page, PT, PhD, ATC, CSCS Performance Health Baton Rouge, Louisiana—USA

International Associate Editors: Colin Paterson, University of Brighton Brighton, England —United Kingdom Anthony G. Schneiders, PT, PhD Central Queensland University Bundaberg, Queensland – Australia Kristian Thorborg, PT, PhD Copenhagen University Hospital Hvidovre Hvidovre—Denmark

Editorial Board: Scott Anderson, PT, Dip Sport PT Alliance Health and Wellness Regina, Saskatchewan – Canada

Robert J. Butler, PT, DPT, PhD St. Louis Cardinals Jupiter, Florida – USA

Lindsay Becker, PT, DPT, SCS, CSCS Buckeye Performance Golf Columbus, Ohio – USA

Duane Button, PhD, CSEP-CEP Memorial University St. John’s, Newfoundland and Labrador – Canada

David Behm, PhD Memorial University of Newfoundland St. John’s, Newfoundland—Canada

Rick Clark, PT, DScPT, CCCE Tennessee State University Nashville, Tennessee – USA

Barton Bishop, PT, DPT, SCS, CSCS Sport and Spine Rehab of Rockville Rockville, Maryland – USA

George J. Davies, PT, DPT, SCS, ATC, FAPTA Armstrong Atlantic State University Savannah, Georgia – USA

Mario Bizzini, PT, MSc Schulthess Clinic Zürich – Switzerland

Todd S. Ellenbecker, DPT, SCS, OCS Physiotherapy Associates Scottsdale Sports Clinic Scottsdale, Arizona – USA

Turner A. “TAB” Blackburn, Jr., MEd, PT, ATC Clemson Sports Medicine and Rehabilitation Manchester, Georgia – USA

John A. Guido, Jr., PT, MHS, SCS, ATC, CSCS Ochsner Health Systems New Orleans, Louisiana – USA

Lori A Bolgla, PT, PhD, MAcc, ATC Augusta University Augusta, Georgia – USA

Walter L. Jenkins, PT, DHS, ATC Nazareth College Rochester, New York - USA

EDITORIAL STAFF & BOARD

Henning Langberg, PT, PhD, MSc Institute of Sports Medicine Copenhagen – Denmark

Timothy F. Tyler, PT, ATC NISMAT Lenox Hill Hospital New York, New York – USA

Daniel S. Lorenz, PT, DPT, ATC, CSCS Providence Medical Center Kansas City, Kansas - USA

Timothy Uhl, PT, PhD, ATC University of Kentucky Lexington, Kentucky – USA

Terry Malone, PT, EdD, ATC, FAPTA University of Kentucky Lexington, Kentucky – USA

Mark D. Weber, PT, PhD, SCS, ATC University of Mississippi Medical Center Jackson, Mississippi – USA

Charles E. Rainey, PT, DSc, DPT, MS, OCS, SCS, CSCS, FAAOMPT United States Public Health Service Springfield, Missouri - USA Michael P. Reiman, PT, DPT, OCS, SCS, ATC, FAAOMPT, CSCS Duke University School of Medicine Durham, North Carolina – USA Mark F. Reinking, PT, PhD, SCS, ATC Regis University Denver, Colorado – USA Kevin Robinson, PT, DSc, OCS Belmont University Nashville, Tennessee – USA Barbara Sanders, PT, PhD, SCS, FAPTA Texas State University-San Marcos San Marcos, Texas – USA Teresa L. Schuemann, PT, DPT, SCS, ATC, CSCS Colorado Physical Therapy Specialists Fort Collins, Colorado – USA Brandon Schmitt, PT, DPT, ATC PRO Sports Physical Therapy of Westchester Scarsdale, New York - USA Barry I. Shafer, PT, DPT, ATC Elite Motion Physical Therapy and Sports Medicine Pasadena, California - USA Laurie Stickler, MSPT, OCS Grand Valley State University Grand Rapids, Michigan – USA Amir Takla, PT, B.Physio, Mast.Physio (Musc).

University of Melbourne Melbourne— Australia Steven R. Tippett, PT, PhD, SCS, ATC Bradley University Peoria, Illinois – USA

Statistical Consultant Patrick Sells, DA, ES Belmont University Nashville, Tennessee – USA

IJSPT

international JOURNAL OF SPORTS PHYSICAL THERAPY

I N T E R N AT I O N A L J O U R N A L OF SPORTS PHYSICAL THERAPY

SPORTS PHYSICAL THERAPY SECTION

Editorial Staff

Executive Committee

Michael L. Voight, PT, DHSc, OCS, SCS, ATC Editor-in-Chief

Walter L. Jenkins, PT, DHS, LATC, ATC President

Barbara Hoogenboom, PT, EdD, SCS, ATC Grand Valley State University Grand Rapids, Michigan - USA Senior Associate Editor

Blaise Williams, PT, PhD Vice President

Robert Manske, PT, DPT, Med, SCS, ATC, CSCS Wichita State University Wichita, Kansas – USA Associate Editor, Thematic Issues Phil Page, PT, PhD, ATC, CSCS Performance Health Baton Rouge, Louisiana—USA Associate Review Editor Associate Editors John Dewitt PT, DPT, SCS, ATC The Ohio State University Sports Medicine Columbus, Ohio - USA Terry Grindstaff PhD, PT, ATC Creighton University Omaha, Nebraska - USA International Associate Editors

Colin Paterson, University of Brighton Brighton, England —United Kingdom

Mitchell Rauh, PT, PhD, MPH, FACSM Secretary Bryan Heiderscheit, PT, PhD Treasurer Stacey J. Pagorek, PT, DPT, SCS, ATC Representative-At-Large

Administration Mark S. De Carlo, PT, DPT, MHA, SCS, ATC Executive Director Mary Wilkinson Director of Marketing/Webmaster Managing Editor, Publications

Contact Information P.O. Box 431 Zionsville, Indiana 46077 877.732.5009 Toll Free 317.669.8276 Fax www.spts.org

Anthony G. Schneiders, PT, PhD Central Queensland University Bundaberg, Queensland – Australia Kristian Thorborg, PT, PhD Copenhagen University Hospital Hvidovre Hvidovre—Denmark Ashley Campbell Associate Editor, Manuscript Coordinator

IJSPT is a bimonthly publication, with release dates in February, April, June, August, October and December.

ISSN 2159-2896 Mary Wilkinson Managing Editor

Advertising Sales The International Journal of Sports Physical Therapy accepts advertising. Email Mary Wilkinson, Marketing Director, at mwilkinson@spts.org or contact by phone at 317.501.0805.

I N T E R N AT I O N A L J O U R N A L OF SPORTS PHYSICAL THERAPY is a publication of the Sports Physical Therapy Section of the American Physical Therapy Association. IJSPT is also an official journal of the International Federation of Sports Physical Therapy (IFSPT).

T

IFSPT

TABLE OF CONTENTS VOLUME 13, NUMBER 3 Page

Article Title

SYSTEMATIC REVIEW – META ANALYSIS 321 Is Multi-Joint Or Single Joint Strengthening More Effective In Reducing Pain And Improving Function In Women With Patellofemoral Pain Syndrome? A Systematic Review And Meta-Analysis.

Authors: Scali K, Roberts J, McFarland M, Marino K, Murray L 335

Exercise Therapy in the Non-Operative Treatment of Full-Thickness Rotator Cuff Tears: A Systematic Review.

Authors: Jeanfavre M, Husted S, Leff G

379

The Effect of Bracing and Balance Training On Ankle Sprain Incidence Among Athletes: A Systematic Review With Meta-Analysis.

Authors: Bellows R, Wong C

ORIGINAL RESEARCH 389 Comparison Of The “Back in Action” Test Battery To Standard Hop Tests And Isokinetic Knee Dynamometry In Patients Following Anterior Cruciate Ligament Reconstruction.

Authors: Ebert JR, Edwards P, Currie J, Smith A, Joss B, Ackland T, Buelow J, Hewitt B 401

The Lower Extremity Grading System (LEGS) to Evaluate Baseline Lower Extremity Perfromance in High School Athletes Authors: Smith J, DePhillipo N, Azizi S, McCabe A, Beverine C, Orendurff M, Pun S, Chan C

410

Pre-season Lower Extremity Functional Test Scores Are Not Associated with Lower Quadrant Injury – A Validation Study with Normative Data on 395 Division III Athletes Authors: Brumitt J, Wilson V, Ellis N, Peterson J, Zita C, Reyes J

422

Two-year ACL Reinjury Rate of 2.5%: Outcomes Report Of The Men In A Secondary ACL Injury Prevention Program (ACL-SPORTS).

Authors: Arundale A, Capin J, Zarzycki R, Smith A, Snyder-Mackler L

432

Influence of Anterior Cruciate Ligament Reconstruction on Dynamic Postural Control.

Authors: Heinert B, Willett K, Kernozek T

441

Altered Sagittal Plane Hip Biomechanics in Adolescent Male Distance Runners with a History of Lower Extremity Injury.

Authors: Lachniet PB, Taylor-Haas J, Paterno M, DiCesare C, Ford K

453

Reliability of Two-dimensional Video-Based Running Gait Analysis.

Authors: Reinking M, Dugan L, Ripple N, Schleper K, Scholz H, Spadino J, Stahl C, McPoil T

462

Short-term Effects of Trigger Point Dry Needling On Pain And Disability In Subjects With Patellofemoral Pain Syndrome.

Authors: Sutlive T, Golden A, King K, Morris WB, Morrison JE, Moore J, Koppenhaver S

474

Comparison of Three Different Density Type Foam Rollers on Knee Range of Motion and Pressure Pain Threshold: A Randomized Controlled Trial.

Authors: Cheatham S, Stull K

483

Influence of Topically Applied Menthol Cooling Gel on Soft Tissue Thermodynamics and Arterial and Cutaneous Blood Flow At Rest.

Authors: Hunter A, Grigson C, Wade A

493

Pitching Mechanics in Female Youth Fastpitch Softball, Authors: Oliver G, Plummer H, Washington J, Saper M, Dugus J, Andrews J

501

Reference Values for Glenohumeral Joint Rotational Range Of Motion In Elite Tennis Players.

Authors: Nutt C, Mirkovic M, Hill R, Ranson C, Cooper S

CASE SERIES / STUDIES 511 Rehabilitation Considerations for An Uncommon Injury of the Knee: A Case Report.

Authors: Baumann E, Rice W, Selhorst M 520

The Use of Serial Platelet Rich Plasma Injections with Early Rehabilitation to Expedite Grade III Medial Collateral Ligament Injury in A Professional Athlete: A Case Report.

Authors: Bagwell M, Wilk K, Colberg R, Dugas J

TABLE OF CONTENTS VOLUME 13, NUMBER 3 LITERATURE REVIEW 526 Evidence-Based Procedures for Performing the Single Leg Squat and Step-Down Tests in Evaluation of Non-Arthritic Hip Pain: A Literature Review.

Authors: McGovern R, Martin R, Christoforetti J, Kivlan B 537

Evaluating the Progress of Mid-Portion Achilles Tendinopathy During Rehabilitation: A Review of Outcome Measures For Muscle Structure and Function, Tendon Structure, and Neural and Pain Associated Mechanisms Authors: Murphy M, Rio E, Debenham J, Docking S, Travers M, Gibson W

CLINICAL COMMENTARY 552 Theoretical Applications of Blood Flow Restriction Training in Managing Chronic Ankle Instability in the Basketball Athlete.

Authors: Faltus J, Owens J, Hedt C

IJSPT

SYSTEMATIC REVIEW WITH META-ANALYSIS

IS MULTI-JOINT OR SINGLE JOINT STRENGTHENING MORE EFFECTIVE IN REDUCING PAIN AND IMPROVING FUNCTION IN WOMEN WITH PATELLOFEMORAL PAIN SYNDROME? A SYSTEMATIC REVIEW AND META-ANALYSIS. Kristen Scali, SPT1 Jordan Roberts, SPT1 Megan McFarland, SPT1 Katie Marino, SPT1 Leigh Murray, PT, PhD1

ABSTRACT Background: Patellofemoral pain syndrome is one of the most common causes of knee pain, especially in the female population. Conflicting evidence exists on whether a multi-joint strengthening program produces a greater outcome when compared to a single joint approach.

Purpose: The aim of this systematic review and meta-analysis was to investigate the effectiveness of a multi-joint strengthening program compared to a traditional single joint strengthening program in reducing pain and improving function in females diagnosed with patellofemoral pain syndrome.

Study Design: Systematic Review and Meta-Analysis.

Methods: A computer-based search (population: women with patellofemoral pain syndrome, intervention: multi-joint strengthening exercises, comparator: single joint strengthening exercises, outcome: pain and function) was performed.

Databases including PubMed, CINAHL, SPORTDiscus, Cochrane, PEDro, and Scopus were searched up to May 23, 2017 for randomized clinical trials published since 2004. A hand search of relevant articles and exploration of Grey Literature (including clinical trials.gov, Grey Literature Report, and Open Grey) was also completed. Data was extracted for the following information: exercises prescribed, outcome measures, and overall results from the study.

Results: Five studies, each of high quality based on the PEDro scale, met the inclusion criteria for this systematic review and meta-analysis. Statistically different outcomes were found that favored the multi-joint intervention group for short-term and long-term self-reported pain and functional pain, short-term functional performance, and longterm self-reported function.

Conclusion: The results of this review show that statistically significant data are available that favor implementing a multi-joint exercise program in comparison to a single joint program for the reduction of pain in females with patellofemoral pain syndrome. Limited statistical evidence, however, is available to support a multi-joint program over a single joint program in the improvement of short-term functional performance and long-term self-reported function in females with patellofemoral pain syndrome.

Key words: Hip, knee, multi-joint, patellofemoral pain syndrome, single-joint, strengthening program.

Level of Evidence: 1a

1

Walsh University, North Canton, OH

Conflict of Interest statement: The authors have no stated conflict of interest.

CORRESPONDING AUTHOR Leigh Murray, PT, PhD Professor Walsh University 2020 East Maple St. North Canton, OH 44720 E-mail: Lmurray@walsh.edu

The International Journal of Sports Physical Therapy | Volume 13, Number 3 | June 2018 | Page 321 DOI: 10.26603/ijspt20180321

INTRODUCTION Patellofemoral pain syndrome (PFPS) is one of the most common causes of knee pain in many populations.1-6 PFPS is caused by many different factors, including increased foot pronation, increased internal rotation (IR) of the tibia with increased valgus stress, excessive lateral tracking of the patella, muscle imbalance, or overuse.1,2,4-6 Women in particular are prone to biomechanical disadvantages including decreased quadriceps and hip external rotator strength, altered kinematics with dynamic tasks, increased Q angle, and increased hip IR, all of which may predispose women to the symptoms associated with PFPS.1,7 Given these biomechanical factors, women experience an increased prevalence of PFPS when compared to their male counterparts. The prevalence has been reported as high as 1.5 times greater in females than in males.8 Due to the increased prevalence of females experiencing symptoms of PFPS, attention to females when investigating treatment options is imperative.

During stair navigation, all females demonstrate hip adduction and knee abduction, while individuals already diagnosed with PFPS display greater ipsilateral trunk lean, contralateral pelvic drop, hip adduction, and knee abduction when compared to males and individuals not diagnosed with PFPS.9 These results suggest that the female population, as a whole, present with similar biomechanical factors, whether or not they have been diagnosed with PFPS, resulting in a functional disadvantage.

The deficits observed with stair negotiation suggest that PFPS occurs as a result of weak hip and knee joint muscles. Focusing on strengthening of the hip abductors could decrease ipsilateral trunk lean, contralateral pelvic drop, and hip adduction, while focusing on strengthening the primary movers of the knee joint could decrease knee abduction. Two randomized controlled trials that compared hip only strengthening interventions to knee only strengthening interventions found that individuals in the hip intervention groups experienced a decrease in pain sooner than the knee only intervention groups, although both intervention groups showed similar improvements in symptoms during a longer follow up period.10,11 This suggests that implementing

a multi-joint exercise program that addresses both the hip and knee joints would likely be beneficial to reduce pain and functional impairments experienced with PFPS. Several researchers have examined the effectiveness of combined hip and knee strengthening on decreasing symptoms of PFPS, but fewer have examined the effects of this treatment on women specifically. Two recent systematic reviews found that a hip and knee strengthening protocol reduced pain and improved function for both short- and long-term periods following intervention.5,12 Another recent study contrasted these findings, reporting that hip and knee strengthening are equally effective in reducing pain and improving function, with limited evidence to support the benefits of the addition of hip strengthening.13 Limited high-quality evidence exists on whether or not the addition of hip strengthening is beneficial in decreasing pain and improving function in patients with PFPS.14 Additionally, no systematic reviews were found that focus on the female population alone. Thus, the aim of this systematic review and meta-analysis was to investigate the effectiveness of a multi-joint strengthening program compared to a traditional single joint strengthening program in reducing pain and improving function in females diagnosed with patellofemoral pain syndrome.

METHODS Research topic, pilot title, and protocol were registered online on the PROSPERO database with registration number: CRD42016051313. The Reporting Checklist for Meta-Analyses of Observational Studies (MOOSE) guidelines were utilized throughout the research process.15 Eligibility Criteria, Search Strategy, and Study Selection Eligibility for this review included randomized controlled trials that compared multi-joint and single joint exercise programs in women diagnosed with PFPS (described as patellofemoral pain, patellofemoral pain syndrome, or anterior knee pain), but no other concurrent knee conditions. Studies must have included outcome measures assessing pain and function, as well as reported outcomes separated by gender. Multi-joint exercises were defined as therapeutic

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exercise that focused on strengthening the musculature about more than one joint, including at least the hip and knee. Single joint exercises were defined as exercises strictly focusing on strengthening at the musculature of the knee joint (closed kinetic chain or open kinetic chain approach). While exercise protocols investigating a single joint (either the knee or hip) will inherently produce activation of muscles spanning both joints (i.e. the quadriceps), the sole focus of a single joint protocol is the activation of the primary movers of that joint. For example, while the ascending portion of a standing squat requires hip extension and utilizes specific musculature required for that motion, the focus of the exercise is knee extension and the concentric activation of the quadriceps musculature. Examples of common exercises that were used in the studies included in this review for both the multi-joint and single joint groups can be found in Table 1. Studies published prior to 2004 were not included in order to focus on the most recent literature on this topic. While studies regarding this topic were published prior to 2004, the majority of high quality studies focusing specifically on females with the syndrome have been published within the past 13 years. Non-English studies were also excluded.

Electronic databases including PubMed, CINAHL, SPORTDiscus, Cochrane, PEDro, Scopus were searched in consultation with a librarian on

November 20, 2017 and May 23, 2017. Keywords included “PFPS,” “anterior knee pain,” and “patellofemoral pain”. An example of a specific search strategy used can be found in Table 2. A hand search of relevant articles and exploration of Grey Literature (including clinicaltrials.gov, Grey Literature Report, and Open Grey) were also completed for any additional studies not identified in the database search.

After duplicates were removed, titles were screened by two authors and disagreements were resolved by a third author. Screening of abstracts was completed by four authors and any disagreements were discussed with unanimous consensus reached for inclusion. Further screening of full texts was completed by two authors and all disagreements were resolved by a third author. Search results are displayed in Figure 1.

Quality Assessment Quality assessment of articles was completed by two authors and any discrepancies that arose were settled by a third author. Methodological quality of each study was assessed using the PEDro scale,16 which consists of 11 items, each of which is scored by a “yes” or a “no” response. A “yes” is equivalent to one point on the scale and is only assigned if the criteria are specifically stated within the text. A “no” is assigned to categories not specifically stated within the text. Specific guidelines and criteria for

Table 1. Sample exercises for multi-joint and single joint protocols30-32,34

Table 2. Example search strategy entered into PubMed

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Figure 1. Prisma flow diagram.

the grading with the PEDro scale are outlined in Verhagen et al.16 The reliability of the PEDro scale has been assessed as having inter-rater reliability ranging from moderate to substantial reliability (κ = .50 – .79).17 Using the PEDro scale for assessment, the articles with more “Yes” scores are of higher quality given the scale of the assessment.18 Data Extraction and Analysis The outcome measures were categorized into four groups based on the constructs investigated, and included self-reported pain at rest, functional pain, self-reported function, and functional performance.

Self-reported pain at rest is a subjective report of pain while the individual is not completing any physical activity. This is measured by the Visual Analog Scale (VAS). Functional pain is a subjective measure of pain that the individual experiences while performing physical activity or activities of daily living (ADLs) and is also measured by the VAS and Numeric Pain Rating Scale (NPRS). Both the VAS

and the NPRS have been found to have excellent and high test-retest reliability (r= 0.97 and r=0.92 respectively).19, 20 Self-reported function is a subjective report of the individual’s functional ability to perform daily activities and is measured by the Lower Extremity Functional Scale (LEFS), the Anterior Knee Pain Scale (AKPS), or the Kujala Function Score. The LEFS and Kujala have each been found to have excellent test-retest reliability (r=0.94 and r=0.944 respectively),21, 22 while the AKPS was shown to have excellent inter-rater reliability (r=0.95).23 Finally, functional performance testing is an objective measure of functional ability and these investigate either muscle power measured by the Single Limb Hop Test or muscle endurance measured by the Step Down Test or Single Leg Squat Test. The single limb hop test is an assessment of lower extremity function that measures the distance jumped by the study participant in a single attempt. The single limb hop

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test has been reported to produce high inter-rater reliability (ICC=0.77-0.99).24 The step down test is performed with the participant keeping the testing leg on a raised platform while the contralateral limb descends to a lower surface. The step down test has been reported to have high intra-rater reliability (ICC=0.94).25 The single leg squat is performed in single leg stance by flexing and extending the knee to a predetermined angle in a controlled manner.

Both tests are quantitative assessments of lower extremity function as they measure the number of repetitions of these exercises completed by the subject in a given time frame. Established reliability values were not found for the single leg squat test.

Data extraction was completed by four authors who independently collected pertinent data from each included study. All data was cross-checked by another author. Participant inclusion/exclusion criteria, sample size, interventions, and follow-up times were synthesized as well as means, medians, standard deviations, and p-values for the multi-joint and single joint groups in each study.

Meta-analyses were made using Comprehensive Meta-Analysis, Version 3 wherever possible. All meta-analyses were completed using standardized mean difference (SMD) as the summary measure of effect. SMD with 95% confidence intervals (CI) were used as this method is seen to be more generalizable and also allows the use of different scales to assess the same general construct. I2 statistics were calculated in order to determine the level of heterogeneity or lack thereof between included studies. The I2 statistic is more useful than the Q test, which only indicates the presence versus absence of heterogeneity.26 Percentages used by Higgins and Thompson27 were utilized to quantify the magnitude of heterogeneity: 25% = low, 50% = medium, 75% = high heterogeneity. Utilizing the scale, if I2 was <50%, a fixed effects model was used, and if the I2 was >50%, a random effects model was used.

Interpretation of effect size used Cohen’s criteria for pooled estimates.28 Cohen describes 0.2 as small, 0.5 as moderate, and 0.8 as large effect sizes.27 Risk of bias was assessed via funnel plot construction. A symmetrical funnel plot indicates low risk of publication bias, whereas an asymmetrical funnel plot indicates a higher risk of publication bias.29

RESULTS The search process returned 475 records on this topic. There were 470 articles excluded through title, abstract, and full-text assessments because they did not meet inclusion criteria, were not randomized controlled trials, or the study design and interventions did not match the research question. The remaining five studies were used to complete this systematic review and meta-analysis.30-34 Substantial agreement between reviewers was demonstrated in the title screening process, with κ = 0.719 (95% CI, 0.632 to 0.805) p<.05, and excellent agreement between reviewers was found during the full-text screening process, with κ = 0.915 (95% CI, 0.753 to 1) p<.05.35 The methods of the study selection and exclusion are shown in figure 1.

Quality Assessment The five included articles30-34 were assessed using the PEDro scale with κ = 1.0 (95% CI, 1.0 to 1.0) p<0.05, demonstrating excellent agreement between reviewers.35 Each of the included articles30-34 received scores of at least 8. Given the scores as assessed by the PEDro scale, all included articles are of high quality.18 All five studies30-34 used assessor blinding to decrease the risk of measurement bias, used concealed assignment to randomize the subjects in each group, and all groups were statistically similar prior to intervention, which reduced the risk of selection bias. Results from the PEDro quality checklist assessment are summarized in Table 3.

Study Characteristics Individual study details including sample size, patient age, intervention and comparison group protocols, results, and exercise prescription are presented in Table 4. All included studies investigated exercise protocols of the hip and knee musculature in comparison to exercise protocols of knee musculature only. The results of each of these studies were categorized into two different time periods: short-term and long-term. The short-term period was defined as the timeframe that treatment was provided. The long-term period is defined as the follow-up period after treatment has ended. During the short-term period, treatment duration lasted either four, six, or eight weeks. The long-term follow-up period lasted 12 weeks. No structured intervention

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Table 3. Quality Check Assessment

was performed during the follow-up period. Data were analyzed separately for short-term and longterm periods.

Effects of Multi-Joint Compared with Single Joint Exercise Programs All five studies30-34 compared multi-joint exercise programs with single joint exercise programs in females. Outcome measures of four of the five studies evaluating pain and function were assessed at two different time points: pre and post treatment (short-term).30,31,33,34 Three of the five studies30,32,34 also evaluated pain and function after treatment was ended (long-term). Four out of five studies provided clear outlines of the exercise programs performed per each intervention group.30-32, 34 Razeghi et al. only provided the targeted muscle groups in each of the intervention categories and did not include specific exercise protocols that participants followed.33 A summary of meta-analysis results can be found in Table 5 and Table 6.

Self-Reported Pain at Rest Three of the five studies30,33,34 used in the meta-analysis examined self-reported pain utilizing the VAS scale. In the short term, evidence suggests a large effect28 and a significant decrease in pain (SMD, 0.87, CI: 0.48, 1.26, pâ&#x2030;¤0.001) favoring multi-joint interventions over single joint interventions (Figure 2A). Two studies30,34 were included in the meta-analysis of the long-term period, and evidence demonstrated a large effect 28 and a significant decrease in pain (SMD, 0.89, CI: 0.43, 1.34, pâ&#x2030;¤0.001) in favor of

multi-joint interventions over single joint interventions (Figure 3A). Heterogeneity for self-reported pain at rest was low for both short- and long-term effects (I2 = 0). See Tables 5 and 6 for meta-analysis results.

Pain During Functional Activities Three of the five studies31,32,34 used in the meta-analysis investigated pain during functional activities.

Activities analyzed included pain with ascending and descending stairs, ramp negotiation, running, squatting, standing, and walking. Results demonstrated significant decreases in pain with a variety of activities and a moderate short-term (SMD, 0.46, CI: 0.05, 0.88, p=0.03) and a large long-term effect (SMD, 0.97, CI: 0.02, 1.93, p=0.05) in favor of multijoint interventions over single joint interventions (Figures 2B and 3B respectively). Heterogeneity for self-reported pain at rest during the short term was low (I2 = 0) and was high for the long-term effects (I2 = 77.34). See Tables 5 and 6 for meta-analysis results.

Self-Reported Function Four of the five studies30-32,34 used in the meta-analysis investigated self-reported function but utilized different questionnaires as their subjective measures (Kujala, AKPS, and LEFS). Three of the four studies30,31,34 analyzed self-reported function in the short term, and did not demonstrate statistically significant improvements in self-reported function in favor of multi-joint interventions over single joint interventions but did report a moderate effect size

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Table 4. Individual Study Demographics

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Table 5. Meta-analysis for short term impact

Table 6. Meta-analysis for long term impact

(SMD=0.50, CI: -0.14, 1.13, p=0.13) (Figure 2C).

Heterogeneity for self-reported function in the short term was low (I2 = 0).

Two of the five studies30,32,34 were analyzed with regards to long-term self-report of function and did demonstrate statistically significant improvements in self-reported function in favor of multi-joint interventions over single joint interventions with a large effect size (SMD=1.36, CI: 0.30, 2.41, p=0.01) (Figure 3C). Heterogeneity for self-reported function in the long term was high (I2 = 71.13). See Tables 5 and 6 for meta-analysis results.

Functional Performance Testing Four of the five studies30-32,34 included in the metaanalysis investigated functional performance and used a variety of measures including the Single Hop Test, Triple Hop Test, Single Leg Squat, and Step Down Test. Functional performance during the short term was analyzed in three of the four studies.30,31,34 The results demonstrate a statistically significant improvement in functional performance in favor of multi-joint interventions over single joint interventions (SMD=0.44, CI: 0.08, 0.80, p=0.02) (See Figure 2D). Two of the four studies32,34 were analyzed

with regard to long-term reports of functional performance, however, statistically significant improvements in function were not reported in favor of multi-joint interventions over single joint interventions with a moderate effect size (SMD=0.54, CI: -0.22, 1.31, p=0.17) (Figure 3D). Heterogeneity for functional performance was high for both short- and long-term effects (I2 = 67.48; 85.97). See Tables 5 and 6 for meta-analysis results.

DISCUSSION The goal of this systematic review and meta-analysis was to analyze the effectiveness of a multi-joint exercise protocol compared to a single joint protocol in reducing pain and improving function in females diagnosed with PFPS. Through meta-analysis of all five studies,30-34 statistical significance was found that favored the multi-joint intervention group for shortterm and long-term self-reported pain and functional pain, short-term functional performance, and longterm self-reported function. These findings suggest that strengthening musculature about both the hip and knee joints is more effective in decreasing pain and improving function in females with PFPS when compared to strengthening musculature about the

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Figure 2. Standard difference in means in individual studies for short-term (A) self-reported pain, (B) pain with functional activity, (C) self-reported function, and (D) function after completion of treatment. Squares represent study-specific findings and diamond represents summary estimates of fixed/random effects meta-analysis. SJ single joint, MJ multi-joint, CI Confidence Interval.

knee joint alone. The results potentially support an intervention that may directly target the inherent mechanical disadvantage that women face at both the hip and knee joint. These disadvantages include an increased Q-angle, increased hip internal rotation, possibly resulting from decreased strength of the quadriceps and hip external rotators.1,7 Strengthening the musculature about both the hip and knee joints could help to provide better stability and posture at both joints through improved neuromuscular activation, muscular hypertrophy, and increased muscle cross-sectional area which may counteract many of the inherent anatomical factors that predispose women to the symptoms of PFPS. This in turn

may have a positive impact on pain and function in this population.

The Minimal Clinically Important Difference (MCID) for the VAS and NPRS has been reported as 1.4 and -1.5 to -3.5 respectively.36,37 The MCID is the minimal change in a scale that can be detected as “different” from a patient’s perspective and warrants a change in the intervention that is used for a particular condition. All included studies reported mean post-intervention pain changes that exceeded established MCID values. Multi-joint intervention groups also displayed mean changes in reported pain that were larger than the mean reported

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Figure 3. Standard difference in means in individual studies for long-term (A) self-reported pain, (B) pain with functional activity, (C) self-reported function, and (D) function during the follow-up period. Squares represent study-specific findings and diamond represents summary estimates of fixed/random effects meta-analysis. SJ single joint, MJ multi-joint, CI Confidence Interval.

changes in the single joint groups. This is clinically significant because individuals experiencing pain demonstrated improvement after using a treatment approach focused on both the hip and knee. Statistical significant outcomes with moderate to large effect sizes were found for decreasing pain at rest and with functional activities in favor of individuals completing a multi-joint exercise protocol when compared to those completing a single joint protocol. In addition, clinical and statistical significant differences found using the VAS and NPRS could be attributed to all included studies utilizing a validated subjective measure of pain, which provided a larger sample size from which to draw these conclusions. This data provides clinical and statistical

significance, supporting the use of a multi-joint protocol in clinical practice.

Calculated effect size and statistical significance values were inconsistent throughout the self-reported function measures. While both the short-term and long-term periods demonstrated moderate to large effect sizes, the meta-analysis found statistical significant support for improvement in self-reported function for the long-term periods, but not shortterm. When breaking down the short-term results, the study that least favored the multi-joint group consisted of a four-week strengthening protocol.31 One possible explanation for this finding is that this shorter frequency and duration of treatment is not

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long enough to allow for significant muscle hypertrophy or biomechanical changes that would allow for a noticeable improvement in function. The literature has shown that four weeks is not long enough to create significant muscular hypertrophy and increases in muscular cross-sectional area.38 The subjects that received at least six weeks of treatment may be more likely to demonstrate greater improvements simply because of increased strength gains, increased muscular hypertrophy, or other biomechanical improvements that may occur given a longer timeframe. In the study conducted by Fukuda et al.31 the participants also received the lowest number of total treatments (12) while the other two studies who received significantly more treatment sessions (24 and 30, respectively).30,31,34 This suggests that the dosage of training is a major factor in the design and implementation of multi-joint protocols.

Comparing the results of the studies with the established MCID values for the LEFS and AKPS may indicate possible clinical relevance for self-reported function during both short- and long-term periods despite the lack of statistical significance. The established MCID for the LEFS has been reported by a change of 12 points.39 The three studies that used the LEFS as an outcome of self-reported function demonstrated results that were greater than the established MCID across all time frames.30-32 Also, the MCID for the AKPS has been reported as an average of 10 points.40 Both studies that included the AKPS as an outcome measure of self-reported function exceeded the MCID for the multi-joint group, while the single joint did not, thereby exhibiting clinically significant improvements in the multi-joint group.

Similar to self-reported function, the meta-analysis found moderate to large effect sizes and statistically significant outcomes in functional performance but for the short-term period and not the long-term.

Several different functional performance tests were used across the studies, including the triple hop, single hop, step down, and single leg squat tests. One possible explanation for the variety of results found among these tests is the variance in the nature of the tests used. The single and triple hop tests are dynamic activities that rely on muscle power, whereas the step down and single leg squat tests are static activities that rely more on muscle endurance.

No statistically significant difference was found in the one study31 observing the single hop test over a period of only four weeks. This same test measure, however, was found to produce statistically significant differences in another study32 over a 12-week period. The triple hop test was found to produce statistically significant differences favoring the multijoint intervention over the single joint intervention for the triple hop test, but over a period of eight weeks.30 As stated previously, it is very possible that the longer intervention periods allow for increased muscular strength compared to the shorter periods, producing better statistical results for the multi-joint group in comparison to the single joint group. The single study34 that investigated the use of the step down and single leg squat test found statistically significant differences favoring the multi-joint group over the single joint group. These results were found over a six-week period, which is a relatively shorter time frame; however, the activities measured are more static activities, as opposed to more dynamic activities like the single hop and triple hop tests (Figures 2D and 3D). It is likely that static stability will develop before dynamic stability during training, and that the dynamic activities may be more difficult for a sedentary, untrained population, like the participants in these studies, who likely have less experience with activities requiring significant power. Another possible explanation is that some of the exercises performed in the training protocols are similar to the step down and single leg squat tests, which could give the participants an advantage over time. These factors, in addition to smaller sample sizes within each of these studies may have caused the variance in the results for functional performance. It should also be noted that the functional performance measures do not necessarily correlate with return to higher level activities such as sport.

Rather, these tests display an ability to dynamically control the knee joint and surrounding musculature, which may correlate with normal activities of daily living such as ascending and descending stairs.

Two major limitations of the studies analyzed in this meta-analysis exist. First, the included studies had relatively low sample sizes ranging from n=31 to n=64. Second, differences among intervention protocols (i.e. duration, follow-up period, and

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frequency of exercise) may be another factor. The results of this meta-analysis suggest that duration and dosage of exercise are major factors because the participants who received at least six weeks of treatment showed greater improvements than those who only received four weeks of treatment. This is an extremely important consideration for clinicians and future researchers as they design their exercise protocols for females with PFPS because even though the subjectsâ&#x20AC;&#x2122; scores still improved following the shorter intervention periods, greater improvements were displayed in the groups that had longer treatment periods and more treatment sessions.

Consideration must also be given to the fact that some participants in the included studies received up to 30 treatment sessions, which may be more visits than typically allowed by most insurance plans.

Clinicians need to consider this when applying the results of this review to clinical practice, and prescribe a strong home exercise program based on the design of the included studies in this review combined with adequate patient education, which may allow patients to achieve the desired results despite a limited number of visits.

A potential limitation of this review is the exclusion of non-English language studies. The exclusion of studies that did not have separate data available for males and females is another potential limitation.

These studies observed the effects on both genders and did not present data to analyze the differences between genders. These were excluded because they did not address the research question, however, this could have left out potentially useful information and data. One final limitation of this particular study is that along with the relatively small sample sizes of each individual study, this review itself only included five studies, which limited the total number of participants to be included in the aggregate calculations and comparisons. Undoubtedly, had more studies been included the recommendations to be made could have been stronger.

Based on the findings of this systematic review and meta-analysis, the use of a multi-joint protocol can be supported for the reduction of pain in females with PFPS. However, there are still inconsistencies in the findings for improvement in function within this population. Therefore, more research needs to

be conducted with larger sample sizes and more consistent exercise dosage, which could provide more definitive findings that would support a stronger recommendation for the use of a multi-joint exercise protocol in improving function in females with PFPS. Future research should continue to focus on gender-specific data and further investigate both short- and long-term outcomes of multi-joint exercise programs for females with PFPS. Increasing the study sample sizes, greater uniformity of duration and dosage of exercise protocols, and standardizing universal outcome measures to assess pain and function could help reduce variability in data reporting in future studies.

CONCLUSIONS Previously conducted systematic reviews and metaanalyses have concluded that there is not enough strong statistical evidence to support the use of a multi-joint exercise approach compared to a single joint approach when including both male and female participants.5,12,13 However, this systematic review and meta-analysis found statistically significant outcomes and strong effect sizes in favor of using a multi-joint protocol in comparison to single joint protocol for all areas analyzed, except short-term self-reported function and long-term functional performance, for reducing pain and improving function in females with PFPS. The included studies were similar in terms of the population measured, which allows these findings to be generalized to many different clinical settings.

These findings allow for a strong recommendation to be made for the use of a multi-joint protocol for the reduction of pain in females with PFPS; however, more research needs to be completed for a strong recommendation to be made for the improvement of function in this population.

REFERENCES 1. Boling M, Padua D, Marshall S, et al. Gender differences in the incidence and prevalence of patellofemoral pain syndrome. Scand J Med Sci Sports. 2010;20(5):725-730.

2. Clijsen R, Fuchs J, Taeymans J. Effectiveness of exercise therapy in treatment of patients with patellofemoral pain syndrome: systematic review and meta-analysis. Phys Ther. 2014; 94:1697-1708.

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3. Glaviano N, Kew M, Hart J, et al. Demographic and Epidemiological Trends in Patellofemoral Pain. Int J Sports Phys Ther. 2015;10(3):281-290.

4. Kim S. Comparative evaluation of ambulation patterns and isokinetic muscle strength for the application of rehabilitation exercise in patients with patellofemoral pain syndrome. J Phys Ther Sci. 2016;28(12):3279-3282.

5. Peters J, Tyson N. Proximal exercises are effective in treating patellofemoral pain syndrome: a systematic review. Int J Sports Phys Ther. 2013;8(5):689-700.

6. Powers C. The inďŹ&#x201A;uence of abnormal hip mechanics on knee injury: a biomechanical perspective. J Orthop Sports Phys Ther. 2010;40(2):42-51.

7. Boling M, Padua D, Marshall S, et al. A prospective investigation of biomechanical risk factors for patellofemoral pain syndrome: the Joint Undertaking to Monitor and Prevent ACL Injury (JUMP-ACL) cohort. Am J Sports Med. 2009;37(11):2108-2116.

8. Taunton JE, Ryan MB, Clement DB, et al. A retrospective case-control analysis of 2002 running injuries. Br J Sports Med. 2002;36(2):95-101.

9. Nakagawa T, Moriya E, Maciel C, Serrao F. Frontal Plane Biomechanics in Males and Females with and without Patellofemoral Pain. Med Sci Sports Exerc.

2012;44(9):1747-1755.

10. Dolak KL, Uhl TL. Hip Strengthening Prior to Functional Exercises Reduces Pain Sooner than Quadriceps Strengthening in Females with Patellofemoral Pain Syndrome: A Randomized Clinical Trial. J Orthop Sport Phys Ther.

2011;41(8):560-570.

11. Ferber R, Emery C, Bolgla L, Earl-Boehm JE, Hamstra-Wright K. Strengthening of the hip and core versus knee muscles for the treatment of patellofemoral pain: A multicenter randomized controlled trial. J Athl Train. 2015;50(4):366-377.

12. Lack S, Barton C, Sohan O, et al. Proximal muscle rehabilitation is effective for patellofemoral pain: a systematic review with meta-analysis. Br J Sports Med. 2015;49(21):1365-1376.

13. Thomson C, Krouwel O, Kuisma R, et al. The outcome of hip exercise in patellofemoral pain: A systematic review. Man Ther. 2016;26:1-30.

14. Van der Heijden RA, Lankhorst NE, van Linschoten R, Bierma-Zeinstra SMA, van Middelkoop M. Exercise for treating patellofemoral pain syndrome.

Cochrane Database of Systematic Reviews. 2015;1:203.

15. Stroup DF, Berlin JA, Morton SC, et al. Meta-analysis of observational studies in epidemiology - A proposal for reporting. JAMA. 2000;283(15):2008-2012.

16. Verhagen AP, de Vet HC, de Bie RA, et al. The Delphi List: a criteria list for quality assessment of randomized clinical trials for conducting systematic reviews developed by Delhi consensus. J Clin Epidemiol. 1998;51(12):1235-41.

17. Maher C, Sherrington C, Herbert R, et al. Reliability of the PEDro Scale for rating quality of randomized controlled trials. Phys Ther. 2003;83(8):713-721.

18. Moher D, Jadad A, Tugwell P. Assessing the quality of randomized controlled trials. Current issues and future directions. Int J Technol Assess Health Care.

1996;12(2):195-208.

19. Bijur PE, Silver W, Gallagher EJ. Reliability of the Visual Analog Scale for Measurement of Acute Pain.

Acad Emerg Med. 2001;8(12):1153 1157.

20. Jensen MP, Mcfarland CA. Increasing the reliability and validity of pain intensity measurement in chronic pain patients. Pain. 1993;55(2):195-203.

21. Binkley JM, Stratford PW, Lott SA, et al. The Lower Extremity Functional Scale (LEFS): Scale Development, Measurement Properties, and Clinical Application. Phys Ther. 1999;79(4):371-383.

22. Kuru T, Dereli EE, Yaliman A. Validity of the Turkish version of the Kujala patellofemoral score in patellofemoral pain syndrome. Acta Orthop Traumatol Turc. 2010;44(2):152-156.

23. Watson CJ, Propps M, Ratner J, et al. Reliability and Responsiveness of the Lower Extremity Functional Scale and the Anterior Knee Pain Scale in Patients With Anterior Knee Pain. J Orthop Sports Phys Ther.

2005;35(3):136-146.

24. Booher LD, Hench KM, Worrell TW, et al. Reliability of Three Single-Leg Hop Tests. J Sport Rehabil.

1993;2(3):165-170.

25. Loudon JK, Wiesner D, Goist-Foley HL, et al.

Intrarater Reliability of Functional Performance Tests for Subjects with Patellofemoral Pain Syndrome. J Athl Train. 2002;37(3):256-261.

26. Huedo-Medina T, Sanchez-Meca J, Martin-Martinez F. Assessing heterogeneity in meta-analysis: Q statistic or I2 index? The center for Health, Intervention, and Prevention (CHIP): Digital Commons; 2006.

27. Higgins J, Thompson SG. Quantifying heterogeneity in a meta-analysis. Stat Med. 2002; 21(11):1539-58.

28. Cohen J. Statistical Power Analysis for the Behavioral Sciences. 2nd Ed. Hillsdale, NJ: Lawrence Erlbaum Associates; 1988.

29. Liberati A, Altman DG, Tetzlaff J, et al. The PRISMA statement for reporting systematic reviews and meta-analyses of studies that evaluate healthcare interventions: explanation and elaboration. Br Med J. 2009;339:b2700.

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30. Baldon R, Serrão F, Scattone Silva R, et al. Effects of functional stabilization training on pain, function, and lower extremity biomechanics in women with patellofemoral pain: a randomized clinical trial. J Orthop Sports Phys Ther. 2014;44(4):240-A8.

31. Fukuda T, Rossetto F, Magalhaes E, et al. Short-Term Effects of Hip Abductors and Lateral Rotators Strengthening in Females With Patellofemoral Pain Syndrome: A Randomized Controlled Clinical Trial. J Orthop Sports Phys Ther. 2010;40(11):736-742.

32. Fukuda T, Melo W, Martin R, et al. Hip posterolateral musculature strengthening in sedentary women with patellofemoral pain syndrome: a randomized controlled clinical trial with 1-year follow-up. J Orthop Sports Phys Ther. 2012;42(10):823-830.

33. Razeghi M, Etemadi Y, Taghizadeh S, et al. Could Hip and Knee Muscle Strengthening Alter the Pain Intensity in Patellofemoral Pain Syndrome?. Iranian Red Crescent Med J. 2010;12(2):104-110.

34. Şahin M, Ayhan F, Borman P, et al. The effect of hip and knee exercises on pain, function, and strength in patients with patellofemoral pain syndrome: a randomized controlled trial. Turk J Med Sci. 2016;46(2):265-277.

35. Landis JR, Koch GG. The Measurement of Observer Agreement for Categorical Data. Biometrics.

1977;33(1):159-174.

36. Abbott J, Schmitt J. Minimum Important Differences for the Patient-Specific Functional Scale, 4 RegionSpecific Outcome Measures, and the Numeric Pain Rating Scale. J Orthop Sports Phys Ther.

2014;44(8):560-564.

37. Tashjian R, Hung M, Chamberlain A, et al.

Determining the minimal clinically important difference for the American Shoulder and Elbow Surgeons score, Simple Shoulder Test, and visual analog scale (VAS) measuring pain after shoulder arthroplasty. J Shoulder Elbow Surg. 2017;26(1):144148.

38. Abe T, DeHoyos DV, Pollock ML, et al. Time course for strength and muscle thickness changes following upper and lower body resistance training in men and women. Eur J Appl Physiol. 2000;81(3):174-180.

39. McCormack J, Underwood F, Slaven E, et al. The minimal clinically important difference on the VISA-A and LEFS for patients with insertional achilles tendinopathy. Int J Sports Phys Ther.

2015;10(5):639-644.

40. Crossley K, Bennell K, Cowan S, et al. Analysis of outcome measures for persons with patellofemoral pain: which are reliable and valid? Arch Phys Med Rehabil. 2004;85(5):8.

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IJSPT

SYSTEMATIC REVIEW

EXERCISE THERAPY IN THE NON-OPERATIVE TREATMENT OF FULL-THICKNESS ROTATOR CUFF TEARS: A SYSTEMATIC REVIEW Michael Jeanfavre, PT, DPT, CSCS1 Sean Husted, PT, DPT, CSCS2 Gretchen Leff, PT, DPT, MSPT, OCS1

ABSTRACT Background: Although commonly prescribed, the evidence to support exercises therapy (ET) and conservative management for the treatment of full-thickness rotator cuff tears (FTT) is equivocal.

Purpose: The purpose of this systematic review of the literature was to determine the current level of evidence available for ET in the treatment of FTT and to provide a formal Grading of Recommendations Assessment, Development and Evaluation (GRADE) Working Group of recommendation.

Methods: Five databases were systematically searched to evaluate the effectiveness of ET for FTT. Inclusion criteria: experimental or observational studies of adults clinically diagnosed with FTT, or massive, or inoperable tears that contained a treatment group that received ET for FTT. Exclusion criteria included: history of surgical repair, concurrent significant trauma, neurological impairment, and level V studies.

Articles were assessed for quality, the level of evidence (I – V) and GRADE of recommendation (A to F) was determined. Data extraction included: demographics, specific interventions, and outcomes.

Results: One thousand, five-hundred and sixty-nine unique citations were identified, 35 studies were included: nine randomized controlled studies, six cohort studies, 15 case series and five case reports. There were 2010 shoulders in 1913 subjects with an average age of 64.2 years, 54% males, 73% of tears were >1 cm and 37% were classified as massive. Based on studies that reported, >58% of tears were >1 year and 73% were atraumatic. Of the non-operatively treated cohorts that reported the respective outcomes: 78% improved in pain (9/10 cohorts that reported statistically significant differences [stat-sig] p<0.05), 81% improved in ROM (14/14 cohorts that reported, met stat-sig), 85% improved in strength (7/8 cohorts that reported, met stat-sig), 84% improved in functional outcomes (17/17 cohorts that reported, met stat-sig).

Dissatisfied outcomes occurred in 15% of patients, who then transitioned to surgery.

Conclusion: The current literature indicates GRADE B recommendation (moderate strength) to support the use of ET in the management of FTT. There is further need for well-designed randomized controlled trials.

Level of Evidence: 2a Key Words: Exercise therapy, full-thickness rotator cuff tear, non-operative management

1 2

Stanford Health Care, Redwood City, CA, USA Advanced Physical Therapy, Thousand Oaks, CA, USA

Conflicts of Interest: The authors declare no conflicts of interest in the authorship or publication of this contribution.

CORRESPONDING AUTHOR Michael Jeanfavre, PT, DPT, CSCS Stanford Health Care Stanford Orthopaedic and Sports Medicine Physical Therapy Clinic 450 Broadway, Redwood City, CA 94063 E-mail: Michael.jeanfavre@gmail.com

The International Journal of Sports Physical Therapy | Volume 13, Number 3 | June 2018 | Page 335 DOI: 10.26603/ijspt20180335

INTRODUCTION Rotator cuff tears (RCT) result in disability, poor quality of life, expensive utilization of healthcare resources1 and have been shown to affect 20-28% individuals between the ages of 60-69,2,3 31-40.7% in patients over the age of 70,2 51-62% in individuals over 80 years of age,4 with an increase of 2.69 odds of a RC tear for every decade of life (p = 0.005).5 Aggregate mean prevalence rates are estimated at 39% of asymptomatic individuals and 64% of symptomatic individuals,6 with the expectation that 50% of asymptomatic tears will become symptomatic at a mean of 2.8 years after the time of initial discovery.7,8 Though partial thickness rotator cuff tears (PTT) are more common than full-thickness rotator cuff tears (FTT),9,10 PTT tend to progress to FTT, developing pathological changes due to muscle retraction, fatty infiltration, and muscle atrophy and thus, are associated with greater disability.6,8,11-14 These facts are consistent with the prevalence of FTT in symptomatic patients progressing with age, with 28% of patients ≥60 years old, 50% of patients ≥70 years old, and 80% of ≥80 years old.5,7,9,15 Other potential predisposing factors besides age,2,4,5,7,11,16 include both non-modifiable factors (gender,17 hand dominance,18-20 pathology of the contralateral shoulder,21-23 family history,24 glenohumeral instability,25,26 coracoid and/or acromion anatomy25) and modifiable factors (smoking,27-29 posture,6,30,31 and poor or insufficient diet25,32-35).

Given the high prevalence, the substantial financial burden on both patients and society,9,36-40 and the associated disability associated with FTTs,41 determining effective management is of high priority for researchers and healthcare providers. Several reviews42-46 have compared the effectiveness of operative treatment to non-operative management, with some literature supporting surgical options47-50 and others demonstrating comparable outcomes between the two options.32,40,51,52 Similar ambiguity is seen with the surprising fact that of the 25 to 90% of surgical repairs that fail,40,53-61 the reported satisfaction levels and clinical outcomes scores are comparable to individuals with intact repairs.9,40 Given the discrepancies in finding between non-operative and operative management, as well as the unpredictable surgical re-tear rates, perhaps it is no surprise

only 5% of the 5.7 million (as of 2010) patients over the age of 60 in the U.S. with RCTs in the U.S. were treated surgically.40 It is encouraging that exercise and physical therapy have been shown to be viable and alternative treatment option,9,32,40,45 especially in incidences where rotator cuff (RC) tendons have retracted beyond the glenoid rim,32,58,59 are massive in size (≥ 5 mm)62, and/or surgery is contraindicated due to comorbidities. However, researchers have had difficulty drawing strong conclusions as to the true comparative effectiveness of non-operative management of FTTs due to low-quality studies.32,42,43 This, in addition to the heterogeneity of conservative exercise programs, has made it difficult to synthesize and establish robust evidence-based rehabilitation programs. The limitations of this recent publication

by Edwards et al9 was: (1) the fact that it was Level 5 evidence due to the lack of a systematic search to establish the protocol and (2) the proposed protocol was not specific to FTT. Described conservative treatment of RCT are multimodal, ranging from exercise therapy, modalities (cryotherapy, thermal therapy, electrotherapy, acupuncture, ultrasound, and electrotherapy), taping, injection therapy, pharmacological management.9,32,42,63 However, as there is no consensus or gold standard exercise program of FTT, clinicians and researchers are left to use other shoulder pathology rehab programs40,63 or expert opinion9 to guide the clinical practice and clinical trials for the treatment of FTT. Though there have been a number of reviews on non-operative RCTs interventions in the last 15 years,32,43-46,64 these are either not specific to FTT,43 exercise therapy,44 or have focused on comparing surgical vs. non-surgical treatment rather than identifying and synthesizing the specific components of an optimal conservative management.45,64 The most recently published systematic review45 only identified three randomized control trials citations, which demonstrates the paucity of high-quality studies. This, in turn, makes it acceptable to conduct a systematic review including observational studies.65 The last systematic review32 to conduct a search of both randomized controlled trials and observational studies, specific to exercise therapy of FTT is over 10 years old and needs to be updated due to time elapsed,66 new evidence becoming available,67 and based on need or priority.68

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The primary purpose of this systematic review is to: (1) update a prior review32 by synthesizing the available research on the effectiveness of exercise therapy for FTT, (2) use the Grading of Recommendations Assessment, Development and Evaluation (GRADE) Working Group criteria69 to evaluate the current level evidence of exercise therapy (with and without the addition of supplemental non-operative modalities and treatments) to provide a grade of recommendation.

METHODS The PRISMA guidelines were employed in this systematic literature review.70 A formal research question was developed as is recommended by PRISMA guidelines:71 • Population: skeletally mature human adults (greater than 18 years of age).

• Intervention: exercise rehabilitation (in isolation or combination with other non-operative interventions).

• Comparison: control, sham treatment, placebo, education, or other non-operative interventions • Outcome: change in pain, strength, range of motion, and function of the shoulder.

• Time: not specified Information sources and search parameters The following databases have been searched until December 2016: Embase, Medline (PubMed), CINHAL Database, Cochrane Database of Systematic Reviews, PEDro, and Web of Science. Keywords used in the aforementioned review, Ainsworth et al 200732, as well as those derived from the research question were used. A medical school research librarian was consulted on formulated initial search for Medline (PubMed), as well as for translating the search to other databases utilizing the respective thesaurus for indexing articles and free entries. The search strategies for each of the respective databases can be found in Appendix A. Study selection Prior to conducting the search, inclusion and exclusion criteria for articles were defined. The inclusion

and exclusion criteria were kept consistent with the original review,32 as is standard practice in updating systematic reviews.68 Identified studies were filtered by the following inclusion criteria: randomized clinical trials or observational studies, skeletally mature human adults with a clinical diagnosis of FTT, or massive, or inoperable RCTs. Additionally, it was required that studies explicitly state that at least one treatment group received exercise therapy, in isolation or in conjunction with other non-operative treatment, for FTT. The only criteria that differed from the original study32 were that only full-texts available in the English language were included due lack of translation resources42 and that included studies also needed to report one of the following outcomes: pain, ROM, strength, and/or functional outcome scores.

Though not ‘included’, prior systematic reviews pertinent to these inclusion criteria were identified, the quality assessment made, and conclusions comparisons made to those of the current review. This decision was made in order to capture the complete spectrum of conservative treatment FTT literature and to allow comparison of prior conclusions and synthesized data of such reviews.

Identified studies were also filtered by the following exclusion criteria: surgical repair at any previous time point, concurrent significant trauma or derangement to the shoulder (i.e. prior surgery, acromioclavicular joint separation, Hill-Sachs lesion of any kind, etc.), neurological diagnosis or impairment affecting the patients’ shoulder function (i.e. stroke, brachial plexus injury, spinal cord injury, etc.), inability to access full text article (i.e. exhausting all efforts and resources of medical school librarians and contacting the respective corresponding authors by email, social media, and/or phone), level 5 evidence such as, clinical commentaries, editorials, and grey literature.

All identified citations were filtered independently by two of the authors (M.J. and S.H.) based upon the title, then the title and abstract, and finally, by full text via the above inclusion and exclusion criteria. Any disagreements (n = 0) were resolved by consensus. The consensus was achieved on all publications included in the review without the need

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to resolved disagreements by a third independent reviewer (G.L.). Study design was determined by the ‘traditional’ classification method as described

by Furlan et al.72 Assessment of trial quality: The quality of any identified systematic review was assessed using the Assessment of Methodological Quality of Systematic Reviews (AMSTAR) guidelines,73,74 as this has previously been demonstrated to be a valid and rigorous assessment of orthopedic literature.75 Prior to conducting our search, the methodological quality of any randomized control trial identified would be according to the Cochrane Collaboration’s domain-based evaluation framework.76 The use of this assessment tool differs from the PEDro scale77 described in methods of the review32 being updated. However, much more recent and higher quality systematic reviews45,64 within the rotator cuff tear literature have used the Cochrane Collaboration’s domain-based evaluation framework,76 and thus, for consistency this quality assessment tool was chosen. The included observational studies would be assessed using the guidance from the NHS Centre for Reviews and Dissemination tool.78 As more recent reviews within the shoulder have not considered observational studies this quality assessment tool was kept consistent with the original publication.

One reviewer (M.J.) assessed the methodological quality of included studies, and a second reviewer (S.H.) verified the data for accuracy and completeness.

Reviewers resolved discrepancies by consensus, and thus, an independent third party was not required.

Level of evidence: The Level of Evidence of all included references was determined using criteria described by the Oxford Center of Evidence-Based Medicine (OCEBM),

Oxford, United Kingdom (Table 1). Originally developed in 1998 and since modified in 2011, the OCEBM Levels of Evidence enables the appraisal on a scale from I to V based on study design, randomization, blinding, and the amount of bias, with a designation of I, being the highest level of evidence.79 The overall Grade of Recommendation for exercise therapy (with or without other non-operative treatment) treating FTT as a whole, based off of the aggregate level of evidence, was determined using The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) Working Group.

Initiated in 2000 The GRADE Working group has developed a hierarchal, alphabetical letter scale of A to F (Table 2) which takes into account the quality of evidence and strength of recommendations to aid in applying research to clinical decisions and judgments in healthcare.69 The Investigators justified using the OCEBM Levels of Evidence and The GRADE Working Group criteria to determine the quality of evidence as both scales are endorsed by the American Physical Therapy Association (APTA) for grading Clinical Practice Guidelines.80 Data extraction: The methods and results sections of the included studies were to be reviewed and data regarding the study demographics, methodology were extracted and placed in table form. Individual outcomes for pain, range of motion, strength, and function were cataloged. Justification for extracting these specific outcomes is based on (1) remaining consistent with the original review32 and (2) these outcomes are synonymous with a comprehensive review considering exercise therapy in RC impingement.63 The effectiveness of these outcomes was assessed over time (intra-group evaluation) and when appropriate,

Table 1. Level of evidence modified from the Oxford Center of Evidence Based Medicine (OCEBM)96

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Table 2. Grading of Recommendations Assessment, Development and Evaluation (GRADE) Working Group Criteria86

across groups (between-group evaluation). When available, statistically significant differences (within and across cohorts) in pre- and post- outcomes were recorded. Clinical significance (when statistical significance was p < 0.05 and the intra-group or between group difference was ≥20%)63 was also reported when feasible to determine. The rationale to incorporate both statistical and clinical significance was (1) clinical significance is likely to be more valuable to practicing clinicians and (2) this is consistent with the methodology of the fore mentioned RC impingement review,63 which also set out to develop an evidence-based protocol from those results. Additionally, if no statistical significance was calculated or reported for the outcome of ‘function’ (includes shoulder specific disability outcomes) than the currently accepted minimally clinically important difference (MCID) (if previously established) of the outcome measure in question was used to determine the significance of the post-intervention change in the respective cohorts.

Synonymous with the methods of the data extraction, one reviewer (M.J.) extracted the methodology, the results, demographics, outcomes, and statistics of included studies, and a second reviewer (S.H.) verified the data for accuracy and completeness.

Heterogeneity of included studies: Due to inclusion criteria of accepting randomized and non-randomized clinical trials, calculation of heterogeneity across studies was deemed inappropriate on the basis of methodological heterogeneity and thus, a meta-analysis was not performed.

Statistical analysis: All numerical data was calculated by inputting the extracted data into Microsoft Excel (2016) spreadsheets and using the appropriate mathematical functions (i.e. ‘SUM’, ‘PERCENTILE’, etc.) to calculate the respective numerical values and results.

RESULTS Study selection: An aggregate total of 1570 citations was identified from the search after duplicates were removed (Figure 1). Based upon the number of identified studies, the search strategy was sufficiently comprehensive, returning more than our times the number results of previous reviews that investigated similar questions.32,45 After title and abstract screening 111 articles remained. Of the 72 articles excluded by full text, 48 were eliminated due to not meeting the inclusion criteria and 24 of them were eliminated due to meeting the exclusion criteria. Only one study81 was excluded due to not being able to find a full text version after exhausting all available resources (online databases previously mentioned, researchgate.com, Stanford University medical libraries and their network resources, attempting to contact the corresponding author). A total of 39 studies were included: five case reports,82-86 16 case series,1,87-101 six cohort studies (two retrospective102,103 and four prospective),40,104-106 and nine randomized control trials.47-49,52,107-111 Additionally, three relevant systematic reviews32,42,45 were identified. Details of included studies and patient demographics can be seen in Table 3.

It is important to note, there were two instances, Moosmayer et al 201047 and 201448 and with Kukkonen

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Figure 1. Flow diagram based on the recommendations of the Preferred Reporting Items for Systematic Reviews and MetaAnalyses (PRISMA) Statement.

et al 201451 and 2015,52 in which consecutive, but separate studies (an original study and a long-term followup study) were published on the same patient cohort.

To avoid the results of these studies having excessive weight during this investigation, the data extraction, and statistical analysis used the most current publication of these cohorts (Moosmayer et al 201448 and Kukkonen et al 201552). This justification has been used in previous RC intervention reviews.45,112

to conservative management of RCT, as well as the means by which Sieda et al64 separated (compared) the surgical and non-operative results provided sufficient criteria to include the review in this investigation. Ryosa et al,45 the most recent review, was specific to randomized control trials.48,49,52 All three which have been included in this review as well.

Further details regarding the scope of these systematic reviews are summarized in Appendix B.

There were three systematic reviews after the filtering that exclusively included a cohort of studies that met the inclusion and exclusion criteria of this review. The earliest of these publications, Ainsworth et al (2007),32 is the systematic review that is being updated by this current investigation. Sieda et al64 included both surgically and conservatively treated RCT. However, the included studies specific

The primary purpose for including pertinent systematic reviews was to: (1) provide a comprehensive view of the literature for other researchers and clinicians and (2) compare the comprehensiveness, methodology, and findings of this review to that of current systematic review literature on this topic.

The results and conclusions of the reviews are summarized in Appendix C. The comparison of the

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Table 3. Patient Demographics

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Table 3. Patient Demographics (continued)

results and conclusions of these reviews to the current investigation is elaborated on in the discussion section of this manuscript.

Patient demographics: The aggregate number of shoulders was n = 2010, in 1913 subjects. There was an even distribution between males (53.8%, n = 1042) and females (46.2%, n = 896). Discrepancy (n = 25) in the total subjects

and the sum of the number of men and women is due to 22 patientsâ&#x20AC;&#x2122; gender not being recorded in Kuhn et al (2013)40 and Kukkonen et al (2015)52 not reporting the gender for 4 of 13 subjects who were lost to followup. Additionally, Moosmayer et al (2017)95 included 13 of 49 subjects from other included cohorts47,48 but the gender of these 13 subjects was not specified and thus, were unable to be adjusted for when calculating the aggregate total of males and females.

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Of the total number of shoulders included in this current investigation (n = 2010), 1643 (82%) were treated non-operatively, 85 (4%) were controls or received no intervention, 256 (13%) shoulders were originally designated to a surgical cohort group, 292 (15%) were unsatisfied with non-operative treatment and went on to have surgery. Subject numbers were further broken down into a number of shoulders per study design. Randomized control trials accounted for 562 (28%) shoulders, cohort studies included 692 (34%) shoulders, case series included 751 (37%) shoulders, and case reports included 5 shoulders (<1%). Ages of the cohorts ranged from 23 to 80 years of age, the mean age for all included subject was 64.1 years old. (Table 3)

used as the authors identified the specific tendon(s) involved and stratified the stages of fatty infiltrate via the Goutallier classification.113 (Table 3).

Diagnosis & Involved Muscles All but three studies89,97,110 stated the specific advanced imaging (ultrasonography: nine studies, magnetic resonance imaging (MRI): 26 studies, arthrogram: seven studies, and/or arthroscopy: one study) that was used to confirm the diagnosis of FTT. Regarding the three studies in which the specific imaging study was not stated, Wirth et al97 and Ainsworth et al (2009)110 confirmed diagnosis by “radiographically documented full thickness tears” and in the third study, Collin et al,89 it is assumed that MRI was

Tear size was reported in 1155 (57%) shoulders.

Though there are multiple RCT classification systems,115,116 the one proposed by DeOrio and Cofield117 was most commonly reported in the included studies. Thus, this system was used to stratify the different sizes of tears reported. A graphical representation of these results can be seen in Figure 2.

The tendon(s) or number of tendons involved were reported in 1311 (65%) shoulders. Of those reported on, supraspinatus (848 shoulders, 65%) and infraspinatus (184 shoulders, 14%) were the most common tendons involved. This is consistent with prior reports of the junction between these two tendons (16 and 15 mm posterior to the long head of the biceps tendon) being the most prevalent location of tear initiation.114 Subscapularis tendon involvement occurred in only 44 (3%) shoulders and teres minor was reported in 3 (<1%) shoulders. (Table 3). Multiple tendons were involved in 232 shoulders (18% of those reported on).

Mechanism and Duration of Symptoms The mechanism of injury was classified into four groups: traumatic, atraumatic, “insufficient trauma”,

Figure 2. A graphical representation of the distribution of the rotator cuff tear sizes for the shoulders described in the included studies.

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or not reported. The mechanism of injury was reported in 1462 (73%) shoulders with atraumatic onset being the predominant mechanism of injury, occurring in 1192 (82%) shoulders. (Table 3) The duration of shoulder symptoms prior to investigation ranged from one day to 5.5 years and was reported in 1133 (56%) shoulders. Given the variability in which the duration of symptoms was reported (i.e. “not-acute”, “chronic”, “greater than or equal to 3 mo.), this data was synthesized into <3 months, 3-6 months, 6-12 months, or >12 months. (Table 3) Study quality assessment: Observational studies The evaluation of the quality of the included 27 observational studies (Table 4) revealed concerns in the methodology. Only one study106 met all criteria, however, the primary purpose of the study was identifying predictive baseline factors for failed conservative treatment and thus, no follow-up disability or impairment measurements were taken. All studies included relevant subjects, established ‘appropriate

inclusion criteria’, and accounted for subjects lost to follow-up. Though, all but two case reports84,86 used ‘appropriate disability outcomes’ and 22 (65%) studies had an ‘appropriate impairment outcome.’ Only 12 (31%) observational studies explicitly stated that it was a prospective investigation, while 20 (74%) studies had an ‘adequate follow’ of ≥ one year. The criterion that was most often missed was the statement of a ‘blinded assessment.’ Only three studies,95,105,106 stated the blinded follow-up assessments were performed. The suspected reason for the lack of blinding was due to the high prevalence of case series. As there is most often only one cohort in these study designs, it may have seemed of lower importance for authors to blind the assessor.

Randomized control trials When considering the potential bias in the included randomized control trials, it was determined that all 8 revealed an aggregate ‘low’ risk of bias based on the seven criteria assessed by the Cochrane Collaboration’s domain-based evaluation framework.76 However, all of the randomized control trials did demonstrate a ‘high’

Table 4. Observation study methodology - methodological quality criteria for assessment of observational studies95

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risk of bias due to lack of blinding of participants, personnel, and outcome assessments. (Table 5).

Systematic reviews The AMSTAR guidelines demonstrated sufficient rigor to identify flaws in the methodology of the identified systematic reviews. Though none of the three reviews met all criteria both Sieda et al64 and Ryosa et al45 demonstrated ‘Good’ methodology, meeting 10 and 9 out of the 11 methodology criteria, respectively. Ainsworth et al (2007)32 methodology was rated as ‘Fair’ as it met only 5 of the 11 methodology criteria. (Table 6) Outcomes Individual outcomes of pain, range of motion, strength, and function were extracted from each of the studies. Each outcome is discussed below. The data extraction for the each of the outcomes can be found in Appendices D - G. Graphical representation of the outcomes are also provided in Figure 3 and Figure 4.

Pain Pain was reported in 26 (79%) of the studies with an average follow-up time of 2.7 years (32.5 months).

Over half of the studies (n = 16, 59%) measured pain through disability or impairment outcome measures, while the remaining 11 (41%) studies used a specific pain tool; either the visual analog scale (VAS) or the numerical rating pain scale (NRPS). Tanaka et al96 was the only study with a cross-sectional design, and thus, a change in pain outcome could not be determined. Pain outcomes improved in the remaining 26 (96%) studies with non-operative treatment.

Statistical significance for within group change was reported in eight (29% of the 26) studies, all of which were statistically significantly different (p<0.05; 95% CI) and clinically significant (improvement by ≥20%). The pain reported outcomes for all studies can be found in Appendix D. When comparing across cohorts, two studies103,111 compared physical therapy with and without the addition of corticosteroid injection. Both studies favored physical therapy plus corticosteroid injection with a statistically significant difference (p<0.05).

However, only in the short term (1 to 3 months) was this difference determined to be clinically significant (p<0.001).111 Additionally, there were four studies that compared non-operative treatment to surgical cohorts, and though all of these reported

Table 5. Randomized control trial – Risk of bias93

Table 6. Assessment of methodological quality of systematic reviews (AMSTAR) guidelines90,91

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Figure 3. A graphical representation and data table of the pain, range of motion (ROM), strength and function for the conservatively treated shoulders in the included studies. The shoulders from the different study designs are represented by the different color shades as noted in the legend.

Figure 4. A graphical representation and data table of the pain, range of motion (ROM), strength and function for the conservatively treated shoulders in the included studies. The statistical and clinical significant differences are noted by the different color shades in the legend. Clinical significance, statistical significance (P<0.05) and improves by >20%; MCID, minimal clinical importance difference, Stat-Sig, statistical significance (P<0.05); *, MCID was only used for functional outcome measures when no statistical significance was reported and when an accepted MCID had previously been established within the literature.

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improvements in both groups, three of them demonstrated statistically significant improvements in pain (p<0.05; 95% CI) in the surgical groups.48,49,52 None of these met clinical significance. The remaining study reported no statistical difference between the pain in the non-operative cohort and the operative cohort.96 There were nine cohorts (133 shoulders) in which pain did not improve enough for a ‘satisfactory’ result.1,48,91,92,95,96,103,111 Four of the cohorts converted to surgery.1,48,96,103 In another cohort,111 ‘physical therapy’ was the control and number of shoulder injections was the independent variable. Factors that differentiated the remaining ‘unsatisfied’ cohorts was ‘sleep loss due to night pain’ (p = 0.01 when compared to the ‘satisfied’ cohort in this study)91 and tear size progressing > 20 mm from initial measurement (p<0.004).95 In summary, pain outcomes were reported for 40 non-operatively treated cohorts that included 923 shoulders. Of these, 31 (78%) cohorts, consisted of 790 (86%) shoulders that reported improvements in pain versus nine (22%) of cohorts consisting of 133 (14%) shoulders that did not improve or not to a ‘satisfactory’ level. Statistical significance was calculated in 10 (25%) cohorts consisting of 264 (29%) shoulders, all but one of these demonstrated both statistically (p<0.05) and clinically significant improvements.

Range of motion Range of motion (ROM) was reported in 28 (85%) studies as shown in Appendix E. The average followup for these reported outcomes was 2.4 years (29.2 months). A motion specific tool was used in 19 (68%) of these studies, while the remaining studies captured the ROM through disability and impairment outcomes. In the studies that specified the direction of motion, the most common ROM movements that were recorded were abduction (16 studies, 57%), flexion (15 studies; 54%), and external rotation (13 studies; 46%). Internal rotation (7 studies; 25%) and extension (one study; 4%) were much less common.

All of the studies that reported ROM demonstrated improvement in ROM post intervention in at least one cohort that received exercise therapy

and conservative management. Of the nine studies1,92,94,98,100,101,103-105,109,111 that reported statistically significant within group change all nine demonstrated significant differences (p<0.05; 95% CI) in at least one direction and in eight1,94,100,101,103-105,109 of these cohorts the improvement increased by ≥20% meeting clinical significance. There were only three select studies whose subjects’ ROM did not improve.

Itoi et al92 identified a subset of patients who did not have ‘satisfied’ outcomes following conservative treatment and found that predictive factors were poor abduction ROM (108.0° vs 149.0°; p<0.05) and abduction weakness (3/5 on manual muscle testing (MMT)). Merolla et al1 developed a predictive score of 17 baseline variables and used a cutoff score of ≥13 out of 21 to identify patients who were likely to be ‘unsatisfied’ and opt for surgery within one year.

The third cohort111 who did not demonstrate improvement was a control group who did not receive a corticosteroid injection in addition to physical therapy.

Statistically significant intragroup (pre and post rehab ET intervention) abduction ROM differences were demonstrated in nine studies (p<0.05) and in seven (83%)1,94,101,103-105,109 of these studies the cohorts achieved clinically significant improvements. Likewise, significant intragroup flexion ROM differences were demonstrated in five studies (p<0.05) with statistically significant differences in four (80%) studies1,100,101,104 and clinically significant differences in three (60%).1,100,104 Intragroup external rotation differences were reported in five studies and in three (60%) of these101,109,111 the improvements were both statistically (p<0.05) and clinically different.

Though it is likely of interest and benefit to clinicians and future researchers to identify which movements are most likely to significantly improve (both statistically and clinically) it should be noted that comparison across different planes of motion cannot be directly compared to one another from the above results due to the uneven distribution of different ROMs being reported.

Nine studies statistically examined intergroup differences. Three studies48,52,96 compared nonoperative cohorts to surgically treated cohorts, none of which found statistically significant difference between groups. Two studies compared conservative

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management with and without corticosteroid injections. One111 of these studies found no difference at six months, while the other study103 demonstrated no difference in the outcome but that the cohort that had received physical therapy plus corticosteroid injection took less time (5.3 months) to reach maximum abduction ROM (p<0.05). The conclusions that can be drawn from other intergroup comparisons is that supervised occupation therapy (OT) and home exercise program demonstrates no difference in abduction, flexion, or external rotation ROM outcomes107 and that flexion and abduction ROM outcomes do not differ between cohorts whose tear progresses of tears by ≥20 mm or ≤20 mm.95 In summary, ROM outcomes were reported for 44 non-operatively treated cohorts that included 1369 shoulders. Of these, 36 (82%) cohorts, consisting of 1140 (83%) shoulders that reported improvements in ROM versus eight (19%) of cohorts consisting of 229 (17%) shoulders that did not improve or not to a ‘satisfactory’ level. Intra-group statistical differences were calculated in 14 (33%) cohorts, consisting of 272 (27%) shoulders, all of which demonstrated statistically significant differences in ROM (p<0.05).

Improvements in ROM were also clinically significant in 10 (23%) cohorts, 264 (19%) shoulders.

Strength Strength was reported as an outcome in 21 (64%) studies with an average follow-up time of three years (35.5 months). See Appendix F for summarized strength outcomes and the specific tools and equipment used for measurement.

All studies that reported strength outcomes demonstrated improvement in at least one cohort that was treated with non-operative management. However, statistical comparisons for intragroup strength improvements was only reported in seven (33%) studies. Of these, six (75%) studies92,94,100,101,105,109 demonstrated statistically significant improvement (p<0.05) and four (57%) studies the intragroup difference was also clinically significant.94,101,105,109 It is important to discuss the four instances in which a cohort’s strength improvements were not statistically improved. In one study104 it was suspected that the lack of statistically significant change was due

to too short of a follow-up time (nine weeks). It has been previously established that strength gains continue to progress well beyond the nine-week point of initiating resistance training.118 A second study109 that focused on the effects supplementing physical therapy with corticosteroid injections demonstrated both statistically and clinically significant strength gains at four weeks, but not at 24 weeks post-intervention, as there was a mild decline in each cohorts strength gains. This may speak to both, the transient effects that corticosteroid injections provide, as well as the necessity of a ‘maintenance’ program with rehab to ensure that strength gains are retained for the long term. Moreover, a case series by Hawkins et al91 demonstrated a subgroup of patients with ‘unsatisfied’ results that opted for surgery. Strength was measured in pounds using Constant-Murley score.

Subjects in this subgroup reported average ConstantMurley strength score of 17.1 (equivalent to 15-18 lbs of abduction strength) as compared to the aggregate average Constant-Murley score of 23.2 (equivalent to 22-24 lbs of abduction strength). The difference between the groups was statistically (p = 0.008) and clinically significantly different. Similarly, Itio et al92 had a subgroup of subjects with an ‘unsatisfactory’ outcome (this is the same subgroup that was discussed previously in pain outcomes) who also failed meet statistically significant improvement in strength outcomes. This subgroup was retrospectively identified once outcomes were calculated to determine differences at baseline between the ‘satisfied’ and ‘unsatisfied’ cohorts. The variables that differentiated the ‘unsatisfied’ subgroup at baseline were poor abduction ROM (108.0° vs 149.0°; p<0.05) and abduction weakness (3/5 on manual muscle testing (MMT)). At post intervention followup (average of 3.4 years) only 63% of the ‘unsatisfied’ cohort had abduction strength that was ≥4/5 on MMT as compared to 87% of the ‘satisfied’ cohort.

The intergroup difference was statistically (p<0.05) and clinically significant.

When considering intergroup differences, seven studies reported statistically significant differences across cohorts. Hawkins et al91 and Itio et al92 both compared subgroups with ‘unsatisfied’ outcomes with that of a ‘satisfied’ cohort and, not surprisingly, found statistical (p= 0.008 and p<0.05, respectively)

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and clinically significant differences favoring the ‘satisfied’ cohorts. Two studies compared the outcomes of non-operative treated cohorts to surgically treated cohorts. No difference was found at one year (p = 0.89),48 but statistically significant differences were found at two52 and five years.48 Neither of these differences were clinically significant. One study107 found no significant difference in any strength measurement in cohorts who received supervised occupational therapy versus a home program. Strength gains also proved to be statistically (p< 0.004) and clinically significant between a cohort who had tears that progressed by ≥20 mm over 8.8 years compared to subjects whose tears progressed <20 mm.95 The seventh article that compared across groups used the subjects’ contralateral shoulder as the control (did not receive any rehabilitation) and demonstrated a significant difference in post-intervention strength measures.104 However, a major flaw with this comparison was that the control limbs were only measured at time zero and thus, if a change in strength of the control limbs occurred post intervention it was not captured.

In summary, strength outcomes were reported for 28 non-operatively treated cohorts that included 598 shoulders. Of these, 23 (82%) cohorts, consisted of 514 (86%) shoulders that reported improvements in strength versus five (18%) cohorts consisting of 84 (14%) shoulders that did not improve or not to a ‘satisfactory’ level. Statistical differences were calculated in eight (29%) cohorts. Of these, seven cohorts consisting of 181 (30%) shoulders demonstrated statistically significant improvements (p<0.05), while five (19%) cohorts, 133 (22%) shoulders, also made clinically significant gains for strength.

Function Functional outcomes were reported in 33 (97%) studies with an average follow-up of 2.3 years (27.3 months). Thirty-one (97%) studies captured the function with a shoulder specific outcome measure, while one case report84 determined function by the patient’s ability return to recreational swimming unrestricted.

See Appendix G for details of the specific functional outcome measures used and the data extracted.

All 33 (100%) studies that reported on function demonstrated improvement in function with non-operative

therapy. All 15 (45%) studies1,40,89,90,92,94,98,100-105,109,111 that reported intragroup differences (p< 0.050.0001) for shoulder specific outcomes demonstrated statistically significant differences and 11 (73%) of these studies1,40,90,92,94,98,100,101,103-105,109 demonstrated ≥20% improvement indicating clinically significant change.

Ten (30%) studies47,89,91,100,102,104,105,110,111 reported intergroup differences. Three studies91,95,106 denoted statistically (p=0.038) and clinically significant differences between two conservatively managed cohorts, one with ‘satisfied’ results and another cohort. Hawkins et al91 demonstrated that poor response in ConstantMurley score following conservative therapy differentiated ‘satisfied’ (+7.1 points from baseline) from ‘unsatisfied’ (-1.1 points from baseline) at 3.8 years follow-up (p=0.038). Similarly, Moosmayer et al (2017)95 showed that by dichotomizing subjects by tear progression ≥20 mm or <20 mm over 8.8 years, that subjects with the <20 mm progression had better Constant-Murley scores (<20 mm progression: 81.0 vs >20 mm progression: 58.5; p=0.008), higher functioning ASES scores (<20 mm progression: 90.0 vs >20 mm progression: 60.0; P=0.02), but not significantly different SF-36 scores (p>0.05). Boorman et al,106 on the other hand, sought to identify baseline predictive factors for subjects likely to ‘fail’ conservative therapy and opt for surgery. The authors found that baseline scores out of 100 (‘successful’ rehab cohort: 49 ±21 vs. ‘failed’ rehab cohort: 33 ±15; p=0.017) on the Rotator Cuff Quality of Life Index (RC-QOL,as first described by Hollinshead et al119) was predictive for opting for surgery.

Three additional studies104,107,111 compared the intergroup difference between conservatively managed cohorts. Gialanella et al111 showed that there was no statistically significant difference (p>0.05) in Constant-Murley scores at three, six, or 12 months’ postintervention between cohorts who received single or multiple shoulder injections plus physical therapy as compared to a cohort who only received physical therapy. Krischak et al107 compared a cohort who received ‘standard OT’ to a home exercise cohort and found that there was no difference in Constant-Murley score (p=0.824) or EQ-5DL (p=0.656) at two-month followup, but that there were statistically (p<0.05) and clinically significant differences in the overall change in

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EQ-5DL health status subs-core, favoring the ‘standard OT’ cohort (+17.8 points vs home exercises group: +3.2). The final study, Baumer et al104 demonstrated that despite a statistically (p<0.01) and clinically significant change in the Western Ontario Rotator Cuff (WORC) score after nine months the intervention group score (70.3 ±26) was significantly (p<0.01) different than the baseline score of the healthy control group (98.2 ±2.8). However, a limitation was that the healthy control group was only measured at baseline and thus, making the assumption that there was no change in the healthy control score.

48,49,52,102

Lastly, there were four studies that compared non-operative treatment to surgical RC repair. All of them used the Constant-Murley score as one of the region-specific outcomes. There was no statistically significant difference in total Constant-Murley score at 12 months (p>0.05),49,52 24 months (p>0.05),52 or four years (p=0.61).102 One study48 did show a difference in the Constant-Murley score (p<0.01) and American Shoulder and Elbow Surgeons Shoulder Score (ASES) (p<0.001) after five years, favoring surgical treatment. However, these authors48 also showed that there was no significant difference in SF-36 scores (p=0.38) between the conservative and surgical groups or in the Constant-Murley score (p=0.02) between the cohort who opted for the initial repair at time zero and the cohort who attempted conservative therapy and then transitioned to surgical repair. This suggests that non-operative exercise therapy can be considered as first line treatment for 12 weeks without detriment to clinical outcomes. This is further corroborated by one study108 that found no statistically significant difference (p=0.28) in patient satisfaction rates between conservative and surgically managed cohorts. Outcomes that did favor surgical repair cohorts were the Constant-Murley activity of daily living (ADL) subscore (p<0.0001) at 12 and 24 months post-intervention108and the Disability visual analog scale (VAS) (p=0.002) at 12 months.49 In summary, functional outcomes were reported for 45 non-operatively treated cohorts that included 1610 shoulders. Of these, 38 (84%) cohorts, consisting of 1366 (85%) shoulders that reported improvements in function versus seven (16%) cohorts consisting of 217 (15%) shoulders that did not improve or not to a ‘satisfactory’ level. When statistical differences were

not calculated or reported, and when an accepted value was available for the respective outcome, the MCID was used to 11 (25%) cohorts consisting of 267 (17%) shoulders, of which eight (18%) cohorts including 142 (53%) shoulders met or surpassed MCID. Statistical differences were examined in 17 (38%) cohorts consisting of 749 (47%) shoulders all of which improved statistically (p<0.05) and 13 (29%) cohorts, 650 (87%) shoulders, who also achieved clinically significant improvements for function.

Components of programs The components of the exercise and rehabilitation programs had considerable variation across the studies. However, consistent components of the programs included strengthening (97% of studies), ROM (79% of studies), stretching/flexibility (61% of studies), activity modification/education (57%), home exercise routine (explicitly stated in 32% of studies), manual therapy (18% of studies), heat or cold modalities (21% of studies), and postural interventions (24% of studies). Additional medical interventions that were used to supplement exercise therapy including medications (explicitly stated in 35% of studies) and/or corticosteroid injections (39% of studies) were also considered. Other components of the conservative management programs included scapula-thoracic specific interventions and reintegration into patient-specific activities. Phased progressions were specifically stated and described in 35% of studies and 57% of randomized control trials. (See Appendix H for details of the rehab programs for each included study. Refer to Figure 5 for a graphical representation of the prevalence of the most common rehab program components.)

Scope of prior systematic reviews Two of the three prior systematic reviews identified by these search results were specific to non-operative rotator cuff tears. Ainsworth et al 200732 patient population nearly synonymous with the subjects and shoulders identified in this study, as this was the study that was being updated by this current review.

The current review excluded two non-English studies120,121 that were included within Ainsworth et al 200732 that were excluded from the current review due to inability to accurately translate these texts.

However, the current review included an additional

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Figure 5. A graphical representation of prevalence of the different rehabilitation program components in the included studies. The different colors represent the different types of study designs as described in the legend below the graph.

23 studies published after 2007. Ryosa et al45 studies were all included in this study, but the inclusion criteria were specific to randomized control trials and the purpose of the study was to compare nonoperative therapy to surgical repair. Similarly, Sieda et al64 had a similar purpose as Ryosa et al45 with the exception of including controlled and uncontrolled studies, as well as investigating not only comparing nonoperative to operative RC repair, but also the effectiveness of different types of repairs.

managed shoulders included in the current review).

The other two reviews, Ainsworth et al (2007)32 and Ryosa et al45, included 10 studies (with 272 subjects) and three studies (with 252 subjects), respectively.

Summaries of these reviews are provided in Appendix B and Appendix C. A graphical representation of the number of studies focusing on non-operative treatment for each review can be seen in Figure 6.

While included non-operatively treated shoulders included in each review can be seen in Figure 7.

The number of studies included in the identified reviews varied from 345 to 13764 with the number of total subjects ranging from 25245 to 8,515.64 Though Sieda et al64 was the most comprehensive, including 137 studies and 8,515 subjects, of these only three controlled and seven uncontrolled studies were isolated to non-operative treatment and five studies compared non-operative management to surgical management. These 15 studies combined accounted for 178 non-operatively managed shoulders from controlled studies and 327 non-operatively treated shoulders from uncontrolled studies. A total of 505 subjects (37.5% the number of conservatively

Conclusions of prior systematic reviews All three prior systematic reviews demonstrated difficulty drawing conclusions regarding the effectiveness of non-operatively managed FTT stating that there is either “some” or “limited” and “inconclusive” evidence to support non-operative or exercise therapy alone or in comparison to that of surgical interventions. However, the most recent of these reviews was able to make an explicit recommendation that “a conservative approach is advocated as the initial treatment modality” in FTT.45 (See Appendix C for a summary of the conclusions of prior reviews).

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Figure 6. The graph summarizes the number of non-operative shoulder treatment studies in each of the prior reviews and the current review. *, the review being updated; †, 137 total included articles but only 15 of these were specific to non-operative interventions.

Figure 7. The graph summarizes the aggregate number of non-operative treated shoulders included in each of the prior reviews and the current review. *, the review being updated; †, 137 total included articles but only 15 of these were specific to non-operative interventions.

GRADE of Recommendations According to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) Working Group criteria69 exercise therapy, with and

without supplementary physical therapy and nonsurgical medical interventions, demonstrates Grade B – Moderate strength of recommendation. This is based on the multiple randomized control trials and

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the supplementary level III, level IV, and case report studies with consistent findings that demonstrate that non-operative interventions have on pain, ROM, strength, and function in FTT. DISCUSSION This systematic review identified both randomized control trials (nine studies47-49,52,107-111) and observation studies (four prospective cohort studies,40,104-106 two retrospective cohort studies,102,103 16 case series,1,87-101 and five case reports82-86) that, on the whole, demonstrate the consistent finding that exercise therapy is an effective treatment for the reduction of pain, improvement of ROM, strength, and most dramatically, function. Due to the lack of blinding, the highest level of randomized control trials included were level II studies. This, in combination with a predominant number of level III and IV studies reinforcing the findings of the randomized controls, provided the Grade B â&#x20AC;&#x201C; Moderate strength for recommendation for using exercise therapy in the treatment of FTT. One of the primary goals of this systematic review was to update the last systematic review by Ainsworth et al32 that included both randomized control trials and observational studies, specific to exercise therapy of FTT which is over 10 years old. According to previously established criteria for updating systematic reviews,67,68 it was apparent from those findings that an update was indicated by the amount of new evidence that has become available since its publication and with the profoundly increasing prevalence of RCTâ&#x20AC;&#x2122;s in the setting of an aging population. As is convention, the inclusion and exclusion criteria, search strategy, and the analysis of quality assessment were all kept constant from the original review. No historic date restrictions were set on the search strategy for the current study as means to ensure that no studies were previously overlooked in the original search. Thus, the 10 observational studies84,85,87,88,90-92,97,98,103 included in the original review were also included in the current study. One study, a randomized trial by Shibata et al,109 that was published prior to Ainsworth et al (2007)32 was included in this review, as it met all pre-established criteria, but was not included in the original review.

Despite an overlap in included studies, the results of the current review, were considerably different

from those presented by Ainsworth et al (2007)32 in the total number of studies identified, the level of evidence identified, and the ability to provide a decisive GRADE of recommendation. This speaks to not only to the expansion of the amount of research being published on the conservative management of RCT but also to the overall improvement in the methodology of the more recent literature. This is further demonstrated by the improvement in quality of more recent studies. The average quality assessment score of observational studies since 2007 is 6.4 out of possible 8, compared an average score of 5.3 in the studies included in the initial review.

The second purpose of this review was to establish the effectiveness of the exercise therapy with and without additional physical therapy or medical management interventions. The primary outcomes that were looked at to determine this was pain, ROM, strength, and functional outcome measures. These metrics were chosen (1) because they were consistently reported across a large percentage of the included studies and (2) these have previously been established in similar reviews of shoulder rehabilitation.63 A significant percentage of conservatively treated shoulders demonstrated improvement in each of the outcomes. Of the non-operatively treated shoulders for which it was reported: pain was reduced in 86% of shoulders, ROM improved in 83% of shoulders, strength improved in 89% of shoulders, and functional reported outcomes improved in 85% of non-operatively treated shoulders. (Figures 3 and 4) However, it is important to note that in several of these studies there was a cohort of patients who were unsatisfied with conservative treatment and opted for surgical intervention.1,40,48,49,103,106,108 This, in combination with the knowledge that performing a repair secondary to a trial of conservative therapy does not statistically change the patientsâ&#x20AC;&#x2122; outcomes, suggest that non-operative conservative therapy as a first line intervention for FTT should be considered.40,47,48 This is consistent with the conclusion a recent systematic review and meta-analysis by Ryosa et al,45 that directly compared non-operative treatment to surgery for FTT. Moreover, if individuals do not opt for surgical management within 12 weeks, they are unlikely to do so within the following two years.40,106

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The average follow-up time frame for all of the outcomes ranged from 2.3 to 3.0 years. This is considered an adequate follow-up time period for RC literature as the longest follow-up for any randomized control trial included was five years. However, compared to the length of time that FTT can be symptomatic (conceivably decades, depending on a person’s age of onset), two to three years is a relatively short time frame.

When considering long-term management of RC pathology, it is also important to acknowledge the risk of tear progression and fatty infiltration that can occur in the presence of FTT. Though a couple of studies found similar progression rates, with 23-52% experiencing >5 mm tear size over two to three years with ‘non-operative’ treatment,122-124 fatty infiltrate and tear progression has not been shown to be significantly different between intact RC repairs, retorn rotator cuff repairs, and individuals who received non-operative treatment.49,108 This is also in contrast to PTT, in which only ~10% will progress >5 mm within the same time frame. It is also promising that a small percentage (8-18%) of FTT can show a radiological decrease in size with non-operative treatment.95,122 The proposed mechanism of how the healing occurs is referred to as ‘mechanotherapy’, in which cells respond to mechanical stimuli and resulting in a cellular response to promote tendon healing.9,125 Though serial imaging, either by ultrasound or MRI, can be used to monitor tear progression and fatty infiltration, tear progression can also be monitored through progression in pain intensity, as this has been correlated with tear size progression.9,95,122 Moosmayer et al (2017)95 noted that not all tear progressions have clinical implications and that ‘satisfied’ and ‘unsatisfied’ non-operative treated cohorts can be dichotomized by tears that progress by <20 mm and those that progress ≥20 mm, respectfully.

Another factor that can influence the decision for surgery vs non-operative management is the patient’s respective demographic. The characteristics of the subjects included in this in this review, with an average age of 64 years and the majority of FTT being atraumatic and chronic degenerative tears, are consistent with the patient population and tear characteristics documented in the literature.126 The patient demographic, older age, degenerative tissue, and chronicity of tears have all been shown

to negatively influence the success rates of surgically repaired FTT,127-130 providing further evidence for the consideration for initial non-operative, exercise therapy in this patient population. The consensus is that primary surgical repair is the more active and younger patient populations.126,129-132 Decisions for FTT management can be made by, not only by stratifying a patient’s prognosis of surgical intervention but also by stratifying their prognosis to respond to non-operative treatment. Some variables that have been considered in identifying patients who are more likely to respond to surgical interventions include: age, activity level, history of trauma, severity of fatty atrophy, severity of pre-operative symptoms, and location or size of the tear.58,64,95,131,133-137 Individuals less likely to respond to non-operative treatment have lower baseline abduction ROM, abduction strength, younger age, lower BMI, lower RC-QoL, and lower WORC index (p>0.05).92,106,131 One included study1 proposed a ‘Predictive Score’ that considered 17 baselines variables and a cut off of score 13 out of 21 (higher scores indicative of ‘unsatisfied’ outcomes with nonoperative treatment and opting for surgical treatment within one year) to determine which patients are most likely to respond to conservative therapy.

Some variables in the literature have been shown to be inconsistent predictive factors of surgical or nonoperative treatment include the extent of rotator cuff damage or degeneration on imaging studies.46,138,139 This aligns with the peculiar phenomenon RC injury being found in a large number of asymptomatic patients.139 Though several authors have been unable to fully explain the discrepancy between symptoms, functional limitations, and extent of RC pathology,3,19,40,106 a proposed hypothesis is that once a tear progresses to involve the posterior cuff musculature, there is an imbalance between the forces of the infraspinatus and the subscapularis, leading to a disruption of normal shoulder kinematics, GHJ stability, and loss of fulcrum for concentric rotation of the humeral head leading to a higher propensity of dysfunction and thus, disability and symptoms.9,140 Patient Demographics The patient demographics of the subjects and shoulders within this review were consistent with

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the epidemiology of the RCTs. It is known that the incidence and prevalence of RCTs begin to increase in the sixth to seventh decade of life, which is consistent with the mean age of 64.2 years of age seen in the included subjects of this review.2,3 In regards to gender, there was nearly an even split between males (54%) and women (46%). Though epidemiology studies have found gender not to be a significant risk factor for RCT,18,19 there are large review reviews of RCT that demonstrate a slightly higher incidence in males than females.141 Considerations of the specific tendons of the RC involve is also important. It has been well documented that the supraspinatus tendon is the most commonly torn RC tendon.58,142-145 Proposed rationale for the supraspinatus being predisposed to injury, compared to the other RC tendons are said to be both intrinsic (age, genetics, comorbidities, vascularity of the tendon, anatomical shape of the acromion, etc.) and extrinsic (bursal and articular sided strain, frequency of shoulder use, and prior injury).146-149 A ‘degeneration microtrauma’ mechanism and cascade has been proposed by previous authors in which insufficient healing times between microtraumas to the tendon in combination with increased demand on remaining fibers, and inflammatory mediators and oxidative stress induces tenocyte apoptosis.9,150-153 This is synonymous with the ‘continuum model of tendon pathology’ which describes how the elevation of inflammatory cytokines in response to the cyclic loading of tenocytes can lead to ‘an alteration in tendon synthesis and degeneration’ and eventually a ‘reactive-on-degenerative tendinopathy’.154 These mechanisms are consistent with the supraspinatus tendon having been shown to have reduced healing capacity due to a control tendon, because of the increased degree of tenocyte apoptosis and the reduced production of type I collagen.153 Moreover, there have been additional invivo and cadaver studies that suggest there is a ‘critical zone’ within the supraspinatus tendon which can increase with age, impingement, and larger RC tears.112,155 Second to supraspinatus is the prevalence of infraspinatus tearing. This is not surprising given that the tendons of these muscles blend upon their insertion,156,157 that the most common location for tearing is at the junction of the two tendons,114 and

that injury of the supraspinatus increases the strain and demand of the infraspinatus.149 These findings are consistent with the supraspinatus and infraspinatus having the highest prevalence in the included shoulders of this review.

However, as several of the included studies either did not report the specific tendon involved or listed the FTT as “massive”, there is a high risk of the prevalence of subscapularis and teres minor involvement being under reported. Recent studies have reported subscapularis involvement in RC tears as high as 31.5%, but only 6% in shoulders in which surgical repair was indicated.158 This is twice that of the 3% prevalence reported in this study. Similarly, teres minor tears have suggested to be rare in isolation159 and tend to be involved in “extensive FTT.”160 Despite 37% of tears being massive and/or involving >1 tendon, teres minor involvement was only reported in three (<1%) of shoulders. One potential explanation for this, as mentioned above, is the most common location of FTT is at the junction of infraspinatus and supraspinatus and that teres minor is commonly preserved in the presence of massive FTT with degenerative RC changes and atrophy because the increased physical demand on the muscle can lead to hypertrophy of teres minor, especially in posterior-superior tears.160-162 This information is critical to acknowledge when devising a rehabilitation program that will be successful and strategically overcoming the ROM, strength, and functional deficits that exist in the presence of FTTs. Included RCTs in this review were predominantly chronic and atraumatic in nature of onset. This is also consistent with the literature, As the literature suggests that traumatic and, therefore, more often acute RCTs are more likely to be considered for surgical management,45,163 the distributions of symptom duration and atraumatic onset should be viewed with caution. This is due to the risk of bias in the inclusion and selection criteria of the included studies being more likely to attract subjects who were not considered for a primary RC repair.

Comparison to Prior Reviews There were three prior systematic reviews identified that had a similar scope, patient population, interventions, outcomes, and search strategies to

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the current review.32,45,64 A summary of the scope of these reviews is summarized in Appendix B and Appendix C. It is apparent that an update of Ainsworth et al (2007)32 was warranted as another 25 pertinent publications regarding non-operative management of FTT have been added to the literature since 2007.

Though Sieda et al64 and Ryosa et al45 are more recent, neither study was specific to non-operative management of FTT, as is apparent by the discrepancy in the number of included studies and the aggregate number of subjects. To the knowledge of the authors, the current review has three times the number of relevant studies and close to four times the number of shoulders compared to any prior review specific to the non-operative treatment of FTT. (Figures 6 and 7) However, the authors of the current review were unable to perform a meta-analysis which has been conducted by prior reviews,45,64 thus, the level of current evidence was summarized using a GRADE of Recommendation. This provided a distinct conclusion, in comparison to the language used in the conclusions prior reviews (i.e. ‘some evidence exists’,32 ‘inconclusive’,64 or ‘limited evidence’45).

performed for asymptomatic RCTs, and provided a limited recommendation on RCT repair as an option for patients with chronic, symptomatic FTT. Ironically this described demographic fits the majority of the 2,010 shoulders included in this review, demonstrating that given the aforementioned results, it would appear that conservative, non-operative treatment should be considered a viable alternative to surgical intervention.9 With the known risk of muscle wasting, fatty infiltration, further decline in disability and the potential for continual tear progression natural history progression, pharmacological management, activity modification, professional advice, and/or strategic neglect is not the best option for this patient demographic; exercise therapy through mechanotherapy mechanisms.9,125

It is also important to note the quality of the identified reviews. Based on The AMSTAR guidelines73,74 Sieda et al64 and Ryosa et al45 both demonstrated ‘Good’ quality, 10/11 and 9/11, respectively. Ainsworth et al (2007)32 on the other hand only demonstrated ‘Fair’ quality, 5/11. The quality of methodology assessment of the current review was determined to be ‘Good’ (9/11) as determined by the AMSTAR guidelines (Table 6).

Components of Exercise Therapy Rehabilitation of Full-Thickness Tears The common aspects in the programs of the included studies were identified as: (1) range of motion, (2) flexibility/stretching, (3) strength/resistance exercise, (4) modalities, (5) supplementary pharmaceutical interventions including injections or oral medications, (6) postural and scapulothoracic exercises, and (7) education regarding the pathophysiology of the condition, the how exercise can help and goals of conservative management. Other aspects to consider are including a home exercise program, the specific parameters of the program (frequency, intensity, volume, duration), and whether or not to ‘phase’ the program. The prevalence of each of these interventions in the included articles is provided in Figure 5.

A separate, but seminal, review and position statement that needs be discussed in light of the current findings is the American Academy of Orthopedic Surgeons (AAOS) 2012 Clinical Practice guidelines for “Optimizing the Management of Rotator Cuff Problems” states that there was ‘inconclusive evidence’ to provide a recommendation for exercise as a treatment for RCT.164 It is clear from the current results that since 2012 there is sufficient evidence to not only support the use of exercise therapy in the treatment of FTT but that this is effective in managing pain, improving range of motion, strength, and overall function. Simultaneously, the AAOS 2012 practice guidelines stated that surgery should not be

Despite the predictable and consistent deficits that need to be addressed in the rehabilitation of the patient with a RCT, there is considerable heterogeneity in the components and exercise prescription of the included rehabilitation programs. This variability amongst the intervention programs is a confounding variable and thus, may influence differences in outcomes. This has previously been identified as a source of performance bias in a systematic review in the related pathology of shoulder impingement syndrome.63 The argument for a ‘standardized accepted, evidence-based rehabilitation protocol’ is: (1) clinicians will ‘know that patients are receiving the best available rehabilitation program’, (2) a

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‘standard rehabilitation protocol’ reduces confounding variables and performance bias, (3) it will allow for pooling and comparison of data across studies and different cohorts; (4) such a protocol can also serve as a control, allowing for the study and protocol modifications. It is apparent that the necessity of a synthesized protocol exists. However, it is important to note that a synthesized protocol is designed to serve as a guide for the rehabilitation process and not intended to supersede clinical judgment and decision making that is necessary to meet the unique needs of individual patients. Phased progression of any rehab protocol should be based not only on expected tissue healing timelines but also on clinical presentation and functional capabilities of each individual patient.

Limitations There were limitations in the current review that are important to note. First, there is ambiguity in the literature between RCT and subacromial impingement syndrome (SIS). A number of articles that were excluded from this review discussed the effectiveness of exercise specific to SIS. However, patients with Stage III SIS are described as having key finding of a mechanical disruption of the rotator cuff tendon in the form of either partial or complete cuff tears defined as by Neer et al165 and Khan et al.166 However, certain studies failed to determine and/or state the stage of SIS of the respective subjects, these citations were excluded due to the extent, or lack thereof, of mechanical damage to the rotator cuff muscle(s) of the subjects described in these studies would not have definitively fit the inclusion criteria of this review (FTT).

Similarly, there is considerable heterogeneity in the classification systems used to describe RCTs.115,116 The discrepancies in classification systems used by included studies made it difficult at times to determine the full extent of tendons described. For instance, if it was stated that ‘<50% of the supraspinatus tendon was involved’ this very well could be describing a partial thickness tear in the superior to inferior direction or it could be interpreted as a FTT in the superior to inferior direction that only involved <50% of the tendon in the anterior to posterior direction. Though The International Society of Arthroscopy, Knee Surgery & Orthopedic Sports

Medicine (ISAKOS) published a positional statement defining a synthesized classification system in 2013,116 all of the studies prior to this date (and some after) were using different classifications and thus, providing a risk of miss interpreting the full extent of the rotator cuff pathology. Note, in such cases when a study met all other inclusion criteria and there was ambiguity in the extent of the tear, the corresponding authors were contacted for clarification. This occurred in only three studies.1,86,93 This review was only specific to studies published in the English language. Sieda et al64 extended their search to English, French, and German studies and were able to identify four additional studies120,121,167,168 that otherwise would have been included in this review, but due to the pre-determined English language inclusion criteria and the lack of accessible (and accurate) translation resources, these studies were not included. As mentioned in the results section, there was another outlying study81 due to all available resources being exhausted and not being able to access a full text. Correspondence with the author(s) was attempted but no return response was received.

Another critique of the inclusion and exclusion criteria is the inclusion of case reports, observational studies, and randomized control trials. The lack of randomization and heterogeneity of the studies prevented a pooled analysis. Furthermore, the inclusion of case reports was not necessary as they made of <1% of the aggregate number of shoulders and commonly provide the most clinical utility in ‘recognition patterns’ for rare clinical conditions and reviews on certain topics related to the case.169 FTT are far from a ‘rare’ clinical condition and the topics (i.e. non-operative management) are certainly covered by other observational and randomized studies that were included. The rationale for including both observational and experimental studies and for inclusion criteria was due to the fact that the current review was an update of a prior review.32 As such, it is standard practice to keep inclusion and exclusion criteria as constant.

A final critique, outside of the control of the author, was the fact that there was a lack of reporting of statistical analysis in a large portion of the studies regardless of the outcome in question. When

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possible the MCID was applied to the functional outcome measure in an attempt to demonstrate a meaningful change in the absence of statistical significance. The lack of reporting of statistically significant differences limits impact and interpretation of the results. (Figure 4). Additionally, the lack of level I and II experimental design studies prevented assignment of a a GRADE A Recommendation for the use of exercise therapy in the treatment of FTT.

4. Teunis T, Lubberts B, Reilly BT, Ring D. A systematic review and pooled analysis of the prevalence of rotator cuff disease with increasing age. J Shoulder Elbow Surg. 2014;23(12):1913-1921.

Despite these limitations, this is currently the most comprehensive search that has been conducted in regards to conservative management of FTT. Furthermore, the results have been used to substantiate and provide suggestions to the recently proposed ‘Edwards Protocol’ which can be used to guide clinical practice and provide a starting point for future high-quality randomized control trials.

7. Fehringer EV, Sun J, VanOeveren LS, Keller BK, Matsen FA, 3rd. Full-thickness rotator cuff tear prevalence and correlation with function and co-morbidities in patients sixty-five years and older. J Shoulder Elbow Surg. 2008;17(6):881-885.

CONCLUSION The results of the current systematic review of the current literature provided few high-quality randomized control trials and a predominant number of observational studies, indicating GRADE B Recommendation (moderate strength) to support the use of ET in the management of FTT. There is substantial evidence to support the use of exercise therapy as first line management, especially in individuals >60 years of age with chronic, degenerative FTT. Future efforts should focus on coming to a consensus regarding exercises and interventions that are most effective in the conservative treatment of individuals with full thickness rotator cuff tears.

9. Edwards P, Ebert J, Joss B, Bhabra G, Ackland T, Wang A. Exercise rehabilitation in the non-operative management of rotator cuff tears: A review of the literature. Int J Sports Phys Ther. 2016;11(2):279-301.

External Links 1. Video Presentation Summarizing Review and Results REFERENCES

5. Tempelhof S, Rupp S, Seil R. Age-related prevalence of rotator cuff tears in asymptomatic shoulders. J Shoulder Elbow Surg. 1999;8(4):296-299.

6. Sambandam SN, Khanna V, Gul A, Mounasamy V. Rotator cuff tears: An evidence based approach.

World J Orthop. 2015;6(11):902.

8. Yamaguchi K, Tetro AM, Blam O, Evanoff BA, Teefey SA, Middleton WD. Natural history of asymptomatic rotator cuff tears: a longitudinal analysis of asymptomatic tears detected sonographically. J Shoulder Elbow Surg. 2001;10(3):199-203.

10. Fukuda H. Partial-thickness rotator cuff tears: a modern view on Codman’s classic. J Shoulder Elbow Surg. 2000;9(2):163-168.

11. Lehman C, Cuomo F, Kummer FJ, Zuckerman JD. The incidence of full thickness rotator cuff tears in a large cadaveric population. Bull Hosp Jt Dis. 1995;54(1):30-31.

12. Keener J, Galatz L, Stobbs-Cucchi G, Patton R, Yamaguchi K. Rehabilitation following arthroscopic rotator cuff repair: a prospective randomized trial of immobilization compared with early motion. J Bone Joint Surg Am. 2014;96(1):11-19.

13. Hijioka A, Suzuki K, Nakamura T, Hojo T. Degenerative change and rotator cuff tears. An anatomical study in 160 shoulders of 80 cadavers.

Arch Orthop Trauma Surg. 1993;112(2):61-64.

1.

Merolla G, Paladini P, Saporito M, Porcellini G. Conservative management of rotator cuff tears: literature review and proposal for a prognostic.

Prediction Score. Muslec Lig Tendons J. 2011;1(1):12-19.

14. Gerber C, Meyer DC, Schneeberger AG, Hoppeler H, von Rechenberg B. Effect of tendon release and delayed repair on the structure of the muscles of the rotator cuff: an experimental study in sheep. J Bone Joint Surg Am. 2004;86-A(9):1973-1982.

2.

Kim HM, Teefey SA, Zelig A, Galatz LM, Keener JD, Yamaguchi K. Shoulder strength in asymptomatic individuals with intact compared with torn rotator cuffs. J Bone Joint Surg Am. 2009;91(2):289-296.

15. Park JG, Cho NS, Song JH, Baek JH, Jeong HY, Rhee YG. Rotator Cuff Repair in Patients over 75 Years of Age: Clinical Outcome and Repair Integrity. Clin Orthop Surg. 2016;8(4):420-427.

3.

Sher JS, Uribe JW, Posada A, Murphy BJ, Zlatkin MB. Abnormal findings on magnetic resonance images of asymptomatic shoulders. J Bone Joint Surg Am. 1995;77(1):10-15.

16. Gumina S, Carbone S, Campagna V, Candela V, Sacchetti FM, Giannicola G. The impact of aging on rotator cuff tear size. Musculoskelet Surg. 2013;97 Suppl 1:69-72.

The International Journal of Sports Physical Therapy | Volume 13, Number 3 | June 2018 | Page 358

17. Abate M, Schiavone C, Di Carlo L, Salini V. Prevalence of and risk factors for asymptomatic rotator cuff tears in postmenopausal women.

Menopause. 2014;21(3):275-280.

30. Yamamoto A, Takagishi K, Kobayashi T, et al. The impact of faulty posture on rotator cuff tears with and without symptoms. J Shoulder Elbow Surg.

2015;24(3):446-452.

18. Yamamoto A, Takagishi K, Osawa T, et al.

Prevalence and risk factors of a rotator cuff tear in the general population. J Shoulder Elbow Surg.

2010;19(1):116-120.

31. Gumina S, Di Giorgio G, Postacchini F, Postacchini R. Subacromial space in adult patients with thoracic hyperkyphosis and in healthy volunteers. Chir Organi Mov. 2008;91(2):93-96.

19. Milgrom C, Schaffler M, Gilbert S, van Holsbeeck M. Rotator-cuff changes in asymptomatic adults. The effect of age, hand dominance and gender. J Bone Joint Surg Br. 1995;77(2):296-298.

20. Brasseur JL, Lucidarme O, Tardieu M, et al.

Ultrasonographic rotator-cuff changes in veteran tennis players: the effect of hand dominance and comparison with clinical findings. Eur Radiol.

2004;14(5):857-864.

32. Ainsworth R, Lewis JS. Exercise therapy for the conservative management of full thickness tears of the rotator cuff: a systematic review. Br J Sports Med. 2007;41(4):200-210.

33. Abboud JA, Beason DP, Soslowsky LJ. Emerging ideas: the effect of hypercholesterolemia on tendons.

Clin Orthop Relat Res. 2012;470(1):317-320.

21. Liem D, Buschmann VE, Schmidt C, et al. The prevalence of rotator cuff tears: is the contralateral shoulder at risk? Am J Sports Med. 2014;42(4):826830.

22. Yamaguchi K, Ditsios K, Middleton WD, Hildebolt CF, Galatz LM, Teefey SA. The demographic and morphological features of rotator cuff disease. A comparison of asymptomatic and symptomatic shoulders. J Bone Joint Surg Am. 2006;88(8):16991704.

23. Ro KH, Park JH, Lee SH, Song DI, Jeong HJ, Jeong WK. Status of the contralateral rotator cuff in patients undergoing rotator cuff repair. Am J Sports Med. 2015;43(5):1091-1098.

24. Tashjian RZ, Farnham JM, Albright FS, Teerlink CC, Cannon-Albright LA. Evidence for an inherited predisposition contributing to the risk for rotator cuff disease. J Bone Joint Surg Am. 2009;91(5):1136-1142.

25. Lewis J, Tennent T. How effective are diagnostic tests for the assessment of rotator cuff disease of the shoulder. Evidence Based Sports Med. 2007:327-360.

26. Gombera MM, Sekiya JK. Rotator cuff tear and glenohumeral instability : a systematic review. Clin Orthop Relat Res. 2014;472(8):2448-2456.

27. Baumgarten KM, Gerlach D, Galatz LM, et al.

Cigarette smoking increases the risk for rotator cuff tears. Clin Orthop Relat Res. 2010;468(6):1534-1541.

28. Bishop JY, Santiago-Torres JE, Rimmke N, Flanigan DC. Smoking Predisposes to Rotator Cuff Pathology and Shoulder Dysfunction: A Systematic Review.

Arthroscopy. 2015;31(8):1598-1605.

29. Carbone S, Gumina S, Arceri V, Campagna V, Fagnani C, Postacchini F. The impact of preoperative smoking habit on rotator cuff tear: cigarette smoking influences rotator cuff tear sizes. J Shoulder Elbow Surg. 2012;21(1):56-60.

34. Abboud JA, Kim JS. The effect of hypercholesterolemia on rotator cuff disease. Clin Orthop Relat Res. 2010;468(6):1493-1497.

35. Dougherty KA, Dilisio MF, Agrawal DK. Vitamin D and the immunomodulation of rotator cuff injury. J Inflamm Res. 2016;9:123-131.

36. Mather RC, 3rd, Koenig L, Acevedo D, et al. The societal and economic value of rotator cuff repair. J Bone Joint Surg Am. 2013;95(22):1993-2000.

37. Bell JE. Repair of symptomatic rotator cuff tears after failed nonoperative treatment is cost-effective: commentary on an article by Richard C. Mather III, MD, et al.: “The societal and economic value of rotator cuff repair”. J Bone Joint Surg Am. 2013;95(22):e178.

38. Kuye IO, Jain NB, Warner L, Herndon JH, Warner JJ. Economic evaluations in shoulder pathologies: a systematic review of the literature. J Shoulder Elbow Surg. 2012;21(3):367-375.

39. Yeranosian MG, Terrell RD, Wang JC, McAllister DR, Petrigliano FA. The costs associated with the evaluation of rotator cuff tears before surgical repair.

J Shoulder Elbow Surg. 2013;22(12):1662-1666.

40. Kuhn J, Dunn W, Sanders R, et al. Effectiveness of physical therapy in treating atraumatic fullthickness rotator cuff tears: a multicenter prospective cohort study. J Shoulder Elbow Surg.

2013;22(10):1371-1379.

41. Bunker T. Rotator cuff disease. Curr Orthop.

2002;16(3):223-233.

42. Seida JC, le Blanc C, Schouten JR, et al. Systematic review: nonoperative and operative treatments for rotator cuff tears [with consumer summary]. Ann Int Med. 2010;153(4):246-255. 2010.

43. Huisstede BM, Koes BW, Gebremariam L, Keijsers E, Verhaar JA. Current evidence for effectiveness of interventions to treat rotator cuff tears. Man Ther.

2011;16(3):217-230.

The International Journal of Sports Physical Therapy | Volume 13, Number 3 | June 2018 | Page 359

44. Downie BK, Miller BS. Treatment of rotator cuff tears in older individuals: a systematic review. J Shoulder Elbow Surg. 2012;21(9):1255-1261.

45. Ryosa A, Laimi K, Aarimaa V, Lehtimaki K, Kukkonen J, Saltychev M. Surgery or conservative treatment for rotator cuff tear: a meta-analysis [with consumer summary]. Disabil Rehab.

2016;39(14):1357-1363.

46. Grant HJ, Arthur A, Pichora DR. Evaluation of interventions for rotator cuff pathology: a systematic review. Journal of Hand Therapy. 2004;17(2):274-299.

47. Moosmayer S, Lund G, Seljom U, et al. Comparison between surgery and physiotherapy in the treatment of small and medium-sized tears of the rotator cuff: A randomised controlled study of 103 patients with one-year follow-up. J Bone Joint Surg Br. 2010;92(1):83-91.

48. Moosmayer S, Lund G, Seljom U, et al. Tendon repair compared with physiotherapy in the treatment of rotator cuff tears: a randomized controlled study in 103 cases with a five-year follow-up. J Bone Joint Surg Am. 2014;96(18):1504-1514.

49. Lambers Heerspink FO, van Raay J, Koorevaar RCT, et al. Comparing surgical repair with conservative treatment for degenerative rotator cuff tears: a randomized controlled trial. J Shoulder Elbow Surg.

2015;24(8):1274-1281.

50. Pedowitz RA, Yamaguchi K, Ahmad CS, et al.

American Academy of Orthopaedic Surgeons Clinical Practice Guideline on: optimizing the management of rotator cuff problems. J Bone Joint Surg Am. 2012;94(2):163-167.

51. Kukkonen J, Joukainen A, Lehtinen J, et al.

Treatment of non-traumatic rotator cuff tears: A randomised controlled trial with one-year clinical results. The bone & joint journal. 2014;96-b(1):75-81.

52. Kukkonen J, Joukainen A, Lehtinen J, et al.

Treatment of Nontraumatic Rotator Cuff Tears: A Randomized Controlled Trial with Two Years of Clinical and Imaging Follow-up. J Bone Joint Surg Am. 2015;97(21):1729-1737.

53. Zanetti M, Jost B, Hodler J, Gerber C. MR imaging after rotator cuff repair: full-thickness defects and bursitislike subacromial abnormalities in asymptomatic subjects. Skeletal Radiol. 2000;29(6):314-319.

54. Thomazeau H, Boukobza E, Morcet N, Chaperon J, Langlais F. Prediction of rotator cuff repair results by magnetic resonance imaging. Clin Orthop Relat Res. 1997(344):275-283.

55. Mellado JM, Calmet J, Olona M, et al. Surgically repaired massive rotator cuff tears: MRI of tendon integrity, muscle fatty degeneration, and muscle atrophy correlated with intraoperative and clinical findings. Am J Roentgenol. 2005;184(5):1456-1463.

56. Bishop J, Klepps S, Lo IK, Bird J, Gladstone JN, Flatow EL. Cuff integrity after arthroscopic versus open rotator cuff repair: a prospective study. J Shoulder Elbow Surg. 2006;15(3):290-299.

57. Klepps S, Bishop J, Lin J, et al. Prospective evaluation of the effect of rotator cuff integrity on the outcome of open rotator cuff repairs. Am J Sports Med. 2004;32(7):1716-1722.

58. Harryman DT, 2nd, Mack LA, Wang KY, Jackins SE, Richardson ML, Matsen FA, 3rd. Repairs of the rotator cuff. Correlation of functional results with integrity of the cuff. J Bone Joint Surg Am. 1991;73(7):982-989.

59. Gerber C, Fuchs B, Hodler J. The results of repair of massive tears of the rotator cuff. J Bone Joint Surg Am. 2000;82(4):505-515.

60. Galatz LM, Ball CM, Teefey SA, Middleton WD, Yamaguchi K. The outcome and repair integrity of completely arthroscopically repaired large and massive rotator cuff tears. J Bone Joint Surg Am. 2004;86A(2):219-224.

61. Feng S, Guo S, Nobuhara K, Hashimoto J, Mimori K. Prognostic indicators for outcome following rotator cuff tear repair. J Orthop Surg (Hong Kong).

2003;11(2):110-116.

62. Ladermann A, Denard PJ, Collin P. Massive rotator cuff tears: definition and treatment. Int Orthop.

2015;39(12):2403-2414.

63. Kuhn JE. Exercise in the treatment of rotator cuff impingement: a systematic review and a synthesized evidence-based rehabilitation protocol. J Should Elb Surg. 2009;18(1):138-160. 2009.

64. Seida JC, LeBlanc C, Schouten JR, et al. Systematic review: nonoperative and operative treatments for rotator cuff tears. Ann Intern Med. 2010;153(4):246-255.

65. Norris S, Atkins D, Bruening W, et al. Selecting Observational Studies for Comparing Medical Interventions. In: Methods Guide for Effectiveness and Comparative Effectiveness Reviews. Rockville (MD),2008.

66. Higgins JP, Green S, Scholten R. Maintaining reviews: updates, amendments and feedback. In: Wiley: Chichester, UK; 2008:31.

67. Chalmers I, Enkin M, Keirse MJ. Preparing and updating systematic reviews of randomized controlled trials of health care. Milbank Q. 1993;71(3):411-437.

68. Garner P, Hopewell S, Chandler J, et al. When and how to update systematic reviews: consensus and checklist. Br Med J. 2016;354:i3507.

69. The GRADE working group. Introduction: Grading the quality of evidence and the strength of recommendations. 2005; http://www.gradeworking group.org/intro.htm. Accessed July 3, 2015.

The International Journal of Sports Physical Therapy | Volume 13, Number 3 | June 2018 | Page 360

70. Moher D, Liberati A, Tetzlaff J, Altman DG, Group P. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. J Clin Epidemiol. 2009;62(10):1006-1012.

71. Shamseer L, Moher D, Clarke M, et al. Preferred reporting items for systematic review and metaanalysis protocols (PRISMA-P) 2015: elaboration and explanation. Br Med J. 2015;349:g7647.

72. Furlan AD, Tomlinson G, Jadad AA, Bombardier C. Methodological quality and homogeneity influenced agreement between randomized trials and nonrandomized studies of the same intervention for back pain. J Clin Epidemiol. 2008;61(3):209-231.

73. Shea BJ, Bouter LM, Peterson J, et al. External validation of a measurement tool to assess systematic reviews (AMSTAR). PLoS One. 2007;2(12):e1350.

74. Shea BJ, Grimshaw JM, Wells GA, et al.

Development of AMSTAR: a measurement tool to assess the methodological quality of systematic reviews. BMC Med Res Methodol. 2007;7:10.

75. Gagnier JJ, Kellam PJ. Reporting and methodological quality of systematic reviews in the orthopaedic literature. J Bone Joint Surg Am. 2013;95(11):e771-777.

76. Higgins JP, Altman DG, Gotzsche PC, et al. The Cochrane Collaboration’s tool for assessing risk of bias in randomised trials. Br Med J. 2011;343:d5928.

77. Maher CG, Sherrington C, Herbert RD, Moseley AM, Elkins M. Reliability of the PEDro scale for rating quality of randomized controlled trials. Phys Ther.

2003;83(8):713-721.

78. Khan KS, Ter Riet G, Glanville J, Sowden AJ, Kleinjnen J. Undertaking systematic reviews of research on effectiveness: CRD’s guidance for carrying out or commissioning reviews. 2nd ed: NHS Centre for Reviews and Dissemination; 2001.

79. OCEBM Levels of Evidence Working Group. “The Oxford Levels of Evidence 2”. In: Oxford Centre for Evidence-Based Medicine.

80. American Physical Therapy Association. Clinical Practice Guidelines (CPGs): Getting Started. 2014; http://www.apta.org/EvidenceResearch/Implemen tingEBP/CPGs/GettingStarted/. Accessed July 3, 2015.

81. Lenehan F, Doody C. The benefit of physiotherapy in the conservative and surgical management of full-thickness rotator cuff tears: a systematic review.

Irish Society of Chartered Physiotherapists (ISCP) Conference 2010. Physiotherapy Ireland.

2011;32(1):34-34.

82. Benazzo F, Marullo M, Pietrobono L. Supraspinatus rupture at the musculotendinous junction in a young woman. J Orthop Traumatol. 2014;15(3):231-234.

83. Mischke JJ, Emerson Kavchak AJ, Courtney CA. Effect of sternoclavicular joint mobilization on pain and function in a patient with massive supraspinatus tear. Physiother Theory Pract. 2016;32(2):153-158.

84. Palmer S. Aquatic physical therapy case report: Rehabilitation of a patient with a supraspinatus tear by aquatic therapeutic home exercises. J Aquatic Phys Ther. 1998;6(2):24-27.

85. Piccoli AS, Hasson SM. Conservative management of a large rotator cuff tear to increase functional abilities: a case report. Physiotherapy Theory & Practice. 2004;20(3):201-208.

86. Upadhyaya S, Pike AN, Martin SD. 10-year follow-up of non-operatively treated full thickness rotator cuff tear. Sports Orthop Traumatol. 2016;32(1):67-72.

87. Ainsworth R. Physiotherapy rehabilitation in patients with massive, irreparable rotator cuff tears.

Musculoskeletal Care. 2006;4(3):140-151.

88. Bokor DJ, Hawkins RJ, Huckell GH, Angelo RL, Schickendantz MS. Results of nonoperative management of full-thickness tears of the rotator cuff. Clin Orthop Relat Res. 1993(294):103-110.

89. Collin PG, Gain S, Nguyen Huu F, Ladermann A. Is rehabilitation effective in massive rotator cuff tears?

Orthop Traumatol Surg Res. 2015;101(4 Suppl):S203-205.

90. Goldberg BA, Nowinski RJ, Matsen FA, 3rd. Outcome of nonoperative management of full-thickness rotator cuff tears. Clin Orthop Relat Res. 2001(382):99107.

91. Hawkins RH, Dunlop R. Nonoperative treatment of rotator cuff tears. Clin Orthop Relat Res. 1995(321):178-188.

92. Itoi E, Tabata S. Conservative treatment of rotator cuff tears. Clin Orthop Relat Res. 1992(275):165-173.

93. Kijima H, Minagawa H, Nishi T, Kikuchi K, Shimada Y. Long-term follow-up of cases of rotator cuff tear treated conservatively. J Shoulder Elbow Surg.

2012;21(4):491-494.

94. Miller RM, Popchak A, Vyas D, et al. Effects of exercise therapy for the treatment of symptomatic full-thickness supraspinatus tears on in vivo glenohumeral kinematics. J Shoulder Elbow Surg.

2016;25(4):641-649.

95. Moosmayer S, Gärtner AV, Tariq R. The natural course of nonoperatively treated rotator cuff tears: an 8.8-year follow-up of tear anatomy and clinical outcome in 49 patients. J Shoulder Elbow Surg.

2017;26(4):627-634.

96. Tanaka M, Itoi E, Sato K, et al. Factors related to successful outcome of conservative treatment for rotator cuff tears. Ups J Med Sci. 2010;115(3):193-200.

The International Journal of Sports Physical Therapy | Volume 13, Number 3 | June 2018 | Page 361

97. Wirth MA, Basamania C, Rockwood CA, Jr. Nonoperative management of full-thickness tears of the rotator cuff. Orthop Clin North Am. 1997;28(1):5967.

98. Yamada N, Hamada K, Nakajima T, Kobayashi K, Fukuda H. Comparison of conservative and operative treatments of massive rotator cuff tears.

Tokai J Exp Clin Med. 2000;25(4-6):151-163.

99. Levy O, Mullett H, Roberts S, Copeland S. The role of anterior deltoid reeducation in patients with massive irreparable degenerative rotator cuff tears. J Shoulder Elbow Surg. 2008;17(6):863-870.

100. Guzelant AY, Sarifakioglu AB, Gonen AK, et al.

Massive retracted irreparable rotator cuff tears: what is the effect of conservative therapy? Turk J Geriatri. 2014;17(3):234-241.

101. Baydar M, Akalin E, El O, et al. The efficacy of conservative treatment in patients with fullthickness rotator cuff tears. Rheumatol Int. 2009;29(6):623-628.

102. Lunn JV, Castellanos-Rosas J, Tavernier T, Barthelemy R, Walch G. A novel lesion of the infraspinatus characterized by musculotendinous disruption, edema, and late fatty infiltration. J Shoulder Elbow Surg. 2008;17(4):546-553.

103. Vad VB, Warren RF, Altchek DW, O’Brien SJ, Rose HA, Wickiewicz TL. Negative prognostic factors in managing massive rotator cuff tears. Clin J Sport Med. 2002;12(3):151-157.

104. Baumer TG, Chan D, Mende V, et al. Effects of rotator cuff pathology and physical therapy on in vivo shoulder motion and clinical outcomes in patients with a symptomatic full-thickness rotator cuff tear. Orthop J Sports Med. 2016;4(9):1-10.

105. Christensen BH, Andersen KS, Rasmussen S, Andreasen EL, Nielsen LM, Jensen SL. Enhanced function and quality of life following 5 months of exercise therapy for patients with irreparable rotator cuff tears - an intervention study. BMC Musculoskelet Disord. 2016;17:252-260.

106. Boorman RS, More KD, Hollinshead RM, et al. The rotator cuff quality-of-life index predicts the outcome of nonoperative treatment of patients with a chronic rotator cuff tear. J Bone Joint Surg Am. 2014;96(22):1883-1888.

107. Krischak G, Gebhard F, Reichel H, et al. A prospective randomized controlled trial comparing occupational therapy with home-based exercises in conservative treatment of rotator cuff tears. J Shoulder Elbow Surg. 2013;22(9):1173-1179.

108. Kukkonen J, Joukainen A, Lehtinen J, et al.

Treatment of non-traumatic rotator cuff tears: A randomised controlled trial with one-year clinical results. Bone Joint J. 2014;96-b(1):75-81.

109. Shibata Y, Midorikawa K, Emoto G, Naito M. Clinical evaluation of sodium hyaluronate for the treatment of patients with rotator cuff tear. J Shoulder Elbow Surg. 2001;10(3):209-216.

110. Ainsworth R, Lewis J, Conboy V. A prospective randomized placebo controlled clinical trial of a rehabilitation programme for patients with a diagnosis of massive rotator cuff tears of the shoulder. Shoulder & Elbow. 2009;1(1):55-60.

111. Gialanella B, Prometti P. Effects of corticosteroids injection in rotator cuff tears. Pain medicine (Malden, Mass). 2011;12(10):1559-1565.

112. Hegedus EJ, Cook C, Brennan M, Wyland D, Garrison JC, Driesner D. Vascularity and tendon pathology in the rotator cuff: a review of literature and implications for rehabilitation and surgery. Br J Sports Med. 2010;44(12):838-847.

113. Goutallier D, Postel JM, Bernageau J, Lavau L, Voisin MC. Fatty muscle degeneration in cuff ruptures. Pre- and postoperative evaluation by CT scan. Clin Orthop Relat Res. 1994(304):78-83.

114. Kim HM, Dahiya N, Teefey SA, et al. Location and initiation of degenerative rotator cuff tears: an analysis of three hundred and sixty shoulders. J Bone Joint Surg Am. 2010;92(5):1088-1096.

115. Belangero PS, Ejnisman B, Arce G. A review of rotator cuff classifications in current use. In: Shoulder Concepts 2013: Consensus and Concerns.

Springer; 2013:5-13.

116. Calvo E. ISAKOS Classification System for Rotator Cuff Tears. In: Shoulder Concepts 2013: Consensus and Concerns. Springer; 2013:15-23.

117. DeOrio JK, Cofield RH. Results of a second attempt at surgical repair of a failed initial rotator-cuff repair. J Bone Joint Surg Am. 1984;66(4):563-567.

118. Kraemer WJ, Kent A, Cafarelli E, et al. American College of Sports Medicine position stand.

Progression models in resistance training for healthy adults. Med Sci Sports Exerc. 2009;41(3):687-708.

119. Hollinshead RM, Mohtadi NG, Vande Guchte RA, Wadey VM. Two 6-year follow-up studies of large and massive rotator cuff tears: comparison of outcome measures. J Shoulder Elbow Surg. 2000;9(5):373-381.

120.Koubâa S, Ben Salah FZ, Lebib S, Miri I, Ghorbel S, Dziri C. Traitement conservateur des ruptures transfixiantes de la coiffe des rotateurs. Étude prospective ouverte. À propos de 24 patients.

Annales de Réadaptation et de Médecine Physique.

2006;49(2):62-67.

121. Heers G, Anders S, Werther M, Lerch K, Hedtmann A, Grifka J. [Efficacy of home exercises for symptomatic rotator cuff tears in correlation to the size of the defect]. Sportverletz Sportschaden. 2005;19(1):22-27.

The International Journal of Sports Physical Therapy | Volume 13, Number 3 | June 2018 | Page 362

122. Maman E, Harris C, White L, Tomlinson G, Shashank M, Boynton E. Outcome of nonoperative treatment of symptomatic rotator cuff tears monitored by magnetic resonance imaging. J Bone Joint Surg Am. 2009;91(8):1898-1906.

123. Harris JD, Pedroza A, Jones GL. Predictors of pain and function in patients with symptomatic, atraumatic full-thickness rotator cuff tears: a time-zero analysis of a prospective patient cohort enrolled in a structured physical therapy program.

Am J Sports Med. 2012;40(2):359-366.

124. Safran O, Schroeder J, Bloom R, Weil Y, Milgrom C. Natural history of nonoperatively treated symptomatic rotator cuff tears in patients 60 years old or younger. Am J Sports Med. 2011;39(4):710-714.

125. Khan KM, Scott A. Mechanotherapy: how physical therapists’ prescription of exercise promotes tissue repair. Br J Sports Med. 2009;43(4):247-252.

126. Tashjian RZ. Epidemiology, natural history, and indications for treatment of rotator cuff tears. Clin Sports Med. 2012;31(4):589-604.

127. Kim IB, Kim MW. Risk Factors for Retear After Arthroscopic Repair of Full-Thickness Rotator Cuff Tears Using the Suture Bridge Technique: Classification System. Arthroscopy. 2016;32(11):21912200.

128. Lee YS, Jeong JY, Park CD, Kang SG, Yoo JC. Evaluation of the Risk Factors for a Rotator Cuff Retear After Repair Surgery. Am J Sports Med. 2017:363546517695234.

129. Sherman SL, Lyman S, Koulouvaris P, Willis A, Marx RG. Risk factors for readmission and revision surgery following rotator cuff repair. Clin Orthop Relat Res. 2008;466(3):608-613.

130. Marx RG, Koulouvaris P, Chu SK, Levy BA. Indications for surgery in clinical outcome studies of rotator cuff repair. Clin Orthop Relat Res. 2009;467(2):450-456.

131. Kweon C, Gagnier JJ, Robbins CB, Bedi A, Carpenter JE, Miller BS. Surgical Versus Nonsurgical Management of Rotator Cuff Tears: Predictors of Treatment Allocation. Am J Sports Med. 2015;43(10):2368-2372.

132. Clement ND, Nie YX, McBirnie JM. Management of degenerative rotator cuff tears: a review and treatment strategy. Sports Med Arthrosc Rehabil Ther Technol. 2012;4(1):48.

133. Boileau P, Brassart N, Watkinson DJ, Carles M, Hatzidakis AM, Krishnan SG. Arthroscopic repair of full-thickness tears of the supraspinatus: Does the tendon really heal? J Bone Joint Surg Am. 2005;87A(6):1229-1240.

134. Burkhart SS, Barth JRH, Richards DP, Zlatkin MB, Larsen M. Arthroscopic repair of massive rotator cuff tears with stage 3 and 4 fatty degeneration.

Arthroscopy. 2007;23(4):347-354.

135. Beaudreuil J, Bardin T, Orcel P, Goutallier D. Natural history or outcome with conservative treatment of degenerative rotator cuff tears. Joint Bone Spine. 2007;74(6):527-529.

136. Lahteenmaki HE, Hiltunen A, Virolainen P, Nelimarkka L. Repair of full-thickness rotator cuff tears is recommended regardless of tear size and age: A retrospective study of 2 patients. J Should Elbow Surg. 2007;16(5):586-590.

137. Braun C, Hanchard NC, Batterham AM, Handoll HH, Betthäuser A. Prognostic Models in Adults Undergoing Physical Therapy for Rotator Cuff Disorders: Systematic Review. Phys Ther.

2016;96(7):961-971.

138. Unruh KP, Kuhn JE, Sanders R, et al. The duration of symptoms does not correlate with rotator cuff tear severity or other patient-related features: a cross-sectional study of patients with atraumatic, full-thickness rotator cuff tears. J Shoulder Elbow Surg. 2014;23(7):1052-1058.

139. Wolf BR, Dunn WR, Wright RW. Indications for repair of full-thickness rotator cuff tears. Am J Sports Med. 2007;35(6):1007-1016.

140. Thompson WO, Debski RE, Boardman ND, 3rd, et al. A biomechanical analysis of rotator cuff deficiency in a cadaveric model. Am J Sports Med. 1996;24(3):286-292.

141. Zhang AL, Montgomery SR, Ngo SS, Hame SL, Wang JC, Gamradt SC. Analysis of rotator cuff repair trends in a large private insurance population. Arthroscopy. 2013;29(4):623-629.

142. Wheeless CR. Wheeless’ textbook of orthopaedics. CR Wheeless, MD; 1996.

143. Minagawa H, Yamamoto N, Abe H, et al.

Prevalence of symptomatic and asymptomatic rotator cuff tears in the general population: from mass-screening in one village. J Orthop.

2013;10(1):8-12.

144. Garavaglia G, Ufenast H, Taverna E. The frequency of subscapularis tears in arthroscopic rotator cuff repairs: A retrospective study comparing magnetic resonance imaging and arthroscopic findings. Int J Should Surg. 2011;5(4):90.

145. Harryman DT, 2nd, Sidles JA, Harris SL, Matsen FA, 3rd. The role of the rotator interval capsule in passive motion and stability of the shoulder. J Bone Joint Surg Am. 1992;74(1):53-66.

146. Seitz AL, McClure PW, Finucane S, Boardman ND, Michener LA. Mechanisms of rotator cuff

The International Journal of Sports Physical Therapy | Volume 13, Number 3 | June 2018 | Page 363

147.

148.

149.

150.

151.

152.

153.

tendinopathy: intrinsic, extrinsic, or both? Clinical Biomech. 2011;26(1):1-12.

Karas V, Wang VM, Dhawan A, Cole BJ. Biomechanical factors in rotator cuff pathology.

Sports Med Arthrosc. 2011;19(3):202-206.

Longo UG, Berton A, Papapietro N, Maffulli N, Denaro V. Biomechanics of the rotator cuff: European perspective. In: Rotator Cuff Tear. Vol 57.

Karger Publishers; 2012:10-17.

Karas V, Cole BJ, Wang VM. Role of biomechanics in rotator cuff pathology: North American perspective. In: Rotator Cuff Tear. Vol 57. Karger Publishers; 2012:18-26.

Via AG, De Cupis M, Spoliti M, Oliva F. Clinical and biological aspects of rotator cuff tears. Muscl Lig Tendons J. 2013;3(2):70-79.

Nho SJ, Yadav H, Shindle MK, Macgillivray JD. Rotator cuff degeneration: etiology and pathogenesis. Am J Sports Med. 2008;36(5):987-993.

Morikawa D, Itoigawa Y, Nojiri H, et al.

Contribution of oxidative stress to the degeneration of rotator cuff entheses. J Shoulder Elbow Surg.

2014;23(5):628-635.

Yuan J, Murrell GA, Wei AQ, Wang MX. Apoptosis in rotator cuff tendonopathy. J Orthop Res. 2002;20(6):1372-1379.

154. Cook JL, Rio E, Purdam CR, Docking SI. Revisiting the continuum model of tendon pathology: what is its merit in clinical practice and research? Br J Sports Med. 2016;50(19):1187-1191.

155. Funakoshi T, Iwasaki N, Kamishima T, et al. In vivo visualization of vascular patterns of rotator cuff tears using contrast-enhanced ultrasound. Am J Sports Med. 2010;38(12):2464-2471.

156. Clark JM, Harryman DT, 2nd. Tendons, ligaments, and capsule of the rotator cuff. Gross and microscopic anatomy. J Bone Joint Surg Am. 1992;74(5):713-725.

157. Charousset C, Grimberg J, Duranthon LD, Bellaiche L, Petrover D, Kalra K. The time for functional recovery after arthroscopic rotator cuff repair: correlation with tendon healing controlled by computed tomography arthrography. Arthroscopy.

2008;24(1):25-33.

158. Narasimhan R, Shamse K, Nash C, Dhingra D, Kennedy S. Prevalence of subscapularis tears and accuracy of shoulder ultrasound in pre-operative diagnosis. Int Orthop. 2016;40(5):975-979.

159. Zaman SU, Syed HM. Arthroscopic Repair of an Isolated Teres Minor Tear. A Case Report. 2016;6(2):e40.

160. Itoi E. Rotator cuff tear: physical examination and conservative treatment. J Orthop Sci. 2013;18(2):197204.

161. Kikukawa K, Ide J. The appearance of the teres minor muscle in rotator cuff tears. J Shoulder Elbow Surg.23(5):603.

162. Tokish JM, Alexander TC, Jr. Implementation of a Comprehensive Orthopaedic Registry System. Instr Course Lect. 2016;65:593-599.

163. Mall NA, Lee AS, Chahal J, et al. An evidencedbased examination of the epidemiology and outcomes of traumatic rotator cuff tears.

Arthroscopy. 2013;29(2):366-376.

164. Pedowitz RA, Yamaguchi K, Ahmad CS, et al.

Optimizing the management of rotator cuff problems. J Amer Acad Orthop Surgeons.

2011;19(6):368-379.

165. Neer CS, 2nd, Craig EV, Fukuda H. Cuff-tear arthropathy. J Bone Joint Surg Am. 1983;65(9):12321244.

166. Khan Y, Nagy MT, Malal J, Waseem M. The Painful Shoulder: Shoulder Impingement Syndrome. Open Orthop J. 2013;7:347-351.

167. Scheuermann R, Behrens P, Egbers H, Havemann D. Early functional treatment of the injured shoulder supported by an active shoulder bandage.

Aktuelle Traumatol. 1991;21(2):58-63.

168. Ghroubi S, Chaari M, Elleuch H, Guermazi M, Baklouti S, Elleuch MH. [Functional and quality of life outcome of non-operated rotator cuff tears].

Ann Readapt Med Phys. 2008;51(9):714-721.

169. Carleton HA, Webb ML. The case report in context.

Yale J Biol Med. 2012;85(1):93.was this difference

determined to be clinically significant (p<0.001).111 Additionally, there were four studies that compared non-operative treatment to surgical cohorts, and though all of these reported improvements in both groups, three of them demonstrated statistically significant improvements in pain (p<0.05; 95% CI) in the surgical groups.48,49,52 None of these met clinical significance. The remaining study reported no statistical difference between

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Appendix A. Search strategies

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Appendix B. Summary table of scope of reviews

Appendix C. Results and conclusions of reviews

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Appendix D. Outcomes for Pain

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Appendix D. Outcomes for Pain (continued)

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Appendix E. Outcomes for range of motion

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Appendix E. Outcomes for range of motion (continued)

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Appendix F. Outcomes for strength

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Appendix F. Outcomes for strength (continued)

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Appendix G. Outcomes for Function

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Appendix G. Outcomes for Function (continued)

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Appendix G. Outcomes for Function (continued)

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Appendix H. Components of conservative management interventions for included studies

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Appendix H. Components of conservative management interventions for included studies (continued)

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Appendix H. Components of conservative management interventions for included studies (continued)

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IJSPT

SYSTEMATIC REVIEW

THE EFFECT OF BRACING AND BALANCE TRAINING ON ANKLE SPRAIN INCIDENCE AMONG ATHLETES: A SYSTEMATIC REVIEW WITH META-ANALYSIS Rachel Bellows, PT, DPT, OCS1 Christopher Kevin Wong, PT, PhD, OCS2

ABSTRACT Background: Ankle sprains are common musculoskeletal injuries in the athletic population that have been addressed with prevention strategies that include bracing and balance training. Many authors have examined ankle sprain incidence after bracing or balance training in athletes at different levels of competition and in various sports. No systematic review has analyzed the results of both interventions.

Purpose: The purpose of this review was to compare the effect of balance training and bracing in reducing the incidence and relative risk of ankle sprains in competitive athletes, with or without prior injury, across different sports.

Design: Systematic review, with meta-analysis Methods: A literature search of four databases was conducted for randomized control trials that reported ankle sprain incidence published from 2005 through 2016. Included articles studied high school, college, or professional level athletes with or without a history of a prior sprain, who received bracing or balance training as an intervention compared to a non-intervention control group. Methodological study quality was assessed by two reviewers using the PEDro scale, with scores â&#x2030;Ľ5 considered moderate quality. Group incidence and relative risk were determined to assess the preventative effect of bracing or balance training compared to control.

Results: From 1832 total citations, 71 full-text articles were reviewed, and eight articles were included in the study. Methodological quality of the available evidence contained in the systematic review was moderate. Five studied the effect of balance training, two studied the effect of bracing, and one studied the effect of bracing and balance training compared to the control condition. In all eight studies, athletes in the control condition did not receive any intervention. Athletes who wore braces had fewer ankle sprains (p=0.0037) and reduced their risk of sprains by 64% (RR=0.36) compared to controls, based on analysis of 3,581 subjects. Athletes performing balance training had fewer ankle sprains (p=0.0057) and reduced their risk by 46% (RR=0.54) compared to controls, based on analysis of 3,577 subjects.

Conclusion: The findings of the current systematic review and meta-analysis support the use of bracing and balance training to reduce the incidence and relative risk of ankle sprains in athletic populations. Clinicians can utilize this information to educate their patients on wearing a brace or performing balance training exercises to decrease the risk of an ankle sprain.

Level of evidence: Level 1a Keywords: Athlete, ankle sprain, balance training, bracing, incidence, prevention

1

Stanford Health Care, Ortho-Sport Physical Therapy, Redwood City, CA, USA 2 Neurologic Institute, Columbia University, New York, NY, USA. The authors have no conďŹ&#x201A;icts of interest to disclose. No funding was used for the completion of this review.

CORRESPONDING AUTHOR Rachel Bellows, PT, DPT, OCS Stanford Health Care 450 Broadway Street Redwood City, CA 94063 E-mail: rbellows18@gmail.com

The International Journal of Sports Physical Therapy | Volume 13, Number 3 | June 2018 | Page 379 DOI: 10.26603/ijspt20180379

INTRODUCTION In the United States, approximately 23-25,000 ankles sprains occur daily, resulting in two billion dollars of health-care costs annually.1,2,3 Ankle sprains occur in sports that require quick direction changes, cutting movements, and rapid acceleration and deceleration4-7 and are one of the most common sport-related injuries. Inversion sprains comprise 80% of all cases.8 The National Electronic Injury Surveillance System for all ankles sprains admitted into American emergency departments reported 41% of the sprains originated from basketball, 9.3% from football and 7.9% from soccer. Higher level of activity and increased competition of high school, college, and professional team athletes increases an individual’s risk of injury. For example, college athletes are seven times more likely to suffer an ankle sprain than their intramural counterparts.3 More than half of high school athletes who sustain an ankle sprain return to play in less than one week.9 A 2008 systematic review found mechanical stability did not occur until at least 6-12 weeks following an ankle sprain, and a substantial percentage of subjects continued to have mechanical laxity and subjective complaints of instability up to one year after injury.10 Diagnostic imaging studies have found an increase in anterior talofibular ligament thickness of approximately 16% in those who have sustained a lateral ankle sprains compared to an uninjured ankle.

Increased ligament thickness can be attributed to scar tissue, which absorbs 60% less energy compared to healthy tissue and may be a factor in the high incidence of recurrent ankle sprains and chronic instability symptoms.11,12 After an ankle sprain, 35-73% report on-going symptoms of instability, decreased function, pain, and/or swelling;10, 13-20 and the risk of a subsequent sprain was 70% more likely.10 The risk for reinjury or early development of osteoarthritis and long-term disability after an ankle sprain makes preventing ankle sprains a priority.21 The high incidence of ankle sprains in the athletic population has motivated sports teams to implement prophylactic measures to decrease the risk of ankle sprains. During the 1980s and 1990s, multiple researchers investigated the impact of semirigid ankle bracing, such as lace-up ankle stabilizing orthoses (ASO), on injury prevention. Results from

one randomized control trial and two cohort studies found that semi-rigid bracing significantly reduced ankle sprain incidence in various athletic population.22-25 In 2001, a Cochrane Library systematic review found limited evidence to support balance training in reducing ankle sprains; though good evidence suggested bracing could reduce ankle sprain incidence, especially for those with a prior sprain.7 Currently, few studies26,27 and no reviews have compared the impact of bracing versus balance training on the incidence of ankle sprains in a competitive athletic population. Most studies lack a control group, investigate a single team or include a single sport, leaving unclear what the most effective approach is for reducing the incidence of ankle sprains in a broader athletic population. Thus, the purpose of this review was to compare the effect of balance training and bracing in reducing the incidence and relative risk of ankle sprains in competitive athletes, with or without prior injury, across different sports.

METHODS Literature search and selection A search of the literature was conducted for English language articles published from 2005-2016 using the Cochrane Library, PubMed, Web of Science, and PEDro databases. The following medical subject headings (MeSH terms) and clinically relevant keywords were used individually and in Boolean combinations: “ankle,” “instability,” “sprain,” “chronic,” “recurrent,” “prevention,” “athlete,” “proprioception,” and “bracing.” Articles were included in this review if they met the inclusion criteria listed in Table 1. Articles were excluded if the study did not recruit athletes, had no control group, did not define intervention groups, or lacked end of the season or year follow-up. Citations were screened for relevance, full-text articles were reviewed for inclusion by the first author, and included articles were then reviewed by both authors to reach consensus for inclusion and exclusion criteria. Bias was assessed independently using the Pedro scale, a study quality assessment measure for randomized control trials, with disagreements resolved through discussion.

The authors operationally defined the following terms for this review: Athletes were considered individuals participating on competitive sports teams

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Table 1. Inclusion Criteria

at the high school, college, or professional level. An ankle sprain included an acute inversion/supination (lateral ankle), eversion/pronation (medial ankle), and/or dorsiflexion/eversion (high ankle/syndesmotic) event during sports participation causing injury associated with pain, swelling, and difficulty weight bearing that resulted in the athlete having to cease sports activity in a game or practice. Balance training, sometimes referred to as proprioceptive training, included static or dynamic exercises on one or two legs, on a variety of surfaces, with or without perturbations, and with eyes open or closed.

Ankle bracing was considered any type of orthosis applied specifically to the ankle joint; all types of taping were not considered as bracing in this review.

Data Analysis Incidence of ankle sprains in a season or year and relative risk were utilized to assess the effect of balance training and bracing treatments in preventing injury compared to no-treatment control. Data was extracted by the first author and independently confirmed by the second author. Chi-Square was used to analyze differences in incidence between athletes receiving bracing or balance training compared to no-treatment; relative risk, the risk ratio for ankle sprains in the treatment groups compared to the control groups, was calculated and illustrated in a forest plot (Figures 2 & 3).

Literature Synthesis and Methodological Quality Electronic database searches yielded 1,832 articles.

After citations were screened for relevance, a total of 71 full-text articles were reviewed for inclusion criteria. Sixty-three articles were excluded based on the inclusion criteria, leaving eight articles for review as presented in the PRISMA diagram (Figure 1). The PEDro scale was utilized to assess the methodological quality of each study (Table 2) with scores â&#x2030;Ľ5 considered to be moderate methodological quality.28 Five studies compared balance training to a control group, two studies compared bracing to a control group, and one study compared balance training, bracing (each separately) to controls (Table 3).26,29-35 RESULTS Study Quality Overall, the quality of the combined evidence was moderate with all studies scoring â&#x2030;Ľ5 on the 10-point PEDro scale.28 Scores ranged from 5 (three studies)29,30,33 to 8 (one study), 32 with four studies scoring a 6 or a 7.26,31,34,35

Figure 1. PRISMA Diagram.

Description of Included Studies The included studies reported results for a total of 7,195 athletes (36% female, 64% male) ranging in levels of competition from high school to professional sports leagues. 26,29-35 The median age was 20 years. The proportion of females in the bracing group (42%) was less than in the balance training group (56%). For the six of eight studies that defined specific sport participation, the proportions of athletes participating in each sport were: 36%

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Figure 2. Effects of Balance Training on the Relative Risk of Ankle Sprains.

Figure 3. Effects of Bracing on the Relative Risk of Ankle Sprains.

basketball, 29% football, 16% volleyball, and 1% soccer. One study reported that the athletes participated in either soccer or basketball without specific numbers;29 another did not specify the sports that the athletes participated in.32 The incidence of ankle sprains during sport activity was reported, although each study varied in the method of determining the occurrence of an ankle sprain. In seven of eight studies, medical professionals (athletic trainers, physical therapists and/or physicians) performed a physical exam to determine if a sprain had occurred.26,29,31-35 In one study, athletes used self-reported ankle sprain occurrences on forms that were assessed by two physiciansâ&#x20AC;&#x201D;blinded to the studyâ&#x20AC;&#x201D;to decipher if the subjective reports were consistent with an ankle sprain diagnosis.33 Bracing Treatment Two of the three studies found that groups receiving bracing reported significantly lower incidence and risk of ankle sprains during athletic activity.34-35 The

bracing group (n=20) in the Mohammadi study sustained fewer sprains than the control group (n=20), though this did not reach a statistically significant difference (Figure 2).26 The three braces utilized in the studies were the McDavid Ultralight34 brace (McDavid Inc, Woodridge, Illinoise), Don-Joy Ankle Stabilizing35 brace (Don-Joy Inc, Vista, California), and Sports Stirrup26 brace (Aircast Inc, Summit, New Jersey), which are shown in Appendix B. From the 3,581 combined subjects from the bracing group and control group, 432/1753 athletes sustained an ankle sprain when wearing a brace, compared to 529/1828 athletes spraining their ankle not wearing a brace.

Overall, athletes wearing ankle braces had a significantly lower incidence of ankle sprains (p=0.0037) and a 64% reduced risk of ankle sprains (RR=0.36) compared to no-treatment control. (Table 3).

Balance Training Treatment Five of the six studies found a significant decrease in the incidence of ankle sprains for athletes

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Table 2. Methodological Quality Assessment, per Pedro Scale

performing balance training compared to no-treatment controls.26,29,30,32,33 Three studies found similar values of reduced ankle sprains, ranging from 35-38%. 29,32,33 Although each of the articles utilized different balance exercises, progressions and time frames in how long to perform the exercises, they used similarly designed balance progressions to progressively challenge the visual, somatosensory, vestibular, and musculoskeletal systems. The exercises were progressed by decreasing the base of support from double to single limb stance, eyes open to eyes closed conditions, changing the surface from stable to unstable and adding perturbations, such as upper extremity motions (Appendix A). Of the combined 3,577 subjects, 178/1867 athletes in the balance training group sustained an ankle sprain compared to 274/1710 in the control group. Athletes performing balance training exercises had a significantly lower incidence of ankle sprains (p=0.0057) and a 46% reduced risk of an ankle sprain (RR=0.54) compared to no-treatment controls. (Table 3) DISCUSSION The results of this systematic review with metaanalysis indicate that athletes with or without a prior sprain receiving either bracing or balance training show reduced incidence and relative risk of ankle sprains compared to no-treatment controls. The results of this review demonstrated that bracing reduced the risk of a sprain by 64%, consistent with

a previous systematic review that examined six randomized control trials and showed bracing reduced ankle sprains by 69%.36 The one study that compared bracing, balance training, and no-treatment was the smallest study (n=80) reviewed and both bracing and balance training reduced injury incidence compared to controls, without significant difference between bracing and balance training.26 The combined results from the three relevant studies indicate that balance training reduced risk of injury between 35-38% compared to no-treatment, which is consistent with an earlier review that found a 36% risk reduction for those athletes that participated in balance training.21 Two of the bracing studies also examined other lower extremity injuries occurrences in the bracing and control groups. 34,35 Interestingly, although ankle bracing decreased the risk of ankle injury by 64% compared to not bracing, the decreased risk for any lower extremity injury was only 25.5% compared to no treatment, leaving open the possibility that bracing at the ankle can contribute to other lower quarter injuries.34,35 Although not examined in this systematic review, the distant effects of ankle bracing should be considered. McGuine et al34 found an increased rate of injury in lower extremity injuries by 85% in the basketball players that braced compared to controls. Of these injuries, 51% were acute muscle or tendon strains in the lower leg (gastrocnemius, peroneals and Achilles), upper

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Table 3. Description of Included Studies

leg (quadriceps, hip flexor and hamstring) and hip/ pelvis (adductors, gluteals). Additionally, 17.9% of the basketball players that braced at the ankle sustained an acute knee injury, in comparison to 8.8% of basketball players who did not brace. The two most common knee injuries were medial collateral

ligament and anterior cruciate ligament sprains or tears.34 During peak dorsiflexion for a cutting task similar to basketball, lace-up ASO and ankle hinge braces increase peak internal rotation angle at the knee by approximately two degrees. Additionally, lace-up ASOs increase anterior knee forces during

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deceleration and increase knee compression forces during the peak ankle dorsiflexion moment during a cutting task.37 These increased knee forces may contribute to the higher incidence of knee injuries in athletes that braced compared to the controls in the two bracing studies.34,35 While bracing does reduce the risk of ankle sprains, an unintended consequence may be other lower extremity injuries.

The studies reviewed for the current systematic review used a variety of balance training exercises. Notable was a general progression to challenge multiple combinations of the four systems that influence postural control, including the musculoskeletal, visual, somatosensory, and vestibular systems. Conflicting (i.e. providing conflicting sensory input) one of the systems challenges another system to work harder to achieve upright balance. For example, the musculoskeletal and visual systems are challenged through the use of standing on an unstable surface with head turning, which provides conflicting information between the somatosensory and vestibular systems.38 It has been found that training on an unstable surface decreases the proprioceptive reflex, which indicates an increased reliance on visual and/or vestibular information to achieve balance.39 In the present review, the balance training exercises were progressed to incorporate the upper extremity and trunk movements in functional activities that simulate sports specific tasks. By having the athlete balance on an unstable surface, especially with perturbations, the visual system is challenged to compensate and the ankle is forced to respond in multiple planes and ranges.

Overall, both bracing and balance training demonstrated a significant effect on preventing ankle sprains in athletes from multiple sports at the competitive high school, college, and professional levels.

The incidence of ankle sprains among athletes performing balance training was 10.6% while the incidence of sprains among athletes wearing braces was more than double at 24.6%. However, the relative risk for athletes wearing braces compared to controls was lower (RR=0.36) than the relative risk for athletes after balance training compared to controls (RR=0.54). Only the smallest study representing 1.1% of the pooled sample directly compared bracing to balance training, preventing any firm conclusions from being drawn with respect to which

intervention was most effective. In addition, different levels of competition may present athletes of different levels of skill development, varied practice times and exposure to injury; however, there were insufficient data to compare the incidence rates per exposure among the different levels. Finally, most studies did not differentiate between athletes who did or did not have prior ankle sprains, precluding analysis between subgroups.

Limitations of this systematic review include heterogeneity of the included studies with respect to different sample sizes, statistical reporting, specific sport, competition levels, exercise protocols, and the orthoses that were utilized. In addition, this type of study poses challenges such as tracking subjects from large samples over long periods of time, lack of blinding and inconsistent compliance, and use of self-reported injuryâ&#x20AC;&#x201D;which may miss more minor ankle sprains that did not result in reduced participation. Future research should investigate differences between subpopulations including athletes with and without prior injury or who those compete at different levels to add information regarding the effect of these interventions.

CONCLUSIONS The results of this systematic review and metaanalysis demonstrate moderate quality of evidence for balance training or bracing to decrease the incidence and reduce the relative risk of ankle sprains in competitive athletes. Although it remains unclear whether bracing, balance training, or both combined provide the most protective effect, the results of this study may enhance clinical decision-making regarding the use of ankle braces and balance training to prevent ankle sprains among the athletic prevention.

REFERENCES 1. McLeod MM, Gribble PA, Pietrosimone BG. Chronic ankle instability and neural excitability of the lower extremity. J Athl Train. 2015:50(8):847-853.

2. Mickel TM, Bottoni CR, Tsuji G, et al. Prophylactic bracing versus taping prevention of ankle sprains in high athletes: A prospective, randomized trial. J Foot Ankle Surg. 2006;25(6):360-365.

3. McCriskin BJ, Cameron KL, Orr DJ, et al.

Management and prevention of acute and chronic lateral ankle instability in athletic patient populations. World J Orthop. 2015;6(2):161-171.

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4. American Academy of Orthopaedic Surgeons. The foot and ankle. American Academy of Orthopaedic Surgeons website. Available at http://orthoinfo.aaos. org/fact/hr_report.cfm?thread_ id=100&topcategory=Foot.

5. Bahr R. Can we prevent ankle sprains? In: MacAuley D, Best TM, eds. Evidence-Based Sports Medicine.

London, England: BMJ Books; 2002:470-490.

6. Garrick JG. The frequency of injury, mechanism of injury, and epidemiology of ankle sprains. Am J Sports Med. 1977;5:241-242.

7. Handoll HHG, Rowe BH, Quinn KM, et al.

Interventions for preventing ankle ligament injuries.

Cochrane Database Syst Rev. 2001;3:CD000018.

Available at http://gateway2.ovid.com/ovidweb.cgi 8. Fong DT, Hong Y, Chan LK, et al. A systematic review on ankle injury and ankle sprain in sports.

Sports Med. 2007;37(1):73-94.

9. Nelson AJ, Collin CL, Yard EE et al. Ankle injuries among United States high school sports athletes.

2005-2006. J Athl Train. 2007;42(3):381-387.

10. Hubbard-Turner T, Turner M. Physical activity levels in college students with chronic ankle instability. J Athl Train. 2015;50(7):742-747.

11. Liu K, Gustavsen G, Royer T et al. Increased ligament thickness in previously sprained ankles as measured by musculoskeletal ultrasound. J Athl Train. 2015;50(2):193-198 12. Frank C, Amiel D, Woo SL, Akeson w. Normal ligament properties and ligament healing. Clin Orthop Related Res. 1985;196:15-25 13. Lohrer H, Nauck T, Gehring D, et al. Differences between mechanically stable and unstable chronic ankle instability subgroups when examined by arthrometer and FAAM-G. J Orthop Surg Res. 2015;10:32. DOI: 10.1186/s13018-015-0171-2 14. Gabriner ML, Houston MN, Kirby JL, et al.

Contributing factors to star excursion balance test performance in individuals with chronic ankle instability. Gait Posture. 2015;41:912-916.

15. Springer S, Gottlieb U, Moran U, et al. The correlation between postural control and upper limb position sense in people with chronic ankle instability. J Foot Ankle Res. 2015;8:23. DOI: 10.1186/ s13047-015-0082-9 16. Ridder R, Willems TM, Vanrenterghem J, et al.

Effects of a home-based balance training protocol on dynamic postural control in subjects with chronic ankle instability. Int J Sports Med. 2015;36:596-602.

17. Hoch MC, Farwell KE, Gaven SL et al. Weightbearing dorsiflexion range of motion and landing biomechanics in individuals with chronic ankle instability. J Athl Train. 2015;50(8):833-839.

18. Wikstrom EA, Brown CN. Minimum reporting standards for copers in chronic ankle instability research. Sports Med. 2014;44:251-268.

19. Guillo S, Bauer T, Lee JW, et al. Consensus in chronic ankle instability: Aetiology, assessment, surgical indications and place for arthroscopy.

Orthop Traumatol Surg Res. 2013;99S:S411-S419.

20. Webster KA, Gribble PA. Functional rehabilitation interventions for chronic ankle instability: A systematic review. J Sport Rehabil. 2010;19:98-114.

21. Hübscher M, Zech A, Pferifer K, et al.

Neuromuscular training for sports injury prevention: A systematic review. Med Sci Sports Exerc.

2010;42(3):413-421.

22. Greene TA, Hillman SK. Comparison of support provided by a semi-rigid orthosis and adhesive ankle taping before, during and after exercise. Am J Sports Med. 1990;18:498-506.

23. Rovere GD, Clarke TJ. Yates CS et al. Retrospective comparison of taping and ankle stabilizers in preventing injuries. Am J Sports Med. 1988;16:228233.

24. Surve I, Schwellnus MP, Noakes T et al. A fivefold reduction in the incidence of recurrent ankle sprains in soccer players using the Sport-Stirrup orthosis.

Am J Sports Med. 1994;22:601-606.

25. Gross MT, Liu HY. The role of ankle bracing for prevention of ankle sprain injuries. J Orthop Sports Phys Ther. 2003;33:572-577.

26. Mohammadi F. Comparison of 3 preventive methods to reduce the recurrent of ankle inversion sprains in male soccer players. Am J Sports Med. 2007;35(6):922926.

27. Janssen K, van Mechelen W, Verhagen E. Bracing superior to neuromuscular training for the prevention of self reported recurrent ankle sprains: a three-arm randomized controlled trial. Br J Sports Med. 2014;48:1235-1239 28. Moseley AM, Herbert RD, Sherrington C and Maher CG (2002). Evidence for physiotherapy practice: A survey of the physiotherapy Evidence Database (PEDro). Australian J Physiother. 48:43-49 29. McGuine TA, Keene JS. The effect of a balance training program on the risk of ankle sprains in high school athletes. Am J Sports Med. 2006;34(7):11031111.

30. Verhagen EALM, Van Tulder M, Van der Beek AJ, et al. An economical evaluation of a proprioceptive balance board training program for the prevention of ankle sprains in volleyball. Br J Sports Med. 2005;39(2):111-115.

31. Emery CA, Rose SM, McAllister JR, et al. A prevention strategy to reduce the incidence of injury

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32.

33.

34.

35.

in high school basketball: A cluster randomized controlled trial. Clin J Sport Med. 2007;17(1):17-24.

Hupperets MD, Verhagen EA, Mechelen MV. Effect of unsupervised home based proprioception training on recurrences of ankle sprains: randomized control trial. Br Med J. 2009;339:b2684.

Eils E, Schrรถter R, Schrรถder M, et al. Multistation proprioceptive exercise program prevents ankle injuries in basketball. Med Sci Sports Exerc.

2010;42(11):2098-2105.

McGuine TA, Brooks A, Hetzel S. The effect of lace-up braces on injury rates in high school basketball players. Am J Sports Med. 2011;39(9):18401848.

McGuine TA, Hetzel S, Wilson J et al. The effect of lace-up ankle braces on injury rates in high school football players. Am J Sports Med. 2012;40(1):49-57.

36. Dizon JM, Reyes JJ. A systematic review on the effectiveness of external ankle supports in the prevention of inversion ankle sprains among elite and recreational players. J Sci Med Sport. 2010;13:309317.

37. Klem NR, Wild CY, Williams SA et al. Effect of external ankle support on ankle and knee biomechanics during the cutting maneuver in basketball players. Am J Sports Med. Epub 2016 Nov 21. DOI: 10.1177/0363546516673988 38. Rogers M, Page P, Takeshima N. Balance training for the older athlete. Int J Sports Phys Ther. 2013;8(4):517530.

39. Van Dieen J, van Leeuwen M, Faber G. Learning to balance on one leg: motor strategy and sensory weighting. J Neurophysiol. 2015;114(5):2967-2982

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Appendix A Exercises and variations of the balance training programs adapted from the available literature

Appendix B Ankle braces utilized in the literature

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IJSPT

ORIGINAL RESEARCH

COMPARISON OF THE ‘BACK IN ACTION’ TEST BATTERY TO STANDARD HOP TESTS AND ISOKINETIC KNEE DYNAMOMETRY IN PATIENTS FOLLOWING ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION Jay R. Ebert, PhD1,2 Peter Edwards, MSc1,2 Justine Currie, BSc1 Anne Smith, PhD3 Brendan Joss, PhD2 Timothy Ackland, PhD, FASMF1 Jens-Ulrich Buelow, MD, FRACS4 Ben Hewitt, MBBS, FRACS5

ABSTRACT Background: Limb symmetry after anterior cruciate ligament reconstruction may be evaluated using maximal strength and hop tests, which are typically reported using Limb Symmetry Indices (LSIs) which may overestimate function.

Purpose: The purpose of this study was to compare the Back in Action (BIA) test battery to standard hop and muscle strength tests used to determine readiness to return to sport (RTS).

Study Design: Prospective cohort.

Methods: Over two test sessions, 40 ACLR patients were assessed at a mean 11.3 months post-surgery. Initially, participants completed the 6 m timed hop and the single, triple and triple crossover hops for distance, and isokinetic knee extensor and flexor strength assessment. The second session involved completion of the BIA battery, including stability tests, single and double leg countermovement jumps (CMJ), and plyometric, speedy jump, and quick feet tests. Pass rates for test batteries were statistically compared, including the BIA, a four-hop battery (≥90% LSI in every one of the four hop tests) and a combined 4-hop and strength battery (≥90% LSI in every one of the four hop tests, as well as ≥90% for both peak knee extensor and flexor strength). LSI differences between the four standard hop tests and the BIA single limb functional tests (the single limb CMJ and the speedy jump test) were evaluated.

Results: Significantly less participants passed the BIA battery (n=1, 2.5%), compared with the four-hop test battery (n=27, 67.5%) (p<0.001) and the four-hop test and isokinetic strength battery (n=17, 42.5%) (p<0.001). Collectively, LSI’s for the standard hop tests were significantly higher than the BIA functional single limb tests (difference = 12.9%, 95% CI: 11.1% to 14.6%, p<0.001).

Conclusion: The BIA test battery appears to include some single limb functional tests that are more physically challenging than standard hop and isokinetic strength tests, highlighted by the significantly lower mean LSI’s during the single limb BIA tests and the lower pass rate when employing the BIA protocol.

Level of Evidence: Level 4, case series.

Key words: Anterior cruciate ligament, return to sport, limb symmetry index, single limb hop test, isokinetic dynamometry.

1

School of Human Sciences, University of Western Australia, Crawley, Western Australia 2 HFRC, Nedlands, Western Australia 3 The School of Physiotherapy and Curtin Health Innovation Research Institute, Curtin University, Bentley, Perth, Western Australia.

4 Perth Orthopaedic and Sports Medicine Centre, West Perth, Western Australia 5 Orthology, Suite 1, West Perth, Western Australia Conflict of Interest Statement: No benefits in any form have been received or will be received from a commercial party related to the subject of this article.

Sources of funding: Nil. Acknowledgements: We thank Surgical Realities for providing the Back in Action unit for this research.

CORRESPONDING AUTHOR Dr Jay R. Ebert The School Human Sciences (M408) The University of Western Australia 35 Stirling Highway, Crawley, 6009, Western Australia Phone: +61-8-6488-2361 Fax: +61-8-6488-1039 E-mail: jay.ebert@uwa.edu.au

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INTRODUCTION Anterior cruciate ligament (ACL) tears are common,1 with the estimated rate of re-injury at 15%.2 In the 24 months following ACL reconstruction (ACLR) patients are almost six times more likely to re-tear compared to a healthy cohort,3 which remains important given individuals are often informed they can return to sport (RTS) well before 12 months.4 A patient’s readiness to RTS and/or re-injury risk should they do so, may be influenced by a range of pre-operative (age, pre-operative rehabilitation, knee extension and neuromuscular control), intraoperative (ACLR graft choice) and post-operative (rehabilitation and psychological factors) factors.5 One major reported reason is the patient’s inability to regain sufficient muscle function and strength.6,7 Recent authors have highlighted the increased rate of re-injury in patients who RTS without adequate strength and functional symmetry, derived from tests such as peak isokinetic knee strength evaluation and single-legged hop performance.8,9 Single limb hop tests may be used to evaluate functional symmetry prior to a RTS, often combined in the form of a hop test battery.10 It has been recommended that these functional hop assessments be complemented along with measures of peak knee extensor and flexor strength.6,11 The outcomes of hop tests are generally reported via Limb Symmetry Indices (LSIs),7 which present the physical status of the operated limb as a percentage of the non-operated limb. Research has revealed an increased re-injury risk if patients do not meet strength and hop test LSIs of at least 90%,8,9 especially those returning to sports involving hard pivoting, cutting, running, twisting and/or turning maneuvers. However, recent research suggests that LSIs frequently overestimate knee function,12 raising concerns about whether reported LSI cut-offs (i.e.

90%) are high enough to pass these physical tests and/or the tests employed are stringent enough to adequately evaluate lower limb function before RTS. Single limb hop tests have been criticized for not sufficiently evaluating functional capacity in ACLR patients,13 while maximal knee extensor and flexor strength measures are not functional movements reflective of a sporting situation. Therefore, various test batteries have been developed in an attempt to create a more comprehensive measure of strength, function and readiness to RTS.8,9,14-16

Recently, a standardized test battery combining various subtests (power, speed, agility, coordination, unilateral cutting and side-to-side movements) was developed, with the intention of determining physical readiness to RTS.17,18 This seven-test battery (‘Back in Action’ - BIA, CoRehab, Trento, Italy) allows for LSIs to be calculated for the individual single limb test components, but further permits comparisons of every test with that of an age and gender matched cohort. Therefore, this battery may include single limb functional tests that may be more physically demanding than standard single limb hop tests. Furthermore, it may overcome some of the existing limitations when employing LSIs to report performance outcomes, such as the inability to evaluate the potential de-conditioning of the non-operated side after surgery (this issue may be bypassed if the comparison is instead made to that of an age and gender matched normative cohort, rather than the non-operated limb).7 The BIA test battery has not been compared to routinely employed functional assessments undertaken for the same purpose (determining readiness to RTS), including tests of functional hop capacity and muscle strength.

The purpose of this study was to compare the BIA test battery to standard hop and muscle strength tests used to determine readiness to return to sport (RTS). Firstly, it was hypothesized that significantly less patients would pass the more comprehensive BIA test battery, compared with a standard fourhop test battery (≥90% LSI on all hops), or a combined four-hop and strength test battery (≥90% LSI on all hops, as well as peak isokinetic quadriceps and hamstrings strength). Secondly, it was hypothesized that group mean LSIs would be significantly higher across the four standard hop tests, compared with the more physically demanding single limb functional tests included in the BIA test battery (the single limb CMJ and the speedy jump test).

METHODS Subjects A total of 40 participants (25 men, 15 women) were evaluated at a mean of 11.3 months (range: 11-12) after ACLR utilizing a hamstring autograft. Individuals taking any analgesic or anti-inflammatory medications were excluded from this study. Furthermore, any

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patient experiencing any persistent pain and/ or perceived disability with their operated knee, contralateral knee and/or lower limbs in general, that they felt could affect their ability to participate well in the testing batteries, were excluded from study participation. Patients were also excluded if they had undergone any other ipsilateral or contralateral lower limb surgery, prior to their ACLR. For this study, only patients actively engaging in Level 1 (participation 4-7 days/week) or Level 2 (participation 1-3 days per week) activities that included jumping, hard pivoting, cutting, running, twisting and/or turning sports prior to their injury were included, as reported via the Noyes Activity Score (NAS).19 Patients who were not planning to return to the aforementioned NAS levels were further excluded.

The mean age of participants included in this study was 23.8 years (range: 15-43) and body mass index was 24.3 (range: 19.6-31.9). A total of 11 participants underwent concomitant meniscectomy. While a detailed review of each patient’s rehabilitation was undertaken at the time of initial review, patients recruited for this study had undertaken rehabilitation through different rehabilitation clinics and under guidance from varied therapists and, therefore, they had not embarked on a standardized rehabilitation protocol. While this topic is irrelevant to the aims of the current study, all patients had been discharged from their orthopaedic surgeon’s care and cleared to RTS from their individual practitioner.

Despite this, upon initial consultation it was clear that only 10 patients (25%) had undergone any formal physical testing including the standard hop tests and/or knee strength measures employed in this study prior to RTS clearance. At the time of testing, 32 patients (80%) had already returned to the aforementioned Level 1 or 2 NAS levels. The other eight patients (20%) had not yet returned for reasons that included: 1) they had only recently been ‘cleared’ by their individual practitioner, 2) it was the ‘offseason’ period of their chosen sport and/or 3) other engagements/commitments had more recently interrupted their planned RTS. Ethics approval was obtained from the relevant hospital ethics committee. The written informed consent was obtained by all participants prior to testing, and the rights of all participants were protected.

This study consisted of two testing sessions undertaken within a private rehabilitation clinic, a mean 6.5 days (range 5-9 days) apart by a single therapist.

Participants were asked to refrain from any strenuous exercise in the 48 hours prior to each evaluation, and every effort was made to undertake the two testing sessions for each patient at a similar time of day.

Testing Session 1 Firstly, a subjective patient review was undertaken, including the collection of patient demographics, occupational and current activity history employing the NAS,19 as well as completion of the International Knee Documentation Committee (IKDC) Subjective Knee Evaluation Form.20 The IKDC is a kneespecific outcome measure evaluating patientperceived symptoms, physical function and sporting activity, and is scored from 0-100 with higher scores indicating a better score. Secondly, participants underwent the six-minute walk test (6MWT),21 employed as a standardized warm up that equally prepared both the operated and non-operated lower limbs. Participants were then offered an optional period of 5-10 minutes to perform any stretches they wanted, which were not standardized and varied between participants based on their own individual preferences and warm up routines.

Thirdly, participants underwent a four-hop test battery performed in the following order: 1) the single hop for distance, 2) the 6 m timed hop, 3) the triple hop for distance, and 4) the triple crossover hop for distance.10 A custom made mat (6m in length, 15cm in width) was created for the hop tests as described previously,10 which contained an embedded tape measure to accurately record distance measures. For the 6 m timed hop, a countdown (i.e. “3, 2, 1, go”) was provided by the tester positioned at the end of the 6 m distance, with the timer started upon initial patient movement and stopped when the patient passed the 6 m mark. Patients were given a verbal description of the individual test prior to each hop test, and were permitted two to three warm-up hops on each limb (of the single hop for distance) prior to initiating the hop test battery. They were then provided with a single practice attempt on each limb for each of the following three hop tests, immediately prior to the individual test. All hop tests were initially performed

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on the unaffected limb, and then alternated between the unaffected and operated limbs. A total of four, two, three and three test trials were collected for the single, 6 m timed, triple and triple crossover hop test, respectively. Previous research has reported three test efforts (one practice and two test efforts) for each of the four hop tests,10 though anecdotally it has been seen that often the fourth effort for the single hop for distance is required to ensure a peak is attained, while two test efforts for the 6 m timed hop is sufficient. The best effort for each standard hop test was used in the analysis. All distance hop tests were measured to the nearest 0.01 m and the 6 m timed hop to the nearest 0.01 sec using a stopwatch.

Finally, isokinetic strength of the quadriceps and hamstrings muscle groups was assessed using an isokinetic dynamometer (Isosport International, Gepps Cross, South Australia). Peak concentric knee extension and flexion strength were measured through a range of 0-90˚ of knee flexion, at a single isokinetic angular velocity of 90°/s. In total, three isokinetic strength trials were undertaken on each limb. Each of the three test trials consisted of four repetitions: three low intensity repetitions of knee extension and flexion, immediately followed by one maximal test effort. The first test trial was initiated on the unaffected limb, and then alternated between the unaffected and operated limbs until the six test trials (i.e. three on each limb) were completed.

Participants were given adequate rest in between all hop and strength testing trials to minimize fatigue, though this was not standardized, and based upon the patient’s readiness to proceed.

Testing Session 2 The second testing session consisted of an identical warm up as session 1, consisting of the 6MWT and optional stretching session, followed by a recently developed and published ACLR test battery (the BIA test battery).17,18 The BIA test package comes complete with a laptop and software, accelerometer (Myotester, Myotest S.A., Sion, Switzerland) and waistband, MFT Challenge Disc (TST, Trend Sport Trading, Grosshöflein, Austria) and the Speedy Basic Jump Set (TST Trendsport, Grosshöflein, Austria). Procedures for the BIA test battery have been published,17,18 and consist of the double leg stability test, the single leg stability test, a double leg

counter-movement jump (CMJ), a single leg CMJ, a plyometric jump test (consisting of four consecutive plyometric jumps), the speedy jump test and the quick feet test, performed in the above order.17,18 These tests are outlined briefly below.

The double and single leg stability tests required participants to stand on the MFT Challenge Disc and balance to the best of their ability over a 20 s period.

Initially, participants were permitted time to familiarize with the board to nullify any learning effect.

The test required participants to maintain balance for 20 s, standing on two feet with the knees slightly flexed (Figure 1). During the trial, participants received instantaneous visual feedback via a computer screen, in which they were required to keep a marker centered within a target for as much of the 20 s time period as possible (i.e. this was instantaneous feedback on center of pressure). After familiarization with the balance board, participants were provided one practice trial, which was followed by two recorded test trials. This was then followed by a single leg balance test over a 20 s period (Figure 1), following the same protocols. The test was initiated on the unaffected limb (one practice, followed by two test trials), then followed by the operated limb as per the published test battery and dictated by the BIA software package.

The double leg CMJ employed the accelerometer provided with the BIA pack which was fixed firmly

Figure 1. The double (A) and single (B) leg balance tests undertaken as part of the Back in Action (BIA) test battery.

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Figure 2. The starting position required for the double (A) and single (B) counter-movement jumps, undertaken as part of the Back in Action (BIA) test battery. Participants were required to quickly ďŹ&#x201A;ex the knee(s) and jump as high as possible, landing in a controlled manner.

using a Velcro strap around the patientâ&#x20AC;&#x2122;s waist, just above the greater trochanter (Figure 2). Participants were instructed to jump as high and as fast as possible during a single jump, involving a quick bend at the knees and a forceful CMJ, jumping off both feet and landing in a controlled manner. For this test, the jump height (cm) and power output (W/kg) were measured via the accelerometer. An initial single practice jump was performed, followed by five individual recorded test trials, with a break in between each of the five individual test efforts. The best individual effort was employed in the analysis. This was followed by a single leg CMJ (Figure 2), initiated on the unaffected limb (one practice, followed by three individual test trials with a break in between) and followed by the operated limb. The accelerometer was fixed on the same side as the test (jump) leg, just above the greater trochanter. The plyometric jump test also employed the accelerometer, with participants instructed to perform four consecutive jumps off both limbs as high and as fast they could, involving a quick bend at the knees and forceful jumps, landing on both feet after each consecutive jump.

Participants were instructed to maximize jump

Figure 3. The speedy jump test undertaken as part of the Back in Action (BIA) test battery. Participants hopped on one leg as fast as they could through the 16-hop course.

height and speed, while minimizing ground contact time between jumps. The jump height (cm) for each of the four jumps were measured. An initial practice test was performed, followed by two test trials.

The speedy jump test required the Speedy Basic Jump Set which was used to create a pre-determined hop coordination course (Figure 3). This consisted of a series of 16 forward, backward and sideways single limb hops, whereby participants were informed that the aim was to perform the hopping course in the shortest time possible. For the hop course, all bars were 50 cm in length, while the height of each hop bar was set at 7 cm from the ground. The timer was initiated when the foot touched the ground in the first hop and was stopped when the foot touched the ground upon completion of the final hop. The test was initiated on the unaffected limb (one practice, followed by two test trials), then followed by the operated limb. The quick feet test also employed the Speedy Basic Jump Set. Participants were instructed

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Figure 4. The quick feet test undertaken as part of the Back in Action (BIA) test battery. Participants had to complete 15 full cycles in the shortest possible time, with each cycle starting with both limbs outside the rectangles (A) and then initiated by bringing the operated limb in (B), the unaffected limb in (C), the operated limb out (D) and the unaffected limb out (E).

to repeatedly step into and out of two rectangles side by side, moving one foot after the other, until 15 repetitions were completed (Figure 4). Participants were instructed to complete the test in the shortest possible time, without touching the barriers, initiating the test with their operated limb, followed by their unaffected limb. Participants were provided one practice trial, followed by two recorded test trials.

Development of the BIA test battery involved the evaluation of 434 healthy participants, who each underwent the seven tests.18 Therefore, while LSIs can be obtained for the individual single limb tests, the normative database also permits comparison of the patient to an age and gender matched unaffected cohort, without any history of lower limb injury or dysfunction. As defined by Hildebrandt et al.18 this cohort was stratified by gender and age category: Children (10-14 years), Youth (15-19 years), Young Adults (20-29 years) and Adults (30-50 years). Within each of these categories, the mean was considered the average (Norm) and half of the standard deviation was then repeatedly added or subtracted from this average to create five scoring categories: Very Weak (Norm – 1 SD), Weak (Norm – 0.5 SD), Norm, Good (Norm + 0.5 SD), Very Good (Norm + 1 SD). As per the BIA test battery, safety to RTS was indicated by a score of at least ‘Norm’ in all seven BIA tests; correspondingly, failure to reach this level in all seven tests was deemed failure of the BIA test battery.

Data and Statistical Analysis Firstly, LSIs were calculated for peak knee extensor and flexor torque, as well as all four standard hop tests undertaken in the first test session, and the single leg stability test, height in the single leg CMJ and time in the speedy jump test undertaken in the second test session as part of the BIA test battery. Where a higher score was indicative of better performance (e.g. peak knee flexor and extensor strength, single limb hops for distance, vertical height and power during CMJs), the LSI was calculated by dividing the best value derived from the operated limb by that of the non-operated limb and converting to a percentage. Where a lower score was indicative of better performance (e.g. 6 m timed hop, time on the speedy hop test and total excursion on the single leg stability test), the LSI was calculated by dividing the best value derived from the non-operated limb by that of the operated limb and converting to a percentage.

McNemar’s exact test for dependent proportions was used to statistically compare the pass rates between the testing batteries, including: (1) ≥90% LSI on all four hop tests, (2) ≥90% LSI on all four hop tests, as well as peak isokinetic quadriceps and hamstrings strength, and (3) the full BIA test battery. An a priori power calculation estimated that a sample of 40 provided 85% power to test the hypothesis that of 30 (75%) participants passing the four hop test, 10 or less would not pass a more stringent test (the BIA

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test battery). A multilevel linear model was used to test the difference between LSIs measured by the four standard hop tests (the 6 m timed hop and the single, triple and triple crossover hops for distance), versus the two single limb functional tests employed within the BIA test battery (the single limb CMJ and the speedy jump test). An a priori power calculation estimated that a sample of 40 provided over 97% power to test the hypothesis that the BIA single limb tests would be at least 5% lower than the four standard hop tests, assuming LSI test standard deviations of 10% and a correlation between tests of 0.6. Data were analysed using Stata/IC for Windows (StataCorp LP, TX USA) and statistical significance was determined at p<0.05.

The mean LSI was >90% for all four standard hop tests and peak isokinetic knee extensor and flexor strength, with the majority of patients ≥90% LSI for each test (Table 1). The mean LSI was <90% for all three single limb tests included in the BIA test battery, with the majority of patients <90% LSI for each test (Table 1). Collectively, the participants LSI’s for the four standard hop tests were significantly higher than those for the two BIA functional single limb tests (single leg CMJ and speedy jump test) (difference = 12.9%, 95% CI: 11.1% to 14.6%, p<0.001).

The number of patients within each category (Very Weak, Weak, Norm, Good, Very Good) for each test, compared with the age and gender matched normative cohort, are provided in Table 2.

RESULTS When employing the standard four-hop test battery and a RTS cut-off pass rate of ≥90% for all four hops, 27 participants (67.5%) passed. When combining the standard four-hop test battery with isokinetic knee flexor and extensor strength, and employing a RTS cut-off pass rate of ≥90% for all four hop and strength tests, a total of 17 participants (42.5%) passed. Significantly more participants passed the four-hop test in isolation than the four-hop test plus isokinetic strength testing (p=0.002). When employing the complete BIA test battery, only one participant (2.5%) passed all criteria required to RTS. Significantly more participants passed the four-hop test battery in isolation (p<0.001), and the four-hop test battery plus isokinetic strength testing (p<0.001), compared with the BIA test battery.

DISCUSSION ACLR is common,1 though a high incidence of re-tear following surgery has been reported.2 While several factors may contribute to re-injury risk, an important reason may be failure to regain muscle function and strength.6,7 The most important finding from this study was that the BIA test battery produced a significantly greater RTS fail rate in ACLR participants, when compared with standard testing batteries (including a combination of functional hop and peak muscle strength assessments).

Grindem et al.8 employed a RTS test battery that required patients to score >90% LSI for quadriceps strength and functional hop capacity, and demonstrated that the re-injury rate was higher for patients who RTS without meeting objective cut-offs

Table 1. Mean International Knee Documentation Committee (IKDC) Subjective Knee Evaluation scores, and mean Limb Symmetry Indices (LSIs – score for the operated limb as a percentage of the non-operated limb) for each of the single limb tests undertaken by participants.

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Table 2. The number (n) of participants in each category (compared to normative data) for the seven Back in Action (BIA) tests employed as part of the BIA test battery, including the double and single leg stability tests, the double and single leg countermovement jumps (CMJ) (absolute jump height and power), the plyometric jump (absolute jump height and contact time), the speedy jump test and the quick feet test. Within each of these categories, the patient was compared to the normative data and mean of the normative data was considered the average (Norm), with half of the standard deviation then repeatedly added or subtracted from this average to create five scoring categories: Very Weak (Norm – 1 SD), Weak (Norm – 0.5 SD), Norm, Good (Norm + 0.5 SD), Very Good (Norm + 1 SD).

(38.2%), versus those who did (5.6%). Similarly, Kyritsis et al.9 reported a four times greater re-injury risk in those who RTS after ACLR, if not meeting certain discharge criteria including >90% LSIs in three of the hop tests employed in the current study, as well as peak isokinetic quadriceps strength. While the present study did not evaluate re-injury rates associated with poor lower limb strength and/or functional symmetry, considering the requirement of >90% LSIs in hop and strength symmetry in existing test batteries, 17 participants (42.5%) in this study would have been considered physically ready to RTS. In comparison to the current findings, Toole et al.22 recently demonstrated an inability of many young patients already cleared to RTS, to pass similar RTS cut-offs as that employed in the current study.

Similar to the current study, the mean LSIs for hop and strength measures were all generally around or above 90%, though only 53% of patients were able to achieve ≥90% in all four standard hop tests, with only 13.9% able to score ≥90% in all four standard hop tests as well as peak isokinetic knee strength (they also included a score >90 on the IKDC). Another

recent study also demonstrated the high proportion of community-level patients already engaging (or seeking engagement) in sport who were <90% LSI on many of the standard hop and strength measures employed, when assessed at a mean 11.0 months (range 10-14) post-surgery.23 Therefore, even with more conventional physical testing methods, these combined results are alarming particularly given the association between re-injury and a failure to meet existing reported cut-offs in these tests.

Only one patient passed the full BIA test battery, and the almost universal failure rate was significantly higher than a battery consisting of standard functional hop tests, even when supplemented with peak isokinetic strength testing. Comparison of participants in all tests (operated and non-operated limbs) to a healthy age and gender matched cohort proved the contributing factor in overall failure rates of the BIA battery. An argument could be made to suggest that the BIA test battery is too rigorous and not realistically attainable, given the low pass rate.

The authors of this study would disagree, given the anecdotal evidence of healthy subjects (of varied

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ages and activity levels) consistently passing the battery, as well as the fact that the threshold required to pass each of the seven tests is relatively low, given each is based on attaining an ‘average’ score.

When considering the single limb CMJ employed in the BIA test battery, 29 participants were below average on the operated limb, while 15 participants were still below average on the non-operated limb.

Studies have shown that reduced strength may occur in the non-operated limb after ACLR.24,25 Whether this was pre-existing or a result of the lengthy period of relative inactivity post-surgery, the true deterioration after surgery and the contribution it plays to the calculation of LSIs is unknown, though must be addressed prior to a RTS. This was also the case for the speedy jump test, whereby 28 (70%) and 24 (60%) participants were below average on the operated and non-operated limbs, respectively, compared to normative data. Even the four-jump plyometric test, which permits the use of both limbs, showed that the majority of participants (63%) were below average. Finally, the speedy jump and quick feet tests which assess speed showed the majority of participants were below average compared to norms.

As outlined in the recommendations of Kyritsis et al.,9 in addition to addressing lower limb strength and functional deficits, readiness to RTS should also be based on the patient’s ability to complete on-field sport-specific rehabilitation. In this context, the BIA test battery may be useful earlier in the rehabilitation program to identify deficits, as well as later in the program to help guide patients toward a sport-specific conditioning program and/or eventual RTS. Recent studies have demonstrated an increased re-injury risk if patients do not meet objective test LSIs within testing batteries of ≥90% before RTS,8,9 inclusive of functional hop and strength assessments.

While this evidence does support the use of these physical objective tests in reducing the risk of knee re-injury, it may be argued that reported LSI cutoffs (i.e. 90%) are not high enough to be considered ‘passing’. This may essentially set a lower required performance pass rate in a patient who may actually require lower limb strength and functional abilities beyond their pre-injury status. Furthermore, given recent research has suggested that LSIs overestimate knee function,12 standard testing methods (e.g.

standard single-legged hop tests) may not be stringent enough to adequately evaluate lower limb function, and achieve a safe and successful RTS. As mentioned above, LSIs do not account for limb asymmetry that may have existed prior to the initial injury, nor the potential de-conditioning of the non-operated side after surgery.7 These are barriers encountered when evaluating outcomes in community level patients who do not have pre-injury comparative measures.

Maximal knee extensor and flexor strength measures, although objective and reliable, are not functional movements reflective of sport, and hop tests have been criticized for not sufficiently evaluating functional capacity in ACLR patients.13 While the group mean LSI for each of the four hop tests ranged from 93-95%, the group mean LSI for the single leg CMJ (i.e. single leg vertical hop) and the speedy jump test within the BIA battery were significantly lower, being 82% and 80%, respectively. Only 28% (single limb CMJ) and 33% (speedy jump test) of participants were ≥90% LSI for these tests. The aim of the single limb CMJ is to generate maximum power to propel the body upwards against gravity, while the speedy jump test evaluates function in forwards, sideways and backwards directions over 16 consecutive hops. Three out of four of the standard hop tests evaluate functional hop capacity in a horizontal and forwards direction only and, while the triple crossover hop for distance does involve some cross directional movement, the magnitude of these angular movements are relatively low given the patient only needs to cross over a 15 cm mat. Therefore, the speedy jump test may be more physically demanding and therefore sensitive to sideto-side differences in functional capacity, compared with the standard hop tests.

In addition to the nature of the test, it is important to note that the single leg CMJ employed as part of the BIA battery requires participants to have their hands fixed on their waist, while arms were not fixed during the four-hop test battery. The decision to allow the use of the arms was made with the aim of closely following the four-hop test battery previously published by Reid et al.,10 which placed no restrictions on the use of the arms. A study by Gustavsson et al.26 found a strong correlation between the single hop for distance and the vertical jump performed as a CMJ, though the arms were fixed for both tests. Hamilton et

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al.27 reported a strong correlation between triple hop for distance and vertical jump performed as a CMJ, with arm action being unrestricted during both tests.

By controlling hand position and the use of the arms for propulsion, participants are only able to generate power through their lower limbs. As a result, future studies should consider the possible contribution of unrestricted arm action on patient’s scores and control for this by outlining restrictions within the four-hop test battery. Nevertheless, while restricted (or unrestricted) arm use may affect performance, it would likely not affect side-to-side LSIs during the hop tests.

Finally, the single limb stability test employed as a measure of balance and postural control, demonstrated a mean LSI of 86%. Barber-Westin et al. 28 reported that deficits in balance, proprioception and neuromuscular control persist for months postsurgery, and suggested that dynamic neuromuscular control should be assessed before embarking on a RTS. While limited evidence exists as to the link between proprioceptive deficits and function in ACLdeficient and post-operative ACLR patients,29 it has been suggested that a longer post-operative recovery phase may be needed until proprioceptive deficits are resolved.30 The standard four-hop test battery used in this study fails to examine this construct directly, with the only indication that a deficit exists observed through the patient’s ability to control the landing of the final hop. Thorough therapist assessment of jumping and landing control, as well as lower limb and trunk mechanics is imperative during these hop tests. However, while inability to control the land during a single limb hop test of any kind would rule the test ineligible, losses of control or biomechanical imperfections are often not quantified. Patients may score well on performance-based tests and present with sound LSIs, in the absence of quality hopping and landing biomechanics (such as lower limb and trunk alignment, adequate knee flexion on weight acceptance and excessive ground reaction forces).

Therefore, ‘biomechanical symmetry’ in addition to ‘performance symmetry’ should still be evaluated throughout these testing batteries, given its potential link to ACL injuries.31-33 Some limitations in this study are acknowledged.

Firstly, two testing batteries were undertaken over

two different sessions in order to minimize any fatigue effect and, while every effort was made to standardize the test conditions, the order of the two test sessions was not randomized. Secondly, for the standard fourhop battery and isokinetic knee strength evaluations, testing alternated between the unaffected and affected limb minimizing any learning effect. However, each test of the BIA battery was always initiated on the unaffected limb, completing all required practice and test efforts before repeating the process on the operated limb. Therefore, there is the possibility that the results obtained from the operated limb could be exaggerated in comparison to the unaffected limb, given the proficiency gained through prior learning. The BIA tests, however, reported lower mean LSIs when compared with the standard hop and strength tests, which would suggest that this possible learning effect may have only presented the LSIs better than they actually were. Thirdly, this study only evaluated patients who had undergone ACLR utilizing hamstring autografts in order to better standardize the cohort. However, while caution should be applied in generalized surgical outcomes across all graft types, research does suggest that postoperative strength and functional outcomes do not significantly differ between hamstrings autografts and other reconstruction methods.34-37 Fourthly, it is acknowledged that the patients recruited for this study received guidance from different rehabilitation clinics and under varied therapists and, therefore, they did not have a standardized rehabilitation protocol. While it was recently demonstrated that rehabilitation is associated with performance during standard hop and strength measures,23 this study sought to investigate differences amongst tests and testing batteries within patients, rather than between patients (making varied rehabilitation pathways irrelevant for this study), at a time when many patients assume (and are informed) they can return to their chosen sport.

While the comparison of performance outcomes to an age and gender matched healthy cohort is considered an advantage of the BIA test battery, this comparison remains limited by the large range of ages included in each sub-grouping. For example, a 28 year old patient would be compared to the young adult bracket (2029 years), meaning that while the comparison to individuals in the upper end of the age bracket would

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be appropriate, there would also be comparison to a younger population. Furthermore, published studies highlighting the development of the BIA test battery failed to provide detailed information on the characteristics of the normative cohort (other than gender, age, height, weight and body mass index, as well as stating that subjects were engaging in competitive sports).17,18 Therefore, normative data relating to a specific activity or sport that may be developed over time, will permit matching these ACLR patients more closely for the demands required of the specific sport.

At this stage, patients are being matched with healthy subjects engaging in competitive sport, without knowing the exact sports. This will further improve the utility of the BIA test battery above and beyond reporting LSIs during standard tests of hop function and strength. Finally, this study did not seek to investigate actual ACL re-tears in patients returning to sport, and their association with LSI and BIA test battery outcomes. This provides an important avenue for future research, in determining whether the BIA test battery has an improved ability over standard hop and strength tests in predicting re-injury.

CONCLUSION The BIA test battery appears to include some single limb functional tests that are more physically challenging than standard hop and isokinetic strength tests, highlighted by the significantly lower mean LSI’s during the single limb BIA tests and the lower pass rate when employing the BIA protocol. Future research should seek to investigate the association between outcomes measured using the BIA and the rate of secondary re-injury.

REFERENCES 1. Salmon L, Russell V, Musgrove T, et al. Incidence and risk factors for graft rupture and contralateral rupture after anterior cruciate ligament reconstruction. Arthroscopy. 2005;21(8):948-957.

2. Wiggins AJ, Grandhi RK, Schneider DK, et al. Risk of secondary injury in younger athletes after anterior cruciate ligament reconstruction: A systematic review and meta-analysis. Am J Sports Med. 2016;44(7):1861-1876.

3. Paterno MV, Rauh MJ, Schmitt LC, et al. Incidence of second ACL injuries 2 years after primary ACL reconstruction and return to sport. Am J Sports Med. 2014;42(7):1567-1573.

4. Ardern CL, Webster KE, Taylor NF, et al. Return to the preinjury level of competitive sport after anterior cruciate ligament reconstruction surgery: two-thirds of patients have not returned by 12 months after surgery. Am J Sports Med. 2011;39(3):538-543.

5. Irarrázaval S, Kurosaka M, Cohen M, et al. Anterior cruciate ligament reconstruction. J ISAKOS. 2016;1:38-52.

6. Thomee R, Kaplan Y, Kvist J, et al. Muscle strength and hop performance criteria prior to return to sports after ACL reconstruction. Knee Surg Sports Traumatol Arthrosc. 2011;19(11):1798-1805.

7. Thomee R, Neeter C, Gustavsson A, et al. Variability in leg muscle power and hop performance after anterior cruciate ligament reconstruction. Knee Surg Sports Traumatol Arthrosc. 2012;20(6):1143-1151.

8. Grindem H, Snyder-Mackler L, Moksnes H, et al.

Simple decision rules can reduce reinjury risk by 84% after ACL reconstruction: the Delaware-Oslo ACL cohort study. Br J Sports Med. 2016;50(13):804808.

9. Kyritsis P, Bahr R, Landreau P, et al. Likelihood of ACL graft rupture: not meeting six clinical discharge criteria before return to sport is associated with a four times greater risk of rupture. Br J Sports Med. 2016;50(15):946-951.

10. Reid A, Birmingham TB, Stratford PW, et al. Hop testing provides a reliable and valid outcome measure during rehabilitation after anterior cruciate ligament reconstruction. Phys Ther. 2007;87(3):337349.

11. Lynch AD, Logerstedt DS, Grindem H, et al.

Consensus criteria for defining ‘successful outcome’ after ACL injury and reconstruction: a DelawareOslo ACL cohort investigation. Br J Sports Med. 2015;49(5):335-342.

12. Wellsandt E, Failla MJ, Snyder-Mackler L. Limb Symmetry Indexes Can Overestimate Knee Function After Anterior Cruciate Ligament Injury. J Orthop Sports Phys Ther. 2017;47(5):334-338.

13. Narducci E, Waltz A, Gorski K, et al. The clinical utility of functional performance tests within one-year post-acl reconstruction: a systematic review. Int J Sports Phys Ther. 2011;6(4):333-342.

14. Bjorklund K, Andersson L, Dalen N. Validity and responsiveness of the test of athletes with knee injuries: the new criterion based functional performance test instrument. Knee Surg Sports Traumatol Arthrosc. 2009;17(5):435-445.

15. Bjorklund K, Skold C, Andersson L, et al. Reliability of a criterion-based test of athletes with knee injuries; where the physiotherapist and the patient

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independently and simultaneously assess the patient’s performance. Knee Surg Sports Traumatol Arthrosc. 2006;14(2):165-175.

16. Gokeler A, Welling W, Zaffagnini S, et al.

Development of a test battery to enhance safe return to sports after anterior cruciate ligament reconstruction. Knee Surg Sports Traumatol Arthrosc.

2016;25(1):192-199.

17. Herbst E, Hoser C, Hildebrandt C, et al. Functional assessments for decision-making regarding return to sports following ACL reconstruction. Part II: clinical application of a new test battery. Knee Surg Sports Traumatol Arthrosc. 2015;23(5):1283-1291.

18. Hildebrandt C, Muller L, Zisch B, et al. Functional assessments for decision-making regarding return to sports following ACL reconstruction. Part I: development of a new test battery. Knee Surg Sports Traumatol Arthrosc. 2015;23(5):1273-1281.

19. Noyes FR, Barber SD, Mooar LA. A rationale for assessing sports activity levels and limitations in knee disorders. Clin Orthop Relat Res. 1989(246):238-249.

20. Irrgang JJ, Anderson AF, Boland AL, et al.

Development and validation of the international knee documentation committee subjective knee form. Am J Sports Med. 2001;29(5):600-613.

21. Enright PL. The six-minute walk test. Respiratory care. 2003;48(8):783-785.

22. Toole AR, Ithurburn MP, Rauh MJ, et al. Young athletes cleared for sports participation after anterior cruciate ligament reconstruction: How many actually meet recommended return-to-sport criterion cutoffs? J Orthop Sports Phys Ther. 2017;47(11):825833.

23. Ebert JR, Edwards P, Yi L, et al. Strength and functional symmetry is associated with post-operative rehabilitation in patients following anterior cruciate ligament reconstruction. Knee Surg Sports Traumatol Arthrosc. 2017: doi: 10.1007/s00167-017-4712-6.

24. Hiemstra LA, Webber S, MacDonald PB, et al.

Contralateral limb strength deficits after anterior cruciate ligament reconstruction using a hamstring tendon graft. Clin Biomech (Bristol, Avon).

2007;22(5):543-550.

25. Larsen JB, Farup J, Lind M, et al. Muscle strength and functional performance is markedly impaired at the recommended time point for sport return after anterior cruciate ligament reconstruction in recreational athletes. Hum Mov Sci. 2015;39:73-87.

26. Gustavsson A, Neeter C, Thomee P, et al. A test battery for evaluating hop performance in patients with an ACL injury and patients who have undergone ACL reconstruction. Knee Surg Sports Traumatol Arthrosc. 2006;14(8):778-788.

27. Hamilton RT, Shultz SJ, Schmitz RJ, et al. Triple-hop distance as a valid predictor of lower limb strength and power. J Athl Train. 2008;43(2):144-151.

28. Barber-Westin SD, Noyes FR. Objective criteria for return to athletics after anterior cruciate ligament reconstruction and subsequent reinjury rates: a systematic review. Phys Sportsmed. 2011;39(3):100110.

29. Gokeler A, Benjaminse A, Hewett TE, et al.

Proprioceptive deficits after ACL injury: are they clinically relevant? Br J Sports Med. 2012;46(3):180192.

30. Iwasa J, Ochi M, Adachi N, et al. Proprioceptive improvement in knees with anterior cruciate ligament reconstruction. Clin Orthop Relat Res. 2000(381):168-176.

31. Myer GD, Ford KR, Khoury J, et al. Biomechanics laboratory-based prediction algorithm to identify female athletes with high knee loads that increase risk of ACL injury. Br J Sports Med. 2011;45(4):245252.

32. Pappas E, Shiyko MP, Ford KR, et al. Biomechanical deficit profiles associated with ACL injury risk in female athletes. Med Sci Sports Exerc. 2016;48(1):107113.

33. Hewett TE, Di Stasi SL, Myer GD. Current concepts for injury prevention in athletes after anterior cruciate ligament reconstruction. Am J Sports Med. 2013;41(1):216-224.

34. Bjornsson H, Samuelsson K, Sundemo D, et al. A randomized controlled trial with mean 16-year follow-up comparing hamstring and patellar tendon autografts in anterior cruciate ligament reconstruction. Am J Sports Med. 2016;44(9):23042313.

35. Chee MY, Chen Y, Pearce CJ, et al. Outcome of patellar tendon versus 4-strand hamstring tendon autografts for anterior cruciate ligament reconstruction: A systematic review and metaanalysis of prospective randomized trials.

Arthroscopy. 2017;33(2):450-463.

36. Herrington L, Wrapson C, Matthews M, et al.

Anterior cruciate ligament reconstruction, hamstring versus bone-patella tendon-bone grafts: a systematic literature review of outcome from surgery. Knee. 2005;12(1):41-50.

37. Holm I, Oiestad BE, Risberg MA, et al. No difference in knee function or prevalence of osteoarthritis after reconstruction of the anterior cruciate ligament with 4-strand hamstring autograft versus patellar tendonbone autograft: a randomized study with 10-year follow-up. Am J Sports Med. 2010;38(3):448-454.

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IJSPT

ORIGINAL RESEARCH

THE LOWER EXTREMITY GRADING SYSTEM (LEGS) TO EVALUATE BASELINE LOWER EXTREMITY PERFORMANCE IN HIGH SCHOOL ATHLETES Joseph Smith, PhD, ATC, OTC, NREMT1 Nick DePhillipo, MS, ATC, OTC, CSCS2 Shannon Azizi, MS, ATC, OTC1 Andrew McCabe, MAT, ATC1 Courtney Beverine, MA, ATC1 Michael Orendurff, PhD1 Stephanie Pun, MD1 Charles Chan, MD1

ABSTRACT Background and Purpose: Lower extremity athletic injuries result in impairments in balance, power, and jump-landing mechanics. Unilateral injury has bilateral effects and the literature supports that it is important to assess neuromuscular impairments such as balance, power, and jumping mechanics following injury and for safe return to sport after injury rehabilitation. Currently, individual tests are established in the literature, but no combined approach or clinical tool exists for this purpose. The purpose of this study is to describe and provide the initial data for the Lower Extremity Grading System (LEGS), comprised of three neuromuscular components for use as a baseline pre-season assessment for high school athletes to assess lower extremity performance.

Furthermore, this study focuses on the differences in baseline lower extremity performance outcomes between male and female soccer and basketball athletes.

Methods: One hundred and eighty-five high school basketball, and soccer athletes (94 female, 91 male; mean age = 15.6 ± 4.4) participated. The participants were administered the LEGS assessment during the preseason for their respective sports, which includes three component tests: (1) Y-balance test, (2) drop vertical jump test, (3) triple-crossover-hop-for-distance test. Participants’ scores on each test were recorded, and then totaled to present an overall LEGS composite score. Participants’ baseline LEGS scores were then analyzed according to sex and sport, and standard normal distribution was calculated for all scores to enable percentile rankings to be established.

Results: Mean scores and standard deviation for each functional performance test are presented. Furthermore, a LEGS composite score combining the test scores was established and presented as a normal distribution curve allowing for further comparison and analysis. The mean LEGS composite score for males was 700.3 (± 76.6), while the mean LEGS composite score for females was 587.4 (± 51.6). Statistically different LEGS composite scores were found between males and females.

Conclusion: The current findings present descriptive data for the utility of the LEGS as a neuromuscular baseline assessment before high school sports participation and/or as a tool for assessing return to sports after injury rehabilitation. The LEGS may augment current assessment tools and may serve as a composite score and combined approach to the assessment of lower extremity risk of injury and readiness to return to sports.

Level of evidence: 3 Keywords: Adolescent, lower extremity, baseline screening, return to play

1

Stanford Children’s Orthopedic & Sports Medicine Center, Stanford, CA, USA 2 The Steadman Clinic, Vail, CO, USA Acknowledgements The research team would like to extend our sincere gratitude to the administration, athletic departments, and student-athletes of the San Mateo Unified High School District, especially Matthew Smith, MA, ATC, and Sara Golec, MS, ATC. Thank you also to Jaco Van Delden, PT. Conflict Of Interest Statement The authors whose names are listed certify that they have no affiliations with or involvement in any organization or entity with any financial interest in the subject matter discussed in this article.

CORRESPONDING AUTHOR Joseph Smith Stanford Children’s Orthopedic & Sports Medicine Center, Stanford, CA, USA E-mail: JosephSmith@StanfordChildrens.org

The International Journal of Sports Physical Therapy | Volume 13, Number 3 | June 2018 | Page 401 DOI: 10.26603/ijspt20180401

INTRODUCTION In the United States of America, over seven million adolescent high school students participate in athletics.1 These student-athletes sustain an estimated 1.5 million injuries each year with the lower extremity (ankle and knee) being the most common site of injury.2-5 Previous authors have reported relationships between factors such as demographics, anthropometrics, balance, and physical performance measures that may contribute to increased risk of suffering lower extremity injuries (or re-injury) in sports.6-8

The LEGS combines individual functional test scores in centimeters from the Y-balance test (YBT), drop vertical jump test (DVJT), and triple crossover hop for distance test (TXHD) into a single baseline LEGS composite score to provide a simplified metric reflecting a combination of lower extremity characteristics that can be used in percentile rankings. Similar scales are used in the Scholastic Assessment Test (SAT) where raw scores in sections such as reading, writing, and math are combined to provide scaled scores for percentile ranking and interpretation.

Barber-Westin, et al. have suggested that it is important and recommended to assess neuromuscular impairments such as balance, power, and jumping mechanics following injury and for safe return to sport activities after injury and rehabilitation.6 Functional performance tests have been used to assess components of sport performance, determine readiness for return to sport, evaluate effectiveness of neuromuscular training interventions, and evaluate potential for injury of the lower extremity.7-11 An advantage of functional tests are that they require minimal personnel, are simple in administration, require only minimal equipment, and can be combined into a single score to assess overall physical performance and lower extremity injury risk.9,12 However in singularity these tests may provide only one dimension of an athleteâ&#x20AC;&#x2122;s function or performance. Furthermore, normative data for these individual tests as well as a composite scoring system to describe the baseline neuromuscular function of high school athletes have not been described.

The functional tests selected for combination for the LEGS have been presented in the literature as reliable and valid assessments for jump-landing mechanics, dynamic balance, and lower limb strength and power.13-15 The reliability for the DVJT has been reported with intraclass correlation coefficients (ICCs) of 0.94 to 0.96, has been shown to be valid, and has been used to identify risks factor for noncontact acute lower extremity injuries.7,8,13,16 The YBT has been proposed as a tool utilized before, during, and after injury to assessment functional improvements and risk of injury (reliability ICCs ranging from 0.80 to 0.85).17 The reliability and validity of hop tests as performance-based outcome measures and for patients undergoing rehabilitation after anterior cruciate ligament (ACL) reconstruction has been reported (reliability ICCs ranging from 0.84 to 0.93).15

The Lower Extremity Grading System (LEGS) is presented in this study as a measure to help clinicians identify the neuromuscular status of the lower extremity using a standardized approach. Additionally the LEGS may also add utility as a preseason baseline indicator of lower extremity neuromuscular components which may be beneficial for the growing, adolescent athlete for assessing both risk of injury and performance potential. Baseline assessments with LEGS could provide valuable pre-injury data on an annual basis, and could also offer a practical clinical data tool which would allow for comparison during the rehabilitation phases of injury management of lower extremity acute non-contact injuries and for return to sport decision making.

Therefore, the purpose of this study is to describe and provide the initial data for the Lower Extremity Grading System (LEGS), comprised of three neuromuscular components for use as a baseline pre-season assessment for high school athletes to assess lower extremity performance. Furthermore, this study focuses on the differences in baseline lower extremity performance outcomes between male and female soccer and basketball athletes.

METHODS Participants One hundred and eighty-five male and female athletes (15.6 Âą 4.4 years) participated in this study.

Sample size was determined by performing a priori power analysis using G*Power statistical software (Version 3.1.9.2) with power set at 0.8 and alpha

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level (p = .05). It was determined that a maximum number of approximately 40 participants was needed in order to demonstrate differences between groups. All participants played at least one of two high school sports: soccer or basketball. These sports were selected based upon the common occurrence of noncontact acute lower extremity injuries involved with sport participation and the performance of several high-risk maneuvers.2 All participants completed pre-participation health history questionnaires to rule out current pathological conditions (any condition that would prohibit clearance to participate in athletics) and contraindications to study participation, which were evaluated by a physician. Exclusionary criteria included: incomplete pre-participation physical exam, and/or inability to physically perform any of the required assessments. No participants were excluded from this study due to previous injury. Prior to study participation all procedures were explained to each participant. Participants and their parents/guardians read and signed assent and consent forms and video use consent forms that were approved by the institutional review board for human subjects.

Procedures Data were collected by the same examiners at all testing sessions. All examiners were NATABOC professional certified athletic trainers at the masterâ&#x20AC;&#x2122;s degree level with education and experience familiarizing them with the assessments and testing procedures. Anthropometric data were recorded before all testing procedures and included height, body mass, body mass index (BMI), age, date of birth, grade, sport, and level of sport participation (freshman, junior varsity, or varsity) by the principal investigators. All testing was performed in a school gymnasium. Before testing, participants conducted a 10 minute dynamic warm-up led by the principal investigators. The dynamic warm up included jogging, backpedaling, side-stepping, and walking stretches. Three testing stations (balance, power, jumping mechanics) were established and participants were assigned randomly to the stations and proceeded with synchronous clockwise rotation until as stations were completed. Standardized oral instructions for each test were rehearsed and read by the examiners to all test groups. Standardized

instructions were designed to maintain consistency of testing procedures, decrease instructional time, and allow concise and precise data collection.

Incorrect test performance required that the test be restarted after a minimum 30-second rest period. No corrective feedback was given to subjects.

The Lower Extremity Grading System (LEGS) The LEGS was developed to assess neuromuscular function of the lower extremities for use as a pre-participation baseline screening and as a tool for evaluating return to sports following injury rehabilitation.

The LEGS employed in this study consisted of previously described assessments of the following three components: (1) dynamic balance, (2) jump-landing mechanics, and (3) lower limb power as measured by the YBT, DVJT, and TXHD, respectively. A copy of the LEGS form is provided in Appendix I. A visual depiction representing each test is provided in Figure 1.

The YBT was used to assess dynamic balance of the stance leg by recording single-leg reach distance in cm(s) on each leg with a standard FMSâ&#x201E;˘ Y-balance kit. Participants stood on the center of the testing kit with one limb and reached with their contralateral limb in the anterior, posteromedial, and posterolateral directions. Participants were given one practice trial on each limb and engaged in one test trial per limb. Participants started on the left limb and repeated the test with a stance on the right limb. The average of the maximum reach distances from the three directions (MaxD) was recorded in centimeters and normalized according to leg length of the stance leg in order to adjust for variances of different anthropometric variables. Leg length was measured with a Gulick tape measure from the anterior superior iliac spine to the distal medial malleolus. The YBT scores were expressed as a percentage of leg length.18 The DVJT was performed as described by Noyes et al.13 An Apple iPad (Apple, Inc., Cupertino, CA) was used to record jump landing mechanics, placed on a 102 cm high stand, positioned approximately 366 cm in front of a box that was 30 cm in height and 38 cm in width. Camera resolution was 1080P at 24 frames per second. Immediately before each subject performed the DVJT, the same examiner placed two sets of 4 x 4 cm florescent pink reference markers over the ASIS and center of patella for each limb.

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Figure 1. The LEGS tests used in this study (from left to right): Y-Balance Test (YBT), Drop Vertical Jump Test (DVJT), and Triple Crossover Hop for Distance Test (TXHD).

Jump landing mechanics were analyzed post-testing session via Dartfish Motion Analysis Software (ProSuite version 4.0.9.0) where lower limb separation distances at the hip and knee were measured.

Hip separation distance (HSD) was measured while standing erect on top of the box and defined as the distance between the most prominent points of each anterior superior iliac spine which were marked with fluorescent tape markers. Knee separation distance (KSD) was measured at the lowest point of each jump landing prior to transition to takeoff into the vertical jump and was defined as the distance between the centers of the patellae, which were marked with fluorescent tape markers. Participants were instructed to jump maximally (â&#x20AC;&#x153;as high as possibleâ&#x20AC;?) upon dropping from the box. The average absolute KSD during three successful trials was recorded in centimeters and then normalized relative to HSD to yield a percentage for each subject.13 The TXHD evaluated maximal hopping distance on a single leg and was assessed in centimeters (cm) with a standard tape measure fixed to the ground, perpendicular to the starting line.15 Participants stood on the designated testing leg with the great toe on the starting line and performed three consecutive maximal hops forward on the same limb, crossing over the tape measure with each hop. Participants started on the left limb and repeated the test with

the right limb. Each participant initiated the hops by hopping in the lateral (outside) direction. Each participant was given one practice trial per limb and two test trials per limb. Arm swing was allowed, and the investigator measured the distance hopped from the starting line to the point where the toe struck the ground upon completing the third hop. The maximum distance achieved of the two test trials was recorded in centimeters and used for analysis.

STATISTICAL METHODS All data were analyzed using SPSS Statistics Version 22.0.0.0 (IBM, Armonk, New York, USA), and Microsoft Excel. Participants were divided into groups according to independent variables such as sex (male or female), and sport (basketball or soccer). Variables of interest included performance on the independent functional performance tests as well as the LEGS composite score. Unpaired t-test were used to compare means between sexes and sports with an alpha level set at p =.05 to determine statistical significance.

The LEGS composite score is presented as a total, and was calculated using the following equation: LEGS Composite Score = average score (cm) / limb length (cm) from the YBT (%) + TXHD maximum hop distance (cm) + (knee separation distance (cm) / hip separation distance (cm)) from the DVJT (%)

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Normal distribution curves were calculated using the mean LEGS composite scores and standard deviations.

LEGS composite scores for females and males which are presented in Figure 3.

RESULTS Participant demographic characteristics, individual functional test scores, and LEGS composite scores are provided in Table 1. Female functional test scores and LEGS composite scores grouped by sport are presented in Table 2. Male functional test scores and LEGS composite scores grouped by sport are presented in Table 3. Mean test scores between males and females are graphically presented in Figure 2.

Each athlete’s individual YBT, DVJT, and TXHD scores were subtracted from the mean score and divided by the standard deviation to create standard normal distributions curves. These standardized scores can then be summed to provide one total z-score for each athlete. These z-scores can be analyzed further as a percentile ranking score based on the total sample. The percentage scores in this study ranged from 8% to 89%. This scoring system may allow interpretation regarding readiness for sport participation similar to how the SAT test is intended to assess intellectual readiness for college.

The mean LEGS composite score for males was 700.3 with a standard deviation of 76.6, while the mean LEGS composite score for females was 587.4 with a standard deviation of 51.6. These data were utilized to create standard normal distribution curves of the

Statistically significant differences were found between male and female scores on all individual

Table 1. Demographics, functional test scores, and LEGS composite scores (mean ± SD).

Table 2. Test scores (females) by sport (mean ± SD).

Table 3. Test scores (males) by sport (mean ± SD).

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Figure 2. Mean test scores females vs. males on Y-Balance Test (YBT) in cm; Drop Vertical Jump Test (DVJT) knee separation distance/hip separation distance (cm) as a percentage; Triple Crossover Hop for Distance Test (TXHD) in cm; and Limb Symmetry Index (LSI) as a percentage. The LSI is calculated as the difference between limb data from both the YBT and TXHD.

Figure 3. Normal distribution curve for LEGS composite scores of males and females.

functional tests and the LEGS composite score. Interestingly, males demonstrated higher scores on all functional tests except the YBT. Female soccer athletes demonstrated the highest YBT scores amongst the sports groups, while male basketball athletes demonstrated the highest DVJT and TXHD scores.

For male athletes, differences between the LEGS composite scores of basketball and soccer athletes were not significantly different. Similarly, for female athletes, the LEGS composite scores of basketball and soccer athletes were not significantly different.

Limb symmetry index (LSI) was calculated as a percentage by dividing scores of the left and right limbs for all participants. The mean LSI for male basketball athletes was 100.3 (± 4.8), while the mean LSI for male soccer athletes was 101.6 (± 5.6). The mean LSI for female basketball athletes was 98.1 (± 4.4), while the mean LSI for female soccer athletes was 98.4 (± 4.8).

DISCUSSION Using a systematic approach to combining objective functional scores from three performance test outcomes, the LEGS composite score was established.

The main result of the present study is the provision of descriptive data regarding baseline lower extremity function in high school athletes competing in soccer and basketball using the LEGS composite score and standardized curves for percentile rankings. Establishing standard normal distribution curves presents this data in a format that may allow for age, sex, or sport-matched comparisons to be made in decision making and rehabilitative planning. Furthermore, differences in baseline lower extremity performance between male and female soccer and basketball athletes is also elucidated.

The advantages of utilizing the LEGS composite scores and functional performance tests described in the present study is the simplicity of administration, the systematic approach to combining functional test scores, and the objective nature of the analysis. The creation of the LEGS composite score is of clinical importance since it allows for an assessment that yields objective data in the form of a single metric, which can be compared to age-related distribution or baseline scores to inform clinical decisions. Previous literature has presented combined functional performance test measurements into a single score to assess overall physical performance and lower extremity injury risk.12 In previous studies, the functional performance tests used in the LEGS application have been shown

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to be reliable and valid.13-15 Evidence in previous literature found no difference in YBT performance between male general college students and male college athletes, while noting the validity of the tool for purposes of preparticipation screening and injury prediction.19 Results in the current study show statistically significant differences between high school female and male YBT scores, with females scoring higher during baseline screening.

The YBT has been proposed as a tool utilized before, during, and after injury to assessment functional improvements and risk of injury.17 Other evidence in the literature describes the inter-rater test-retest reliability of the YBT as well as the utility of dynamic balance as a screening and rehabilitation tool for female collegiate volleyball players.14,20 Butler et al. examined YBT scores in high school, college, and professional soccer players and proposed the need for further establishing normative values for both male and female athletes of all ages, levels of competition, and sports.21 The present study presents data in an attempt to establish normative values for the high school athlete.

Barber-Westin et al. reported on the utility of the DVJT as an indicator of an athleteâ&#x20AC;&#x2122;s lower limb control, while other researchers have reported the simplicity of the DVJT administration for identifying risk for injury.22,23 The results of the present study show significant differences in male and female DVJT scores when used as a baseline screen in basketball and soccer athletes. This may indicate decreased lower limb control in high school-aged female sports participants when compared to their male counterparts and may result in an increased potential risk of injury.

Previous literature has noted the need for normative data on limb symmetry indices and hop test performance grouped by age, sports, sex, etc.24 The results of the present study may contribute to this need by indicating the significant differences between male and female single leg hopping power via the TXHD. The reliability and validity of hop tests as performance-based outcome measures for patients undergoing rehabilitation after anterior cruciate ligament (ACL) reconstruction has also been reported.15 In a systematic review, Barber-Westin et al. demonstrated the need for objective measurements of

strength, stability, and neuromuscular function in return to play decision-making models.6 Similarly, the 2016 consensus statement on return to sports outlines the need for focused research on defining, measuring, and reporting return to sport outcomes using a standardized approach.25 The results of the current study provide a systematic approach for combining data from multiple reliable and valid tests into a singular metric which can be translated into comparative ranking.

The outcomes of this study are relevant particularly for the high school athletic population for establishing normative data to describe lower extremity function and symmetry in baseline preparticipation screening. In this study, both sexes demonstrated limb symmetry indices near 100% demonstrating that baseline evaluation of healthy high school athletes indicates symmetry between limbs. Limb symmetry is often used as a clinical indicator for return of function of the lower extremity after injury or surgical intervention. The LEGS composite score could be utilized for comparing LSI measures during rehabilitation to baseline LSI measures for return to sport decision making.

Future direction and research with LEGS should include larger sample sizes and the inclusion of baseline LEGS composite scores from athletes participating in other sports. Furthermore, validation studies comparing baseline scores to post-injury scores for return to play decisions may also further assess the utility of the LEGS. CONCLUSION The current study presents descriptive data for the utility of the LEGS as a neuromuscular baseline assessment before high school sports participation and/or as a tool for assessing return to sports after injury rehabilitation. The LEGS may augment current assessment tools and may serve as a composite score and combined approach to the assessment of lower extremity risk of injury and readiness to return to sports. The LEGS composite score and standardized curves for percentile rankings establishes standard normal distribution curves which allow for age, sex, or sport-matched comparisons to be made in decision making and rehabilitative planning.

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REFERENCES 1. Centers for Disease Control and Prevention.

Guidelines for school and community programs to promote lifelong physical activity among young people. J Sch Health. 1997;67(6):202-19.

2. Darrow CJ, et al. Epidemiology of severe injuries among United States high school athletes. Am J Sports Med. 2009;37(9):1798-805.

3. Rechel JA, Yard EE, Comstock RD. An epidemiologic comparison of high school sports injuries sustained in practice and competition. J Athl Train.

2008;43(2):197-204.

4. Le Gall F, Carling C, Reilly T. Injuries in young elite female soccer players: an 8-season prospective study. Am J Sports Med. 2008;36(2):276-84.

5. Nelson AJ, et al. Ankle injuries among United States high school sports athletes 2005-2006. J Athl Train.

2007;42(3):381-7.

6. Barber-Westin SD, Noyes FR. Factors used to determine return to unrestricted sports activities after anterior cruciate ligament reconstruction.

Arthroscopy. 2011;27(12):1697-1705.

7. Noyes FR, et al. A training program to improve neuromuscular and performance indices in female high school basketball players. J Strength Cond Res. 2012;26(3):709-19.

8. Noyes FR, et al. A training program to improve neuromuscular and performance indices in female high school soccer players. J Strength Cond Res. 2013;27(2):340-51.

9. Brumitt J, et al. Lower extremity functional tests and risk of injury in division iii collegiate athletes. Int J Sports Phys Ther. 2013;8(3):216-27.

10. Hegedus EJ, et al. Clinician-friendly lower extremity physical performance measures in athletes: a systematic review of measurement properties and correlation with injury, part 1. The tests for knee function including the hop tests. Br J Sports Med. 2015:49(10):642-8.

11. Hegedus EJ, et al. Clinician-friendly lower extremity physical performance tests in athletes: a systematic review of measurement properties and correlation with injury. Part 2-the tests for the hip, thigh, foot and ankle including the star excursion balance test.

Br J Sports Med. 2015:49(10):649-56.

12. Smith J, DePhillipo N, Kimura I, et al. Prospective functional performance testing and relationship to lower extremity injury incidence in adolescent sports participants. Int J Sports Phys Ther. 2017:12(2): 206-218.

13. Noyes FR, et al. The drop-jump screening test: difference in lower limb control by gender and effect of neuromuscular training in female athletes. Am J Sports Med. 2005;33(2):197-207.

14. Shaffer S, Teyhen D, Lorenson C, et al. Y-balance test: a reliability study involving multiple raters. Mil Med. 2013:178(11): 1264-1270.

15. Reid A, et al. Hop testing provides a reliable and valid outcome measure during rehabilitation after anterior cruciate ligament reconstruction. Phys Ther.

2007;87:337-349.

16. Sigward S, Havens K, Powers C. Knee separation distance and lower extremity kinematics during a drop land: implications for clinical screening. J Athl Train. 2011:46(5):471-5.

17. Teyhen DS, et al. Clinical measures associated with dynamic balance and functional movement. J Strength Cond Res. 2014;28(5):1272-1283.

18. Kendall F, McCreary E, Provance PG, et al. Muscles Testing and Function With Posture and Pain 5th ed.

Baltimore, MD: Williams & Wilkins; 2005.

19. Engquist KD, et al. Performance comparison of student-athletes and general college students on the functional movement screen and the Y-balance test.

J Strength Cond Res. 2015;29(8):2296-2303.

20. Hudson C, Garrison JC, Pollard K. Y-balance normative data for female collegiate volleyball players. Phys Ther Sport. 2016;61-65.

21. Butler RJ, et al. Differences in soccer players’ dynamic balance across levels of competition. J Athl Train. 2012;47(6):616-620.

22. Barber-Westin SD, et al. The drop-jump video screening test: retention of improvement in neuromuscular control in female volleyball players.

J Strength Cond Res. 2010;24(11)3055-3062.

23. Redler LH, et al. Reliability of a field-based drop vertical jump screening test for ACL injury risk assessment. Phys Sportsmed. 2016;44(1):46-52.

24. Myers, et al. Normative data for hop tests in high school and collegiate basketball and soccer players.

Int J Sports Phys Ther. 2014;9(5):596-603.

25. Ardern CL, et al. 2016 consensus statement on return to sport from the first world congress in sports physical therapy, Bern. Br J Sports Med. 2016;0:1-12.

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APPENDIX I.

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IJSPT

ORIGINAL RESEARCH

PRESEASON LOWER EXTREMITY FUNCTIONAL TEST SCORES ARE NOT ASSOCIATED WITH LOWER QUADRANT INJURY – A VALIDATION STUDY WITH NORMATIVE DATA ON 395 DIVISION III ATHLETES Jason Brumitt, PT, PhD, ATC, CSCS Victor Wilson, PT, DPT Natalie Ellis, PT, DPT Jordan Petersen, PT, DPT Christopher John Zita, PT, DPT Jordon Reyes, PT, DPT

ABSTRACT Background: Preseason performance on the lower extremity functional test (LEFT), a timed series of agility drills, has been previously reported to be associated with future risk of lower quadrant (LQ = low back and lower extremities) injury in Division III (D III) athletes.

Validation studies are warranted to confirm or refute initial findings.

Hypothesis/Purpose: The primary purpose of this study was to examine the ability of the LEFT to discriminate injury occurrence in D III athletes, in order to validate or refute prior findings. It was hypothesized that female and male D III athletes slower at completion of the LEFT would be at a greater risk for a non-contact time-loss injury during sport. Secondary purposes of this study are to report other potential risk factors based on athlete demographics and to present normative LEFT data based on sport participation.

Methods: Two hundred and six (females = 104; males = 102) D III collegiate athletes formed a validation sample. Athletes in the validation sample completed a demographic questionnaire and performed the LEFT at the start of their sports preseason. Athletic trainers tracked non-contact time-loss LQ injuries during the season. A secondary analysis of risk based on preseason LEFT performance was conducted for a sample (n = 395) that consisted of subjects in the validation sample (n = 206) as well as athletes from a prior LEFT related study (n = 189).

Study Design: Prospective cohort Results: Male athletes in the validation sample completed the LEFT [98.6 (± 8.1) seconds] significantly faster than female athletes [113.1 (± 10.4) seconds]. Male athletes, by sport, also completed the LEFT significantly faster than their female counterparts who participated in the same sport. There was no association between preseason LEFT performance and subsequent injury, by sex, in either the validation sample or the combined sample. Females who reported starting primary sport participation by age 10 were two times (OR = 2.4, 95% CI: 1.2, 4.9; p = 0.01) more likely to experience a non-contact time-loss LQ injury than female athletes who started their primary sport at age 11 or older. Males who reported greater than three hours per week of plyometric training during the six-week period prior to the start of the preseason were four times more likely (OR = 4.0, 95% CI: 1.1, 14.0; p = 0.03) to experience a foot or ankle injury than male athletes who performed three or less hours per week.

Conclusions: The LEFT could not be validated as a preseason performance measure to predict future sports injury risk. The data presented in this study may aid rehabilitation professionals when evaluating an injured athlete’s ability to return to sport by comparing their LEFT score to population norms.

Level of Evidence: 2 Keywords: Agility, college, epidemiology, functional test, lower quadrant

1

George Fox University, Newberg, OR, USA

Conflict of Interest / Declaration Statement The authors do not have any conflict of interests to report

CORRESPONDING AUTHOR Jason Brumitt, PT, PhD, ATC, CSCS Assistant Professor of Physical Therapy School of Physical Therapy George Fox University Newberg, OR, USA E-mail: jbrumitt@georgefox.edu Phone: (503) 554-2461

The International Journal of Sports Physical Therapy | Volume 13, Number 3 | June 2018 | Page 410 DOI: 10.26603/ijspt20180410

INTRODUCTION The lower extremity functional test (LEFT) consists of a series of 8 agility drills performed on a diamond shaped course (Figure 1).1-3 The LEFT was originally designed as a functional test to qualitatively and quantitatively assess an athlete’s ability to return to sport after a lower extremity injury.1-3 Recently the LEFT has been assessed for its ability to discriminate injury risk in athletic populations.4,5 In an initial prospective cohort study, female Division III (D III) athletes who completed the LEFT in 118 seconds or more (e.g., slower female athletes) were six times more likely to experience a thigh or knee injury during the season.4 Slower females (LEFT score ≥ 118 seconds or more) experienced an initial (e.g., first in-season injury) time-loss lower quadrant (LQ = low back and lower extremities) injury rate of 4.8 per 1000 athletic exposures (AE).5 Slower female athletes experienced a subsequent (e.g., any injury after the first in-season injury) time-loss LQ injury at a rate of 17.4 per 1000 AEs.5 Interestingly, faster male D III athletes with a LEFT score of 100 seconds

Figure 1. Course Dimensions for the Lower Extremity Functional Test. Distance between the Northern and Southern triangles is 9.14 m (30 feet). Distance between the Eastern and Western triangles is 3.05 m (10 feet).

or less were three times more likely to experience a time-loss LQ injury and six times more likely to sustain time-loss foot or ankle injury.4 The authors of the initial study hypothesized that faster males may have had a greater risk of injury due to having more exposure (e.g., more minutes devoted to practice or game) than slower males; however, this form of athletic exposure (e.g., tracking minutes played) had not been collected (note: exposure in that study was based only on participation during a practice or game and not on minutes played per event).4 A recent trend in sport science research is to attempt to identify athletes at risk for injury based on preseason measures of fitness.6,7 Several functional performance tests (FPT), including the LEFT, have been assessed for their ability to discriminate injury risk in various athletic populations.4,5,8-12 Many of the initial cohort studies that have assessed the potential predictive value of preseason FPT scores have reported significant relationships between suboptimal scores and future injury risk. However, these initial studies should be viewed with caution. Subsequent studies are warranted to validate the previously reported risk profiles. For example, Kiesel et al12 reported a score of 14 or less on the Functional Movement Screen™ (FMS™) was associated with an 11-fold increased risk of professional football players experiencing a time-loss injury requiring a minimum of three weeks on the disabled list. However, since this initial report,12 a majority of subsequent studies have failed to validate the original cutoff score (14 or less) and have failed to identify an alternate composite cutoff score for the FMS in order to discriminate injury risk in various sport populations.13-20 Likewise, Plisky et al reported that female high school basketball players were 6.5 times more likely to have experienced a lower extremity injury when their composite score on the star excursion balance test (later developed into the Y-balance test) was less than or equal to 94 percent of their lower extremity (LE) length.8 Subsequent studies, albeit with different sport populations, have reported different cutoff scores.20,21 As detailed in the prior paragraph, subsequent studies designed to validate risk profiles based on preseason FPT measures may not support initial findings.

Thus, there is a need to conduct subsequent studies

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to validate initial findings. The association between preseason LEFT scores and subsequent sport related injury has yet to be validated. The primary purpose of this study was to examine the ability of the LEFT to discriminate injury occurrence in D III athletes, in order to validate or refute prior findings. It was hypothesized that female and male D III athletes slower at completing the LEFT would be at a greater risk for a non-contact time-loss injury during sport.

Secondary purposes of this study are to report other potential risk factors based on athlete demographics and to present normative LEFT data based on sport participation. It was hypothesized that those who spent less time training during the off-season, who started sport at an older age, and/or who had a prior history of injury would have a greater risk of injury.

METHODS Participants Two hundred and six Division III athletes (females = 104, males = 102) from one university were recruited to participate in this study and served as a validation sample. Inclusion criteria for this study was participation in a varsity level sport. Athletes were excluded from the study if: a) he/she was under the age of 18 or b) if he/she was restricted from full sport participation by their primary care provider or team athletic trainer at the start of the season. The validation sample consisted of athletes from the following sports: women’s soccer = 35, men’s soccer = 41, women’s volleyball = 32, men’s basketball = 15, women’s track = 26, men’s track = 40, women’s tennis = 11, men’s tennis = 6.

The validation sample (n = 206) combined with 189 athletes from a different D III university formed the “combined sample”. The purpose of the combined sample was to a) assess injury risk profiles, per sex, in a large population of D III athletes and b) present normative data for the LEFT based on sex and sport participation. The initial sample of D III athletes (n = 189)4 consisted of athletes from the following sports: women’s soccer = 30, men’s soccer = 19, women’s cross-country = 5, men’s cross-country = 6, women’s volleyball = 26, men’s wrestling = 14, women’s basketball = 7, men’s basketball = 14, softball = 10, baseball = 12, women’s track = 2, men’s track = 6, women’s lacrosse = 17, women’s tennis = 9, men’s tennis = 12.

The Institutional Review Boards of George Fox University and Pacific University approved this study. Athletes provided informed consent prior to testing.

Procedures Demographic measures, off-season training habits, prior injury history, and LEFT scores were collected from each athlete at the start of their sports preseason. Prior to performing the LEFT, each athlete provided the following information: age, years in university, age they started participating in their sport, and average weekly time devoted to training (in four categories: weightlifting, cardiovascular exercise, plyometric training, scrimmaging) during the six-week period of time prior to the start of the season.

Dynamic Warm-Up Prior to performing the LEFT, each athlete performed a five-minute dynamic warm-up. This warmup routine was performed to metabolically prepare the athlete for activity and to reduce the risk of injury.22 Athletes were instructed to perform the following active movements at their own pace: forward walking, backward walking, forward lunging, backward lunging, and high knee marching.

Lower Extremity Functional Test Protocol The LEFT is performed on a diamond shaped course: 9.14 m (30 ft.) in the North-South direction and 3.05 m (10 ft.) in the East-West direction (Figure 1).1-3,23,24 Triangles, made with 0.305 m (1.0 ft.) strips of athletic tape, were placed at the end of each axis. The following agility drills are performed during the test in the following order: forward run, backward run, side shuffle, cariocas (Figure 2), Figure 8s, 45° cuts (plant outside foot), 90° cuts (plant outside foot), crossover 90° cuts (plant inside foot), forward run, and backward run.1-3,23,24 The athlete is positioned at the Southern triangle to start the test. The forward run (sequence: South – North – South) and backward run (sequence: South – North – South) are performed first at the start of the test and repeated at the end of the test. The remaining drills are performed both in a counterclockwise and a clockwise direction. Consistent verbal instruction from an investigator is necessary due to the variety of skills performed and fatigue onset.25

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habits, and LEFT scores between sexes within the validation sample. Independent t-tests were also utilized to compare means between sexes within the combined sample for demographics, training habits, and LEFT scores. Mean (± SD) LEFT scores were calculated, using data from the combined sample, and presented by sex for each sport. Independent t-tests were utilized to compare mean LEFT scores between sexes by sport. The PI collected injury records on a weekly basis from the ATC team.

Figure 2. Athlete Demonstrating Carioca Progressing from the West Triangle toward the North Triangle.

A researcher provided verbal instruction as to the next movement and its associated course direction as the athlete neared completion of a task. One trial of the LEFT was performed by each athlete. Time was recorded in seconds using a stopwatch. Testretest reliability for the LEFT is 0.95 to 0.97.24 Injury Surveillance The university’s athletic training (ATC) staff documented all non-contact time-loss injuries to the LQ for all athletes. The operational definition of an injury was any musculoskeletal injury resulting from a non-contact injury mechanism to the lower quadrant (LQ) [categorized by region: low back, hip, thigh, knee, leg, ankle, or foot] that occurred during practice or competition that resulted in the athlete either failing to complete that day’s event or requiring the athlete to miss a subsequent practice or competition.25,26 The athletic trainers also provided athletic exposure data. In this study one athletic exposure was equal to participation in one practice or one game.

Statistical Analyses A minimum of 67 subjects per sex, based on an a priori calculation, were needed to identify statistically significant associations between LQ injury and LEFT measures for the validation sample. Descriptive statistics (means ± SD) were calculated for demographic information, off-season training habits, and LEFT scores. Independent t-tests were utilized to compare means for demographics, training

Cutoff Scores Multiple receiver-operator characteristic (ROC) curves (by sex) were created in order to identify potential cutoff scores that maximized sensitivity and specificity for demographic information, offseason training reports, and LEFT scores [Note: separate ROC curves analyzing LEFT scores were created for both the validation sample and the combined sample. The additional ROC curve analyses for demographic and training variables were only created using the combined sample]. Analysis of ROC curves for the validation sample failed to identify a cutoff score for the LEFT; thus, previously reported cutoff scores for the LEFT were used for regression analysis.4 A majority of the ROC curves for the combined sample failed to identify a cutoff score for numerous variables; however, the category “age starting sport” was significant for “all LQ injuries” and “thigh or knee injuries”. For female athletes in the combined sample, the area under the curve associated with all LQ injuries was 0.66 (95% CI: 0.57, 0.76) (Figure 3a) and the area under the curve associated with thigh or knee injuries was 0.66 (95% CI: 0.55, 0.77) (Figure 3b). All other measures were dichotomized based on either mean scores from the combined sample population or previously reported cutoff scores (for off-season training variables).27 Univariate logistic regression was performed to calculate odds ratios (OR) and 95% confidence intervals (CI). Logistic regression was performed for both the validation sample (per sex) and for the combined sample (per sex). Risk profiles were calculated based on region of the body injured: 1) all injuries (e.g., all LQ injuries), 2) thigh or knee injuries, and 3) foot or ankle injuries. Data analysis was performed using SPSS Statistics 23 (Chicago, IL) with the alpha level set at 0.05.

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Figure 3. (a) Receiver Operator Characteristic (ROC) Curve Associated with All Female Athletes (e.g., Combined Sample) and All LQ Injury during Sport. For this ROC curve: a “smaller” test result (e.g., younger age starting sport) was associated with a greater risk of injury. (b) Receiver Operator Characteristic (ROC) Curve Associated with All Female Athletes (e.g., Combined Sample) and Thigh or Knee Injury during Sport. For this ROC curve: a “smaller” test result (e.g., younger age starting sport) was associated with a greater risk of injury.

RESULTS Demographic information, off-season training habit reports, and LEFT scores for subjects in the validation sample and for the combined sample of D III athletes are presented in Table 1. Male athletes, in both samples, completed the LEFT significantly faster than their female counterparts (p ≤ 0.0001).

Male athletes also reported more time devoted to off-season training in each category except for plyometric training.

In this study, females in the validation study completed the LEFT in 113.1 (± 10.4) seconds and males completed the LEFT in 98.6 (± 8.1) seconds. Normative data for the LEFT has been previously reported based on either small sample sizes or for heterogeneous populations. Table 2 presents a comparison of LEFT scores between this study and prior studies.

Normative LEFT data per sport and gender is presented in Table 3 (this data includes LEFT scores for the combined sample). For all female D III athletes (n = 210) the mean LEFT score was 115.1 (± 10.6) seconds with a range of 91 to 162 seconds. For all male D III athletes (n = 185) the mean LEFT

score was 101.6 (± 9.0) seconds with a range of 85 – 135 seconds. In each sex based comparison, males completed the LEFT significantly faster than their female counterparts.

A total of 34 non-contact time-loss LQ injuries were experienced by subjects in the validation sample (n = 206). Female athletes in the validation sample experienced 17 total non-contact time-loss LQ injuries with 12 occurring at the thigh or knee region and five occurring at the ankle or foot. Male athletes in the validation sample experienced 17 total noncontact time-loss LQ injuries with 14 occurring at the thigh or knee region and two occurring at the ankle or foot. For the combined sample (n = 395) a total of 78 non-contact time-loss LQ injuries were recorded. Female athletes sustained a total of 22 injuries to the thigh or knee, 17 injuries to the foot or ankle, and three injuries to other regions of the LQ. Male athletes sustained a total of 21 injuries to the thigh or knee, 11 to the foot or ankle, and 4 injuries to other regions of the LQ. Odds ratios (OR) associated with the validation sample for female and male populations are presented in

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Table 1. Demographic Information and Lower Extremity Functional Test Scores (Seconds) for Female and Male Division III Athletes: Sex Based Comparisons for Validation Sample and for Combined Sample.

Table 2. Comparison of Lower Extremity Functional Test Scores (Seconds) between the Current Study (Validation Sample and Combined Sample) and Previously Reported Populations.

Table 4. No significant relationships between LEFT measures and cutoff scores were found for either sex; thus unable to validate the risk profile previously reported4 for a general D III athlete population.

Odds ratios for the combined sample were calculated and presented in Tables 5 and 6. Crude OR were calculated for demographics, off-season training habits, and LEFT scores by sex. Table 5 presents OR for

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Table 3. Comparison of Lower Extremity Functional Test Scores (Seconds) between Sexes based on Sport: Normative Data for 395 Division III Athletes.

Table 4. Odds Ratios for Lower Extremity Functional Test Scores (Seconds) for Division III Athletes: Validation Sample.

all (e.g., combined sample) female D III athletes.

Only one category was associated with future risk of injury: age starting sport. Females who started participating in their primary sport at age 11 or older were significantly less likely (OR = 0.4, 95% CI: 0.2, 0.8; p = 0.01) to experience â&#x20AC;&#x153;any LQ injuryâ&#x20AC;? and less likely (OR = 0.3, 95% CI: 1.4, 10.0; p = 0.009) to experience a thigh or knee injury. Stated in the converse, female athletes who were 10 years of age

or younger when starting sport were two times (OR = 2.4, 95% CI: 1.2, 4.9) more likely to experience any LQ injury and three times (OR = 3.2, 95% CI: 1.2, 8.1) more likely to experience a thigh or knee injury). Multivariate regression of demographic, training, or LEFT scores did not change risk profiles.

Table 6 presents OR for all (e.g., combined sample) male D III athletes. Only one category was

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Table 5. Crude Odds Ratios for Demographic and Lower Extremity Functional Test Scores for All (Combined Sample) Female Division III Athletes (N = 210).

associated with future risk of injury: off-season plyometric training. Males who reported performing plyometric exercises less than three hours a week were significantly less likely (OR = 0.3, 95% CI: 0.1, 0.9; p = 0.03) to experience a foot or ankle injury. In other words, males who reported performing greater than 3 hours per week of plyometric exercises were four times more likely (OR = 4.0, 95% CI: 1.1, 14.0) to experience a foot or ankle injury.

DISCUSSION The primary purpose of this study was to validate or refute the previously reported4 risk profile for athletes based on their preseason performance of the LEFT. The results of the current study were not able to validate the utility of the LEFT as an individual test to discriminate injury risk. A secondary purpose to this study was to evaluate demographic variables as potential risk factors. Only one demographic

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Table 6. Odds Ratios for Demographic and Lower Extremity Functional Test Scores for All (Combined Sample) Male Division III Athletes (N = 185).

variable (age starting sport â&#x2030;¤ 10 years) was associated with injury risk in female athletes and only one off-season training category (> 3 hr/week) was associated with injury risk in male athletes.

This study illustrates the importance of performing subsequent prospective cohort studies to assess preseason FPT measures and future injury risk in athletic populations. Based on the results in this study the LEFT should not be used in isolation to

determine risk of injury in a general population of collegiate athletes.

The LEFT may have utility as a test for either a specific athlete population or as part of battery of tests for a general population of athletes. For example, a general population of D III female athletes that presented with suboptimal scores on a battery of FPT (shorter standing long jump measures, shorter single-leg hop for distance measures performed

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bilaterally, and slower LEFT scores) were nine times more likely to experience a thigh or knee injury during sport.28 Additional studies are warranted to identify the LEFT’s predictive utility in either homogeneous sport populations or as one component of a battery of preseason performance tests.

In addition to assessing the utility of the LEFT as a predictor of injury, numerous demographic and offseason training variables were assessed for their ability to dichotomize athletes into at risk and lesser risk groups. For female athletes, the age starting sport was identified as a risk factor. Interestingly, female athletes who reported starting sport at a younger age (10 years of age or earlier) had a greater risk than those who started playing their primary sport at age 11 or older. A possible explanation for this finding may be related to sport specialization and the observation that athletes who participate in one sport experience a greater rate of injury when compared to those who participate in multiple sports.29-33 Athletes who start sport participation at a later age may have been less likely to focus on only one sport throughout their adolescent athletic career. It is important to note though that information regarding the sport participation history for each athlete was not collected, thus this finding should be viewed with caution.

For male athletes time spent performing plyometric exercises during the six-week period prior to the official start of the preseason was associated with future foot and ankle injury. This finding is contrary to what one might expect. Plyometric training is considered an important component of athletic strength and conditioning training programs and injury prevention programs.34,35 The authors do not suggest that an athlete or a team should reduce time devoted to plyometric training. Rather, it is possible that athletes that devoted more time in the off-season to unsupervised plyometric training devoted less total time to other forms of training that may have had a protective effect (e.g., injury protection).

It should be noted that there is a lack of prospective studies assessing the role of training parameters (e.g., mode of exercise, volume, etc.) and subsequent risk of injury in a population of D III athletes.

A novel feature of this study is the presentation of sex and sport specific normative data for the LEFT.

In this study’s validation sample, male athletes completed the LEFT in 98.6 (± 8.1) seconds and female athletes completed the LEFT in 113.1 (± 10.4) seconds. Healthy female D III athletes, in this study and in prior studies,4,24 appear to be able to complete the LEFT faster than originally described.1 This may be due in part to the sample population from Davies et al1 (athletic demographics unknown) or the sample’s health status (e.g., recovering from injury vs. healthy status). Male D III athletes in this study appear to complete the LEFT in a period of time similar to those previously reported.1,4,24 The LEFT is used clinically by rehabilitation professionals to assess an athlete’s readiness to return to sport.1-3 The presentation of normative data per sport and sex can aid clinicians as they make determinations regarding an athlete’s ability to return to sport after a low back or LE injury.

Limitations A few limitations to this study are noted. First, the risk profiles for females (age starting sport) and males (plyometric training) may be subject to recall bias. It is possible that an athlete under or overreported training habits or the age that they started sport. Prospective cohort studies are warranted to confirm these findings. Second, the risk profiles presented here are for a general population of D III athletes and may not be generalizable to other levels of competition. Third, as part of this study athletic exposures (e.g., 1 AE = either participation in one practice or one game) were collected; however, this measure of exposure did not quantify exposure per minutes played (Note: collecting athletic exposures are necessary to calculate injury rates per LEFT cutoff scores. Injury rates based on cutoff scores were not calculated because there were no significant relationships between LEFT measures and sports injury occurrence). It is possible that categorizing athletes by their LEFT measures and exposures per minutes played during practice or competition could help discriminate at risk athletes.36 For example, increased time playing in Division I football games was associated with injury.36 However, increased playing time may not always be associated with greater injury risk. In a cohort of male, collegiate basketball players, one being a starter was no more likely to get injured than their non-starter counterparts.25

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CONCLUSION A prior study reported an association between preseason LEFT scores and subsequent injury in a general population of D III athletes. However, in this validation study, the LEFT test failed to discriminate athletes at risk for a sports injury. The LEFT may provide utility as a preseason performance test for either specific sport populations or as part of a battery of tests; however, this requires future study. Finally, the data presented in this study may aid rehabilitation professionals when evaluating an injured athlete’s ability to return to sport by comparing their LEFT score to population norms.

REFERENCES 1. Davies GJ, Zillmer DA. Functional progression of a patient through a rehabilitation program. Orthop Phys Ther N Am. 2000; 9: 103-117.

2. Ellenbecker TS, Davies GJ. Closed Kinetic Chain Exercise: A Comprehensive Guide to Multiple-Joint Exercises. Champaign, IL: Human Kinetics; 2001.

3. Davies GJ, Heiderscheit BC, Clark M. The scientific and clinical rationale for the use of open and closed kinetic chain rehabilitation. In: Ellenbecker TS, ed.

Knee Ligament Rehabilitation. Philadelphia, PA: Churchill Livingstone; 2000: 291-300.

4. Brumitt J, Heiderscheit BC, Manske RC, et al. Lower extremity functional tests and risk of injury in division III collegiate athletes. Int J Sports Phys Ther.

2013; 8: 216-227.

5. Brumitt J, Heiderscheit BC, Manske RC, et al. The lower-extremity functional test and lower-quadrant injury in NCAA division iii athletes: a descriptive and epidemiologic report. J Sport Rehabil. 2016; 25: 219-226.

6. Manske R, Reiman M. Functional performance testing for power and return to sports. Sports Health.

2013; 5: 244-250.

7. Chimera NJ, Warren M. Use of clinical movement screening tests to predict injury in sport. World J Orthop. 2016; 7: 202-217.

8. Plisky PJ, Rauh MJ, Kaminski TW, et al. Star excursion balance test as a predictor of lower extremity injury in high school basketball players. J Orthop Sports Phys Ther. 2006; 36: 911-919.

9. Smith CA, Chimera NJ, Warren M. Association of y balance test reach asymmetry and injury in division I athletes. Med Sci Sports Exerc. 2015; 47: 136-141.

10. Opar DA, Williams MD, Timmins RG, et al.

Eccentric hamstring strength and hamstring injury risk in Australian footballers. Med Sci Sports Exerc.

2015; 47: 857-865.

11. Opar DA, Williams MD, Timmins RG, et al. The effect of previous hamstring strain injuries on the change in eccentric hamstring strength during preseason training in elite Australian footballers. Am J Sports Med. 2015; 43: 377-384.

12. Kiesel K, Plisky PJ, Voight ML. Can serious injury in professional football be predicted by a preseason functional movement screen? N Am J Sports Phys Ther. 2007; 2: 147-158.

13. Azzam MG, Throckmorton TW, Smith RA, et al. The functional movement screen as a predictor of injury in professional basketball players. Curr Orthop Pract.

2015; 26: 619-623.

14. Bushman TT, Grier TL, Canham-Chervak M, et al.

The functional movement screen and injury risk: association and predictive value in active men. Am J Sports Med. 2016; 44: 297-304.

15. Walbright PD, Walbright N, Ojha H, Davenport T. Validity of functional screening tests to predict lost-time lower quarter injury in a cohort of female collegiate athletes. Int J Sports Phys Ther. 2017; 12: 948-959.

16. Dossa K, Cashman G, Howitt S, et al. Can injury in major junior hockey players be predicted by a preseason functional movement screen – a prospective cohort study. J Can Chiropr Assoc. 2014; 58: 421-427.

17. Martin C, Olivier B, Benjamin N. The functional movement screen in the prediction of injury in adolescent cricket pace bowlers: an observational study. J Sport Rehabil. 2017; 26: 386-395.

18. Mokha M, Sprague PA, Gatens DR. Predicting musculoskeletal injury in national collegiate athletic association division ii athletes from asymmetries and individual-test versus composite functional movement screen scores. J Athl Train. 2016; 51: 276-282.

19. Moran RW, Schneiders AG, Mason J, et al. Do functional movement screen (fms) composite scores predict subsequent injury? A systematic review with meta-analysis. Br J Sports Med. 2017; 51: 1661-1669.

20. Warren M, Smith CA, Chimera NJ. Association of the functional movement screen with injuries in division i athletes. J Sport Rehabil. 2015; 24: 163-170.

21. Butler RJ, Lehr ME, Fink ML, et al. Dynamic balance performance and noncontact lower extremity injury in college football players: an initial study. Sports Health. 2013; 5: 417-422.

22. McMillian DJ, Moore JH, Hatler BS, et al. Dynamic vs. static-stretching warm up: the effect on power and agility performance. J Strength Cond Res. 2006; 20: 492-499.

23. Reiman MP, Manske RC. Functional Testing in Human Performance. Champaign, IL: Human Kinetics; 2009.

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24. Tabor MA, Davies GJ, Kernozek TW, et al. A multicenter study of the test-retest reliability of the lower extremity functional test. J Sport Rehabil. 2002; 11: 190-201.

25. Brumitt J, Engilis A, Isaak D, et al. Preseason jump and hop measures in male collegiate basketball players: an epidemiologic report. Int J Sports Phys Ther. 2016; 11: 954-961.

26. Rauh MJ, Koepsell TD, Rivara FP, et al.

Epidemiology of musculoskeletal injuries among high school cross-country runners. Am J Epidemiol.

2005; 163: 151-159.

27. Brumitt J, Engilis A, Eubanks A, et al. Risk factors associated with noncontact time-loss lower-quadrant injury in male collegiate soccer players. Sci Med Football. 2017; 1: 96-101.

28. Brumitt J, Heiderscheit B, Manske RC, et al.

Preseason performance on a battery of functional tests is associated with time-loss thigh and knee injury in division iii female athletes. [abstract SPL12 in Sports Physical Therapy Section Abstracts: Platform Presentations SPL1-SPL67] J Orthop Sports Phys Ther. 2016; 46: A29-A57.

29. McKay D, Broderick C, Steinbeck K. The adolescent athlete: a developmental approach to injury risk.

Pediatr Exerc Sci. 2016; 28: 488-500.

30. Feeley BT, Agel J, LaPrade RF. When is it too early for single sport specialization? Am J Sports Med. 2016; 44: 234-241.

31. Pasulka J, Jayanthi N, McCann A, et al.

Specialization patterns across various youth sports and relationship to injury risk. Phys Sportsmed. 2017; 45: 344-352.

32. Post EG, Trigsted SM, Riekena JW, et al. The association of sport specialization and training volume with injury history in youth athletes. Am J Sports Med. 2017; 45: 1405-1412.

33. McGuine TA, Post EG, Hetzel SJ, et al. A prospective study on the effect of sport specialization on lower extremity injury rates in high school athletes. Am J Sports Med. 2017; 45(12): 2706-2712.

34. Slimani M, Chamari K, Miarka B, et al. Effects of plyometric training on physical ďŹ tness in team sport athletes: a systematic review. J Hum Kinet. 2016; 53: 231-247.

35. Alentorn-Geli E, Myer GD, Silvers HJ, et al.

Prevention of non-contact anterior cruciate ligament injuries in soccer players. Part 2: a review of prevention programs aimed to modify risk factors and to reduce injury rates. Knee Surg Sports Traumatol Arthrosc. 2009; 17: 859-879.

36. Wilkerson GB, Colston MA. A reďŹ ned prediction model for core and lower extremity sprains and strains among collegiate football players. J Athl Train.

2015; 50: 643-650.

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IJSPT

ORIGINAL RESEARCH

TWO YEAR ACL REINJURY RATE OF 2.5%: OUTCOMES REPORT OF THE MEN IN A SECONDARY ACL INJURY PREVENTION PROGRAM (ACL-SPORTS) Amelia J.H. Arundale1 Jacob J. Capin1 Ryan Zarzycki1 Angela H. Smith2 Lynn Snyder-Mackler1,2

ABSTRACT Background: The Anterior Cruciate Ligament-Specialized Post-Operative Return to Sports (ACL-SPORTS) randomized control trial (RCT) examined an evidence-based secondary ACL injury prevention training program, involving progressive strengthening, agility training, and plyometrics. The RCT examined the benefit of the training program with and without a neuromuscular training technique called perturbation training.

Hypothesis/Purpose: The purpose of this study was to report the return to sport and second ACL injury incidence outcomes of the men in the ACL-SPORTS trial.

Study Design: Secondary analysis of a RCT Methods: Forty cutting and pivoting sport male athletes participated in the ACL-SPORTS trial, return to sport testing, and in follow-up sessions at one and two years after ACL reconstruction. Variables of interest at one and two years were return to sport, return to preinjury level of sport, and second ACL injuries. Mean time to passing return to sport criteria, the number of athletes returning to sport and preinjury level of sport and the incidence proportion of second ACL injuries were calculated.

Results: Athletes passed return to sport criteria 232±99 days after ACLR. One year after ACL reconstruction 95% had returned to sport, 78% at their preinjury level. Two years after ACL reconstruction all athletes had returned to sport, 95% at their preinjury level and only one athlete had a second ACL injury.

Conclusions: The results of this study indicate that men in the ACL-SPORTS trial had much higher return to sport rates and much lower second ACL injury rates than those reported in the literature.

Level of Evidence: 1b Key Words: Anterior cruciate ligament, sport, athletes, return to sport, second injury, rehabilitation

1

Biomechanics and Movement Science Program, University of Delaware, Newark, USA. 2 Department of Physical Therapy, University of Delaware, Newark, USA. Acknowledgements: The authors would like to thank Kathleen Cummer (formerly White) for her contributions to the ACL-SPORTS randomized control trial and data collection. The authors would also like to thank the faculty and staff of the University of Delaware Physical Therapy Clinic for their patient care and assistance in this study. Further the authors would like to thank the Delaware Research Core (supported by NIH U54 GM104941), especially Martha Callahan for her help with scheduling and randomization.

Conflict of Interests: The authors have no competing or conflicts of interest.

Funding: Funding for this project was provided by NIH R01 AR048212.

Amelia Arundale and also received support for some of their work from R44 HD068054 and a Promotion of Doctoral Studies I Scholarship from the Foundation for Physical Therapy. Jacob Capin also received support for some of his work from a Promotion of Doctoral Studies I Scholarship from the Foundation for Physical Therapy. In addition, some of Ryan Zarzycki’s work was supported by NIH R37 HD037985.

CORRESPONDING AUTHOR Amelia Arundale Address: 540 S. College Ave, Newark DE 19711 Telephone: +1-971-409-6134 Email: arundale@udel.edu

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INTRODUCTION Before ACL reconstruction, 91% percent of athletes believe they will return to their preinjury levels of sport.1 After surgery, only 65% actually return to that level.2 Athletes who do return to their preinjury levels are at higher risk for a second ACL injury, compared to those who do not return or have no history of ACL injury.3-5 Returning to cutting and pivoting sports increases an athlete’s odds for an ipsilateral second ACL injury by 3.9 times and for a contralateral injury by five times.5 Such low return to sport and high second ACL injury rates support a need for targeted secondary ACL injury prevention and return to sport programs, however to-date there is a lack of evidence-based programs that report outcomes.

The training program examined in the Anterior Cruciate Ligament-Specialized Post-Operative Return to Sports (ACL-SPORTS) single blinded randomized control trial was developed to be a sport-specific secondary ACL injury prevention program used in the return to sport phase of ACL reconstruction rehabilitation.6 The training program utilized best practices from the primary ACL injury prevention literature; employing multiple exercise modalities during training,7 having multiple training sessions per week8 for a total training duration ≥30 minutes per week,9 and modeling after primary ACL injury prevention programs shown to be effective in improving landing biomechanics in young female athletes10 and reducing primary ACL injuries.11 Both groups in the ACL-SPORTS randomized control trial received the training program consisting of progressive strengthening, plyometric, agility, and secondary ACL injury prevention exercises. One group received the training program (SAP group) alone, while the other received the training program with the addition of perturbation training (SAP+PERT group).6,12 Eighty athletes (40 men) participated in the ACL-SPORTS randomized control trial. Enrollment of men proceeded more quickly than women, and all of the men reached the two-year study endpoint before the women. Primary outcomes in the men indicated that at one and two years after ACL reconstruction there were differences between the groups in limb symmetry during three dimensional motion analysis of walking gait.13 Further,

there were also no differences between the SAP and SAP+PERT groups in knee function or patientreported outcomes measures, but both groups had better outcome scores after training than published registry data.14 These studies indicated that the SAP and SAP+PERT groups could be combined in subsequent secondary analyses, such as this study.

As the training program at the heart of the ACLSPORTS trial was designed to be a secondary ACL injury prevention program used during the return to sport phase of ACL reconstruction rehabilitation; the purpose of this study was to determine the return to sport, return to preinjury level of sport, and second ACL injury rate of the men who participated in the ACL-SPORTS trial. The authors hypothesized that athletes in the ACL-SPORTS trial would have higher return to sport and lower second ACL injury rates than those published in the literature.

METHODS The randomized control trial was approved by the University of Delaware Institutional Review Board and registered at clinicaltrials.gov (NCT01773317).

Prior to participation, all athletes gave written informed consent (or assent if <18 years old with parent/guardian written informed consent). The methods of the randomized control trial have been published previously.6 The current study reports on only the men (n=40) in the original trial. Data collection and analysis of the 40 women in the trial is on-going, and will be published in future work.

As this is a publically funded study, the authors feel it is important to inform the public of the trial results as they become available, thus have decided to publish these results as follow-up on the women continues.

The median age of the athletes was 21.5 (range 15-54 years old), and all athletes were regular participants (≥50 hours per year) in Level I (n=38) or II (n=2) 15 cutting and pivoting type sports prior to their ACL injuries.6 As is typical with most athletes,1 all athletes enrolled in the ACL-SPORTS trial intended to return to their preinjury levels of activity. To collect a generalized sample, athletes were recruited from the local community through surgeon and physical therapist referrals, newspaper advertisements, and word of mouth. Athletes were of various skill

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Figure 1. CONSORT ďŹ&#x201A;ow diagram of athletes through study.

As a result of primary outcome studies indicating no difference between athletes who received the training program (SAP) and athletes who received the training program with perturbation training (SAP+PERT),13,14 particularly in functional measures and patient reported outcomes the groups were collapsed for analysis.13,14

levels ranging from NCAA Division I (the highest level of university sports in the United States) to youth and adult recreational level. ACL reconstructions were performed by 21 experienced orthopedic surgeons, and post-operative rehabilitation was performed in multiple community physical therapy clinics. Rehabilitation prior to enrollment was not standardized, but enrollment criteria were utilized to ensure a homogenous entry point and athlete safety. Athletes were enrolled at the point where they are typically discharged from physical therapy in the United States; upon achieving activities of daily living goals and beginning to run. Enrollment criteria were: three to nine months after unilateral ACL reconstruction with â&#x2030;Ľ80% quadriceps strength

limb symmetry (QI), minimal effusion, no pain, full range of motion, and successful completion of a running progression.6,16 Athletes were excluded (Figure 1) if they had a concomitant >1 cm2 full thickness chondral defect (assessed via arthroscopy or MRI) or grade three ligamentous injury (example medial or lateral collateral ligament), previous ACL reconstruction, a history of major lower extremity injury or surgery to either limb, or had already returned to sport. Only six athletes screened for study were unable to resolve strength, range of motion, effusion, and pain impairments within nine months of their ACL reconstruction indicating these criteria were not too stringent or selective (Figure 1). The primary reason for exclusion from the study were

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Table 1. Exercises performed by each group as part of this study6

a history of a previous ACL reconstruction (n=27), declining to participate in the study (n=16), and not being a Level I or II athlete (n=14).

The male athletes in the ACL-SPORTS trial were enrolled between November 2011 and June

2014. Upon enrollment, athletes were randomized into either the SAP group (n=20, Table 1) or the SAP+PERT group (n=20). Randomization and concealed allocation were performed using a random number generator by a research coordinator (MC) who had no contact with the athletes beyond

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scheduling. All researchers performing data collections were blinded to group allocation.

For clarity, the term “training program” was used to refer to the exercises that all athletes performed regardless of group; Nordic hamstring, standing squat, drop jump, triple single-leg hopping, tuck jump exercises and progressive agility drills (Table 1). In accordance with each athlete’s sport, the training program was made sport-specific by incorporating movements, such as throwing or kicking, and equipment, such as balls or sticks.6 Training was performed twice a week for five weeks, a total of ten sessions. Sessions were progressed according to soreness and effusion guidelines (Appendix B),6,16 and supervised by a physical therapist from the University of Delaware Physical Therapy Clinic. Where needed, therapists educated the athletes on correct landing technique and lower extremity alignment during exercises, particularly avoiding knee valgus collapse.

Upon completion of the program all athletes were required to pass return to sports criteria before being cleared to begin to return to sport/activity. These criteria were ≥90% quadriceps strength limb symmetry index (measured isometrically on an electromechanical dynamometer6), ≥90% limb symmetry index on four single-legged hop tests (single, crossover, and triple hops for distance and the six meter timed hop tests),17 and ≥90% scores on the Knee Outcomes Survey-Activities of Daily Living Scale (KOS-ADLS)18 and the global rating of perceived knee function (global rating). These criteria have been used in previous studies,3,19 and achieving ≥90% limb symmetry is not uncommon in the literature.16,20,21 The number of days from ACL reconstruction to passing the return to sport criteria was recorded. If an athlete did not pass the criteria on the first attempt, a detailed progressive home exercise program was prescribed to address the athlete’s deficits and they were retested in approximately one month. Once athletes were cleared to return to sport they were given instructions on how to gradually acclimatize to sport, starting with returning to training without contact, then introducing contact in controlled small groups, progressing to full contact during training sessions and eventually full participation in games.16

As part of a comprehensive clinical follow-up, one and two years after ACL reconstruction athletes answered the questions “Have you returned to sports or recreational activities?” and “Have you returned to the same level of sports or recreational activities as before your injury?” Athletes also reported if they had sustained a second ACL injury (contralateral or graft rupture). Only two of the 40 men were unable to participate in follow-up sessions in-person but were contacted and answered via telephone.

As previous work examining the primary functional and biomechanical outcomes at one and two years after ACL reconstruction indicated no difference between groups,13,14 the SAP and SAP+PERT groups were combined for analysis of return to sport and second ACL injury outcomes. Demographic and anthropometric data, such as age, height, weight, mechanism of injury, and graft type were compiled, and mean time to passing the return to sport criteria, return to sport and return to preinjury level of sport rates were calculated. The incidence proportion of second ACL injuries was also calculated by dividing the number of second ACL injuries by the number of men in the ACL-SPORTS study. Means and standard deviations were calculated using Microsoft Excel (Redmond, Washington, USA).

RESULTS Forty men were enrolled and completed all ten sessions of the training program with no adverse events. (Table 2) The most common sports that subjects participated in were soccer, basketball, American football, lacrosse, ultimate frisbee, flag football, and ice hockey.

Return to sport: The mean time to passing return to sport criteria was 232 ± 99 days (~7.5 months) after ACL reconstruction. One year after ACL reconstruction all but two (95%) athletes had returned to sport at some level (Table 3). One athlete had not yet passed the return to sport criteria, and the other cited changes in lifestyle/not enough time.

Seven other athletes had not returned to their preinjury level of sport. Three cited fear of reinjury as their reason. Two of the three athletes citing fear had returned to Level III activities (low level jogging and weight lifting) but had not been cleared to return to

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Table 2. Demographics and anthropometrics

Table 3. Number of athletes who returned to sport and preinjury level of activity at each time point

their preinjury level as they had not yet passed the return to sport criteria. The other reasons cited for not returning to preinjury level of sport were swelling (1), not enough time (2), and waiting for final clearance from surgeon (1).

At two years all athletes had returned to sport (Table 3), and only two athletes had not returned to their preinjury level. One of these athletes cited not enough time, the other cited fear of reinjury and although he had returned to level III sports, he had not yet passed return to sport criteria.

Second ACL injury: Only one athlete had a second ACL injury. This injury was a graft rupture (allograft) in a 32-year-old. The overall incidence proportion of second ACL injuries was 0.025 injuries/athlete.

DISCUSSION All athletes in the ACL-SPORTS trial participated in a secondary ACL injury prevention training program designed for use during the return to sport phase of ACL reconstruction rehabilitation. The training program involved ten sessions over five weeks. Each session lasted approximately 60-90 minutes and could be performed in a clinic or on a field/court. As

athletes in the United States are typically discharged from physical therapy when they begin basic athletic tasks, such as running; the program was designed to introduce higher-level athletic movements and guide an athlete towards a safe return to sport. The results of the current study indicate that in the first two years after ACL reconstruction all of the men who participated in the ACL-SPORTS trial returned to sport, 95% returned to their preinjury level of sport, and only one experienced a second ACL injury. The findings of this study indicate that the training program may be beneficial for men who wish to safely return to sport after ACL reconstruction.

Return to sport: A 2011 meta-analysis reported that 77% of athletes attempt to return to sport in the first year after ACL reconstruction.22 In the current study, at one year 95% of athletes had returned to sport at some level, and 78% had already returned to their preinjury levels. A 2014 meta-analysis of return to sport rates found that over the five to seven years after ACL reconstruction 81% of athletes had returned to some level of activity, but only 65% returned to their preinjury level.2 More recently, Failla et al.23 described a cohort similar in demographics and athletic participation to the one in this study, a subgroup of Multicenter Orthopedic Outcomes Network (MOON) cohort. The return to preinjury level of sport rate in that MOON subgroup at two years after ACL reconstruction was 63%. In contrast, by two years after ACL reconstruction 100% of athletes in this study had returned to sport, and 95% had returned to their preinjury level, 37 of 38 to Level I sports.

Studies with return to sport rates as high as those in this study have been published, but are in samples of elite or professional athletes. WaldĂŠn et al.24 reported that in elite level soccer 94% of athletes returned to training and 89% returned to match play within one year of their ACL reconstruction.

A 2017 meta-analysis found a pooled return to sport rate of 83% for elite athletes, with a 5.3% second ACL injury rate.25 Elite athletes are known to return to play at higher rates than athletes at lower levels2 though, potentially because they may receive higher quality or have more frequent access to physical therapy.26 The results of this study demonstrate that high return to sport rates are not limited to elite

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level athletes. The cohort in this study had a diverse array of skill levels, ranging from NCAA Division I athletes to high school level players and recreational level adult league participants. Thus, these results suggest that in a general athletic population the rehabilitation involved in the training program may help male athletes return to sport at a higher rate than that reported in the current literature.

Second ACL injury: Second ACL injury rates in young athletes range between 23-36%.5,27-29 The current study found a second ACL injury incidence of 2.5%.

No second ACL injuries occurred in the first year after ACL reconstruction, a known high-risk window.27,30 The only second ACL injury, an ipsilateral allograft injury in a 32-year-old soccer player, occurred late in the second post-operative year. Allografts are known to have a higher risk for graft ruptures compared to autografts.27 Although the injury was non-contact, the athlete attributed the injury to the uneven surface of the soccer field. Following his reinjury, the athlete had no episodes of giving way and met the criteria for non-operative ACL injury treatment.32,33 He returned to his preinjury level of sport within one year of his second ACL injury and remains at this level, non-operatively managed, three years later; suggesting that neuromuscular control was not the primary contributor to this injury. The low rate of second ACL injuries in this study compared to the previous literature indicates that the training program in the ACL-SPORTS trial may be beneficial in secondary ACL injury prevention in men.

There are additional factors beyond the exercise components that could be contributing to the success of the training program. The enrollment criteria ensured that athletes were safe to perform the exercises involved in the training program. Each athlete was required to pass strict return to sport criteria, prior to returning to their preinjury level of sport.

Previous authors have shown that passing these return to sport criteria can reduce the risk of reinjury.3 Further, each athlete performed a course of post-operative rehabilitation, followed by the training program, and then were required to pass return to sport criteria. This sequence meant that most athletes passed the return to sport criteria around 7.5 months, likely returning to their preinjury level in the ensuing weeks as they completed their gradual

acclimatization. Time delays between ACL reconstruction and return to sport may also have implications for reinjury.3 Future research should examine the implications of each of these factors, but they do not detract from the results of this study. When used together, enrollment criteria, the training program, and strict return to sport criteria produced higher return to sport and lower second ACL injury rates than those available in the published literature.

Strengths and Limitations: This study only examined the outcomes of the 40 men in the randomized control trial. Second ACL injury risk is higher in women than men,27,30 and future analyses will examine the results of the women in the ACL-SPORTS randomized control trial. Further prospective studies examining the training program in other, particularly larger, cohorts are needed to discern second ACL injury rates as well as to compare this program to other return to sport programs. This study also relied on athletesâ&#x20AC;&#x2122; self-report for return to sport and second injury data and did not include exposure data. A strength of this study is its sample. Athletes came from a variety of surgeons and performed their post-operative physical therapy in a number of different community clinics, making the cohort generalizable. The study set reasonable enrollment criteria, to ensure athletes had a standardized entry point into the study, were safe to perform the advanced sport-related tasks but were not selective of only elite or high performing athletes. The generalizability of this cohort, combined with the enrollment criteria, the training program, and the strict return to sport criteria mean that the results of this study have good external validity, and can be implemented clinically.

CONCLUSIONS In conclusion, all of male athletes enrolled in the ACL-SPORTS trial returned to sport at some level and 95% returned to their preinjury level (39/40, 37/38 to Level I sports) with only one athlete sustaining a second ACL injury in the two years after ACL reconstruction. These results when compared to previous literature demonstrate much higher return to sport and much lower second ACL injury rates. Previous studies have shown that men who participated in the ACL-SPORTS trial had higher knee function

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and patient reported outcome measure scores than published registry data one and two years after ACL reconstruction.14 Combined with the results of this study, it seems that the training program examined in the ACL-SPORTS trial may be a beneficial return to sport phase ACL reconstruction rehabilitation intervention for men who wish to safely return to sport.

REFERENCES 1. Feucht M, Cotic M, Saier T, et al. Patient expectations of primary and revision anterior cruciate ligament reconstruction. Knee Surg Sport Traumatol Arthrosc. 2016;24(1):201-207.

2. Ardern CL, Taylor NF, Feller JA, et al. Fifty-five per cent return to competitive sport following anterior cruciate ligament reconstruction surgery: An updated systematic review and meta-analysis including aspects of physical functioning and contextual factors. Br J Sports Med. 2014;48(21):15431552.

3. Grindem H, Snyder-Mackler L, Moksnes H, et al.

Simple decision rules can reduce reinjury risk by 84% after ACL reconstruction: The delaware-oslo ACL cohort study. Br J Sports Med. 2016.

4. Mohtadi N, Chan D, Barber R, et al. Reruptures, reinjuries, and revisions at a minimum 2-year follow-up: A randomized clinical trial comparing 3 graft types for ACL reconstruction. Clin J Sports Med. 2016;26(2):96-107.

5. Webster KE, Feller JA, Leigh WB, et al. Younger patients are at increased risk for graft rupture and contralateral injury after anterior cruciate ligament reconstruction. Am J Sports Med. 2014:641-647.

6. White K, Di Stasi S, Smith A, et al. Anterior cruciate ligament- specialized post-operative return-to-sports (acl-sports) training: A randomized control trial.

BMC Musculoskelet Disord. 2013;14(1):108.

7. Sugimoto D, Myer GD, Foss KDB, et al. Specific exercise effects of preventive neuromuscular training intervention on anterior cruciate ligament injury risk reduction in young females: Metaanalysis and subgroup analysis. Br J Sports Med. 2015;49(5):282.

8. Sugimoto D, Myer GD, Bush HM, et al. Compliance with neuromuscular training and anterior cruciate ligament injury risk reduction in female athletes: A meta-analysis. J Athl Train. 2012;47(6):714.

9. Sugimoto D, Myer G, Barber Foss K, et al. Dosage effects of neuromuscular training intervention to reduce anterior cruciate ligament injuries in female athletes: Meta- and sub-group analyses. Sports Med. 2014;44(4):551.

10. Hewett T, Stroupe A, Nance T, et al. Plyometric training in female athletes. Decreased impact forces and increased hamstring torques. Am J Sports Med. 1996;24(6):765 - 773.

11. Hewett T, Lindenfeld T, Riccobene J, et al. The effect of neuromuscular training on the incidence of knee injury in female athletes. A prospective study.

Am J Sports Med. 1999;27(6):699 - 706.

12. Fitzgerald GK, Axe MJ, Snyder-Mackler L. The efficacy of perturbation training in nonoperative anterior cruciate ligament rehabilitation programs for physically active individuals. Phys Ther.

2000;80(2):128-140.

13. Capin JJ, Zarzycki R, Arundale A, et al. Report of the primary outcomes for gait mechanics in men of the acl-sports trial: Secondary prevention with and without perturbation training does not restore gait symmetry in men 1 or 2 years after ACL reconstruction. Clin Orthop Rel Res. 2017;43(10):2513-2522.

14. Arundale A, Cummer K, Capin J, et al. Report of the clinical and functional primary outcomes in men of the acl-sports trial: Similar outcomes in men receiving secondary prevention with and without perturbation training 1 and 2 years after acl reconstruction. Clin Orthop Rel Res. 2017.

15. Daniel DM, Stone ML, Dobson BE, et al. Fate of the ACL-injured patient: A prospective outcome study.

Am J Sports Med. 1994;22(5):632-644.

16. Adams D, Logerstedt D, Hunter-Giordano A, et al.

Current concepts for anterior cruciate ligament reconstruction: A criterion-based rehabilitation progression. J Orthop Sports Phys Ther.

2012;42(7):601-614.

17. Noyes FR, Barber SD, Mangine RE. Abnormal lower limb symmetry determined by function hop tests after anterior cruciate ligament rupture. Am J Sports Med. 1991;19(5):513-518.

18. Irrgang JJ, Snyder-Mackler L, Wainner RS, et al.

Development of a patient-reported measure of function of the knee. J Bone Joint Surg.

1998;80(8):1132-1145.

19. Hartigan EH, Axe MJ, Snyder-Mackler L. Time line for noncopers to pass return-to-sports criteria after anterior cruciate ligament reconstruction. J Orthop Sports Phys Ther. 2010;40(3):141-154.

20. Kyritsis P, Bahr R, Landreau P, et al. Likelihood of acl graft rupture: Not meeting six clinical discharge criteria before return to sport is associated with a four times greater risk of rupture. Br J Sports Med. 2016;50(15):946-951.

21. Myer GD, Schmitt LC, Brent JL, et al. Utilization of modified NFL combine testing to identify functional deficits in athletes following acl reconstruction. J Orthop Sports Phys Ther. 2011;41(6):377-387.

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22. Ardern CL, Webster KE, Taylor NF, et al. Return to the preinjury level of competitive sport after anterior cruciate ligament reconstruction surgery: Two-thirds of patients have not returned by 12 months after surgery. Am J Sports Med. 2011;39(3):538-543.

23. Failla MJ, Logerstedt DS, Grindem H, et al. Does extended preoperative rehabilitation influence outcomes 2 years after ACL reconstruction?: A comparative effectiveness study between the moon and delaware-oslo ACL cohorts. Am J Sports Med. 2016.

24. Waldén M, Hägglund M, Magnusson H, et al.

Anterior cruciate ligament injury in elite football: A prospective three-cohort study. Knee Surg Sport Traumatol Arthrosc. 2011;19(1):11-19.

25. Lai CCH, Ardern CL, Feller JA, et al. Eighty-three per cent of elite athletes return to preinjury sport after anterior cruciate ligament reconstruction: A systematic review with meta-analysis of return to sport rates, graft rupture rates and performance outcomes. Br J Sports Med. 2017.

26. Ekstrand J. A 94% return to elite level football after ACL surgery: A proof of possibilities with optimal caretaking or a sign of knee abuse? Knee Surg Sport Tr A. 2011;19(1):1-2.

27. Paterno MV, Rauh MJ, Schmitt LC, et al. Incidence of second ACL injuries 2 years after primary ACL reconstruction and return to sport. Am J Sports Med. 2014;42(7):1567-1573.

28. Webster KE, Feller JA. Exploring the high reinjury rate in younger patients undergoing anterior cruciate ligament reconstruction. Am J Sports Med. 2016.

29. Wiggins AJ, Grandhi RK, Schneider DK, et al. Risk of secondary injury in younger athletes after anterior cruciate ligament reconstruction: A systematic review and meta-analysis. Am J Sports Med. 2016.

30. Paterno MV, Rauh MJ, Schmitt LC, et al. Incidence of contralateral and ipsilateral anterior cruciate ligament (ACL) injury after primary acl reconstruction and return to sport. Clin J Sports Med. 2012;22(2):116-121.

31. Maletis GB, Inacio MCS, Funahashi TT. Risk factors associated with revision and contralateral anterior cruciate ligament reconstructions in the kaiser permanente aclr registry. Am J Sports Med. 2015;43(3):641-647.

32. Fitzgerald G, Axe M, Snyder-Mackler L. A decisionmaking scheme for returning patients to high-level activity with nonoperative treatment after anterior cruciate ligament rupture. Knee Surg Sport Traumatol Arthrosc. 2000;8(2):76-82.

33. Fitzgerald GK, Axe MJ, Snyder-Mackler L. Proposed practice guidelines for nonoperative anterior cruciate ligament rehabilitation of physically active individuals.

J Orthop Sports Phys Ther. 2000;30(4):194-203.

Appendix A

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Appendix B

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IJSPT

ORIGINAL RESEARCH

INFLUENCE OF ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION ON DYNAMIC POSTURAL CONTROL Becky Heinert, MS, PT, SCS1,3 Kari Willett, SPT2 Thomas W. Kernozek, PhD, FACSM2,3

ABSTRACT Background: Athletes that have had anterior cruciate ligament (ACL) reconstruction are at a greater risk for reinjury. The relationship between ACL reconstruction and the dynamic postural sway index (DPSI) has not yet been examined.

Hypothesis/Purpose: The purpose of this study was to examine the DPSI in a surgically reconstructed ACL limb compared to the uninjured leg in athletes that had been cleared for sport. It was hypothesized that in a bilateral limb comparison, the leg that underwent ACL reconstruction would demonstrate poorer postural stability measures (greater DPSI) during a single leg landing activity as compared to the non-surgical limb.

Design: Case-control study.

Methods: 14 subjects (7 male, 7 female; age range 16-23 years) with a history of unilateral ACL reconstruction and clearance for return to sport (mean 14 months post-operatively, range 8 to 24 months) performed five single leg hops over a 12 inch hurdle in the anterior direction from a distance corresponding with 40% of their height, onto a force platform. DPSI for the medial-lateral, anterior-posterior, vertical directions and a composite score were calculated for each trial on the surgical and non-surgical legs. A multivariate analysis with repeated measures was used to compare surgical and non-surgical legs for the total DPSI measure as well as for each component.

Results: Significant differences (p < .05) in dynamic postural stability were observed in the medial-lateral, anterior-posterior, vertical indices and DPSI total between the surgical and non-surgical limb.

Conclusion: Deficits in dynamic postural control persist in ACL-reconstructed limbs compared to the non-surgical limb after the clearance for full activity. Clinicians should consider assessing single limb dynamic stability prior to releasing the athlete back to full activity.

Level of evidence: Level 3 Keywords: Anterior cruciate ligament, Dynamic postural stability index, kinetics, single limb hop

1

Gundersen Health System, La Crosse, WI, 54601, USA University of Wisconsin-La Crosse, Department of Health Professions, Physical Therapy Program, La Crosse, WI, 54601, USA 3 La Crosse Institute for Movement Science, La Crosse, WI, 54601, USA 2

All authors report no conďŹ&#x201A;ict of interest based on this work.

CORRESPONDING AUTHOR Thomas W. Kernozek, PhD, FACSM University of Wisconsin-La Crosse Department of Health Professions, Physical Therapy Program 1300 Badger Street, La Crosse, WI 54601, USA. Work (608)785-8468, Fax (608)785-8460 E-mail: kernozek.thom@uwlax.edu

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INTRODUCTION Athletes that have sustained a tear to the anterior cruciate ligament (ACL) and return to sport after surgical reconstruction appear to be at a greater risk for ACL re-injury. The recurrence rate for a second ACL tear has been estimated to be between 6-25% within five years following reconstruction, with nearly 50% occurring in the contralateral limb, the majority as non-contact injuries.1 Factors such as altered knee proprioception, decreased lower extremity strength, poor neuromuscular control, performance flaws in the biomechanics of landing, poor postural stability and fear avoidance beliefs have all been implicated in this greater risk of re-injury.2â&#x20AC;&#x201C;11 In a clinical setting, postural stability is often determined statically as the athlete attempts to maintain their center of mass over a stationary base of support by comparing the amount of time that the individual can maintain their balance on their injured vs. non-injured limb.12 This is used to assess lower extremity proprioceptive deficits. These measures are often incorporated in school and clinical settings because of the relative ease in which they can be administered and interpreted without sophisticated equipment. However, static postural stability measures alone have been described as insensitive, nonfunctional, and poorly related to dynamic values.12â&#x20AC;&#x201C;16 Alternatively, a measure that requires the individual to maintain their center of gravity over a base of support when moving or when an external perturbation is applied to the body may be a more challenging and sensitive method to assess changes in the limbâ&#x20AC;&#x2122;s proprioceptive capabilities. Paterno et al.3 reported deficits in dynamic postural stability that were predictive of a second ACL injury in surgically reconstructed participants using a Balance system with a moveable platform. However, since the majority of injuries to the ACL are non-contact and are often associated with more dynamic activities such landing, cutting or deceleration, it may be of greater value to assess postural stability during activities that are dynamic and more closely mimic the athletic activity.

Two methods are often used in measuring dynamic lower extremity postural control. The Dynamic Postural Sway Index (DPSI) measures limb stability using a single leg hop test onto a force plate. The DPSI is a highly reliable assessment (ICC = 0.96) and provides

a composite score of anterior-posterior, medial-lateral, and vertical stability indices bases on the ground reaction forces.17 This metric was developed with the underlying premise that dynamic postural stability largely depends on lower extremity kinematics, muscle activation and eccentric control utilized in landing.17 Time to Stabilization (TTS) is another dynamic postural stability measure with good reliability that has been used to assess landing activities (ICC=.65-.79).16 TTS is defined as the time required to minimize resultant ground reaction forces of a jump landing to within a range of the baseline, or static ground reaction force. TTS also provides information on directional forces occurring during landing (anterior-posterior, medial-lateral, and vertical), however the TTS methods utilize no composite score which may preclude observations regarding global changes in dynamic limb stability.17 DPSI is considered a more reliable and precise measure of dynamic postural stability than TTS during a single leg hop activity.17 To date, no previous studies have evaluated postural stability in the ACL reconstructed population using DPSI methods. It is hypothesized that in a bilateral limb comparison, the leg that underwent ACL reconstruction would demonstrate poorer postural stability measures (greater DPSI) during a single leg landing activity as compared to the non-surgical limb.

METHODS Subjects All subjects or their parents provided their signed informed consent prior to participation approved by the university institutional review board. Fourteen subjects were recruited from the local area into the ACL reconstructed (ACLR) group each had received their surgical intervention within the prior two years and having received full clearance for athletic activity by their physician and physical therapist. All had some physical therapy intervention after surgery but all did not use the same surgeon nor therapist for treatment. Subjects were excluded from the study if they were experiencing any lower extremity or back pain.

Procedures Upon arrival to the laboratory, anthropometric data were collected including height, weight, and activity level. All subjects were issued standardized footwear (625 New

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Figure 1. Dynamic postural control index is calculated based on the performer hopping with both legs over a 12” barrier and landing on one leg with either their surgical or non-surgical limb.

Balance, Boston, MA) and completed a five minute warm up on a stationary bicycle at a self-selected speed.

The subjects were asked to perform five successful single landings over a 12 inch hurdle in the anterior direction (Figure 1) onto a force platform sampled at 1200 Hz (Bertec Corp, Columbus, OH). The participants began from a distance corresponding with 40% of their height to the force platform. They were allowed to use their arms to propel themselves over the barrier and assist with obtaining postural control.

Participants were given instructions to place their hands on their hips immediately following stabilization and hold that position for 10 seconds. If the subject flailed their arms during the terminal stabilization period, missed the force plate, made contact with the hurdle, touched the ground with the opposite leg or jumped with a single leg, the trial was repeated. Five trials were selected as this number has been shown to provide excellent reliability during similar single leg hop tasks for dynamic postural control indices (ICC = 0.90-0.97).17 Prior to data collection, subjects were allowed as many practice sessions as needed in order to become familiar with the testing procedure. The order of the limb tested was randomized.

Analysis Force data were filtered using a zero-lag fourth order low pass Butterworth filter with a 20 Hz cutoff frequency. Directional postural stability indices (ML, AP and vertical) and the composite dynamic postural

stability index (DPSI) were calculated for the five trials for each leg (surgical and non-surgical). For each condition, mean postural stability indices of five trials were exported for statistical analysis. The first three seconds of the GRF data after impact, defined as the instant the vertical GRF exceeds 10N, was used to calculate a postural stability index in the ML, AP, and vertical (V) directions for each trial using the following root mean square equations presented by Wikstrom et al.17

ML PSI = √∑⌠(0- GRFx)²/ number of data points⌡ AP PSI = √∑⌠(0- GRFy)²/ number of data points⌡ V PSI = √∑⌠(body weight- GRFz)²/ number of data points⌡ where GRFx corresponds to the mediolateral GRF data, GRFy corresponds to the anteroposterior GRF data, and GRFz corresponds to the vertical GRF data.

A composite dynamic postural stability index (DPSI) was calculated using the following equation:

DPSI = √⌠∑(0- GRFx)² + ∑(0- GRFy)² + ∑(body weight- GRFz)² / number of data points⌡.

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A multivariate analysis with repeated measures was used to compare between the surgical and non-surgical leg for each DPSI component (ML PSI, AP PSI, V PSI) as well as the total DPSI with alpha set to 0.05.

Follow up univariate tests (paired t-tests) were then performed separately on each DPSI component and total using the Bonferoni procedure.

RESULTS Group demographics are reported in Table 1. Seven males and seven females participated in the study.

The mean age of the subjects was 19 years (1623), mean height of 171.1±9.0 cm, mean weight of 76.5±18.9 kg and mean Tegner score of 6±2. Six participants had patellar tendon autografts, seven participants had hamstring autografts, and one participant had a hamstring allograft. The average time from surgery was approximately 14 months with a range of 8 to 24 months.

Multivariate analysis showed a difference between limbs (Wilk’s lambda = .002, p<0.05). Follow up univariate tests indicated that there were differences in all directional, dynamic postural stability indexes between the surgical and non-surgical limb for each direction as well as for the total score (p < .05) (Table 2). The indexes were higher on the

surgical side by 24% in the medial-lateral direction, 9% in the anterior-posterior direction, 12% for vertical direction and 12% for the total DPSI. DISCUSSION Athletes that have had an ACL reconstruction appear to demonstrate differences in dynamic postural stability during a single limb jump-landing activity on their surgical limb when compared to their nonsurgical limb within two years post-surgery. The participants in the current study demonstrated differences in DPSI total scores as well as all directional components.

The findings of the present study appear to be similar to Webster et al.18 who reported deficits in TTS during a single leg maximum vertical hop and forward jump in Division I female athletes who had undergone ACL reconstruction compared to uninjured controls. In their analysis, the ACL reconstructed group took 0.11 seconds longer to stabilize after a jump landing as compared to the control group.

These authors reported that their strong effect size suggested that this difference was clinically important and that athletes who have completed their rehabilitation and are cleared for sport may still lack the appropriate level of postural stability during a

Table 1. Demographic data for 14 participants

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Table 2. Means (Âą Standard Deviation) in Newtons for dynamic postural stability indices (Medial-lateral, Anterior-Posterior, Vertical and Total) in the non-surgical and surgical legs for Anterior Cruciate Ligament Reconstructed participants while landing during a single-leg hop test

task that mimics sport. The testing protocol in the current study was similar to Sell12 who compared the standard deviation in force platform static variables of force with eyes open and closed to the DPSI in healthy athletes during a barrier jump. However, the mean total DPSI for the healthy subjectâ&#x20AC;&#x2122;s dominant leg in their investigation was 348 whereas in the current study the mean of the uninjured limb was 436 indicating poorer dynamic postural control overall.

Similarly, Mohammadi et al.5 studied the relationship between static and dynamic postural stability in athletes an average of eight months after ACL reconstruction and reported differences in the surgical limb compared to the uninjured limb and compared to healthy controls for all parameters of postural stability including anterior-posterior and medial and lateral amplitude and velocity. Furthermore, the loading rates on the ACL reconstructed limb during a drop landing was approximately 45% greater than on the non-injured limb. These authors suggested that presence of residual postural stability asymmetries may predispose athletes to future re-injury. Differences in loading rates during dynamic tasks were also reported by Pratt and Sigward19 in subjects 6-24 months after ACL reconstruction during single leg landing and running activities. The authors reported that the surgical limb peak power absorption was approximately 50% less than the uninjured limb and suggested that the ACL reconstructed subjects may be reluctant or unable to dynamically accommodate the forces at the knee. Although knee loading patterns were not specifically measured in the current

study, subjects demonstrated greater vertical component of the DPSI which may indicate greater knee stiffness. It is plausible that the demands required during a single leg deceleration activity may be too great for the ACL reconstructed limb and could result in a landing pattern that is stiffer and require increased dynamic postural movements from other segments as the body attempts to stabilize the leg. To address this, clinicians should consider incorporating exercises that require adaptation to various loading variables such as during progressive plyometric training during the rehabilitation of the ACL reconstructed athlete. However, the relationship between knee loading variables and postural stability during dynamic activities requires further investigation.

Although time to stabilization has been used to provide information on dynamic postural stability and motor control in populations effected by ACL injury and functional ankle instability,5,13,17,18 its relationship to DPSI in the ACL population is currently unknown. Intuitively, one would expect some relationship. However, in their comparison of dynamic control measures in injured runners, Meardon et al.20 reported no differences in stability measures of the injured limb using the star excursion test or TTS during a single leg barrier jump but reported differences in the vertical postural stability index and DPSI composite scores. To date, there are no published studies that have utilized the DPSI to assess dynamic postural stability during single limb landing in the ACL reconstructed sample. Because the DPSI includes a global score as well as multiple directional force attenuation components (anterior-posterior, medial-lateral sway and vertical force), it may provide a comprehensive depiction of specific dynamic postural sway deficits that the athlete utilized to absorb ground reaction forces in landing. This may serve to better guide decisions regarding an athleteâ&#x20AC;&#x2122;s readiness for return to play. It appears that that these ACL reconstructed participants had a poorer total DPSI as well poorer outcomes during each component. However, the cause and relevance of the directional component differences are currently unknown and may be influenced by individual differences in lower extremity strength, calf flexibility, innate foot architecture and previous injury history including chronic ankle instability which has previously been related to decreased dynamic balance using TTS and DPSI measures.14,21

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Changes in knee proprioception after ACL injury and post reconstruction have been widely reported within the literature.3,5,18,22,23 The ACL mechanoreceptors are thought to provide direct afferent information to the spinal cord and supraspinal area regarding joint position, knee motion, and tissue deformation.5 Schutte et al.22 reported the neurologic composition of the ACL include neural connections from the ACL to the spinal cord and supraspinal areas. Following reconstruction of the ligament, restoration of the sensory function may not fully recover. Young et al.24 found no evidence of mechanoreceptor reinnervation in reconstructed ACLs an average of 6.9 years after surgery. This lack of sensory input may influence dynamic postural stability and movement strategies in the ACL reconstructed athlete.

The most commonly described methods of measuring knee proprioception are joint position sense and threshold to detect movement.25â&#x20AC;&#x201C;27 Despite the general agreement regarding the loss of the proprioceptive mechanoreceptors from the native ACL after ACL reconstruction, the validity of the current testing strategies to measure this change continues to be debated.23,27,28 Relph and Herrington23,29 reported differences in knee joint position sense as measured in the ability to actively reproduce knee joint position after passive positioning in two separate investigations while Littmann et al.26 reported no difference after ACL reconstruction. In a meta-analysis of proprioception acuity measures following ACL injury, Gokeler et al.27 concluded that there is limited evidence that proprioceptive deficits as detected by the commonly used tests adversely affect function in subjects returning to sports. Likewise, Relph and Herrington23 reported that the minor differences in knee proprioceptive sense may not influence performance or the likelihood of a second injury.

Therefore, the application of the DPSI to the ACL population may provide a more clinically relevant assessment tool that could provide a link between biomechanical and neurosensory characteristics in a more dynamic and challenging environment.

The relationship between ACL re-injury and some aspects of postural stability have been previously examined. Paterno et al.3, reported that individuals with residual balance deficits in their surgical knee as compared to the non-surgical limb were twice

as likely to sustain a second injury to the ACL as compared to those without postural differences.

Their study used a Biodex Balance System to evaluate unilateral postural stability while standing on a force plate. Although this system uses a moveable force platform, it still may be considered a more static examination of postural sway with debatable application or relationship to a more dynamic, sportspecific task. Previous authors have also reported a poor relationship between static and dynamic postural stability measures.12,16,21 Sell12 reported very poor correlations (r= .05-.23) between static and dynamic measures of postural stability in healthy adults using a single leg balance test with eyes open and eyes closed compared to the DPSI measures from a forward and lateral hop. In their study of athletes with functional ankle instability, Ross et al.16 reported poor to moderate reliability for anterior-posterior (ICC=.32) and medial-lateral sway (ICC=.60) during single leg standing while TTS following a single leg vertical jump in the same subjects displayed either poor to moderate reliability (ICC=.61) for anterior-posterior and .80 for mediallateral force components. Together, these findings may suggest that assessing dynamic postural stability during a dynamic task may be a more sensitive means of determining balance deficits. However, the relationship between the dynamic postural control indices and ACL re-injury certainly warrants further investigation.

Participants in the present investigation displayed greater vertical postural instability in the surgical limb suggesting that the ACL reconstructed extremity was not able to attenuate the vertical ground reaction force as well compared to the non-surgical side. In addition to the sensorimotor adaptations that presumably occur following ACL reconstruction, changes in the ability to absorb the vertical ground reaction forces may be related to alterations in lower extremity joint moments and muscle activation patterns that were not examined in the current study.

Numerous studies have reported changes in landing patterns after ACL reconstruction.3,30â&#x20AC;&#x201C;34 Lower extremity asymmetries between limbs including decreases in knee extension moments, changes in peak vertical ground reaction forces and loading rates have been well-documented in the ACL reconstructed patient.30â&#x20AC;&#x201C;33 Furthermore, these differences

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appear to persist for even 2-3.5 years post ACL reconstruction.5,33 Although the relationship between deficits in dynamic postural control and lower extremity force production was not directly studied in the present investigation, it is plausible that lower extremity compensatory mechanisms may be required to achieve single limb stability due to interruption of the normal sensorimotor planning required for high level coordinated movements.

Nyland et al.35 suggested that altered afferent feedback may result in the motor cortex propagating a modified motor plan that is more reliant on proximal and distal segments such as the hip or ankle complex. Compensatory movement patterns such as excessive truncal movements, hip internal rotation, increased knee valgus and decreased knee flexion angles may be present during landing as the proximal stabilizers are required greater role in dynamic stability.3,30,36,37 Altered sensorimotor programming may also influence the ability of the surgical limb to generate force and power production that are necessary during athletic activities. A stiffer landing pattern due to deficits in quadriceps or hamstring recruitment or greater reliance of the gastrocnemius during jumping may be observed in athletes as they transition to sports-related activities.3,30,33,37–40 Dai et al.31 also reported decreases in knee joint moments in ACL reconstructed subjects, suggesting that these changes may be attributed to deficits in dynamic strength, muscle inhibition, altered neuromuscular function or fear avoidance beliefs. These factors may influence an athlete’s ability to return to a previous level of sport and play a role in the incidence of a second ACL. Myer et al.9 compared the effects of plyometric versus dynamic stabilization balance training on power, balance, and landing force in healthy female athletes. They reported that both types of training programs are effective at increasing measures of neuromuscular power by improvements in vertical jump performance (approximately 4 centimeters in the balance group and 2.5 centimeters in the plyometric group), and an average increase of 11.6% greater torque of the knee flexors measured isokinetically. However, differences were shown in lower extremity force attenuation in the dominant leg with the balance group having a 7% decrease in impact force whereas the plyometric group had a

7.6% increase. Both training groups demonstrated a decrease in medial-lateral single leg sway after landing from a single leg hop with their dominant leg.

These authors suggested that the absence of balance and dynamic control activities where subjects are required to control their landing may have had influence on force dissipation during single limb landing.9 In the present study, the relationship between DPSI and the surgical limb’s ability to generate the power performance measures important to sports performance was not examined. The persistence of limb differences in dynamic postural stability may predispose ACL reconstructed athletes to re-injury and should likely need to be considered when determining readiness for a full return to sport. Furthermore, the relationship between the DPSI and athletic performance factors important for the return to play appears to warrant future investigation.

CONCLUSION The results of the present investigation indicate that deficits in dynamic postural control as measured during a single limb landing persist in ACL-reconstructed limbs compared to the non-surgical limb after the clearance for full activity. These deficits may lead to abnormal landing patterns that may place the athlete at risk for re-injury. These findings appear to support the assessment of dynamic postural control measures prior to the return to sport.

REFERENCES 1. Schilaty ND, Nagelli C, Bates NA, et al. Incidence of second anterior cruciate ligament tears and identification of associated risk factors from 2001 to 2010 using a geographic database. Orthop J Sports Med. 2017;5(8):2325967117724196. doi:10.1177/2.

2. Myer GD, Paterno MV, Ford KR, Quatman CE, Hewett TE. Rehabilitation after anterior cruciate ligament reconstruction: criteria-based progression through the return-to-sport phase. J Orthop Sports Phys Ther. 2006;36(6):385-402.

3. Paterno MV, Schmitt LC, Ford KR, et al.

Biomechanical measures during landing and postural stability predict second anterior cruciate ligament injury after anterior cruciate ligament reconstruction and return to sport. Am J Sports Med. 2010;38(10):1968-1978.

4. Paterno MV, Schmitt LC, Ford KR, Rauh MJ, Myer GD, Hewett TE. Effects of sex on compensatory landing strategies upon return to sport after anterior

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cruciate ligament reconstruction. J Orthop Sports Phys Ther. 2011;41(8):553-559.

5. Mohammadi F, Salavati M, Akhbari B, Mazaheri M, Khorrami M, Negahban H. Static and dynamic postural control in competitive athletes after anterior cruciate ligament reconstruction and controls. Knee Surg Sports Traumatol Arthrosc.

2012;20(8):1603-1610.

6. Wilk KE, Romaniello WT, Soscia SM, Arrigo CA, Andrews JR. The relationship between subjective knee scores, isokinetic testing, and functional testing in the ACL-reconstructed knee. J Orthop Sports Phys Ther. 1994;20(2):60-73.

7. Wojtys EM, Huston LJ. Longitudinal effects of anterior cruciate ligament injury and patellar tendon autograft reconstruction on neuromuscular performance. Am J Sports Med. 2000;28(3):336-344.

8. Wild CY, Steele JR, Munro BJ. Insufficient hamstring strength compromises landing technique in adolescent girls. Med Sci Sports Exerc. 2013;45(3):497-505.

9. Myer GD, Ford KR, Brent JL, Hewett TE. The effects of plyometric vs. dynamic stabilization and balance training on power, balance, and landing force in female athletes. J Strength Cond Res. 2006;20(2):345-353.

10. Schmitt LC, Paterno MV, Hewett TE. The impact of quadriceps femoris strength asymmetry on functional performance at return to sport following anterior cruciate ligament reconstruction. J Orthop Sports Phys Ther. 2012;42(9):750-759.

11. Chmielewski TL, Jones D, Day T, Tillman SM, Lentz TA, George SZ. The association of pain and fear of movement/reinjury with function during anterior cruciate ligament reconstruction rehabilitation. J Orthop Sports Phys Ther. 2008;38(12):746-753.

12. Sell TC. An examination, correlation, and comparison of static and dynamic measures of postural stability in healthy, physically active adults.

Phys Ther Sport . 2012;13(2):80-86.

13. Colby SM, Hintermeister RA, Torry MR, Steadman JR. Lower limb stability with ACL impairment. J Orthop Sports Phys Ther. 1999;29(8):444-451; discussion 452-454.

14. Brown CN, Mynark R. Balance deficits in recreational athletes with chronic ankle instability. J Athl Train. 2007;42(3):367-373.

15. Harrison EL, Duenkel N, Dunlop R, Russell G. Evaluation of single-leg standing following anterior cruciate ligament surgery and rehabilitation. Phys Ther. 1994;74(3):245-252.

16. Ross SE, Guskiewicz KM. Examination of static and dynamic postural stability in individuals with functionally stable and unstable ankles. Clin J Sport Med . 2004;14(6):332-338.

17. Wikstrom EA, Tillman MD, Smith AN, Borsa PA. A new force-plate technology measure of dynamic postural stability: the dynamic postural stability index. J Athl Train. 2005;40(4):305-309.

18. Webster KA, Gribble PA. Time to stabilization of anterior cruciate ligament-reconstructed versus healthy knees in national collegiate athletic association division I female athletes. J Athl Train.

2010;45(6):580-585.

19. Pratt KA, Sigward SM. Knee loading deficits during dynamic tasks in individuals following anterior cruciate ligament reconstruction. J Orthop Sports Phys Ther. 2017;47(6):411-419. .

20. Meardon S, Klusendorf A, Kernozek T. Influence of injury on dynamic postural control in runners. Int J Sports Phys Ther. 2016;11(3):366-377.

21. Ross SE, Guskiewicz KM, Gross MT, Yu B. Balance measures for discriminating between functionally unstable and stable ankles. Med Sci Sports Exerc.

2009;41(2):399-407.

22. Schutte MJ, Dabezies EJ, Zimny ML, Happel LT. Neural anatomy of the human anterior cruciate ligament. J Bone Joint Surg Am. 1987;69(2):243-247.

23. Relph N, Herrington L. Knee joint position sense ability in elite athletes who have returned to international level play following ACL reconstruction: A cross-sectional study. The Knee.

2016;23(6):1029-1034.

24. Young SW, Valladares RD, Loi F, Dragoo JL. Mechanoreceptor reinnervation of autografts versus allografts after anterior cruciate ligament reconstruction. Orthop J Sports Med. 2016;4(10):2325967116668782.

25. Relph N, Herrington L, Tyson S. The effects of ACL injury on knee proprioception: a meta-analysis.

Physiotherapy. 2014;100(3):187-195.

26. Littmann AE, Iguchi M, Madhavan S, Kolarik JL, Shields RK. Dynamic-position-sense impairment’s independence of perceived knee function in women with ACL reconstruction. J Sport Rehabil.

2012;21(1):44-53.

27. Gokeler A, Benjaminse A, Hewett TE, et al.

Proprioceptive deficits after ACL injury: are they clinically relevant? Br J Sports Med. 2012;46(3):180192.

28. Howells BE, Ardern CL, Webster KE. Is postural control restored following anterior cruciate ligament reconstruction? A systematic review. Knee Surg Sports Traumatol Arthrosc . 2011;19(7):11681177.

29. Relph N, Herrington L. The effect of conservatively treated ACL injury on knee joint position sense. Int J Sports Phys Ther. 2016;11(4):536-543.

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30. Orishimo KF, Kremenic IJ, Mullaney MJ, McHugh MP, Nicholas SJ. Adaptations in single-leg hop biomechanics following anterior cruciate ligament reconstruction. Knee Surg Sports Traumatol Arthrosc.

2010;18(11):1587-1593.

31. Dai B, Butler RJ, Garrett WE, Queen RM. Using ground reaction force to predict knee kinetic asymmetry following anterior cruciate ligament reconstruction. Scand J Med Sci Sports.

2014;24(6):974-981.

32. Decker MJ, Torry MR, Noonan TJ, Riviere A, Sterett WI. Landing adaptations after ACL reconstruction.

Med Sci Sports Exerc. 2002;34(9):1408-1413.

33. Paterno MV, Ford KR, Myer GD, Heyl R, Hewett TE. Limb asymmetries in landing and jumping 2 years following anterior cruciate ligament reconstruction.

Clin J Sport Med . 2007;17(4):258-262.

34. Ernst GP, Saliba E, Diduch DR, Hurwitz SR, Ball DW. Lower extremity compensations following anterior cruciate ligament reconstruction. Phys Ther.

2000;80(3):251-260.

35. Nyland J, Gamble C, Franklin T, Caborn DNM. Permanent knee sensorimotor system changes following ACL injury and surgery. Knee Surg Sports Traumatol Arthrosc . 2017;25(5):1461-1474.

36. Hewett TE, Myer GD, Ford KR, et al. Biomechanical measures of neuromuscular control and valgus loading of the knee predict anterior cruciate ligament injury risk in female athletes: a prospective study. Am J Sports Med. 2005;33(4):492-501.

37. Di Stasi S, Myer GD, Hewett TE. Neuromuscular training to target deďŹ cits associated with second anterior cruciate ligament injury. J Orthop Sports Phys Ther. 2013;43(11):777-792, 38. Decker MJ, Torry MR, Noonan TJ, Riviere A, Sterett WI. Landing adaptations after ACL reconstruction.

Med Sci Sports Exerc. 2002;34(9):1408-1413.

39. Miranda DL, Fadale PD, Hulstyn MJ, Shalvoy RM, Machan JT, Fleming BC. Knee biomechanics during a jump-cut maneuver: effects of sex and ACL surgery. Med Sci Sports Exerc. 2013;45(5):942-951.

40. Morgan KD, Donnelly CJ, Reinbolt JA. Elevated gastrocnemius forces compensate for decreased hamstrings forces during the weight-acceptance phase of single-leg jump landing: implications for anterior cruciate ligament injury risk. J Biomech.

2014;47(13):3295-3302.

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IJSPT

ORIGINAL RESEARCH

ALTERED SAGITTAL PLANE HIP BIOMECHANICS IN ADOLESCENT MALE DISTANCE RUNNERS WITH A HISTORY OF LOWER EXTREMITY INJURY Pamela B. Lachniet, MD, PhD1,2,3 Jeffery A. Taylor-Haas, PT, DPT, OCS, CSCS4 Mark V. Paterno, PT, PhD, SCS, ATC4 Christopher A. DiCesare, MS, CSCS1 Kevin R. Ford, PhD, FACSM5

ABSTRACT Background: Lower extremity overuse injuries, including bone stress injuries (BSI), are common in runners and may result in prolonged recovery and time off from running. Identifying risk factors for running-related overuse injuries may have a clinically relevant role in prevention of these injuries.

Purpose: The purpose of this study was to compare an adolescent and young adult population of male runners known to have a history of BSI with an injury-free cohort and retrospectively assess for kinematic differences that may differentiate the two cohorts Study Design: Controlled laboratory case control investigation Level of Evidence: Level 3 Methods: 25 male high school and collegiate cross-country runners were enrolled. Ten self-reported a prior history of BSI consisting of lower extremity stress fracture or shin splints/medial tibial stress syndrome and were categorized as injured (INJ). Fifteen self-reported no prior history of lower extremity injury and were categorized as uninjured (UNINJ). All runners were pain-free at time of testing. Runners ran at a self-selected speed on a treadmill with retro-reflective markers attached to thorax, pelvis, and each lower extremity segment. Three-dimensional kinematic calculations were made during stance phase (initial treadmill heel contact to toe off) and averaged over 20 steps. One-way ANCOVA was used to compare kinematic differences at the hip and knee between the INJ and UNINJ cohort.

Results: Runners in the INJ group demonstrated greater peak hip flexion during stance phase on both the right limb [INJ=32.5°(±3.8°) vs. UNINJ=26.9°(±4.6°); p<0.01] and the left limb [INJ=31.2°(±4.8°) vs. UNINJ=26.8°(±3.1°); p=0.01] when compared to the UNINJ group. No significant difference in step length or step rate between the INJ and UNINJ cohorts was noted when normalized to height and weight (p=0.39 and 0.39).

Conclusions: The results of this study demonstrate increased peak stance phase hip flexion in a population of young adult male runners with a previous history of BSI. This association may represent an important preliminary finding in the development of a clinically relevant tool to identify risk of BSI. Due to the retrospective nature of this study, future prospective investigations are warranted to validate these findings to determine if these alterations are compensatory following an injury or predictive of a future injury.

Keywords: Bone stress injury, kinematics, running

1

Division of Sports Medicine, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA. 2 Division of Emergency Medicine, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA. 3 Anderson Hills Pediatrics, Cincinnati, OH, USA. 4 Division of Occupational Therapy & Physical Therapy, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA. 5 Department of Physical Therapy, School of Health Sciences, High Point University, High Point NC, USA. Financial Disclosure and Conflict of Interest: We affirm that we have no financial affiliations (including research funding) or involvement with any commercial organization that has a direct financial interest in any matter included in this manuscript.

CORRESPONDING AUTHOR Jeffery A. Taylor-Haas, PT, DPT, OCS, CSCS Coordinator, Division of OT/PT-Sports Medicine and Orthopaedics Cincinnati Children’s Hospital Medical Center MLC 11033, 3333 Burnet Avenue Cincinnati, OH 45229 Phone: 513-636-3418 Fax: 513-636-2528 E-mail: Jeffery.Taylor-Haas@cchmc.org

The International Journal of Sports Physical Therapy | Volume 13, Number 3 | June 2018 | Page 441 DOI: 10.26603/ijspt20180441

INTRODUCTION Injuries in the running population are common, with estimates of 17-79% of runners affected.1 Of particular concern is the high rate of injuries in young athletes, with high school cross-country runners reported to have an annual incidence of injury as high as 17 per 1000 athletic exposures.2 Overuse injuries involving bone, often referred to as bone stress injury (BSI), occur along a spectrum of disorders starting with stress reaction and progressing to stress fracture and complete bone fracture as the repetitive loading stresses on the bone exceeds the boneâ&#x20AC;&#x2122;s capacity to repair itself.3 In high school athletes participating in cross-country and/or track and field teams, previous injuries were reported by 68% of female subjects and 59% of male subjects.4 While the etiology of such injuries is likely multifactorial and involves both extrinsic and intrinsic factors, the identification of altered kinematics for BSI may have a clinically relevant role in prevention. Given that the micro-damage to the bone in BSI is a product of both frequency of loading as well as the intensity of loading, training errors such as increased training intensity, longer running distance, and rapid increases in mileage, have been cited as consistent contributors to BSI.5 A frequently noted stress reaction afflicting distance runners is medial tibial stress syndrome (MTSS) which can progress to a tibial stress fracture if bone stress continues to exceed bone repair and healing. Previous studies have identified specific risk factors that may contribute to MTSS, including prior history of MTSS, female gender, less running experience, use of orthotics, increased BMI, and, in males, increased hip external rotation range of motion (ROM).6,7 Various kinematic and kinetic factors implicated in tibial stress fractures in adult females include increased peak hip adduction, absolute free moment, peak rear-foot eversion, and vertical loading rates.8,9 It is not known, however, whether these factors are associated with tibial stress fracture risk in adolescent and young adult male long-distance runners.

Longer step lengths have also been linked to an increased probability of developing tibial stress fractures.10 The vertical impact and loading rates at the tibia are higher with longer step lengths11,12,13 which increase the bone strain. In contrast, manipulation

of step rates above preferred rates with a concomitant decrease in step length results in a significant reduction in vertical impact peak, vertical instantaneous loading rate, and vertical average loading rate.13 Kinematic changes are observed in the lower extremities of runners who self-select lower step rates, including longer step length, increased peak hip flexion, decreased knee flexion at initial contact (IC), and increased peak knee flexion.14 These changes place the foot in front of the center of mass at IC in a position of over-striding, decreasing the capacity to absorb and attenuate ground reaction forces, and increasing the risk for BSI.14 While previous studies of running injuries have mostly focused on adults, females, and military populations,15,16 there are relatively few studies specifically comparing the running kinematics of previously injured and uninjured high school and collegiate long-distance runners. The purpose of this study was to compare an adolescent and young adult population of male runners known to have a history of BSI with an injury-free cohort and retrospectively assess for kinematic differences that may differentiate the two cohorts. It was hypothesized that runners with a previous BSI would demonstrate unique sagittal plane running kinematics at the hip and knee, as well as a lower step rate and increased step length, when compared to a previously uninjured cohort.

METHODS Participants Twenty-five male high school (n=11) and collegiate (n=14) cross-country runners participated in this study. The age, height, mass, and BMI for the participants are listed in Table 1. Informed written consent was obtained from each subject in accordance with the protocol approved by the Institutional Review Board at Cincinnati Childrenâ&#x20AC;&#x2122;s Hospital Medical Center. Data were collected immediately prior to the fall cross-country season for each athlete. Athletes met inclusion criteria if they were currently participating on a high school or collegiate crosscountry team and free from pain during testing, by self-report. Athletes were excluded from the study if they were currently under medical supervision and had not been fully cleared to participate in a structured running program.

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Table 1. Subject Demographics.

At the start of the study protocol, participants were asked to complete a survey developed by the research team to report their history of previous shin splints (MTSS), exertional compartment syndrome, and lower extremity stress fractures (tibia, fibula, femur, metatarsal, navicular, or pelvis) and weekly mileage (Appendix 1). Study data were collected and managed using REDCap electronic data capture tools hosted at Cincinnati Children’s Hospital.17 Ten runners self-reported a prior history of tibial stress fracture and/or MTSS (INJ group). No prior history of lower extremity injury (UNINJ group) was reported by 15 of the participants.

Kinematic data collection Lower extremity 3D kinematics during running using a self-selected speed on a custom-built treadmill were calculated as previously described.18 The average speed was 3.8 (±0.2) m·sec-1 (UNINJ) and 3.8 (±0.2) m·sec-1 (INJ) (p=0.592), which corresponds to a light training pace of 7.0 min·mile-1.

Following an acclimation period of three to five minutes, a one-minute trial was collected. All participants were provided with a standard Adidas neutral running shoe during data collection.

Reflective markers were placed on the thorax (posterior cluster of 3 markers), pelvis (right ASIS, left ASIS, and sacrum), and each lower extremity segment (thigh, shank, foot) with a minimum of three tracking markers on each segment (Figure 1).19 Specifically, hip and knee angular displacement were calculated based on the distal segment rotating relative to the proximal segment. Three-dimensional marker trajectories were collected using a motion analysis system (Motion Analysis Corporation,

Figure 1. Marker Set-Up and Treadmill Protocol. Reprinted with permission from IJSPT.

Santa Rosa, CA) with 10 digital cameras as previously described.18 Thirty consecutive steps were recorded, defined as initial contact of the foot with the treadmill to toe-off when the foot left the treadmill (the total of which was the stance phase). Proper stance phase identification in each trial was verified by a frame-by-frame inspection of the identified gait events, i.e., initial contact and toe-off, performed by one reviewer for all participants. This was done by ensuring that, for a given event, the foot was in a reasonable posture (as opposed to mid-swing, for example). Calculations were made during stance phase and averaged over the first 20 recorded steps. One-way analysis of covariance (ANCOVA) was used to compare kinematic differences at the hip and knee between the INJ and UNINJ cohorts while controlling for variables of interest. An exploratory α level of 0.05 was determined a priori to indicate statistical significance.

Foot strikes were determined in Visual3D (C-Motion, Inc., Germantown, MD) using a previously described algorithm.20 In order to classify runners as either rear-foot strikers or mid-foot strikers, Cartesian coordinate data were determined at initial contact for each of the markers affixed to the runner’s heel and lateral foot at the fifth metatarsal. Runners were classified as rear-foot strikers if the heel marker had smaller vertical displacement than the lateral foot marker at initial contact. Conversely, runners were classified as forefoot strikers if the lateral foot marker had smaller vertical displacement than the heel marker at initial contact. To differentiate between mid-foot and forefoot striking, visual inspection of

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the video was performed; this was determined by assessing which of the toe and lateral foot markers had the smaller vertical displacement at initial contact for these runners.

RESULTS Demographics One-way ANOVA was used to compare demographic variables of the INJ and UNINJ groups of runners.

There was no statistically significant difference in age between the UNINJ (18.3±1.5 years) vs INJ (19.8±2.0 years) cohorts (p=0.05). The average heights (p=0.03) and weights (p=0.008) of the INJ runners were significantly greater than the UNINJ cohort but there was no significant difference in BMI (p>0.05) noted (Table 1). There was no significant difference (p=0.17) in weekly mileage between the INJ and UNINJ cohorts (Table 1).

Comparison of hip kinematics Hip kinematics in the sagittal plane were compared between the INJ and UNINJ groups. Peak hip flexion was used as the dependent variable while history of prior injury was the independent variable. Subject height and weight were used as covariates in the in the analysis. Runners in the INJ cohort demonstrated greater peak hip flexion (Table 2) during the stance phase on both the left limb [INJ=31.2°(±4.8°) vs.

UNINJ=26.8°(±3.1°); p=0.003] (Figure 2) and the right limb [INJ=32.5°(±3.8°) vs. UNINJ=26.9°(±4.6°); p=0.012] (Figure 3) when compared to runners in the UNINJ cohort.

The timing for which peak hip flexion occurred during the stance phase was compared to the magnitude of peak hip flexion in both limbs. For the UNINJ cohort, no association was noted between the peak hip flexion angle and the point in the gait cycle at

Table 2. Running Kinematics. Reported in degrees (SD) except when noted.

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Figure 2. Average Peak Hip Flexion of the Left Limb: Prior history of injury vs. No prior history of injury. (CI = confidence interval).

Figure 3. Average Peak Hip Flexion of the Right Limb: Prior history of injury vs. No prior history of injury. (CI = confidence interval).

which this occurred (Figure 4). Conversely, runners in the INJ cohort demonstrated a positive correlation between these variables with higher peak hip flexion angles occurring later in the stance phase of the gait cycle (16-18% of the gait cycle; R2 linear=0.252, Figure 5).

Comparison of knee kinematics Knee kinematics in the sagittal plane were compared between the INJ and UNINJ groups. Peak knee flexion was used as the dependent variable while history of prior injury was the independent variable. Subject height and weight were used as covariates in the

Figure 4. Relationship between peak hip flexion and percent of stance phase at which time peak hip flexion occurs in male runners with no prior history of lower extremity injury.

Figure 5. Relationship between peak hip flexion and percent of stance phase at which time peak hip flexion occurs in male runners with a prior history of lower extremity injury.

analysis. Knee kinematics were compared in the sagittal plane between the INJ and UNINJ groups. Peak knee flexion (Table 2) in both the left and right limbs was not statistically significantly different, although each demonstrated a trend towards significance with greater flexion in the INJ cohort (p=0.09 and 0.07, respectively).

Foot strike, step length, and step rate No significant difference in step length or step rate between the INJ and UNINJ cohorts was noted (p=0.39 and 0.39, respectively; Table 2). Despite

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no significant difference in BMI between the two cohorts, the INJ runners were heavier and taller than the UNINJ runners (Table 1). Step length and step rates, therefore, were normalized to height and weight for each cohort. Foot strike patterns were not significantly different between the INJ and UNINJ cohorts (Table 2). Of the 25 males studied, 21 were classified as rear-foot strikers, two as forefoot strikers, and two as mid-foot strikers.

DISCUSSION It was hypothesized that adolescent and young adult male runners who previously experienced a lower extremity BSI would demonstrate unique sagittal plane running kinematics at the hip and knee, as well as a lower step rate and increased step length when compared to a previously uninjured cohort.

This hypothesis was partially supported in that the group of previously injured male runners showed a statistically significant increase in bilateral peak hip flexion during the stance phase with a trend towards significance in increased peak knee flexion. No significant differences were noted in step length or step rate between the two groups.

In this study, the altered kinematics of the previously injured male cohort most closely resembles the running kinematics of runners who self-select a reduced step rate.14 Although changes in step rate and step length have been theoretically tied to a decreased risk of BSI,10 to the authorsâ&#x20AC;&#x2122; knowledge the association between increased peak hip flexion and BSI is a novel finding. Since no difference in step rate or length was observed despite the altered kinematics, it is possible that the altered sagittal plane hip kinematics themselves are a risk factor for injury. However, due to the cross-sectional nature of the study, cause and effect cannot be clearly determined. The differences in hip kinematics between groups may be a result of compensatory alterations following a BSI injury.

It was further observed that the timing of peak hip flexion during the stance phase varied between runners. Previously injured runners who attained peak hip flexion later in the stance phase of the gait cycle also exhibited an association with a greater magnitude of hip flexion. No association between the timing and magnitude of peak hip flexion was observed

in the uninjured runners. It is postulated that the runners who had delayed hip flexion may not have been effectively pre-activating their gluteal muscles in anticipation of ground contact. A previous study performed in uninjured runners showed an increase in activity of the gluteus maximus and medius during late swing/pre-activation when step rates were increased by 10% over preferred, effectively reducing over-striding.21 As the gluteus maximus eccentrically controls stance hip flexion, delayed hip flexion in the previously injured runners may be indicative of altered gluteal activation. As gluteal activation was not directly measured, further investigations are warranted.

The demographics of the male runners differed in that the INJ cohort was taller, and heavier. Despite the INJ cohort presenting with increased weight and height measurements compared to the UNINJ cohort, the BMI measurements between the two cohorts were not significantly different. Average self-reported weekly mileage between the two cohorts, which can be viewed as a marker for the amount of repetitive bone stress incurred, was also not significantly different.

Limitations The retrospective design limits the ability to draw cause and effect conclusions between injury and altered kinematics. It is possible that the kinematic differences noted were modifications made by the runners secondary to their previous injuries, rather than the cause of their injuries. All runners, however, were pain-free at the time of testing and had been medically cleared for running. In addition, for convenience all data collection was performed on a treadmill rather than overground running. Previous studies comparing overground vs treadmill running have shown that the kinematic data obtained is similar, particularly for the hip.22,23 The differences in knee flexion showed a trend towards significance. It is possible that the current study was underpowered to detect a statistically significant difference. Further, all runners ran in a standard running shoe in an attempt to remove shoe design as a covariate that could impact running mechanics.24, 25 While this practice is common,26 running in a novel shoe may have influenced the runnersâ&#x20AC;&#x2122; mechanics.

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Additionally, kinetic data was not available for this study which could have assisted in interpreting kinematic results. Finally, this data was collected on a competitive, male cohort and thus these results must be viewed with caution when comparing to other running populations.

Future studies should focus on prospective data collection to determine if runners with increased hip flexion during running gait have a higher incidence of lower extremity BSI and should include a female cohort. This would enable investigation of causality as well as a potential area of intervention for injury prevention. In addition, future studies should consider assessing gluteal muscle activation as an improved means of determining the potential effects of altered stance phase hip mechanics on muscle activation and timing. Finally, as bone stress injuries are influenced by factors such as dietary preferences, bone density, and training habits, future studies should consider additional screening questions at the time of data collection.

CONCLUSION In conclusion, the results of the current study indicate altered stance phase sagittal plane hip kinematics in a population of young adult male runners with a previous history of bone stress injury. These novel findings warrant future investigative efforts to further delineate associations and potential prospective risks, if any, in this patient population.

REFERENCES 1. van Gent RN, Siem D, van Middelkoop M, et al.

Incidence and determinants of lower extremity running injuries in long distance runners: a systematic review. Br J Sports Med. 2007;41(8):469-480.

2. Rauh MJ, Koepsell TD, Rivara FP, et al.

Epidemiology of musculoskeletal injuries among high school cross-country runners. Am J Epidemiol.

2006;163(2):151-159.

3. Warden SJ, Davis IS, Fredericson M. Management and prevention of bone stress injuries in longdistance runners. J Orthop Sports Phys Ther.

2014;44(10):749-765.

4. Tenforde AS, Sayres LC, McCurdy ML, et al. PM R. 2011;3(2):125-131.

5. Hreljac A, Ferber R. A biomechanical perspective of predicting injury risk in running: review article. Int SportMed J: Running Injuries. 2006;7(2):98-108.

6. Hubbard TJ, Carpenter EM, Cordova ML. Contributing factors to medial tibial stress syndrome: a prospective investigation. Med Sci Sports Exerc.

2009;41(3):490-496.

7. Newman P, Witchalls J, Waddington G, et al. Risk factors associated with medial tibial stress syndrome in runners: a systematic review and meta-analysis.

Open Access J Sports Med. 2013;4:229-241.

8. Milner CE, Ferber R, Pollard CD, et al.

Biomechanical factors associated with tibial stress fracture in female runners. Med Sci Sports Exerc.

2006;38(2):323-328.

9. Pohl MB, Mullineaux DR, Milner CE, et al.

Biomechanical predictors of retrospective tibial stress fractures in runners. J Biomech.

2008;41(6):1160-1165.

10. Edwards WB, Taylor D, Rudolphi TJ, et al. Effects of stride length and running mileage on a probabilistic stress fracture model. Med Sci Sports Exerc.

2009;41(12):2177-2184.

11. Derrick TR, Hamill J, Caldwell GE. Energy absorption of impacts during running at various stride lengths. Med Sci Sports Exerc. 1998;30(1):128135.

12. Hamill J, Derrick TR, Holt KG. Shock Attenuation and Stride Frequency during Running. Hum Mov Sci. 1995;14(1):45-60.

13. Hobara H, Sato T, Sakaguchi M, et al. Step frequency and lower extremity loading during running. Int J Sports Med. 2012;33(4):310-313.

14. Heiderscheit BC, Chumanov ES, Michalski MP, et al.

Effects of step rate manipulation on joint mechanics during running. Med Sci Sports Exerc. 2011;43(2):296302.

15. Rauh MJ, Macera CA, Trone DW, et al. Selected static anatomic measures predict overuse injuries in female recruits. Mil Med. 2010;175:329-35.

16. Sharma J, Golby J, Greeves J, et al. Biomechanical and lifestyle risk factors for medial tibial stress syndrome in army recruits: a prospective study. Gait Posture. 2011;33(3):361-5.

17. Harris PA, Taylor R, Thielke R, et al, Research electronic data capture (REDCap) â&#x20AC;&#x201C; A metadatadriven methodology and workďŹ&#x201A;ow process for providing translational research informatics support.

J Biomed Inform. 2009;42(2):377-81.

18. Ford KR, Taylor-Haas JA, Genthe K, et al.

Relationship between Hip Strength and Trunk Motion in College Cross-Country Runners. Med Sci Sports Exerc. 2013;45(6):1125-1130.

19. Taylor-Haas JA, Hugentobler JA, DiCesare CA, et al.

Reduced hip strength is associated with increased hip motion during running in young adult and

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adolescent male long-distance runners. Int J Sports Phys Ther. 2014;9(4):456-467.

20. Stanhope SJ, Kepple TM, McGuire DA, et al.

Kinematic-based technique for event time determination during gait. Med Biol Eng Comput.

1990;28(4):355-360.

21. Chumanov ES, Wille CM, Michalski MP, et al.

Changes in muscle activation patterns when running step rate is increased. Gait Posture. 2012;36(2):231235.

22. Fellin RE, Manal K, Davis IS. Comparison of lower extremity kinematic curves during overground and treadmill running. J Appl Biomech. 2010;26(4):407414.

23. Riley PO, Dicharry J, Franz J, et al. A kinematics and kinetic comparison of overground and treadmill running. Med Sci Sports Exerc. 2008;40(6):1093-1100.

24. Mullen S, Toby EB. Adolescent runners: the effect of training shoes on running kinematics. J Pediatr Orthop. 2013;33(4):453-7.

25. Rose A, Birch I, Kuisma R. Effect of motion control running shoes compared with neutral shoes on tibial rotation during running. Physiotherapy 2011;97(3):250-5.

26. Williams DS, Tierney RN, Butler RJ. Increased medial longitudinal arch mobility, lower extremity kinematics, and ground reaction forces in higharched runners. J Athl Train. 2014;49(3):290-6.

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APPENDIX

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IJSPT

ORIGINAL RESEARCH

RELIABILITY OF TWO-DIMENSIONAL VIDEO-BASED RUNNING GAIT ANALYSIS Mark F. Reinking, PT, PhD, SCS, ATC1 Leigh Dugan, SPT1 Nolan Ripple, SPT1 Karen Schleper, SPT1 Henry Scholz, SPT1 Jesse Spadino, SPT1 Cameron Stahl, SPT1 Thomas G. McPoil, PT, PhD1

ABSTRACT Background: While two-dimensional (2D) video running analysis is commonly performed in the clinical setting, the reliability of quantitative measurements as well as effect of clinical experience has not been studied.

Purpose: The purpose of this study was to assess the intra-rater and inter-rater reliability of six different raters using 2D video analysis of sagittal and frontal plane kinematic variables while running on a treadmill.

Study Design: Cross-sectional Study Methods: Running videos from 10 individuals (five female, five male) with a mean age of 22.8 years were selected for analysis. Two raters had over 10 years of experience with running video analysis and the other four raters had no prior experience. Before beginning analyses, the senior investigator conducted two hours of training with all raters to review the measurement procedures and the movement analysis software program. After completing training and one practice analysis, each rater assessed four 60-second video clips for the 10 runners twice (20 total). A minimum of one week separated the two assessments on each runner. The order of the runner analyses were randomly assigned and each rater completed a single analysis within 24 hours. After the rater had completed their initial assessment on all 10 runners, a second analysis was completed one week later with a different order of randomization. Eight sagittal plane (SAG) and four frontal plane (FRT) quantitative variables were measured for the left and right lower extremities on all 10 runners. Intra- and inter-rater reliability was assessed using intraclass correlation coefficients (ICC) and standard error of the measurement (SEM).

Results: The intra-rater ICC values for experienced raters ranged from 0.75 to 0.98 for the SAG and 0.45 to 0.96 for FRT variables. The inter-rater ICC values between the experienced raters ranged from 0.76 to 0.99 for the SAG and 0.82 to 0.98 for FRT variables. The intra-rater ICC values for inexperienced raters ranged from 0.54 to 0.99 for the SAG and 0.08 to 0.97 for FRT variables. The inter-rater ICC values between the inexperienced raters ranged from 0.93 to 0.99 for the SAG and 0.79 to 0.98 for FRT variables. Intra-rater SEM values based on average means of all raters ranged from 1 to 47% of the mean values obtained for the SAG and from 6 to 158% for the FRT variables.

Conclusions: The intra-rater and inter-rater reliability levels were higher for SAG quantitative variables assessed in this study in comparison to FRT variables. Experience does not appear to be a factor when consistency is required with repeated analyses on the same runner.

Level of Evidence: 4, Controlled laboratory study Keywords: Gait analysis, interrater, intra-rater, reliability, running assessment

1

Rueckert-Hartman College of Health Professions, School of Physical Therapy, Regis University, Denver, CO, USA The authors declare no conďŹ&#x201A;ict of interest in matters associated with this paper.

CORRESPONDING AUTHOR Mark F. Reinking School of Physical Therapy Regis University 3333 Regis Blvd, G-4 Denver, CO 80221 E-mail: reinking@regis.edu

The International Journal of Sports Physical Therapy | Volume 13, Number 3 | June 2018 | Page 453 DOI: 10.26603/ijspt20180453

INTRODUCTION While two-dimensional (2D) video running analysis is commonly performed in the clinical setting, the ability of a single clinician or multiple clinicians to reliably analyze various lower extremity alignment variables quantitatively in both the sagittal and frontal planes is still unclear. Although three-dimensional (3D) video-based running gait analysis has long been considered the gold standard, the expense of the required equipment and complexity of the analysis software makes this type of running gait analysis prohibitive for most sports physical therapy clinics. In general, a video running analysis assesses various body postures and alignments in both the sagittal and frontal planes. Maykut et al1 compared frontal plane motion variables captured using 2D and 3D video analysis techniques and reported a strong correlation between both analysis methods when assessing the hip adduction angle. The clinical interest in the hip adduction angle, which is a measure of pelvic drop, is based on findings demonstrating that excessive pelvic drop has been linked to patellofemoral pain syndrome and tibial stress fracture.2,3 Wille et al4 reported that several SAG kinematic variables during running were predictive of ground reaction force variables and joint kinetics during running. These SAG kinematic variables included center of mass (COM) height at midstance and double float, foot inclination angle at initial contact, horizontal distance from shoe heel to COM line at initial contact, and peak knee flexion angle.

Although Wille et al4 utilized 3D video running analysis for data collection, they suggested that 2D video analysis would likely be sufficient to capture these kinematic variables given the strong correlations between 3D and 2D SAG motions during running.

Schurr et al5 reported a high correlation in SAG variables between 2D and 3D video analysis, but poor correlations for the FRT variables. At present, little research has been conducted on the reliability of these analyses based on clinician experience as well as when the analyses are performed over time.

Damsted et al6 assessed the reliability of two experienced raters to measure knee and hip flexion angles at initial foot strike of 18 individuals running on a treadmill using 2D video recordings. They reported that intra-rater and inter-rater reliability was sufficient

between the two experienced raters but that clinicians should be aware that measurement variations can occur, especially when measurements are taken over different days. Unfortunately, their conclusions are limited to those two SAG variables. Krummen et al7 determined only the inter-rater reliability of 12 physical therapists to assess various sagittal and frontal plane running characteristics of six individuals running on a treadmill. While they reported that the inter-rater reliability between the 12 therapists ranged from fair to strong, their research was published as a platform presentation abstract. Thus, specific details regarding data collection and analysis procedures are unknown. One factor that could have affected the results was that Krummen et al7 used an iPad to film the six runners. While the iPad provides an easy tool for recording gait in the clinic, the low frame rate (30 frames per second) available on the iPad used by these researchers could be a factor affecting the results. Most researchers agree that the minimum frame rate that should be used for recording running is at least 120 frames per second.8 In a more recent study, Pipkin et al9 assessed the reliability of three experienced raters performing a qualitative video analysis of 15 individuals running at a self-selected pace on a treadmill using a single camera filming at rate of 120 frames per second. Raters assessed eight sagittal and seven frontal plane body posture and alignment variables using a 3-point or 5-point scoring scale. Using a weighted Kappa statistic, they reported that the level of intrarater agreement was substantial to excellent for 11 of the 15 variables, whereas only five of the 15 variables had the same level of inter-rater agreement.

Of the five variables achieving a rating of substantial (Kappa greater than 0.60) or higher, three were FRT and two were SAG variables. While this study provides valuable information on the reliability of experienced raters performing a 2D video-based running analysis, there are several factors that restrict the application of the study findings. Since only experienced raters were used, the amount of training and experience required to achieve a satisfactory level of reliability is unknown. Additionally, Pipkin et al9 provided each rater with pre-identified still frames to ensure that raters were evaluating the same frame and stride within the video. Since clinicians typically perform a running analysis by randomly selecting a

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stride for analysis, the pre-identified still frames in the Pipkin et al9 study could have positively affected the levels of agreement among raters. Just as importantly, while qualitative analysis provides valuable information to the runner, there are also situations in which quantitative kinematic measurements are of value. These situations may include counseling a runner for injury prevention or when documenting changes in the running kinematics because of rehabilitation following injury. For example, Dierks et al10 suggested that a knee flexion difference less than 40° between initial contact and midstance during stance phase can be associated with patellofemoral pain.

Based on previous research, the consistency of quantitative measurements for sagittal and frontal plane variables when performing a video-based running analysis has not been assessed throughout the entire running cycle. In addition, the influence of rater experience on the reliability of quantitative measurements is unknown. Therefore, the purpose of this study was to assess the intra-rater and interrater reliability of six different raters in assessing various sagittal and frontal plane kinematic variables recorded while running on a treadmill using 2D video analysis. Based on previous research, it was hypothesized that 1) quantitative measurements for SAG kinematics would have higher levels of reliability, irrespective of rater experience, than quantitative measurements for frontal plane kinematics, and 2) experienced raters would demonstrate higher levels of reliability than inexperienced raters when assessing both sagittal and frontal plane kinematics.

METHODS Video Selection Running gait analysis videos from 10 individuals (five female) were selected from pre-existing 2D videos recorded as part of a previous research study that assessed running-gait between recreational and competitive runners (high school and college cross country runners). Ten runners were selected based on subject size used in previous running reliability studies1,6,9,11,12 and number of raters in this study. The mean age of the 10 runners was 22.8 years, with a range of 15 to 29 years. The videos of the 10 individuals were randomly selected from a video pool of 90

runners who were known to be without injury at the time of video capture. All videos were recorded while the individuals ran on a treadmill (Model Mercury S, Woodway USA Inc., Waukesha, WI 53186) using one camera mounted to a portable tripod (Model# EX FH25, Casio America Inc., Dover, NJ 07801) at a rate of 240 frames per second. All 10 individuals had previous experience running on a treadmill and ran at a self-selected speed. To facilitate the observation of marker movement, each participant wore running shorts with the males wearing no shirts and the females wearing a halter-top. Each participant was initially asked to run for five minutes to acclimate to the testing treadmill. Once acclimated, 9 mm spherical reflective markers were placed on each lower extremity over the following locations: anterior superior iliac spine (ASIS), posterior superior iliac spine (PSIS), lateral epicondyle of the femur, lateral malleolus, lower posterior calf above the Achilles tendon (two markers), and over the midline of the heel (two markers). To minimize ASIS and PSIS marker movement, elastic self-adhesive wrapping was applied around the individualâ&#x20AC;&#x2122;s waist prior to marker placement. Once all markers were attached, the participant was then asked to start running on the treadmill at his or her pre-selected running speed. Once the subject indicated they were in their typical running pattern, they continued to run at their preferred speed for five minutes while video data was recorded.

Video data were collected sequentially using one camera for the following four views; right sagittal (side); left sagittal (side), full posterior (frontal), and posterior leg/heel (frontal). All runners selected for this study had previously met the following inclusion criteria: (1) between the ages of 14 to 40 years; (2) ran at least 18 miles per week for one-year prior to participation in the study; (3) had experience running on a treadmill; (4) no previous history of lower extremity congenital or traumatic deformity or previous surgery that resulted in altered bony alignment; and (5) no acute injury three months prior to the start of the study that led to inability to run at least three consecutive days during that time. The Regis University Institutional Review Board approved the study protocol and all participants provided written informed consent prior to participation in the study, and for subjects under 18 years old, parental consent was obtained.

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Video Analysis Procedures Sixty-second video clips (approximately 10 complete strides per clip) were created from each of the original five-minute videos for the reliability assessment.

To ensure that the video clip represented the most acclimated pattern of running, the original video recording for each view (five minutes or 300 seconds in length) was trimmed so that the 60-second video clip began after three minutes or 180 seconds of running on the treadmill. Six raters, two experienced and four inexperienced, were asked to assess the video clips for each of the ten runners. The two experienced raters had over 10 years of experience performing 2D video-based running analyses on both collegiate and recreational runners. The four inexperienced runners were second-year graduate physical therapy students with no prior experience in performing a video-based running analysis.

Prior to initiating the video assessments, all raters whether experienced or inexperienced received a total of three hours of training by the senior investigator. During the initial training two-hour training session, all raters were given written and verbal instructions for performing each of the quantitative measurements used in the study as well as the freeaccess video analysis software program (Kinovea, version 0.8.15, http://www.kinovea.org) used by all raters. At the end of the initial training session, all raters were asked to complete a “practice” 2D running analysis on a runner not included in the 10 runners used for the reliability assessment. The results of analysis on the “practice” runner completed by each rater were then reviewed with all raters during another one-hour training session so that any questions or concerns with the measurement procedures or video analysis software could be addressed.

At the completion of this second training session, the reliability assessment for the 10 runners was initiated. Each rater assessed all four video clips for each of the 10 runners twice (20 total assessments) with at least one week separating the two assessments of the same runner. A study coordinator, who did not perform any video assessments, randomly assigned a runner for assessment to each rater.

When assigned a runner for analysis, the rater was provided a file with the four video clips and asked to complete the assessment within 24 hours. All raters

were instructed to select a stride for analysis after the third foot strike on the video clip to allow them the opportunity to observe the runner’s gait pattern and enhance the rater’s ability to identify initial foot contact. Once the video analysis was completed, the rater returned the data sheet with the quantitative measurements to the study coordinator. Once the study coordinator received the video clips and data sheet, they provided the rater with the next runner’s file with the video clips to be assessed. The same assignment process was used until each rater completed their initial assessment on all 10 runners, at which time the process was repeated with a different order of randomization of the 10 runners for the repeated set of analyses.

Each rater assessed the following variables on the left and right lower extremities for all 10 runners.

SAG variables included; 1) angle of the shoe to treadmill at initial contact, 2) angle of the lower leg at initial contact, 3) knee flexion at initial contact, 4) knee flexion at midstance, 5) position of the COM to the posterior point of shoe at initial contact, 6) knee flexion at midswing, 7) vertical position of the center of mass at midstance, and 8) vertical position of the center of mass at double float.

FRT variables included; 1) hip adduction angle at initial contact, 2) hip adduction angle at midstance, 3) rearfoot angle at initial contact, and 4) rearfoot angle at midstance. All angles were measure in degrees and all distance measurements were taken in centimeters.

Data analysis Intraclass correlation coefficients (ICC) were calculated to determine the consistency of each rater to repeatedly perform the measurements individually (intra-rater; ICC3,1) between the two video analysis sessions as well as in comparison to the other raters (inter-rater; ICC2,k). The level of reliability for the ICC was classified using the characterizations reported by Landis and Koch.13 These characterizations were: slight, if the correlation ranged from 0.00 to 0.20; fair, if the correlation ranged from 0.21 to 0.40; moderate, if the correlation ranged from 0.41 to 0.60; substantial, if the correlation ranged from 0.61 to 0.80; and almost perfect, if the correlation ranged from 0.81 to 1.00. The inter-rater reliability

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Table 1. Participant Demographics

was assessed between the two experienced raters, the four inexperienced raters, and between the experienced and inexperienced raters. For the comparison between the two experienced raters and between the four inexperienced raters, the variable measures for the two sessions were averaged.

To calculate the inter-rater reliability between the experienced raters and the inexperienced raters, the average measure of each rater was averaged for the experienced raters (n=2) and for the inexperienced raters (n=4). The standard error of the measurement (SEM) was also calculated as another indicator of intra-rater for all six raters. The SEM is in the same units as the original measurement and represents how the measurements would vary if

measured more than once by each rater.14All statistical analyses were performed using SPSS software, Version 23 and an alpha level of 0.05 was established for all tests of significance.

RESULTS Demographic data for the 10 participants in the study are listed in Table 1. The intra-rater ICC and SEM values for SAG and FRT variables are listed in Table 2 and 3, respectively. The inter-rater ICCs for SAG and FRT variables are provided in Table 4.

Sagittal Plane Variables. The intra-rater ICC values for all raters and all variables ranged from 0.54 to 0.99 with the SEM ranging from 1% to 47% of the mean value for all variables assessed. For the experienced raters, the intra-rater ICC values ranged from 0.75 to 0.98 with the SEM ranging from 1% to 38% of the mean values for all variables. For the inexperienced raters, the intra-rater ICC values ranged from 0.54 to 0.99 with the SEM ranging from 1% to 47% of the mean values for all variables. For all raters, 70% of all SAG SEM values were less than 10% of the variable

Table 2. Intra-rater Reliability of Sagittal Plane Variables (ICC3,1), Mean (2 measures), and SEM (standard error of measurement)

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Table 3. Intra-rater Reliability of Frontal Plane Variables (ICC3,1), Mean (2 measures), SEM (standard error of measurement)

mean with only 10% of SAG SEM values above 20% of the variable mean.

The inter-rater ICC value between the two experienced raters were all greater than 0.88 except for right knee flexion at initial contact which was 0.76. The inter-rater ICC value between the four Table 4. Inter-rater Intraclass Correlation CoefďŹ cients (ICC3,k) with 95% ConďŹ dence Interval (CI)

inexperienced raters were all greater than 0.92. The inter-rater reliability between experienced and inexperienced raters ranged between 0.97 and 0.99.

Frontal Plane Variables. The intra-rater ICC values for all raters ranged from 0.08 to 0.97 with SEM values ranging from 6% to 158% of the mean value for all variables assessed. For the experienced raters, the intra-rater ICC values ranged from 0.45 to 0.96 with the SEM values ranging from 6% to 64% of the mean values for all variables. For the inexperienced raters, the intra-rater ICC values ranged from 0.08 to 0.97 with the SEM values ranging from 7% to 158% of the mean values for all variables. For all raters, 48% of all FRT SEM values were less than 20% of the variable mean and 52% of FRT SEM values were above 20% of the variable mean.

The inter-rater ICC for all variables ranged from 0.84 to 0.98 for the experienced raters. The inter-rater ICC value between the four inexperienced raters ranged from 0.79 to 0.98. The inter-rater reliability between the experienced and inexperienced raters ranged between 0.86 and 0.99.

DISCUSSION The intent of this study was to assess the intra-rater and inter-rater reliability of six different raters, two experienced and four inexperienced, in assessing various sagittal and frontal plane kinematic variables recorded while running on a treadmill using 2D video analysis. Two-dimensional video running analysis is commonly performed in the clinical setting to assess potential kinematic abnormalities

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when screening for injury prevention or when documenting changes in the running kinematics because of rehabilitation following injury. Since it is common for a video analysis to be conducted on more than one occasion to assess whether changes in running kinematics have occurred because of an injury or a modification of a runner’s gait pattern, the consistency of qualitative measurements assessed on different days is important. In addition, the ability of multiple clinicians with varying levels of clinical experience to reliably perform an assessment of quantitative measurements in both the sagittal and frontal planes has not been previously investigated.

Interpretation of the Reliability of Sagittal and Frontal Plane Variables In general, all raters consistently measured each SAG variable between the two sessions, one week apart with high levels of reliability (ICC > 0.75).

Based on the classification scheme proposed by Landis and Koch, all the intra-rater ICC variables for the two experienced raters would be classified as almost perfect except for Rater 1’s ICC for left knee flexion at midstance) which would be classified as substantial. For the inexperienced raters, based on the Landis and Koch13 classification scheme, the intra-rater ICC for 12 of the 16 variables would be classified as almost perfect. Of the remaining four variables, left tibial angle, left knee angle at initial contact, and right tibial angle would be classified as substantial.

The only intra-rater ICC for the inexperienced raters classified as moderate was right knee angle at initial contact (Rater 4). The results for the inter-rater reliability were quite similar in that the ICC values for the two experienced raters were all classified as almost perfect except for right knee flexion at initial contact which would be classified as substantial.

The inter-rater ICC values between the four inexperienced raters as well as between the experienced versus inexperienced raters would all be classified as almost perfect.

Based on the ICC values, one could conclude that the intra- and inter-rater reliability among all six raters was very high. However, it is important to take into consideration the SEM values for all raters. For the experienced raters, except for the left and right shoe angle, the SEM values for all other SAG variables

were less than or equal to 15% of the mean value.

This would indicate that if a variable mean value was 60°, the degree of variability associated with the measurement by a rater would range between 51° and 69°. For the inexperienced raters, apart from the left and right shoe angle, the SEM values for all other SAG variables were less than or equal to 20% of the mean value. This would indicate that if a variable mean value was 60°, the degree of variability associated with the measurement by a rater would range between 48° and 72°. The only other study that has attempted to evaluate the reliability of quantitative kinematic measures in running was conducted by Damsted et al.6 They assessed the ability of two raters to quantify left knee and hip flexion angles at initial contact during running. They reported that 95% confidence limits for knee flexion ranged from three to 8° within a day and from 9° to 14° between days for the two raters. In the current study, the left mean knee flexion angle at initial contact (averaged across all 6 raters) was 10.43° with the average SEM for all raters 1.36°. Thus, the range for left knee flexion in the current study would be 9.07° to 11.79° which is similar to the values reported by Damsted et al.6 In general, ICC values were lower for the eight FRT variables. For the experienced raters, based on the classification Landis and Koch scheme,13 six of the variables for rater 1 and five of the variables for rater 2 would be classified as almost perfect based on the intra-rater ICC values. The intra-rater ICC values for left hip adduction angle at midstance (Rater 1 and 2), right hip adduction at midstance (Rater 1), and right rearfoot angle at midstance (Rater 2) were classified as substantial, with right hip adduction at initial contact (Rater 2) classified as moderate. Using the Landis and Koch classification scheme, the intra-rater ICC values for only two of the eight variables, left hip adduction at midstance and left rearfoot angle at initial contact would be classified as almost perfect for all four inexperienced raters. For the other six variables, the ICC values would be classified as either substantial or moderate.

The inter-rater ICC for all values was almost perfect between the two experienced and four inexperienced raters except for the right rearfoot angle at midstance which was substantial. The interrater reliability comparing the experienced and

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inexperienced raters was substantial. These findings disagree with Maykut et al1 who reported ICC intra-rater reliability values for hip adduction to be 0.95 for the right and 0.96 for the left using a single rater. Unfortunately, these authors do not provide any information regarding the level of experience of the rater. In the current study, the ICC values for hip adduction angles at initial contact and at midstance ranged from 0.45 to 0.89 for the experienced raters, and 0.08 to 0.92 for the inexperienced raters.

The SEM values for the frontal plane variables were considerably higher in comparison to the SAG variables ranging from 6% to 64% for the experienced raters and from 7% to 158% for the inexperienced raters (Table 3). Based on these findings, the authors confirmed the first hypothesis which stated quantitative measurements for SAG kinematics would have higher levels of reliability, irrespective of rater experience, than quantitative measurements for FRT kinematics.

InďŹ&#x201A;uence of Rater Experience As noted in the introduction, the influence of rater experience on the reliability of quantitative measurements for SAG and FRT variables during running has not been previously investigated. In the current study, two raters had over 10 yearsâ&#x20AC;&#x2122; experience performing running analyses while the other four raters had no previous experience except for a two-hour training session followed by one practice analysis.

Based on intra-rater and inter-rater ICC results for the SAG variables, there was minimal differences between the experienced and inexperienced raters for intra-rater and inter-rater reliability. As noted in the results, all SAG variables demonstrated ICC values greater than 0.75 for the experienced raters with only one variable (right knee angle at initial contact) having an ICC value less than 0.75 for the inexperienced raters. Regarding the FRT variables, both the experienced and inexperienced raters demonstrated lower levels of intra-rater reliability as compared to the SAG variables, with several variables assessed demonstrating ICC values less than 0.75 (three variables for the experienced raters and no variables for the inexperienced raters). These findings would suggest that repeated FRT measurements by the same rater, whether experienced or inexperienced, would

be suspect to variation when performed over multiple days. Based on these results, the authors rejected the second study hypothesis which stated that experienced raters would demonstrate higher levels of reliability than inexperienced raters when assessing both sagittal and FRT kinematics. It would appear based on the current study findings, that experience does not appear to be a factor when consistency is required for repeated analyses on the same runner.

In addition, the findings would suggest that the same clinician can consistently repeat a quantitative running analysis using the sagittal variables assessed in this study irrespective of experience, assuming the level of training used in the current study. When performing an analysis on FRT variables, these results indicate that the same clinician should always perform the analysis, and to be aware of the possibility of greater measurement variability.

It is important to note that the findings of this study are limited to the eight SAG and four FRT kinematic variables assessed in this study. Thus, caution should be used when attempting to generalize these findings to other conditions or kinematic measures obtained using 2D video analysis. Additionally, the reliability in this study may be greater than in clinical running analyses as a result of the use of preplaced reflective markers. These markers aided in the angle measurements during the running analysis. The methodology of this study, however, has addressed previous limitations noted in the literature9 by having both experienced and inexperienced raters perform a running analysis by reviewing the recorded video in slow-motion or frame-by-frame to select the specific points in the running cycle for analysis rather than using pre-identified still frames.

Future research is recommended to compare the reliability of qualitative and quantitative running assessment, and the clinical usefulness of each in making clinical decisions.

CONCLUSION This study is one of the first to assess the reliability of experienced and inexperienced raters assessing quantitative SAG and FRT variables while running on a treadmill using 2D video analysis. The intrarater and inter-rater reliability levels were higher for SAG variables assessed in this study in comparison

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to FRT variables. Experience did not appear to be a factor when consistency is required with repeated analyses on the same runner. The results of the study indicate that the same clinician can consistently repeat a quantitative running analysis using the SAG variables assessed in this study irrespective of experience. Because of poor reliability, the same clinician should always assess FRT variables and be cognizant of greater measurement variability.

REFERENCES 1. Maykut JN, Taylor-Haas JA, Paterno MV, DiCesare CA, Ford KR. Concurrent validity and reliability of 2d kinematic analysis of frontal plane motion during running. Int J Sports Phys Ther. 2015;10(2):136-146.

2. Neal BS, Barton CJ, Gallie R, O’Halloran P, Morrissey D. Runners with patellofemoral pain have altered biomechanics which targeted interventions can modify: A systematic review and meta-analysis. Gait Posture. 2016;45:69-82.

3. Pohl MB, Mullineaux DR, Milner CE, Hamill J, Davis IS. Biomechanical predictors of retrospective tibial stress fractures in runners. J Biomech.

2008;41(6):1160-1165.

4. Wille CM, Lenhart RL, Wang S, Thelen DG, Heiderscheit BC. Ability of sagittal kinematic variables to estimate ground reaction forces and joint kinetics in running. J Orthop Sports Phys Ther.

2014;44(10):825-830.

5. Schurr SA, Marshall AN, Resch JE, Saliba SA. Two-Dimensional Video Analysis Is Comparable to 3d Motion Capture in Lower Extremity Movement Assessment. Int J Sports Phys Ther. 2017;12(2):163172.

6. Damsted C, Nielsen RO, Larsen LH. Reliability of video-based quantification of the knee- and hip angle at foot strike during running. Int J Sports Phys Ther.

2015;10(2):147-154.

7. Krummen K, Kelly S, Briggs M. Reliability of lower externity 2-dimensional video running analysis (Abstract). J Orthop Sports Phys Ther. 2016;46:A42.

8. Souza RB. An Evidence-Based Videotaped Running Biomechanics Analysis. Phys Med Rehabil Clin N Am. 2016;27(1):217-236.

9. Pipkin A, Kotecki K, Hetzel S, Heiderscheit B. Reliability of a Qualitative Video Analysis for Running.

J Orthop Sports Phys Ther. 2016;46(7):556-561.

10. Dierks TA, Manal KT, Hamill J, Davis IS. Proximal and distal influences on hip and knee kinematics in runners with patellofemoral pain during a prolonged run. J Orthop Sports Phys Ther.

2008;38(8):448-456.

11. Alenezi F, Herrington L, Jones P, Jones R. How reliable are lower limb biomechanical variables during running and cutting tasks. J Electromyogr Kinesiol. 2016;30:137-142.

12. Doma K, Deakin GB, Sealey RM. The reliability of lower extremity and thoracic kinematics at various running speeds. Int J Sports Med. 2012;33(5):364369.

13. Landis JR, Koch GG. The measurement of observer agreement for categorical data. Biometrics.

1977;33(1):159-174.

14. Rothstein JM. Measurement in physical therapy. New York: Churchill Livingstone; 1985.

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IJSPT

ORIGINAL RESEARCH

SHORT-TERM EFFECTS OF TRIGGER POINT DRY NEEDLING ON PAIN AND DISABILITY IN SUBJECTS WITH PATELLOFEMORAL PAIN SYNDROME Thomas G. Sutlive, PT, PhD1 Andrew Golden, DPT, OCS2, Cert MDT Kristin King, DPT, OCS3 William B. Morris, DPT, OCS4 John E. Morrison, DPT, OCS5 Josef H. Moore, PT, PhD1 Shane Koppenhaver, PT, PhD, OCS, FAAOMPT6

ABSTRACT Background: Patellofemoral pain syndrome (PFPS) is a prevalent knee disorder. A novel yet increasingly popular treatment for PFPS is trigger point dry needling (DN).

Purpose: The purpose of this study was to determine if DN is more effective at reducing pain and disability than a sham treatment in individuals with PFPS. Study design: Randomized trial.

Materials/Methods: Sixty military health care beneficiaries (36 males) with a clinical diagnosis of PFPS were recruited and completed the study. Subjects underwent a standardized clinical examination and were randomized into a DN or sham treatment group. DN treatment consisted of insertion of an acupuncture-like needle into six sites in the quadriceps femoris muscles of the symptomatic lower extremity based on a palpation examination. The sham grouped received a simulated treatment with a sharp object and needle guide tube without puncturing the skin. Self-reports of pain, disability, and overall status were collected before treatment, immediately after treatment and at 72 hours. Data were analyzed with separate 2x2 repeated measures analysis of variance, with independent variables being Group (DN vs. sham) and Time (pre-treatment vs. immediately post-treatment, and pre-treatment vs. 72 hours). The hypothesis of interest in each case was the Group*Time interaction. The alpha-level was set a priori to .05 using 2-tailed tests.

Results: Both groups exhibited a clinically meaningful reduction in pain based on numeric pain rating scale scores immediately post-treatment and at 72 hours, but there was no statistically significant difference between groups (p=0.219, 0.310).

There was no significant difference between groups for any other outcome measures.

Conclusion: These data suggest that DN treatment is not more effective than a sham DN treatment at reducing short-term pain and disability in individuals with PFPS when used as an isolated treatment approach.

Level of Evidence: 2 Key words: Dry needling, knee pain, patellofemoral pain syndrome, rehabilitation

1

Army-Baylor University Doctoral Program in Physical Therapy, Fort Sam Houston, TX, USA 2 Mendoza Physical Therapy Clinic, Fort Bliss, TX, USA 3 Eisenhower Army Medical Center, Fort Gordon, GA, USA 4 Physical Therapy Clinic, Weed Army Community Hospital, Fort Irwin, CA, USA 5 Physical Therapy Clinic, Blanchfield Army Community Hospital, Fort Campbell, KY, USA 6 Baylor University Doctoral Physical Therapy Program, Waco, TX, USA Financial Disclosure Statement: Each of the above authors affirms that they have no financial affiliations (including research funding) that has direct financial interest in any matter included in this manuscript.

There were no funding sources or conflicts of interest.

Opinions or assertions herein are the private views of the authors and are not to be construed as official or as reflecting the views of the United States Army or the Department of Defense.

CORRESPONDING AUTHOR Thomas G. Sutlive Army-Baylor University Doctoral Program in Physical Therapy 3150 Stanley Road, Room 3107 Fort Sam Houston, TX 78234 Email: sutlivet@gmail.com

The International Journal of Sports Physical Therapy | Volume 13, Number 3 | June 2018 | Page 462 DOI: 10.26603/ijspt20180462

INTRODUCTION Patellofemoral pain syndrome (PFPS) is a prevalent knee disorder seen among young, active individuals and in general practice,1 orthopedic,2 sports3,4 and military clinics.5,6 Dye7 described PFPS as a clinical enigma, and one of the most challenging knee pathologies to manage. The problematic nature of PFPS is highlighted by the fact that 70% to 90% of individuals with the condition have recurrent or chronic symptoms.3,8 Despite the prevalence of the disorder, the etiology of PFPS is poorly understood. A number of abnormal biomechanical and neuromuscular factors may contribute to increased stresses on the patellofemoral joint which in turn can ultimately lead to pain and dysfunction.9-12 Because the etiology may be multifactorial in nature, and due to the variations in the clinical presentation of patients with PFPS, numerous non-operative interventions have been proposed for treatment of the disorder.

Dry needling (DN) is a therapeutic intervention that has been growing in both popularity and supportive research evidence.13-16 DN involves the insertion of small solid filament needles directly into myofascial trigger points in an attempt to reduce muscle tension, restore normal muscle function, and relieve pain.17-19 Myofascial trigger points are locally tender and palpable bands of muscle tissue that can cause pain and muscle dysfunction.20,21 Patients with PFPS often present with weakness and poor motor control of the quadriceps muscles.11,22-25 Restoration of quadriceps muscle strength and function is predictive of a successful rehabilitation outcome for patients with PFPS.26,27 Travell and Simons described trigger points in three of the four quadriceps femoris muscles which, when palpated, could generate the peripatellar and anterior knee pain that is characteristic of PFPS.21 They proposed that treatment of myofascial trigger points may be an effective way to diminish the pain associated with PFPS and to help restore quadriceps muscle function.21 To date, the effects of DN on patients with PFPS have not been investigated. Two previous studies described the use of acupuncture for the management of anterior knee pain,28,29 however the treatment techniques used in those studies and the proposed mechanisms for traditional acupuncture are substantially different than those associated with DN.

While recent investigations have shown that DN can be an effective treatment for patients with a variety of musculoskeletal dysfunctions,14,15,30,31 no study to date has investigated the use of the treatment technique in patients with PFPS. The current level of evidence regarding the use of DN for the management of PFPS is limited to that of expert opinion.21 Research is needed in the form of a randomized controlled trial to determine whether DN is an effective intervention for individuals with PFPS. Therefore, the purpose of this study was to determine if DN is more effective at reducing pain and disability than a sham treatment in individuals with PFPS. The authors hypothesized that the DN group would experience a significantly greater reduction in pain and disability than the sham group.

METHODS Sixty participants were recruited from the military health care beneficiary population at Fort Sam Houston in San Antonio, Texas. All volunteers provided informed consent for participation in the study, which was approved by the Institutional Review Board at Brooke Army Medical Center. Participants were required to be 18-40 years of age and have a clinical diagnosis of PFPS. Participants were determined to have PFPS if they had a complaint of retropatellar or anterior knee pain that was provoked by two or more of the following activities: squatting, stair ascent, stair descent, prolonged sitting, kneeling or isometric quadriceps contraction.9 Individuals were excluded if they had a history of prior knee surgery, any competing knee pathology (meniscal tears, patellar tendinopathy, ligamentous sprains, osteoarthritis, etc.), any systemic disease and/or connective tissue disorders, or signs of lumbosacral nerve root compression. Individual were also excluded those who had received acupuncture, injection, or DN treatment for the knee or quadriceps femoris muscles within the prior six months, individuals who were currently taking anticoagulant medications or had a medical history of a bleeding disorder, and pregnant females.

Volunteers initially received a screening examination consisting of a medical history questionnaire and a standard physical examination to confirm a clinical diagnosis of PFPS and to rule out any

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competing knee pathologies. All screening examinations were performed by licensed physical therapists, who were board certified as a sports clinical specialist (JHM) or orthopedic clinical specialist (TGS). The screening examination consisted of palpation, special tests to rule out competing pathologies such as meniscal tears, patellar tendinopathy, and ligamentous injuries. Altman’s criteria32 were used to screen for individuals with possible knee osteoarthritis. Additionally, a comprehensive neurological screening examination was performed to rule the possibility of lumbosacral nerve root or peripheral nerve involvement. Individuals who met the inclusion and exclusion criteria then underwent a standardized history and physical examination, which included selected testing of lower extremity muscle strength, muscle length, and range of motion. Isometric strength of the knee extensors and flexors, and hip abductors, flexors, internal rotators and external rotators was assessed with a handheld dynamometer. Knee and hip range of motion (ROM) measures were performed using a standard goniometer. To assess muscle length, examiners conducted the Thomas, Ober’s and hamstring 90-90 tests.33 A bubble goniometer was used to measure the angle of hip and knee flexion during the Thomas test, hip abduction during the Ober’s test, and knee flexion during the hamstring 90-90 test. The Q-angle was assessed in the standing position as previously described by Iverson and colleagues.34 Evaluation of a possible leg length discrepancy was performed using a Palpation Meter.35 Participants completed two self-report questionnaires, the Kujala Anterior Knee Pain Scale (AKPS)36,37 and the Lower Extremity Functional Scale (LEFS),38,39 as well as a body chart to provide a thorough description of the location and nature of their symptoms. Demographic information was collected to include age, gender, height, and weight. Participants also rated their pain level during performance of three functional activities (stepping up a 20-cm step, stepping down from the same step, and squatting)34,40 on an 11-point numeric pain rating scale (NPRS).41-43 During the squat test, participants were instructed to maintain their trunk in an upright position and to look straight ahead, while keeping their heels on the floor. As they performed the squat, the

angle of knee flexion at which the participants first experienced their pain was measured with a goniometer and recorded. Documenting the angle of knee flexion at onset of pain allowed the examiners to ask the subject to assess the pain experienced at the same angle with subsequent squats immediately following the intervention and at a 72-hour followup appointment. Examiners were blinded to treatment group allocation.

Prior to enrollment, an investigator not involved with data collection or treatment used a randomnumber generator to create a randomization list and prepared individual, sequentially numbered index cards that indicated group assignment. The cards were then folded and placed in sealed envelopes.

Participants were randomly assigned to one of two treatment groups: dry needling (DN) or sham (SH) needling group. All treatments were performed by an experienced physical therapist (SK) who was trained in dry needling and blinded to the baseline assessment outcomes. After the baseline examination, the treating investigator opened the envelope which indicated the treatment group assignment.

Participants in both groups made a total of two visits to the clinic; once for the baseline examination and intervention and then again at a 72-hour follow-up appointment.

Individuals in the DN group received a single session of dry needling therapy using a standardized protocol. Participants lay in the supine position with a vertical drape positioned at the level of their waist so that they were blinded to the treatment they received. The needling procedure started with systematic manual palpation of three superficial quadriceps femoris muscles (vastus medialis, rectus femoris, vastus lateralis) ipsilateral to the symptomatic knee. This was performed to determine the presence or absence of perceived trigger points, operationally defined as palpable and painful nodules in the muscle tissue and considered present when active or latent,17 and to guide needle placement. Two trigger points were identified for treatment in each of the three targeted quadriceps femoris muscles, for a total of six needle insertions per thigh. Upon the rare occasion that two trigger points were not identifiable in a specific muscle,

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Figure 1. Dry needling technique. Participants were supine with a dark drape positioned at their waist to blind them from the treatment.

DN was provided to the most painful location as determined by palpation. The needling technique included the insertion or a sterile, disposable 0.25 x 40 mm stainless steel acupuncture needle (Seirin Corporation, Shizuoka, Japan) into three of four the quadriceps femoris muscles (vastus medialis, rectus femoris, vastus lateralis) (Figure 1). The “clean technique” was used throughout the treatment procedure, which included hand washing, use of latex-free examination gloves, and skin-surface preparation with an alcohol wipe.44 Needle insertions lasted approximately 5-10 seconds using “sparrow pecking” (in-and-out motion) and “coning” (small redirections of needle angle) techniques in an attempt to elicit as many local twitch responses as possible.

The SH group received a simulated needling intervention that was developed and validated by Sherman and colleagues.45 The procedures performed for the SH group were identical to those described for the DN group, with the exception that a small, sharp object in a needle guide tube was used in place of the acupuncture needle. Firm pressure was applied to the skin of subjects in the SH group to simulate the sensation of an acupuncture needle, but the skin was never punctured. The same sparrow pecking and coning techniques and treatment durations used in the DN group were simulated in the SH group.

Immediately following the treatment session, participants repeated each of the functional tests (step-up, step-down, squat) and rated the pain experienced during each activity on the NPRS. All participants were instructed in a basic home exercise program of isometric quadriceps femoris contractions and quadriceps stretching exercises to be performed daily until they returned for the follow-up appointment.

Participants returned to the clinic 72 hours following the initial session and completed a second AKPS and LEFS, as well as a Global Rating of Change (GROC) questionnaire.46,47 The functional activities and pain assessments were also repeated, as well as selected muscle strength, length and ROM measures. During the follow up session, participants were asked which treatment they believe they received. Following their response, the investigators revealed to each participant which treatment was actually received.

STATISTICAL ANALYSIS A priori power analysis was performed using G*Power 3.48 Estimated sample size was based on having at least 80% power to detect a minimal clinically important difference (MCID) in the LEFS of 8 points38,39 between groups, assuming a standard deviation of 10 points, alpha of 0.05 and 10% attrition at follow up. Enrolling 60 subjects (30 per group) was planned to additionally give adequate power for analysis of secondary outcomes and adequate precision to correlational estimates.

Statistical analyses were performed using IBM SPSS Version 21 software (Chicago, IL). Descriptive statistics were performed on demographic and clinical history characteristics of the sample. Treatment effects were estimated using separate, random intercept and slope linear mixed models for each repeated measure outcome variable. Time, treatment group, and time by treatment group interaction were modeled as fixed effects. Age, sex, and length of symptoms were evaluated for additional fixed effect covariates based on their potential to affect prognosis. For each model, the covariance structure (autoregressive, unstructured, scaled identity) was used based on best model fit and ability of the model to reach convergence. Consistent with the intention to treat principle, missing data points were estimated in the mixed model analyses using

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restricted maximum likelihood ratio estimation with 100 iterations; therefore all participants randomized to a treatment group were included in the analyses of outcome for that group. Alpha level was 0.05 for all analyses.

RESULTS Three of the 60 enrolled participants were unable to attend their 72-hour follow-up appointments, but they were able to complete the self-report instruments either telephonically or via email. One participant was excluded from data analysis due to inconsistent responses on his self-report outcome measures. Therefore, data from 59 participants were available and included in the final analysis (FIGURE 2). Of those 59 individuals, 30 were randomized to the DN group and 29 to the SH group. Baseline demographic and self-reported variables for all participants are shown in Table 1.

Primary results of the between-group comparisons are depicted in Table 2. Overall, both groups exhibited a clinically meaningful reduction in pain with the functional activities (step-up, step-down, squat) immediately post-treatment and at 72 hours, based on a 30% reduction42 in the NPRS scores. But the differences between the groups on the NPRS scores immediately following treatment and at 72 hours were not significant (p=0.22, 0.31). There were no significant or clinically meaningful differences between the groups or over time within each group based on the LEFS, Kujala or GROC scores. The minimal clinically important difference for the LEFS has been reported to be 8 to 9 points,38,39 10 to 13 points for the Kujala scale,37,39 and 3 points for the GROC.46 Based on analysis using Fisherâ&#x20AC;&#x2122;s Exact Test, the number of participants who correctly versus incorrectly guessed the treatment they received was not significantly different between groups (p=0.41).

Seventeen (63%) of the participants in the SH group thought they had received the DN treatment, four (15%) correctly stated they had received the SH treatment, and six (22%) were unsure. Similarly, twenty (71%) of the participants in the DN group correctly identified the treatment they received, two (7%) believed they were in the SH group, and four (14%) were unsure. The remaining individuals either did not attend their follow-up appointment

(n=3) or simply failed to respond to the question regarding perceived treatment (n=3).

None of the participants experienced serious adverse events or had to discontinue the study due to studyrelated procedures. Furthermore, no participants reported any minor transient side effects such as lightheadedness, nausea, or fatigue after receiving the DN or sham treatments.

DISCUSSION PFPS remains a complex and significant clinical problem. Despite its high prevalence among active individuals1-6 and recent innovations in rehabilitation,9-12,26 the etiology of PFPS remains poorly understood. A number of abnormal biomechanical and neuromuscular factors may contribute to increased patellofemoral joint reaction forces, which in turn ultimately lead to pain and dysfunction.9-12,26 Because the etiology of PFPS is multifactorial in nature, and due to the variations in the clinical presentation of patients, numerous treatment strategies have been proposed for the condition. Dry needling is a therapeutic intervention that has been growing in both popularity and supportive research evidence.13-16 DN has been investigated extensively in populations of individuals with low back pain,13,30,31,49,50 neck pain,15,51-54 and shoulder pain,15,16,55-58 while more limited research has been published regarding its effects on less prevalent musculoskeletal conditions such as plantar fascitis,59 Achilles tendinopathy60 and temporomandibular joint dysfunction.61 No previous investigation has examined the effects of DN on symptoms in subjects with PFPS. Therefore, the purpose of the study was to determine if a single session of DN to the quadriceps femoris muscles was more effective at reducing pain and disability than a sham treatment in individuals with PFPS. There were no significant differences in outcomes existed between the groups at any time following the intervention, suggesting that a single session of DN was not more effective than a sham treatment at reducing short-term pain and disability in individuals with PFPS when used as an isolated treatment approach.

While no significant differences were found between groups in any outcome, point estimates of treatment effects consistently favored DN over SH. Therefore, it is certainly possible that DN is effective for some

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Figure 2. Flow of participant recruitment and exclusion.

patients with the condition and not effective for others. This would align with many practitionersâ&#x20AC;&#x2122; clinical experience as well as other evidence suggesting that there are sub-groups of patients with PFPS who respond best to specific interventions based on the identification of distinct clinical characteristics.34,40,62-67 Koppenhaver and colleagues recently identified several baseline examination factors that were associated with clinical improvement after DN in subjects with LBP.30 Future studies of individuals with PFPS should determine if there are variables

from the history and physical examination that are associated with or predictive of a successful response to treatment with DN. The current study specifically investigated the short-term response of individuals with PFPS to a single session of DN or a sham treatment. A possible shortcoming of the study was the fact that the participantsâ&#x20AC;&#x2122; response to the intervention was measured only as far out as 72 hours. The follow up periods reported in most randomized trials of

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Table 1. Baseline demographic and self-reported variables

patients with PFPS tend to be on the order of weeks or months.28,29,68-71 Although clinically meaningful reductions in pain were seen in both groups during the study period, the difference between the two groups was not significant, and the differences in the LEFS, Kujala and GROC scores did not reach clinically meaningful levels. In addition to the short follow up period, the study participants were seen for just a single treatment session. Previous investigations of DN for the treatment of other prevalent musculoskeletal disorders included multiple treatment sessions, with many occurring over a period of several weeks.14,53,59,72,73 Therefore, the single treatment session and brief follow-up period that used in the current study may not reflect typical clinical practice and also made it difficult to draw any strong conclusions about the effectiveness of the intervention, particularly given that PFPS is considered to be a chronic problem with a high recurrence rate.8,74-76 Future investigations should consider the use of multiple treatment sessions to more accurately replicate what is done in a clinical setting. The intervention was also limited to just DN and the authors recognize that using a single treatment modality may not be representative of a typical clinical strategy for the management of patients with PFPS. Clinical experts report that the strongest research evidence shows that multimodal or combined interventions result in the most robust and consistent therapeutic effects for individuals with anterior knee pain.9,26 Therefore,

recommendations for future studies in PFPS populations include the investigation of DN in conjunction with other interventions such as quadriceps and gluteal strengthening, stretching, patellofemoral joint mobilization, and taping.77 Despite these limitations, the current investigators believe that the approach was a reasonable initial venture into examining the specific, isolated effects of one session of DN as an intervention for persons with PFPS. No known published report has examined the use of dry needling for the treatment of PFPS. Two previous investigations28,29 described the use of acupuncture as an intervention for anterior knee pain, with conflicting results. Jensen and colleagues28 treated traditional acupuncture points that included the low back, vastus medialis, vastus lateralis and peripatellar regions. The authors treated their subjects twice a week for 4 weeks and reported that acupuncture reduced pain better than a control at five months post-intervention.28 Naslund et al described sensory stimulation of acupuncture sites just proximal and distal to the knee in subjects with idiopathic anterior knee pain.29 Subjects were randomized into deep (treatment) and minimal superficial (control) groups and treated twice a week for a total of 15 treatments. The investigators reported a clinically meaningful reduction in pain in all subjects at a six-month follow up, with no significant difference between the two groups.29 However, the

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Table 2. Mean and standard deviation (SD) of each self-report instrument over time

treatment techniques used in those studies and the proposed mechanisms for traditional acupuncture are substantially different than DN, making it difficult to draw comparisons with the results of the current study.

The current investigation focused treatment on the quadriceps femoris muscles because patients with PFPS characteristically present with weakness and poor motor control of that muscle group.11,2225,78 Restoration of quadriceps muscle strength and function are predictive of a successful rehabilitation outcome for patients with PFPS.26,27 Travell and Simons described trigger points in three of the four

quadriceps femoris muscles which, when palpated, could generate the peripatellar and anterior knee pain that is characteristic of PFPS.21 They proposed that treatment of these trigger points may be an effective way to diminish the pain associated with PFPS and to help restore quadriceps muscle function.21 Based on their work, the intervention used in this study focused on the vastus medialis, rectus femoris, and vastus lateralis muscles. However, because addressing proximal impairments has been shown in recent studies9,12,26 to be an important component in the successful rehabilitation of patients with PFPS, future investigations should consider DN treatment of hip and trunk muscles that have been

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linked to the disorder. Specific target muscles that should be considered in future needling studies of patients with PFPS are the gluteal, hip lateral rotator,11,26,68,79-83 and trunk muscles.84-86 CONCLUSIONS The authors believe that this was the first study to examine the effects of DN in a population of individuals with PFPS. Both the DN and SH groups experienced clinically meaningful reductions in pain during the study period. However, the differences were not statistically significant, and there were no differences between the groups in terms of the LEFS, Kujala or GROC scores. There were a number of possible shortcomings in the study design, and recommendations for future randomized trials include investigating the effects of DN on patellofemoral pain and disability include multiple treatment sessions, alternative needling sites, longer follow up periods, and DN treatment in conjunction with other interventions such as specific therapeutic exercises, manual therapy, and taping. Additionally, future studies should attempt to identify the characteristics of individuals with PFPS who respond successfully to treatment with DN. Until a clinically relevant subgroup is established, DN should not be considered as an isolated intervention for patients with PFPS. REFERENCES 1. van Middelkoop M, van Linschoten R, Berger MY, Koes BW, Bierma-Zeinstra SM. Knee complaints seen in general practice: active sport participants versus non-sport participants. BMC Musculoskel Disord.

2008;9:36.

2. Wood L, Muller S, G. P. The epidemiology of patellofemoral disorders in adulthood: a review of routine general practice morbidity recording. Prim Health Care Res Dev. 2011;12:157-164.

3. Blond L, Hansen L. Patellofemoral pain syndrome in athletes: a 5.7-year retrospective follow-up study of 250 athletes. Acta Orthopaedica Belgica.

1998;64(4):393-400.

4. Taunton JE, Ryan MB, Clement DB, McKenzie DC, Lloyd-Smith DR, Zumbo BD. A retrospective casecontrol analysis of 2002 running injuries. Br J Sports Med. 2002;36(2):95-101.

5. Rhon DI. A physical therapist experience, observation, and practice with an infantry brigade combat team in support of Operation Iraqi Freedom.

Mil Med. 2010;175(6):442-447.

6. Songer TJ, LaPorte RE. Disabilities due to injury in the military. Am J Sports Med. 2000;18(3 Suppl):33-40.

7. Dye SF. The pathophysiology of patellofemoral pain: a tissue homeostasis perspective. Clin Orthop Rel Res. 2005(436):100-110.

8. Stathopulu E, Baildam E. Anterior knee pain: a long-term follow-up. Rheumatol. 2003;42(2):380-382.

9. Crossley KM, van Middelkoop M, Callaghan MJ, Collins NJ, Rathleff MS, Barton CJ. 2016 Patellofemoral pain consensus statement from the 4th International Patellofemoral Pain Research Retreat, Manchester. Part 2: recommended physical interventions (exercise, taping, bracing, foot orthoses and combined interventions). Br J Sports Med. 2016;50(14):844-852.

10. Davis IS, Powers CM. Patellofemoral pain syndrome: proximal, distal, and local factors, an international retreat, April 30-May 2, 2009, Fells Point, Baltimore, MD. J Orthop Sports Phys Ther. 2010;40(3):A1-16.

11. Powers CM, Bolgla LA, Callaghan MJ, Collins N, Sheehan FT. Patellofemoral pain: proximal, distal, and local factors, 2nd International Research Retreat.

J Orthop Sports Phys Ther. 2012;42(6):A1-54.

12. Witvrouw E, Callaghan MJ, Stefanik JJ, et al.

Patellofemoral pain: consensus statement from the 3rd International Patellofemoral Pain Research Retreat held in Vancouver, September 2013. Br J Sports Med. 2014;48(6):411-414.

13. Furlan AD, van Tulder MW, Cherkin DC, et al.

Acupuncture and dry-needling for low back pain.

Cochrane Database of Systematic Reviews.

2005(1):CD001351.

14. Kietrys DM, Palombaro KM, Azzaretto E, et al.

Effectiveness of dry needling for upper-quarter myofascial pain: a systematic review and metaanalysis. J Orthop Sports Phys Ther. 2013;43(9):620-634.

15. Liu L, Huang QM, Liu QG, et al. Effectiveness of dry needling for myofascial trigger points associated with neck and shoulder pain: a systematic review and meta-analysis. Arch Phys Med Rehabil.

2015;96(5):944-955.

16. Ong J, Claydon LS. The effect of dry needling for myofascial trigger points in the neck and shoulders: a systematic review and meta-analysis. J Bodywork Movement Ther. 2014;18(3):390-398.

17. Dommerholt J. Dry needling - peripheral and central considerations. J Man Manip Ther. 2011;19(4):223-227.

18. Kalichman L, Vulfsons S. Dry needling in the management of musculoskeletal pain. J Am Board Fam Med. 2010;23(5):640-646.

19. Vulfsons S, Ratmansky M, Kalichman L. Trigger point needling: techniques and outcome. Curr Pain Headache Rep. 2012;16(5):407-412.

The International Journal of Sports Physical Therapy | Volume 13, Number 3 | June 2018 | Page 470

20. Lavelle ED, Lavelle W, Smith HS. Myofascial trigger points. Anesth Clin. 2007;25(4):841-851, vii-iii.

21. Simons D, Travell J, Simons L. Travell & Simons’ Myofascial Pain and Dysfunction: The Trigger Point Manual. 2nd ed: Williams & Wilkins; 1999.

22. Cowan SM, Bennell KL, Hodges PW, Crossley KM, McConnell J. Delayed onset of electromyographic activity of vastus medialis obliquus relative to vastus lateralis in subjects with patellofemoral pain syndrome. Arch Phys Med Rehabil. 2001;82(2):183-189.

23. Cowan SM, Hodges PW, Bennell KL, Crossley KM. Altered vastii recruitment when people with patellofemoral pain syndrome complete a postural task. Arch Phys Med Rehabil. 2002;83(7):989-995.

24. Crossley K, Bennell K, Green S, Cowan S, McConnell J. Physical therapy for patellofemoral pain: a randomized, double-blinded, placebo-controlled trial.

Am J Sports Med. 2002;30(6):857-865.

25. Powers CM. Rehabilitation of patellofemoral joint disorders: a critical review. J Orthop Sports Phys Ther.

1998;28(5):345-354.

26. Barton CJ, Lack S, Hemmings S, Tufail S, Morrissey D. The ‘Best Practice Guide to Conservative Management of Patellofemoral Pain’: incorporating level 1 evidence with expert clinical reasoning. Br J Sports Med. 2015;49(14):923-934.

27. Pattyn E, Mahieu N, Selfe J, Verdonk P, Steyaert A, Witvrouw E. What predicts functional outcome after treatment for patellofemoral pain? Med Sci Sports Exerc. 2012;44(10):1827-1833.

28. Jensen R, Gothesen O, Liseth K, Baerheim A. Acupuncture treatment of patellofemoral pain syndrome. J Altern Complement Med. 1999;5(6):521-527.

29. Naslund J, Naslund UB, Odenbring S, Lundeberg T. Sensory stimulation (acupuncture) for the treatment of idiopathic anterior knee pain. J Rehabil Med. 2002;34(5):231-238.

30. Koppenhaver SL, Walker MJ, Smith RW, et al.

Baseline examination factors associated With clinical improvement after dry needling in individuals with low back pain. J Orthop Sports Phys Ther.

2015;45(8):604-612.

31. Koppenhaver SL, Walker MJ, Su J, et al. Changes in lumbar multifidus muscle function and nociceptive sensitivity in low back pain patient responders versus non-responders after dry needling treatment.

Man Ther. 2015;20(6):769-76.

32. Altman R AE, Bloch D, et al. Development of criteria for the classification and reporting of osteoarthritis.

Classification of osteoarthritis of the knee.

Diagnostic and therapeutic criteria committee of the American Rheumatism Association. Arthritis Rheumatol. 1986;29(8):1039-1049.

33. Magee DJ. Orthopedic Physical Assessment. 6th ed.

New York: Saunders; 2013.

34. Iverson CA, Sutlive TG, Crowell MS, et al.

Lumbopelvic manipulation for the treatment of patients with patellofemoral pain syndrome: development of a clinical prediction rule. J Orthop Sports Phys Ther. 2008;38(6):297-309; discussion 309-212.

35. Petrone MR, Guinn J, Reddin A, Sutlive TG, Flynn TW, Garber MP. The accuracy of the Palpation Meter (PALM) for measuring pelvic crest height difference and leg length discrepancy. J Orthop Sports Phys Ther. 2003;33(6):319-325.

36. Crossley KM, Bennell KL, Cowan SM, Green S. Analysis of outcome measures for persons with patellofemoral pain: which are reliable and valid?

Arch Phys Med Rehabil. 2004;85(5):815-822.

37. Kujala UM, Jaakkola LH, Koskinen SK, Taimela S, Hurme M, Nelimarkka O. Scoring of patellofemoral disorders. Arthroscopy. 1993;9(2):159-163.

38. Binkley JM, Stratford PW, Lott SA, Riddle DL. The Lower Extremity Functional Scale (LEFS): scale development, measurement properties, and clinical application. Phys Ther. 1999;79(4):371-383.

39. Watson CJ, Propps M, Ratner J, Zeigler DL, Horton P, Smith SS. Reliability and responsiveness of the lower extremity functional scale and the anterior knee pain scale in patients with anterior knee pain. J Orthop Sports Phys Ther. 2005;35(3):136-146.

40. Sutlive TG, Mitchell SD, Maxfield SN, et al.

Identification of individuals with patellofemoral pain whose symptoms improved after a combined program of foot orthosis use and modified activity: a preliminary investigation. Phys Ther. 2004;84(1):49-61.

41. Abbott JH, Schmitt J. Minimum important differences for the patient-specific functional scale, 4 region-specific outcome measures, and the numeric pain rating scale. J Orthop Sports Phys Ther.

2014;44(8):560-564.

42. Farrar JT, Young JP, Jr., LaMoreaux L, Werth JL, Poole RM. Clinical importance of changes in chronic pain intensity measured on an 11-point numerical pain rating scale. Pain. 2001;94(2):149-158.

43. Price DD, Bush FM, Long S, Harkins SW. A comparison of pain measurement characteristics of mechanical visual analogue and simple numerical rating scales. Pain. 1994;56(2):217-226.

44. Baima J, Isaac Z. Clean versus sterile technique for common joint injections: a review from the physiatry perspective. Curr Rev Musculoskel Med. 2008;1(2):88-91.

45. Sherman KJ, Hogeboom CJ, Cherkin DC, Deyo RA. Description and validation of a noninvasive placebo

The International Journal of Sports Physical Therapy | Volume 13, Number 3 | June 2018 | Page 471

46.

47.

48.

49.

acupuncture procedure. J Altern Complement Med. 2002;8(1):11-19.

Jaeschke R, Singer J, Guyatt GH. Measurement of health status. Ascertaining the minimal clinically important difference. Control Clin Trials.

1989;10(4):407-415.

Juniper EF, Guyatt GH, Willan A, Griffith LE. Determining a minimal important change in a disease-specific Quality of Life Questionnaire. J Clin Epidemiol. 1994;47(1):81-87.

Faul F, Erdfelder E, Lang AG, Buchner A. G*Power 3: a flexible statistical power analysis program for the social, behavioral, and biomedical sciences. Behav Res Methods. 2007;39(2):175-191.

Rainey CE. The use of trigger point dry needling and intramuscular electrical stimulation for a subject with chronic low back pain: a case report. Int J Sports Phys Ther. 2013;8(2):145-161.

50. Tough EA, White AR, Cummings TM, Richards SH, Campbell JL. Acupuncture and dry needling in the management of myofascial trigger point pain: a systematic review and meta-analysis of randomised controlled trials. Eur J Pain. 2009;13(1):3-10.

51. Cagnie B, Castelein B, Pollie F, Steelant L, Verhoeyen H, Cools A. Evidence for the use of ischemic compression and dry needling in the management of trigger points of the upper trapezius in patients with neck pain: a systematic review. Am J Phys Med Rehabil. 2015;94(7):573-583.

52. Cerezo-Tellez E, Lacomba MT, Fuentes-Gallardo I, Mayoral Del Moral O, Rodrigo-Medina B, Gutierrez Ortega C. Dry needling of the trapezius muscle in office workers with neck pain: a randomized clinical trial. J Man Manip Ther. 2016;24(4):223-232.

53. Cerezo-Tellez E, Torres-Lacomba M, FuentesGallardo I, et al. Effectiveness of dry needling for chronic nonspecific neck pain: a randomized, single-blinded, clinical trial. Pain. 2016;157(9):19051917.

54. Segura-Orti E, Prades-Vergara S, Manzaneda-Pina L, Valero-Martinez R, Polo-Traverso JA. Trigger point dry needling versus strain-counterstrain technique for upper trapezius myofascial trigger points: a randomised controlled trial. J Br Med Acupunct Soc. 2016;34(3):171-177.

55. Calvo-Lobo C, Pacheco-da-Costa S, Martinez-Martinez J, Rodriguez-Sanz D, Cuesta-Alvaro P, Lopez-Lopez D. Dry needling on the infraspinatus latent and active myofascial trigger points in older adults with nonspecific shoulder pain: a randomized clinical trial. J Geriatr Phys Ther. 2018;41(1):1-13.

56. Clewley D, Flynn TW, Koppenhaver S. Trigger point dry needling as an adjunct treatment for a patient

57.

58.

59.

60.

61.

62.

63.

64.

65.

66.

67.

68.

with adhesive capsulitis of the shoulder. J Orthop Sports Phys Ther. 2014;44(2):92-101.

Hsieh YL, Kao MJ, Kuan TS, Chen SM, Chen JT, Hong CZ. Dry needling to a key myofascial trigger point may reduce the irritability of satellite MTrPs. Am J Phys Med Rehabil. 2007;86(5):397-403.

Koppenhaver S, Embry R, Ciccarello J, et al. Effects of dry needling to the symptomatic versus control shoulder in patients with unilateral subacromial pain syndrome. Man Ther. 2016;26:62-69.

Eftekharsadat B, Babaei-Ghazani A, Zeinolabedinzadeh V. Dry needling in patients with chronic heel pain due to plantar fasciitis: A singleblinded randomized clinical trial. Med J Islamic Republic Iran. 2016;30:401.

Yeo A, Kendall N, Jayaraman S. Ultrasound-guided dry needling with percutaneous paratenon decompression for chronic Achilles tendinopathy. Knee Surg Sports Traumatol Arthrosc. 2016;24(7):2112-2118.

Blasco-Bonora PM, Martin-Pintado-Zugasti A. Effects of myofascial trigger point dry needling in patients with sleep bruxism and temporomandibular disorders: a prospective case series. Acupunct Med. 2017;35(1):69-74.

Barton CJ, Menz HB, Crossley KM. Clinical predictors of foot orthoses efficacy in individuals with patellofemoral pain. Med Sci Sports Exerc.

2011;43(9):1603-1610.

Crowell MS, Wofford NH. Lumbopelvic manipulation in patients with patellofemoral pain syndrome. J Man Manip Ther. 2012;20(3):113-120.

Huang BY, Shih YF, Chen WY, Ma HL. Predictors for identifying patients with patellofemoral pain syndrome responding to femoral nerve mobilization.

Arch Phys Med Rehabil. 2015;96(5):920-927.

Lesher JD, Sutlive TG, Miller GA, Chine NJ, Garber MB, Wainner RS. Development of a clinical prediction rule for classifying patients with patellofemoral pain syndrome who respond to patellar taping. J Orthop Sports Phys Ther.

2006;36(11):854-866.

Vicenzino B, Collins N, Cleland J, McPoil T. A clinical prediction rule for identifying patients with patellofemoral pain who are likely to benefit from foot orthoses: a preliminary determination. Br J Sports Med. 2010;44(12):862-866.

Watari R, Kobsar D, Phinyomark A, Osis S, Ferber R. Determination of patellofemoral pain sub-groups and development of a method for predicting treatment outcome using running gait kinematics.

Clin Biomech. 2016;38:13-21.

Ferber R, Bolgla L, Earl-Boehm JE, Emery C, Hamstra-Wright K. Strengthening of the hip and core

The International Journal of Sports Physical Therapy | Volume 13, Number 3 | June 2018 | Page 472

69.

70.

71.

72.

versus knee muscles for the treatment of patellofemoral pain: a multicenter randomized controlled trial. J Athl Train. 2015;50(4):366-377.

Mason M, Keays SL, Newcombe PA. The effect of taping, quadriceps strengthening and stretching prescribed separately or combined on patellofemoral pain. Physiother Res Intl. 2011;16(2):109-119.

Mills K, Blanch P, Dev P, Martin M, Vicenzino B. A randomised control trial of short term efficacy of in-shoe foot orthoses compared with a wait and see policy for anterior knee pain and the role of foot mobility. Br J Sports Med. 2012;46(4):247-252.

Osorio JA, Vairo GL, Rozea GD, et al. The effects of two therapeutic patellofemoral taping techniques on strength, endurance, and pain responses. Phys Ther Sport. 2013;14(4):199-206.

France S, Bown J, Nowosilskyj M, Mott M, Rand S, Walters J. Evidence for the use of dry needling and physiotherapy in the management of cervicogenic or tension-type headache: a systematic review.

Cephalalgia. 2014;34(12):994-1003.

73. Haser C, Stoggl T, Kriner M, et al. Effect of dry needling on thigh muscle strength and hip flexion in elite soccer players. Med Sci Sports Exerc.

2017;49(2):378-383.

74. Collins NJ, Bierma-Zeinstra SM, Crossley KM, van Linschoten RL, Vicenzino B, van Middelkoop M. Prognostic factors for patellofemoral pain: a multicentre observational analysis. Br J Sports Med. 2013;47(4):227-233.

75. Lankhorst NE, van Middelkoop M, Crossley KM, et al. Factors that predict a poor outcome 5-8 years after the diagnosis of patellofemoral pain: a multicentre observational analysis. Br J Sports Med. 2016;50(14):881-886.

76. Nimon G, Murray D, Sandow M, Goodfellow J. Natural history of anterior knee pain: a 14- to 20-year follow-up of nonoperative management. J Ped Orthop 1998;18(1):118-122.

77. Collins NJ, Bisset LM, Crossley KM, Vicenzino B. Efficacy of nonsurgical interventions for anterior knee pain: systematic review and meta-analysis of randomized trials. Sports Med. 2012;42(1):31-49.

78. Bolgla LA, Earl-Boehm J, Emery C, Hamstra-Wright K, Ferber R. Comparison of hip and knee strength in males with and without patellofemoral pain. Phys Ther Sport. 2015;16(3):215-221.

79. Baldon Rde M, Piva SR, Scattone Silva R, Serrao FV. Evaluating eccentric hip torque and trunk endurance as mediators of changes in lower limb and trunk kinematics in response to functional stabilization training in women with patellofemoral pain. Am J Sports Med. 2015;43(6):1485-1493.

80. Barton CJ, Lack S, Malliaras P, Morrissey D. Gluteal muscle activity and patellofemoral pain syndrome: a systematic review. Br J Sports Med. 2013;47(4):207214.

81. Bolgla LA, Malone TR, Umberger BR, Uhl TL. Comparison of hip and knee strength and neuromuscular activity in subjects with and without patellofemoral pain syndrome. Int J Sports Phys Ther.

2011;6(4):285-296.

82. Hamstra-Wright KL, Earl-Boehm J, Bolgla L, Emery C, Ferber R. Individuals with patellofemoral pain have less hip flexibility than controls regardless of treatment outcome. Clin J Sport Med. 2017;27(2):97103.

83. Thomson C, Krouwel O, Kuisma R, Hebron C. The outcome of hip exercise in patellofemoral pain: A systematic review. Man Ther. 2016;26:1-30.

84. Bazett-Jones DM, Cobb SC, Huddleston WE, O’Connor KM, Armstrong BS, Earl-Boehm JE. Effect of patellofemoral pain on strength and mechanics after an exhaustive run. Med Sci Sports Exerc.

2013;45(7):1331-1339.

85. Nakagawa TH, Moriya ET, Maciel CD, Serrao FV. Trunk, pelvis, hip, and knee kinematics, hip strength, and gluteal muscle activation during a single-leg squat in males and females with and without patellofemoral pain syndrome. J Orthop Sports Phys Ther. 2012;42(6):491-501.

86. Noehren B, Pohl MB, Sanchez Z, Cunningham T, Lattermann C. Proximal and distal kinematics in female runners with patellofemoral pain. Clin Biomech. 2012;27(4):366-371.

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IJSPT

ORIGINAL RESEARCH

COMPARISON OF THREE DIFFERENT DENSITY TYPE FOAM ROLLERS ON KNEE RANGE OF MOTION AND PRESSURE PAIN THRESHOLD: A RANDOMIZED CONTROLLED TRIAL Scott W. Cheatham, PhD, DPT, PT, OCS, ATC, CSCS1 Kyle R. Stull, DHSc, MS, LMT, CSCS, NASM-CPT, CES2

ABSTRACT Background: Foam rolling is a popular form of roller massage. To date, no studies have examined the therapeutic effects of different density type rollers. Understanding the different densities may provide clinicians with the knowledge to accurately prescribe a particular foam roller and safely progress the client.

Purpose: The purpose of this study was to compare the immediate effects of three different density type foam rollers on prone passive knee flexion range of motion (ROM) and pressure pain thresholds (PPT) of the quadriceps musculature.

Study Design: Pretest, posttest randomized controlled trial.

Methods: Thirty-six recreationally active adults were randomly allocated to one of three groups: soft density, medium density, and hard density foam roller. The intervention lasted a total of two minutes. Outcome measures included prone passive knee flexion ROM and PPT. Statistical analysis included parametric and non-parametric tests to measure changes among groups.

Results: Between group comparisons revealed no statistically significant differences between all three rollers for knee ROM (p=.78) and PPT (p=.37). Within group comparison for ROM revealed an 8⬚ (p< 0.001) post-intervention increase for the medium and hard density rollers and a 7⬚ (p< 0.001) increase for the soft density roller. For PPT, there was a post-intervention increase of 180 kPa (p< 0.001) for the medium density roller, 175 kPa (p< 0.001) for the soft density roller, and 151 kPa (p< 0.001) for the hard density roller.

Conclusion: All three roller densities produced similar post-intervention effects on knee ROM and PPT. These observed changes may be due to a local mechanical and global neurophysiological response from the pressure applied by the roller.

The client’s pain perception may have an influence on treatment and preference for a specific foam roller. Clinicians may want to consider such factors when prescribing foam rolling as an intervention.

Level of evidence: 2C Keywords: Massage, muscle soreness, perceived pain, recovery, roller

1 2

California State University Dominguez Hills, Carson, CA, USA National Academy of Sports Medicine, Chandler, AZ, USA

Conflict of Interest: The authors have no conflict of interest with this study.

CORRESPONDING AUTHOR Scott W. Cheatham, PhD, DPT, PT, OCS, ATC, CSCS Associate Professor California State University Dominguez Hills 1000 E. Victoria Street, Carson, California 90747 E-mail: Scheatham@csudh.edu

The International Journal of Sports Physical Therapy | Volume 13, Number 3 | June 2018 | Page 474 DOI: 10.26603/ijspt20180474

INTRODUCTION The popularity and use of foam rolling has increased over the past decade and has emerged as one of the top 20 fitness trends the past two years (2016-2017) in the United States.1,2 The majority of research has focused on the effects of foam rolling as a form of roller massage.3 The research suggests that foam rolling may be used as a warm-up without negatively effecting performance and may enhance joint mobility at the shoulder,4,5 lumbopelvis,6,7 hip,8-14 knee,14-18 and ankle.19,20 Researchers have found that foam rolling may reduce post exercise decrements in muscle performance,3,21-24, increase posttreatment pressure pain thresholds (PPT),15,16,22,24-27 and reduce the effects of delayed onset muscle soreness in healthy individuals.3,21,28-30 Several recent studies have also documented positive post-exercise effects of rolling for different sports,29,31-33 occupations,34 and fibromyalgia.35 Many different foam rollers are available to consumers which vary in density, shape, and surface texture. These architectural differences may influence how the myofascial tissues are being massaged during treatment. More specifically, the density and surface texture of the foam roller may provide a more effective massage to the tissue than a less dense roller. Curran et al36 investigated the pressure being applied by a higher density, multilevel textured surface foam roller and a lower density, solid EVA roller with a uniform textured surface to the lateral thigh of ten subjects (N=10). The researchers found that the higher density, multilevel textured roller produced more pressure and isolated contact area on the target tissues than the less dense, smooth textured roller.36 Despite the small sample size, this study has become a reference standard and has prompted researchers to use higher density foam rollers in their investigations.3,15,21,28,37 Since the Curran et al36 study, no other investigators have compared the therapeutic effects of different density rollers. They have either used commercial high-density rollers or developed their own custom high-density roller.3,21,28 The unknown therapeutic effects of various density rollers create a knowledge gap that has potential implications for clinical practice. The clinician is challenged with the inability to provide an evidence based recommendation for the type of foam roller for a patient and may depend on

personal preference.3 Furthermore, the client may purchase a foam roller based upon price, personal preference, or recommendation by a clinician.

Further investigation into the therapeutic effects of different density foam rollers is warranted given the gap in the knowledge about foam rolling. Understanding the effects of different density foam rollers may provide clinicians with the knowledge to more accurately prescribe a particular foam roll and to safely progress the client through different densities.

The purpose of this study was to compare the immediate effects of three different density type rollers on passive knee range of motion (ROM) and pressure pain threshold (PPT). The authors of this study hypothesized that the higher density foam roller will have a greater effect than the less dense roller. This investigation was also considered exploratory and a starting point for future research.

METHODS This pretest, posttest randomized controlled trial was approved by the Institutional Review Board (IRB:18-023) at California State University Dominguez Hills.

Subjects Thirty-six recreationally active adults (Males=26, Females=10) were recruited via convenience sampling (e.g. flyers) and randomly allocated into three groups of 12 subjects: (1) soft density, (2) medium density, and (3) hard density foam roller intervention groups (Table 1). Recruited subjects reported participated in recreational fitness activities (e.g. walking) and prior experience using a foam roller within the last two years but were not currently using any devices. Exclusion criteria included the presence of any musculoskeletal, systemic, or metabolic disease that would affect lower extremity joint ROM or tolerance to PPT testing and the inability to avoid medications that may affect testing. Descriptive demographic information is provided in Table 2.

Instruments Two instruments were used in this investigation to measure ROM and PPT. For ROM, the baseline digital inclinometer (Fabrication Enterprises, White Plains, NY, USA) was used to measure passive knee flexion ROM. The manufacturer reports an accuracy

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Table 1. Consort Flow Diagram

Table 2. Subject demographics

of ± 0.5 degrees.19 This device has been shown to be valid and reliable for measuring lower extremity ROM (Figure 1)38-41 and has been used in prior foam roller research.15,26,37 Second, The JTECH (Midvale, UT) Tracker Freedom® wireless algometer (Figure 2) was used with the accompanying Tracker

5® Windows® based software to measure PPT. The manufacturer reports an accuracy error of <± 0.5% (.05kg/cm2) for this technology.42 Algometry is a valid and reliable tool for measuring pressure pain thresholds.25,43-45 This instrument has also been used in prior foam roller research.15,26,37

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Figure 1. Baseline digital inclinometer.

Figure 3. Soft (silver), medium (orange), and hard (black) foam rollers.

GRID X roller (black) had a hard, hollow core that was wrapped in very firm EVA foam (Figure 3).

Figure 2. JTECH algometer.

Instructional Video and Foam Rollers A commercial internet-based instruction video was used in this investigation (TriggerPoint, a division of Implus, LLC, Austin, Texas). The short foam rolling instructional video demonstrated the use of the foam roller on the left quadriceps muscle group. This video has been used in prior foam roll research.15,26,37 The three foam rollers used in this study were manufactured by TriggerPointâ&#x201E;˘ and all had the same multilevel GRID surface pattern and diameter (14cm) which allowed for a direct comparison. The difference between the three rollers was the density. The soft density CORE roller (silver) was constructed of solid EVA foam, the medium density GRID roller (orange) had a hard, hollow core that was wrapped in moderately firm EVA foam, and the hard density

Outcome Measures Two outcome measures were used for the pretest and posttest measures for each group. For passive knee flexion ROM, subjects lay prone on a carpeted floor. The examiner grasped the left ankle and passively moved the left knee to the end of the available flexion ROM to the point where the knee could no longer be passively moved without providing overpressure or point of initial discomfort.15,26,37,46-48 The ROM measurement was then taken by the examiner. The examiner monitored for any compensatory movement through the lower extremity and pelvis. This testing technique was chosen since it replicated the same hip position and knee movements that occurred during the foam roll interventions.15,26,37 For PPT, the left quadriceps group was tested with the subject in the relaxed standing position (average of two measurements).16,49,50 The 1.0-cm2 probe of the algometer was placed into the midline of the left quadriceps (rectus femoris) midway between the iliac crest and superior border of the patella. The graded force was applied at a constant rate of 50-60 kilopascals per second (kPa/sec) until the subject verbaelly reported the presence of pain.16,49,50 These outcome measures have been used in prior foam roller research.15,26,37 Pilot Study Prior to data collection, a two-session pilot training was conducted to establish intrarater reliability. The

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primary investigator took all the measurements. The primary investigator is a licensed physical therapist with over 13 years of experience and board certified in orthopaedics. Ten independent subjects were recruited and tested for this portion of the study.

The intrarater reliability was calculated using the Intraclass Correlation Coefficient (ICC model 3, 3).

There was excellent intrarater reliability for passive knee flexion ROM (ICC= 0.95; 95% CI 0.83-0.99) and pressure algometry (ICC= 0.94; 95% CI 0.61-0.90).51 Procedures All eligible participants were given an IRB approved consent form to read and sign before testing. Participants then completed a questionnaire to provide demographic information. All participants were tested by one investigator and were blinded from the results and other participants enrolled in the study.

Testing was conducted between the hours of 10 AM and 2 PM and subjects were instructed to refrain from any strenuous activity for three hours prior to testing and from taking any medication that would interfere with testing. All subjects underwent one session of testing that included: pretest measures, followed by the intervention, then immediate posttest measures.

Prior to testing, the primary investigator first explained the process to each subject and answered any questions. Then each subject was given a foam roller (based on group allocation) and followed an instructional video that demonstrated the use of the foam roll on the left quadriceps muscle group.15,26,37 Subjects followed the video with no feedback from the observing primary investigator. The instructor in the video provided a brief introduction and then discussed the foam rolling technique. The instructor divided the left quadriceps into zone one: top of patella to middle of the quadriceps and zone two: middle quadriceps to anterior superior iliac spine.

The model in the video was instructed to get in the plank position, position the roller above the left patella and roll back and forth longitudinally in zone one four times at a cadence of one inch per second.

The model was then instructed to stop at the top of zone one followed by four active knee bends to 90 degrees. This sequence was repeated for zone two.

The intervention portion lasted a total of two minutes. Subjects used the specific foam roll they were assigned to based upon their group allocation (e.g.

soft, medium, or hard density). These procedures have been used in prior foam roller research.15,26,37 STATISTICAL ANALYSIS Analysis Statistical analysis was performed using SPSS version 24.0 (IBM SPSS, Chicago, IL, USA). Subject descriptive data was calculated and reported as the mean and standard deviation (SD) for age, height, body mass, and body mass index (BMI) (Table 2).

Group differences were calculated using the ANOVA statistic for continuous level data and the Kruskal Wallis statistic for ordinal level data. Between group difference were calculated using the ANCOVA statistic.52 For the ANCOVA, the independent variable was the group, dependent variable was post-test scores, and pretest scores was the covariate. Within group comparisons were calculated using the paired t-test. Effect size (ES) was calculated (d = M1 - M2 / σpooled) for each group. Effect size of >.70 was considered strong, .41 to .70 was moderate, and < .40 was weak.53 All statistical assumptions were met for the ANOVA, ANCOVA and paired t-test statistics. Statistical significance was considered p< .05 using a conservative two-tailed test.

RESULTS Thirty-six subjects completed the study (Table 1).

There was no statistically significant difference between groups for age (p=.81), height (p=.66), body mass (p=.38), or BMI (p=.27). There were no adverse events or subject attrition during data collection.

Patient demographic data is presented in Table 2.

Between Group Analysis Between group comparisons were calculated. For passive knee flexion ROM, the between group analysis revealed no significant difference between the three types of foam rollers [F (2,32) =.247, p=.78, partial η2=.015]. For PPT, no significant differences were found between the three types of rollers [F (2, 32) =1.02, p=.37, partial η2=.196].

Within Group Comparison Within group comparison results are presented in Table 3. For passive knee flexion ROM, within group analysis revealed a posttest increase of 7° (p<.001, ES: .92) for the soft density roller, 8° degrees

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Table 3. Pretest, posttest descriptive results

(p<.001, ES: 0.76) for the medium density roller, and an 8° (p<.001, ES: 1.26) increase for the hard density roller. For PPT, a posttest increase of 175 kPa (p<.001, ES: 0.76) for the soft density roller, 180 kPa (p<.001, ES: 0.85) increase for the medium density roller, and a 151 kPa (p<.001, ES: 0.60) increase for the hard density roller. All densities of rollers demonstrated comparable changes in ROM and PPT. DISCUSSION This investigation compared the effects of three different density type rollers with the same multilevel surface pattern. This allowed for a direct comparison of different foam roll densities which may have clinical implications. The between group analysis revealed that all three density type rollers produced statistically similar post-test increases in passive knee flexion ROM (p=0.78) and PPT (p=0.37). Curran et al36 is the only known investigation to document the effects of two foam rollers with different densities and surface architecture on myofascial tissues. The researchers did not measure the therapeutic effects of the rollers. This current investigation built upon the prior study by measuring the effects of three density type rollers on knee joint ROM and PPT of the quadriceps.

Clinical Implications The results of this investigation should be considered exploratory and a starting point for future research.

The results suggest that the myofascial system may respond to different density foam rollers in a statistically comparable manner as observed by the postintervention changes in joint ROM and PPT. These

observed changes may be due to a mechanical and neurophysiological response.19,37,54 The direct pressure of the roller may produce a local mechanical and global neurophysiological effect that influences tissue relaxation and pain reduction in the target and surrounding tissues.25,55,56 For tissue relaxation, the local pressure from the roller may affect the viscoelastic properties of myofascia which may be responsible for the changes. Other mechanisms that may be involved include thixotropy (reduced viscosity), myofascial restriction, fluid changes, and cellular responses.19,54 Researchers have also found that rolling reduces arterial stiffness57, increases arterial tissue perfusion,58 and improves vascular endothelial function57 which are related to tissue relaxation.

For pain reduction, researchers have postulated that the pressure from the roller may modulate pain through stimulation of cutaneous receptors,25 mechanoreceptors,55 afferent central nociceptive pathways (gate theory of pain),25,59 and descending anti-nociceptive pathways (diffuse noxious inhibitory control).7,25 Researchers have found that rolling decreases evoked pain59 and reduces spinal excitability55 which provides evidence for these theories.

Because the post-intervention changes among all three density rollers were similar, clinicians may want to consider the client’s pain perception when prescribing a particular roller. The Curran et al36 study supports the effectiveness of a harder density roller but did not consider the influence of a client’s pain perception. Pain is a very complex multidimensional process involving the central nervous system and other systems of the body.60,61 Clients may choose a foam roller based upon their pain perception and

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threshold during rolling. For example, a hard density roller may produce more discomfort during the intervention eliciting a protective muscle guarding response.62,63 Understanding this may help guide the clinician in prescribing a specific foam roll and progressing them through the different densities.

Limitations There are specific limitations to the investigation that need to be discussed. First, this investigation tested healthy subjects which limits the generalizability of the results to this population. Second, the three foam rollers used had the same multilevel GRID pattern surface and diameter which allowed for a direct comparison. Other foam rollers with different surface patterns, diameters, and densities may have produced different results. Third, the short-term effects of each foam roll intervention was studied with the left leg only. Fourth, the testing examiner was not blinded to the results of the study which could have led to testing biases. Last, the instructional video used in the intervention only demonstrated one foam rolling technique on the left quadriceps group. Other rolling techniques may have produced different results as well as testing other muscle groups.

Future research Future studies are needed to validate the results of this study and to develop a consensus on the optimal type of foam roller for specific clients. Furthermore, research should attempt to determine the longerterm effects of different types of foam rollers based upon surface patterns, density, and foam roll material using the similar research methods. The current foam roller research is variable with different methodology which prevents a direct comparison among studies.3,28 CONCLUSION This was the first investigation to measure the shortterm effects of different density foam rollers on passive knee flexion ROM and PPT of the quadriceps musculature. All three foam roll densities produced statistically similar post-intervention effects on both ROM and PPT. These observed changes may be due to a mechanical and neurophysiological response that can be triggered by low, moderate, or high-density

roller pressure. The density of the roller and client’s pain perception may have an influence on treatment and preference for a specific foam roller. Clinicians may want to consider such factors when prescribing foam rolling as a myofascial intervention.

REFERENCES 1. Thompson WR. Worldwide survey of fitness trends for 2016: 10th Anniversary Edition. ACSM’s Health Fitness J. 2015;19(6):9-18.

2. Thompson WR. Worldwide survey of fitness trends for 2017. ACSM’s Health Fitness J. 2016;20(6):8-17.

3. Cheatham SW, Kolber MJ, Cain M, et al. The effects of self-myofascial release using a foam roll or roller massager on joint range of motion, muscle recovery, and performance: a systematic review. Int J Sports Phys Ther. 2015;10(6):827-838.

4. Le Gal J, Begon M, Gillet B, et al. Effects of SelfMyofascial Release on Shoulder Function and Perception in Adolescent Tennis Players. J Sport Rehabil. 2017:1-19.

5. Fairall RR, Cabell L, Boergers RJ, et al. Acute effects of self-myofascial release and stretching in overhead athletes with GIRD. J Bodyw Mov Ther.

2017;21(3):648-652.

6. Grieve R, Goodwin F, Alfaki M, et al. The immediate effect of bilateral self myofascial release on the plantar surface of the feet on hamstring and lumbar spine flexibility: A pilot randomised controlled trial.

J Bodyw Mov Ther. 2015;19(3):544-552.

7. Sullivan KM, Silvey DB, Button DC, et al. Rollermassager application to the hamstrings increases sit-and-reach range of motion within five to ten seconds without performance impairments. Int J Sports Phys Ther. 2013;8(3):228-236.

8. DeBruyne DM, Dewhurst MM, Fischer KM, et al.

Self-Mobilization Using a Foam Roller Versus a Roller Massager: Which Is More Effective for Increasing Hamstrings Flexibility? J Sport Rehabil. 2017;26(1):94100.

9. Behara B, Jacobson BH. Acute Effects of Deep Tissue Foam Rolling and Dynamic Stretching on Muscular Strength, Power, and Flexibility in Division I Linemen. J Strength Cond Res. 2017;31(4):888-892.

10. Monteiro ER, Cavanaugh MT, Frost DM, et al. Is self-massage an effective joint range-of-motion strategy? A pilot study. J Bodyw Mov Ther.

2017;21(1):223-226.

11. Bushell JE, Dawson SM, Webster MM. Clinical Relevance of Foam Rolling on Hip Extension Angle in a Functional Lunge Position. J Strength Cond Res. 2015;29(9):2397-2403.

The International Journal of Sports Physical Therapy | Volume 13, Number 3 | June 2018 | Page 480

12. Mohr AR, Long BC, Goad CL. Effect of foam rolling and static stretching on passive hip-flexion range of motion. J Sport Rehabil. 2014;23(4):296-299.

13. Vigotsky AD, Lehman GJ, Contreras B, et al. Acute effects of anterior thigh foam rolling on hip angle, knee angle, and rectus femoris length in the modified Thomas test. PeerJ. 2015;3:e1281.

14. Murray AM, Jones TW, Horobeanu C, et al. Sixty seconds of foam rolling does not affect functional flexibility or change muscle temperature in adolescent athletes. Int J Sports Phys Ther. 2016;11(5):765-776.

15. Cheatham SW, Kolber MJ, Cain M. Comparison of video-guided, live instructed, and self-guided foam roll interventions on knee joint range of motion and pressure pain threshold: a randomized controlled trial. Int J Sports Phys Ther. 2017;12(2):242-249.

16. Cheatham SW, Stull KR, Kolber MJ. Comparison of a vibrating foam roller and a non-vibrating foam roller intervention on knee range of motion and pressure pain threshold: a randomized controlled trial. J Sport Rehabil. 2017; [Epub ahead of print] 17. Su H, Chang NJ, Wu WL, et al. Acute Effects of Foam Rolling, Static Stretching, and Dynamic Stretching During Warm-Ups on Muscular Flexibility and Strength in Young Adults. J Sport Rehabil.

2017;26(6):469-477 18. Couture G, Karlik D, Glass SC, et al. The Effect of Foam Rolling Duration on Hamstring Range of Motion. Open Orthop J. 2015;9:450-455.

19. Kelly S, Beardsley C. Specific and cross-over effects of foam rolling on ankle dorsiflexion range of motion. Int J Sports Phys Ther. 2016;11(4):544-551.

20. Skarabot J, Beardsley C, Stirn I. Comparing the effects of self-myofascial release with static stretching on ankle range-of-motion in adolescent athletes. Int J Sports Phys Ther. 2015;10(2):203-212.

21. Schroeder AN, Best TM. Is self myofascial release an effective preexercise and recovery strategy? A literature review. Curr Sports Med Rep. 2015;14(3):200-208.

22. Macdonald GZ, Button DC, Drinkwater EJ, et al.

Foam rolling as a recovery tool after an intense bout of physical activity. Med Sci Sports Exerc.

2014;46(1):131-142.

23. MacDonald GZ, Penney MD, Mullaley ME, et al. An acute bout of self-myofascial release increases range of motion without a subsequent decrease in muscle activation or force. J Strength Cond Res. 2013;27(3):812-821.

24. Cavanaugh MT, Aboodarda SJ, Hodgson D, et al.

Foam Rolling of Quadriceps Decreases Biceps Femoris Activation. J Strength Cond Res. 2017;31(8):2238-2245

25. Aboodarda SJ, Spence AJ, Button DC. Pain pressure threshold of a muscle tender spot increases following local and non-local rolling massage. BMC Musculoskelet Disord. 2015;16:265.

26. Cheatham SW, Baker R. Differences in pressure pain threshold among men and women after foam rolling.

Journal of Bodywork and Movement Therapies.

2017;21(4):978-982 27. Cheatham SW, Baker R. Differences in pressure pain threshold among men and women after foam rolling.

J Bodyw Mov Ther. 2017;21(4):978-982.

28. Beardsley C, Skarabot J. Effects of self-myofascial release: A systematic review. J Bodyw Mov Ther.

2015;19(4):747-758.

29. Rey E, Padron-Cabo A, Costa PB, et al. The Effects of Foam Rolling as a Recovery Tool in Professional Soccer Players. J Strength Cond Res. 2017; [Epub ahead of print] 30. Romero-Moraleda B, La Touche R, Lerma-Lara S, et al. Neurodynamic mobilization and foam rolling improved delayed-onset muscle soreness in a healthy adult population: a randomized controlled clinical trial. PeerJ. 2017;5:e3908.

31. D’Amico A, Paolone V. The effect of foam rolling on recovery between two eight hundred metre runs. J Hum Kinet. 2017;57:97-105.

32. D’Amico AP, Gillis J. The influence of foam rolling on recovery from exercise-induced muscle damage. J Strength Cond Res. 2017; [Epub ahead of print] 33. Grgic J, Mikulic P. Tapering practices of croatian open-class powerlifting champions. J Strength Cond Res. 2017;31(9):2371-2378.

34. Kalen A, Perez-Ferreiros A, Barcala-Furelos R, et al.

How can lifeguards recover better? A cross-over study comparing resting, running, and foam rolling.

Am J Emerg Med. 2017;35(12):1887-1891 35. Ceca D, Elvira L, Guzman JF, et al. Benefits of a self-myofascial release program on health-related quality of life in people with fibromyalgia: a randomized controlled trial. J Sports Med Phys Fitness. 2017;57(7-8):993-1002.

36. Curran PF, Fiore RD, Crisco JJ. A comparison of the pressure exerted on soft tissue by 2 myofascial rollers. J Sport Rehabil. 2008;17(4):432-442.

37. Cheatham SW, Kolber MJ. Does Self-myofascial release with a foam roll change pressure pain threshold of the ipsilateral lower extremity antagonist and contralateral muscle groups? an exploratory study. J Sport Rehabil. 2017 1;27(2):165169 38. Roach S, San Juan JG, Suprak DN, et al. Concurrent validity of digital inclinometer and universal goniometer in assessing passive hip mobility in

The International Journal of Sports Physical Therapy | Volume 13, Number 3 | June 2018 | Page 481

39.

40.

41.

42.

43.

44.

45.

46.

47.

48.

49.

50.

healthy subjects. Int J Sports Phys Ther. 2013;8(5):680688.

Romero-Franco N, Montano-Munuera JA, JimenezReyes P. Validity and Reliability of a Digital Inclinometer to Assess Knee Joint Position Sense in a Closed Kinetic Chain. J Sport Rehabil. 2017 ;26(1):1-5 Konor MM, Morton S, Eckerson JM, et al. Reliability of three measures of ankle dorsiflexion range of motion. Int J Sports Phys Ther. 2012;7(3):279-287.

Gnat R, Kuszewski M, Koczar R, et al. Reliability of the passive knee flexion and extension tests in healthy subjects. J Manipulative Physiol Ther.

2010;33(9):659-665.

Monteiro ER, Neto VG. Effect of different foam rolling volumes on knee extension fatigue. Int J Sports Phys Ther. 2016;11(7):1076-1081.

Chesterton LS, Sim J, Wright CC, et al. Interrater reliability of algometry in measuring pressure pain thresholds in healthy humans, using multiple raters.

Clin J Pain. 2007;23(9):760-766.

Nussbaum EL, Downes L. Reliability of clinical pressure-pain algometric measurements obtained on consecutive days. Phys Ther. 1998;78(2):160-169.

Walton DM, Macdermid JC, Nielson W, et al.

Reliability, standard error, and minimum detectable change of clinical pressure pain threshold testing in people with and without acute neck pain. J Orthop Sports Phys Ther. 2011;41(9):644-650.

Lee SY, Sung KH, Chung CY, et al. Reliability and validity of the Duncan-Ely test for assessing rectus femoris spasticity in patients with cerebral palsy.

Dev Med Child Neurol. 2015;57(10):963-968.

Marks MC, Alexander J, Sutherland DH, et al.

Clinical utility of the Duncan-Ely test for rectus femoris dysfunction during the swing phase of gait.

Dev Med Child Neurol. 2003;45(11):763-768.

Peeler J, Anderson JE. Reliability of the Ely’s test for assessing rectus femoris muscle flexibility and joint range of motion. J Orthop Res. 2008;26(6):793-799.

Pearcey GE, Bradbury-Squires DJ, Kawamoto JE, et al. Foam rolling for delayed-onset muscle soreness and recovery of dynamic performance measures. J Athl Train. 2015;50(1):5-13.

Cheatham SW, Kolber MJ, Cain M. Comparison of a video-guided, live instructed, and self-guided foam roll interventions on knee joint range of motion and pressure pain threshold: a randomized controlled trial. Int J Sports Phys Ther. 2017;12(2):1-8.

51. Portney LG, Watkins MP. Foundations of Clinical Research: Applications to Practice. Pearson/Prentice Hall; 2009.

52. Dugard P, Todman J. Analysis of Pre test Post test Control Group Designs in Educational Research.

Educational Psychology. 1995;15(2):181-198.

53. Cohen J. A power primer. Psychol Bull.

1992;112(1):155-159.

54. Jay K, Sundstrup E, Sondergaard SD, et al. Specific and cross over effects of massage for muscle soreness: randomized controlled trial. Int J Sports Phys Ther. 2014;9(1):82-91.

55. Young JD, Spence AJ, Behm DG. Roller massage decreases spinal excitability to the soleus. J Appl Physiol (1985). 2018; [Epub ahead of print] 56. Grabow L, Young JD, Alcock LR, et al. Higher quadriceps roller massage forces do not amplify range of-motion increases or impair strength and jump performance. J Strength Cond Res. 2018; [Epub ahead of print].

57. Okamoto T, Masuhara M, Ikuta K. Acute effects of self-myofascial release using a foam roller on arterial function. J Strength Cond Res. 2014;28(1):69-73.

58. Hotfiel T, Swoboda B, Krinner S, et al. Acute Effects of Lateral Thigh Foam Rolling on Arterial Tissue Perfusion Determined by Spectral Doppler and Power Doppler Ultrasound. J Strength Cond Res. 2017;31(4):893-900.

59. Cavanaugh MT, Doweling A, Young JD, et al. An acute session of roller massage prolongs voluntary torque development and diminishes evoked pain.

Eur J Appl Physiol. 2017;117(1):109-117.

60. Cheatham SW, Kolber MJ, Mokha GM, et al.

Concurrent validation of a pressure pain threshold scale for individuals with myofascial pain syndrome and fibromyalgia. J Man ManipulatTher.

2018;26(1):25-35 61. Cheatham SW, Kolber MJ, Mokha M, et al.

Concurrent validity of pain scales in individuals with myofascial pain and fibromyalgia. J Bodyw Mov Ther.2017 [Epub ahead of print] 62. van der Hulst M, Vollenbroek-Hutten MM, Rietman JS, et al. Back muscle activation patterns in chronic low back pain during walking: a “guarding” hypothesis. Clin J Pain. 2010;26(1):30-37.

63. Bank PJ, Peper CE, Marinus J, et al. Motor consequences of experimentally induced limb pain: a systematic review. Eur J Pain. 2013;17(2):145-157.

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IJSPT

ORIGINAL RESEARCH

INFLUENCE OF TOPICALLY APPLIED MENTHOL COOLING GEL ON SOFT TISSUE THERMODYNAMICS AND ARTERIAL AND CUTANEOUS BLOOD FLOW AT REST Angus M. Hunter1 Christopher Grigson1 Adam Wade1

ABSTRACT Background: Topical application of menthol is a popular form of cold therapy and chemically triggers cold receptors and increases cutaneous blood flow. However, although cutaneous blood flow increases, it remains unknown where this increase arises from. Intramuscular temperature assessment may indirectly indicate a change in muscular blood flow.

Purpose: To establish intramuscular temperature, blood flow responses and subjective temperature sensation following application of menthol-based cooling gel to the anterior thigh.

Study design: Controlled, randomized cross over interventional study Methods: Twenty (age: 21.4 + 1.7) healthy males were treated on three separate days in random order with ice, a menthol-based gel or placebo gel (participant single blinded) on one anterior thigh. All measurements were taken at baseline and for 80 mins following treatment: 1) Skin, core, and intramuscular temperatures (1 & 3 cm deep); 2) femoral arterial blood flow (duplex ultrasound); 3) cutaneous blood flow (laser Doppler) and 4) subjective cold sensation.

Results: Ice and both gels decreased (p<0.0001, CI (Ice): -5.2 to -6.2 and CI (gels) -1.4 to -2.5) intramuscular temperature by 5.7 and 1.9°C respectively, but by 80 mins were similar to each other (1.5-2°C less than pre-treatment). Skin temperature mirrored muscle temperature with 8.8 and 4.2°C respective decline for ice and gels. Menthol gel increased (p<0.0001) cutaneous blood flow by 0.3 ml/min compared to unaltered flow associated with the placebo gel and a decline of 0.3 ml/min for the ice. Menthol gel cold sensation was subjectively reported to be cooler (p<0.0001) than the other two treatments. Core temperature and arterial flow were unaffected.

Conclusion: This is the first study to demonstrate the intramuscular cooling effect of menthol-based gel. However, the likely cause was from evaporative cooling despite menthol-derived increases in cutaneous blood flow and cooling sensation.

Level of evidence: Treatment, level 2.

Key words: Cold therapy, intramuscular temperature, temperature sensation

1

Physiology, Exercise and Nutrition Research Group, University of Stirling, Stirling, Scotland.

The authors have no conflicts of interest to declare.

CORRESPONDING AUTHOR Dr. AM Hunter Room 3A77 University of Stirling Stirling FK9 4LA Scotland Phone: +44 (0) 1786 466497 Fax: +44 (0) 1786 466919 E-mail: a.m.hunter1@stir.ac.uk

The International Journal of Sports Physical Therapy | Volume 13, Number 3 | June 2018 | Page 483 DOI: 10.26603/ijspt20180483

INTRODUCTION Cold therapy is widely used to reduce the amount of soft tissue damage following an acute injury1 and has been proposed to reduce inflammatory response, haematoma, oedema and pain.2–4 Cold therapy is typically administered by either ice or gel packs, ice massage, or cold water immersion. Such forms of therapy can often be impractical due to environmental factors and access issues to freezers and ice baths when travelling. Additionally, these forms of cold therapy require at least 10 minutes of application for effect1 thus, rendering their use for minor injuries during games/competition likewise impractical. Therefore, localized topical application of menthol containing cooling gels may represent a suitable and practical alternative.

Menthol is an ingredient that activates Transient Receptor Potential Melastatin 8 (TRMP8) channels which are non–selective and are known to also open in response to cold temperature (8-28°C).5 Menthol and cold therapy provide cold sensations6 as well as an analgesic effect.7,8 In contrast to traditional ice therapy which decreases cutaneous blood flow,9,10 menthol has been shown to increase cutaneous blood flow.11,12 This increased cutaneous flow occurs through activation of TRMP8 receptors in the vascular cells,12,13 which in turn increase Nitric Oxide production from the endothelial cells resulting in localized vasodilation.12,14,15 This, in itself, could have important clinical benefit for treating patients with peripheral neuropathy by increasing cutaneous blood flow to their hands and feet to help with distal sensation.11 The resultant increased cutaneous blood flow has to occur by diverting blood from another region and there is no topical menthol research describing where this blood may be redirected from. Therefore, it can be speculated that the menthol induced vasodilation and increased cutaneous flow, as previously described,11,12 derives from a diversion of blood from muscle and in doing so may reduce intramuscular temperature. Thus, menthol may induce intramuscular cooling, reduce inflammation and edema with similar endpoints to ice but through an alternative mechanism. However, to the authors’ knowledge, no research has demonstrated if intramuscular temperature decline occurs following treatment of topical menthol. Accordingly, the author’s aim was

to establish intramuscular temperature, blood flow responses and subjective temperature sensation following application of menthol-based cooling gel to the anterior thigh. In order to establish this the authors compared a menthol containing gel; a placebo gel; and a traditional ice pack, within a cross over design. To account for the effects of rest over time the authors also took measurements from the untreated contralateral leg. The authors hypothesized that the menthol gel would increase cutaneous blood flow, by reducing intramuscular temperature while maintaining arterial blood flow and increase cooling sensation.

METHODS Twenty young healthy, active males were recruited for the study, their age; mass and height were 21.4 + 1.7 years, 81.4 + 10.5 and 179.1 + 7.9 cm respectively. A difference of 3.8°C + 1.5°C temperature decline difference between ice and menthol gel treatment for 95% power was used to calculate a minimum sample size requirement of n=5 (G*Power) was estimated (5% significance level).

All participants were to be injury free and had to avoid any unaccustomed exercise during the trial that may cause delayed onset of muscle soreness (DOMS). Participants abstained from strenuous exercise and followed their usual dietary habits for 24 h prior to test sessions, which were conducted at the same time of day to account for circadian variation.16 Skinfold measurements of the anterior thigh did not exceed 20 mm. Approval for the study was granted by the local research ethics committee in accordance with the Helsinki Declaration of 2013 and all participants signed an Informed consent form prior to testing and their rights protected throughout the entire process.

EXPERIMENTAL OVERVIEW Participants attended the laboratory on three separate occasions, in the morning, with at least 48 hours between visits. The participants were asked to refrain from any physical activity 24 hours preceding their visit and arrive following a 10 hour fast whereupon they were fed a standardized breakfast of 30 g of cornflakes and 150 ml of semi skimmed milk one hour prior to testing. They arrived with activity and diet diaries completed for the preceding

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seven days. Every participant received all three different treatments (1 per visit) in random order, by using Excel (Microsoft Office 2013 Professional Plus) RAND function, in a cross over design. The laboratory conditions were kept at a constant 22°C throughout. The leg to be treated was randomly selected, by also using Excel, on the first visit but kept the same for the remaining two visits. The trial was run by an experienced physiologist (PhD) along with a postgraduate physiologist (Mphil). No adverse side effects were reported.

Following breakfast, the participants ingested a telemetric core temperature capsule (Philips VitalSense, Linton Instrumentation, Norfolk, UK) with the assistance of tap water. The participants then had intramuscular temperature probes (13050, 0.7 mm diameter, Ellab, Hilleroed, Denmark) inserted into both anterior thighs, along with surface skin temperature thermisters (MHC, Ellab, Hilleroed, Denmark) attached (Figure 2B) whereupon temperature was recorded prior to resting for 60 minutes. Then femoral arterial blood flow was recorded using a 10-MHz multifrequency linear array transducer attached to a highresolution ultrasound machine (Sonosite, M Turbo, FUJIFILM SonoSite, Inc. Washington) and marked for repeat measurements along with cutaneous blood flow from the vastus lateralis. Then the treatment of either ice pack, menthol-based gel or placebo gel were applied to one thigh while the other thigh was used to control for the effects of rest. Immediately following treatment measurements of skin and intramuscular temperature, cutaneous blood flow and a visual thermal comfort scale17 were taken and repeated every 10 minutes. Femoral arterial flow was measured every 20 minutes. These measurements were continued up until 80 minutes (Figure 1).

Figure 1. Time course of the experimental procedure. During the 80 minute period the temperature measurements will be recorded every 5 minutes whereas the blood ďŹ&#x201A;ow every 20 minutes.

INTERVENTIONS The anterior thigh portion of the leg to be treated was marked; a line was drawn from the greater trochanter of the femur to the lateral tibial condyle, the highest thigh circumference (below the groin) was then measured from this line with half of the circumference drawn across to the other side of the leg. Then, the lowest thigh circumference was drawn from the same line just above the patella with half of this circumference drawn across to the other side of the leg. Then, the two medial half circumferences were joined up to complete the markings for the anterior region to be treated (Figure 2A). Then a flexible plastic grid containing 1.5 cm diameter holes, 1 cm apart from each other, was placed over the marked anterior thigh portion (Figure 2C). Even portions of either Deep Freeze Cold Relief Gel (The Mentholatum Company Ltd, East Kilbride, UK) containing (3% by weight [w/w] levomenthol; 35-40% w/w ethanol) or placebo gel (The Mentholatum Company Ltd, East Kilbride, UK) (0% w/w levomenthol; 3% w/w water; 35-40% w/w ethanol) were then placed into the holes, ensuring sufficient amounts applied by covering the skin area exposed by the holes. The quantity of gel used for each participant was measured by weighing the gel tube twice for pre and post treatment. The overall amount of menthol gel used was 5.1 + 1.2 ml/200 cm2 vs. 5.7 + 1.1 ml/200 cm2 of placebo gel with no statistical difference (paired t-test) between the two. Although this is greater than previous studies which used 1 ml/200 cm2 18,19 and 3.3 ml/200 cm2, these prior studies have used hand/wrist and forearms respectively. Whereas our the present study used the anterior thigh which is a far greater surface area therefore provides greater capacity for gel absorption during massage. The grid was then removed whereupon the gel was gently massaged using a stroking technique grade 120 into the skin for 10 minutes. The sampling area where the probes were located formed ~14% of the overall treatment area; although this sampling area had gel applied it was carefully massaged into the skin by avoiding the probes to prevent disturbing positioning. For the ice treatment two plastic bags containing ice were secured to the marked anterior thigh portion, on top of a dry paper towel for 10 minutes.

The control leg was covered with cloth to protect from the cold effects of the ice.

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Figure 2. Anterior thigh - region of treatment (A), experimental measurements for femoral arterial blood ďŹ&#x201A;ow (Ultrasound duplex), cutaneous blood ďŹ&#x201A;ow (Laser doppler), intramuscular temperature (probes) and skin temperature (thermistor) (B) and gel application (C).

MEASUREMENTS Core, skin and muscle temperature Telemetric Tcore capsules were consumed upon arrival to the laboratory two hours prior to experimental trials to ensure passing into the gastrointestinal tract.21 These capsules then transmitted core temperature to data monitor (Equivital EQ02 LifeMonitor, Cambridge, UK) at a frequency of four samples/min which transmitted to an Android application (eqView, Equivital, Cambridge, UK) for recording. A skin thermistor was attached 5 cm proximal to the intramuscular electrodes of the vastus lateralis (Figure 2B) for the assessment of skin temperature. Thigh skinfold thickness was measured using Harpenden skinfold calipers (Baty International, West Sussex, United Kingdom) and divided by two to determine the thickness of the thigh subcutaneous fat layer over each participantâ&#x20AC;&#x2122;s vastus lateralis, following which the surface area was cleaned with an alcohol swab. Then, intramuscular temperature was assessed using two sterilized needles (1.4 mm diameter), containing sterilized temperature probes; these contain small thermocouple probes have very low

thermal inertia for a fast response and are insulated by a thin polymer layer so the surrounding environment cannot alter the measurement. The needles containing the probes were inserted into the main belly of the vastus lateralis (Figure 2B) at depths of 1 and 3 cm plus one-half the skinfold measurement, following which the needle was carefully withdrawn while ensuring that the probe remained in situ. The retracted needle was then secured to the thigh using surgical tape. Both muscle and skin temperature were then recorded using a hand-held data logger thermometer (HH378, Omega, Manchester, UK) at a frequency of one sample/second. Both intramuscular and skin probes were checked for accuracy by regularly performing two-point calibrations using known water temperatures. The validity of this technique been confirmed previously work where there was observed expected intramuscular temperature rises following exercise induced hyperthermia.22 Heart Rate and Arterial Pressure Heart rate was continuously monitored during the experimental protocol (Accurex Plus, Polar,

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Kempele, Finland). Arterial blood pressure was measured noninvasively via automated brachial auscultation (Dinamap, GE Pro 300V2, Tampa, Florida), and mean arterial pressure was calculated as follows: diastolic / (0.3333 [systolic – diastolic]).

Femoral Artery Blood Flow Femoral artery diameter and velocity were measured using a 10-MHz multifrequency linear array transducer attached to a high- resolution ultrasound machine (Sonosite, M Turbo, FUJIFILM SonoSite, Inc. Washington). The images were taken at the superficial femoral artery ~3 cm distal to the bifurcation (Figure 2B). Ultrasound parameters were set to optimize longitudinal B-mode images of the lumenarterial wall interface. Continuous and synchronized pulsed-wave Doppler velocities were also obtained using the ultrasound machine. Data were collected using an insonation angle of 60°, and each measurement was recorded for 30 seconds. This position was marked on the skin for ultrasound head repositioning during the remaining measures. Post-test analysis of femoral artery diameter was performed using custom-designed edge detection which provides simultaneous and continuous measurements of arterial diameter and blood flow velocity. The assessment of blood flow velocity uses the edge detection algorithm to assess the peak velocity envelope from the Doppler gate, which is placed in the middle of the artery.

From these data, the software calculates blood flow (the product of cross-sectional area and blood flow velocity) at 30 Hz. In this experiment, femoral artery blood was shown to have a coefficient of variation of 20% on the control leg repeat measurement. All data were written to a file and retrieved for analysis in the custom-designed analysis package. The diameter, velocity, and flow were then calculated as the mean of the data acquired across each 30-second period for statistical analysis.

Cutaneous blood flow A laser Doppler probe (BL 52, Transonic, Ithaca, NY, USA) was attached to the mid-anterior thigh, midline, halfway between the inguinal line and the patella (Figure 2B) for the measurement of cutaneous blood flow. Measurements were determined by using the average of samples recorded over 30s time periods for each 10-minute interval.

Subjective measurements The visual 7 point (1 = much too cool; 7=much too warm) Thermal Comfort Scale17 was used to establish thermal comfort every 10 minutes. The authors’ have previously used the scale during exercise induced hyperthermia22 and found a strong relationship with core temperature increases.

Statistical Analysis All data are presented as mean ±SD. Differences between conditions for muscle temperature (1 and 3 cm depth), skin temperature, core temperature, arterial and cutaneous blood flow, subjective thermal rating index were examined using a two factor (condition [menthol gel, placebo gel, ice] 3 × time, 10) repeated measures ANOVA. Effects of rest and contralateral influences between treated leg and control leg were examined by using a two factor (condition [menthol gel; contralateral control leg, Placebo Gel; contralateral control leg], 4 ⫻ time, 10) repeated measures ANOVA. Where necessary, effects were followed by Tukey’s post-hoc tests. All data analysis was performed on statistical software (Graphpad Prism v.6, USA); significance was accepted at α = 0.05.

RESULTS Temperature All three treatments significantly reduced intramuscular temperature at the 1 cm (F9,171, =110.5, p<0.0001) and 3 cm depth (F9,171 = 64.9, p<0.0001) by ~6% for both gels and ~4% for the untreated legs across the full-time course (Table 1; Figure 3A). A significant treatment effect also existed at 1 cm depth (F2,38=9, p<0.001) and a tendency for a difference at 3 cm depth (F2,38=3, p=0.057) (Table 1; Figure 3B); whereas both depths showed significant interaction effects between the treatments and across the time course (1 cm: F18,342=30, p<0.0001, 3 cm: F18,342=7.6, p<0.0001) (Table 1; Figure 3). This interaction effect occurred from significantly (p<0.05) lower intramuscular temperatures of the ice vs. menthol and placebo gels immediately following treatment, which declined by ~15% compared to ~6%; the ice treatment became progressively warmer across the remaining time period with no differences by 60 and 80 min for 1 and 3 cm depths respectively.

By 80 minutes all of the thighs treated by the three

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Table 1. Intramuscular temperatures in °C for Menthol and Placebo Gel treated legs alongside untreated contralateral legs at respective corresponding times from pre-treatment through to 80 minutes’ post-treatment at 1 and 3 cm depths.

treated leg with the contralateral untreated leg: both intramuscular depths displayed significant interactions for both menthol (1 cm: F9,71=9.2, p<0.0001, 3 cm: F27,513=6.8) and placebo gels (1 cm: F9,171=31.2, p<0.0001, 3 cm: F9,171=8.3, p<0.0001) between treated and contralateral untreated legs across all the time points (Table 1). This demonstrated significantly (p<0.0001) cooler values for both gels vs. contralateral untreated legs by 2-4% at all time points for 3 cm depth but at just 0-60 minutes at 1 cm depth (Table 1).

Figure 3. Intramuscular temperatures for both legs (vastus lateralis) at depths of A: 1 cm and B: 3 cm for: both gels vs. ice.

All treatments significantly declined over 80 minutes #p<0.01; time points 0-80 minutes vs. -10 minutes p<0.01 Ice significantly less than the gels **p<0.01; Deep Freeze Gel and Placebo Gel significantly greater than ice € p<0.05 p<0.01 respectively; placebo gel significantly greater than ice $ p<0.05.

conditions were still significantly (p<0.0001) cooler than before treatment by ~7% for 1 cm and ~6% for 3 cm (Table 1; Figure 3).

When controlling for the effects of rest and massage of gel into the leg, the authors compared the

Core temperature remained unchanged across all time points with no difference between conditions (Figure 4A). Skin temperature showed a similar response to muscle temperature by significantly (F9,71=384, p<0.0001) reducing temperature in all three treatments with significantly (p<0.0001) greater reductions in the ice (~32%) vs. both gels (~14%) at 0-60 minutes with no differences at 70 and 80 minutes (Figure 4B). All skin temperatures still remained significantly (p<0.0001) cooler at 80 minutes by ~5% for the ice and ~2% for the gels when compared to baseline but this was not different than the contralateral untreated leg.

Blood Flow Skin perfusion showed a significant (F2,38=6.6, p<0.01) difference between treatments with menthol gel significantly higher than placebo gel (~50%) and ice (~72%) at 20 minutes (p<0.0001) (Figure 5A). Whereas femoral artery blood flow significantly (F8,82=325, p<0.0001) decreased by 67% for all three

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Figure 4. Core temperature (A) and skin temperature (B) for menthol and placebo gel and ice. **p<0.001 *p<0.05 ice vs. both gels # p<0.001 all treatments change over time.

treatments and contralateral legs across the time course with no differences between them (Figure 5B).

Heart Rate and Mean Arterial Pressure Heart rate was not different between treatments but did significantly (F5,95=4.3, p<0.01) decline, for all treatments, over the full time period from ~65 to ~62 beats/minute. Mean arterial pressure was also not different between treatments but did significantly (F9,95=3.6, p<0.01) increase, for all treatments, over the full time period from ~93 to ~96 mmHg. Subjective measures Thermal comfort demonstrated significant effects across time (F9, 171 = 4.8, p<0.0001) between treatments (F2, 38 = 3.7, p<0.05) and for interaction (time ⍝ treatment) (F 18, 342= 2, p<0.01). These differences occurred from: 1) ~7% significantly (p<0.0001) cooler sensation of the menthol gel vs. ice and placebo gel from 10-80 minutes; 2) ice sensation significantly (p<0.0001) declined by ~14% immediately following treatment and recovered by 10 minutes,

Figure 5. Cutaneous bloodďŹ&#x201A;ow (A) and arterial ďŹ&#x201A;ow from baseline (pre-treatment) (B) menthol and placebo gel and ice. *p<0.05 menthol vs. placebo gel $p<0.001 menthol gel vs. ice $$ p<0.0001 all treatments declined over 80 minutes.

whereas there was no decline in the placebo gel, but the menthol gel significantly (p<0.01) declined immediately ~by 9% after but remained lower than baseline at 10, 40, 50, 60 and 70-minute time points.

DISCUSSION This is the first well controlled study to demonstrate that menthol gel increased cutaneous blood flow and reduced intramuscular and skin temperature without any alterations to femoral arterial blood flow and core temperature. However, placebo gel also reduced intramuscular temperature to a similar extent but without cutaneous blood flow changes. Ice packs reduced intramuscular temperature, alongside cutaneous blood flow, to a greater extent than both gels immediately following treatment but was similar by 80 minutes. Core temperature remained unaltered, for all three treatments, while skin temperature followed a similar response to intramuscular temperature. Menthol gel provided a cooler sensation longer compared to ice and placebo gel. Thermoregulation

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remained unaltered for all treatments as evidenced by a decline in heart rate alongside increased MAP due to likely increase in total peripheral resistance to maintain circulation during the resting conditions.23 It is well documented that conductive heat transfer from skeletal muscle to blood occurs in an attempt to reduce muscle temperature.24 The authors hypothesized that menthol gel would increase cutaneous blood flow due to likely activation of vascular cells TRMP8 to increase endothelial function and subsequent vasodilation.12,14,15 Cutaneous blood flow did increase but arterial blood flow remained unchanged, in comparison to ice, placebo gel and control leg, therefore the authors are unsure regarding the source of the increased blood flow. Interestingly, previous studies19,25,26 examining topical menthol effects observed a decline in arterial flow due to presence of TRMP8 receptors in arterial smooth muscle.12 However, these studies applied menthol to the upper arm19,26 and the upper leg (anterior and posterior)25 and took blood flow measurements from brachial and popliteal arteries respectively; whereas the authors took their measurements from the femoral artery which is larger and deeper located than brachial and popliteal arteries,27 therefore the relative effects of menthol gel application are likely to be less. This is despite the relatively higher dosage used in the present study of 5.1 ml/200 cm2 compared to 1ml/200 cm2 used when applying to the upper arm18,19 or 3.3 ml/200 cm when applied to the forearm.19 However, when applied to the both anterior and posterior of the upper leg 7 ml/200 cm2 has been used25. Therefore, it appears that the larger the surface area treated, the more gel can be applied, most likely due to exponentially greater absorbing capacity; however, it is worth noting that the menthol gel used in the present study consisted of 3% levomenthol compared to 3.5% used in all the other reported studies, therefore relative response to the gel may have been less. Nevertheless, the menthol effect could not have caused the observed intramuscular temperature decline as this was similar to the placebo gel both superficially (1 cm depth) and deep (3 cm) into the muscle. This effect was not due to the cooling effect of slowing metabolism from rest28 as these temperatures were still lower than the untreated control leg which also

reduced, over the same time period. Given the menthol content of the menthol gel did not cause the observed temperature decline, it suggests that the ethanol content of the gels, similar to the action of sweat,29 may have increased evaporation30 to reduce intramuscular and skin temperatures. Interestingly, although ice produced far lower temperature immediately after treatment, by 80 minutes the temperature was similar to that of the gels as they were still present in the skin whereas ice was removed after 10 minutes; any longer would have caused severe discomfort. Also, following ice application and removal, intramuscular temperature was becoming progressively warmer, whereas both gels maintained temperature decline for the full 80 minutes, suggesting that beyond this time point the gels could display a greater sustained cooling effect than the ice; which is an important practical consideration for practioners seeking long term cooling effects during sporting activities where ice pack application may be impractical.

Application of menthol gel most likely activated TRMP8 receptors, and have subsequently activated cold temperature sensory nerves;6 which may have caused greater cooler sensation than the other treatments and is associated with analgesic effects,7,8 which is an important consideration when seeking to treat soft tissue injury.

The exact mechanisms by which menthol provides local analgesia remain unclear with some suggested theories; these include increased pain receptor thresholds31,32 which may be as a result of â&#x20AC;&#x153;The Gate Control Theoryâ&#x20AC;?,31 which blocks pain transmission when alternative peripheral stimulus is received, such as hot or cold.32 Recently, a systematic review33 examined the topical analgesic clinical effectiveness of menthol Biofreeze gel on musculoskeletal pain; the review covered neck, back, knee and hand pain and delayed onset of muscle soreness of elbow flexors and knee extensors. Most of the studies demonstrated significant reductions in pain following menthol gel application, although the knee pain studies failed to demonstrate clinically important differences. However, some of the included studies were underpowered and the authors33 recommended follow up research using large randomized clinical trials to fully establish analgesic effects. In

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the present study, the cold sensation of the menthol gel still existed by 70 minutes post treatment, whereas cutaneous blood flow returned to normal by 40 minutes. This is a similar occurrence to that described by Craighead et al34 who showed menthol induced cutaneous blood flow to return by 45 minutes whereas cooling sensation persisted for 60 minutes. Although the authors did not explain why there were different time effects, it is likely due to different location of TRPM8 receptors in sensory nerves, providing cool sensation35 and the vasculature,12,13 causing vasodilation. Therefore, it is possible that the threshold effects of menthol are different depending on activation of sensory nerves TRPM8 or vasculature TRPM8. Nevertheless, to fully understand menthol analgesic effects further study using menthol gel to treat exercise induced muscle damage and soft tissue injury is needed.

Limitations of this study include: 1) the population used were young and healthy males free of any acute injury or chronic illness. Therefore, the findings may not apply to both sexes of different ages that express decrements in cutaneous blood flow; 2) the measurements used were unable to determine where the increased cutaneous blood flow was redirected from; 3) although the participants where blinded to the treatments it was impossible to disguise ice vs. gel treatments and even with the placebo gel used it was difficult to mask the menthol aroma. However, the influence of bias on either the participant or investigator will have been minimal due to the objective measurements used while the participant was in the passive rested state and; 4) due to the electrode placement on the vastus lateralis it was difficult to directly massage this region which may have created a bias in measurements, although this was consistent between the 2 gels.

CONCLUSIONS In conclusion, the results of this study has demonstrate that at rest, menthol cooling gel increases cutaneous blood flow and cooling sensation alongside reduced intramuscular and skin temperatures, which was also shown in the placebo and ice conditions. Although menthol gel intramuscular and skin temperature was reduced over an extended period of time, this was likely from the evaporative effects

of alcohol content in the gel rather than from any pharmacological action of the menthol. Nevertheless, this cooling effect along with the possible analgesic effects of menthol gel, indicates that it could provide an effective practical alternative to ice treatment for practitioners seeking to treat soft tissue injury. Further study is needed to establish whether this is possible.

REFERENCES 1. Bleakley CM, Hopkins JT. Is it possible to achieve optimal levels of tissue cooling in cryotherapy? Phys Ther Rev. 2010;15(4):344-350.

2. Meeusen R, Lievens P. The use of cryotherapy in sports injuries. Sports Med. 3(6):398-414.

3. Swenson C, Swärd L, Karlsson J. Cryotherapy in sports medicine. Scand J Med Sci Sports.

1996;6(4):193-200.

4. Merrick MA, Rankin JM, Andres FA, Hinman CL. A preliminary examination of cryotherapy and secondary injury in skeletal muscle. Med Sci Sports Exerc. 1999;31(11):1516-1521.

5. McKemy DD, Neuhausser WM, Julius D. Identification of a cold receptor reveals a general role for TRP channels in thermosensation. Nature.

2002;416(6876):52-58.

6. Babes A, Ciobanu AC, Neacsu C, Babes R-M. TRPM8, a sensor for mild cooling in mammalian sensory nerve endings. Curr Pharm Biotechnol. 2011;12(1):78-88.

7. Liu B, Fan L, Balakrishna S, Sui A, Morris JB, Jordt S-E. TRPM8 is the principal mediator of mentholinduced analgesia of acute and inflammatory pain.

Pain. 2013;154(10):2169-2177.

8. Premkumar LS, Abooj M. TRP channels and analgesia. Life Sci. 2013;92(8-9):415-424.

9. Ho SS, Coel MN, Kagawa R, Richardson AB. The effects of ice on blood flow and bone metabolism in knees. Am J Sports Med. 1994;22(4):537-540.

10. Thorsson O, Lilja B, Ahlgren L, Hemdal B, Westlin N. The effect of local cold application on intramuscular blood flow at rest and after running. Med Sci Sports Exerc. 1985;17(6):710-713.

11. Craighead DH, Alexander LM. Topical menthol increases cutaneous blood flow. Microvasc Res. 2016;107:39-45.

12. Johnson CD, Melanaphy D, Purse A, Stokesberry SA, Dickson P, Zholos A V. Transient receptor potential melastatin 8 channel involvement in the regulation of vascular tone. AJP Hear Circ Physiol.

2009;296(6):H1868-H1877.

The International Journal of Sports Physical Therapy | Volume 13, Number 3 | June 2018 | Page 491

13. Yang X-R, Lin M-J, McIntosh LS, Sham JSK. Functional expression of transient receptor potential melastatin- and vanilloid-related channels in pulmonary arterial and aortic smooth muscle. AJP Lung Cell Mol Physiol. 2006;290(6):L1267-L1276.

14. Cheang WS, Lam MY, Wong WT, et al. Menthol relaxes rat aortae, mesenteric and coronary arteries by inhibiting calcium influx. Eur J Pharmacol.

2013;702(1-3):79-84.

15. Sun J, Yang T, Wang P, et al. Activation of coldsensing transient receptor potential melastatin subtype 8 antagonizes vasoconstriction and hypertension through attenuating RhoA/Rho kinase pathway. Hypertens (Dallas, Tex 1979).

2014;63(6):1354-1363.

16. Atkinson G, Reilly T. Circadian variation in sports performance. Sports Med. 1996;21(4):292-312.

17. Bedford T. Basic Principles of Ventilation and Heating.

London, pp 101-154: HK Lewis; 1964.

18. Sundstrup E, Jakobsen MD, Brandt M, et al. Acute Effect of Topical Menthol on Chronic Pain in Slaughterhouse Workers with Carpal Tunnel Syndrome: Triple-Blind, Randomized PlaceboControlled Trial. Rehabil Res Pract. 2014;2014:1-7.

19. Olive JL, Hollis B, Mattson E, Topp R. Vascular conductance is reduced after menthol or cold application. Clin J Sport Med. 2010;20(5):372-376.

20. Watt J. Massage for Sport. Malborough: Crowood Press; 1999.

21. Byrne C, Lim CL. The ingestible telemetric body core temperature sensor: a review of validity and exercise applications. Br J Sports Med. 2007;41(3):126-133.

22. Hunter A, Albertus-Kajee Y, St Clair Gibson A. The effect of exercise induced hyperthermia on muscle fibre conduction velocity during sustained isometric contraction. J Electromyogr Kinesiol. 2011;21(5):834-840.

23. Widmaier EP, Raff H, Strang KT. Human Physiology.

Ninth. Boston: Mcgraw Hill; 2004.

24. Raccuglia M, Lloyd A, Filingeri D, Faulkner SH, Hodder S, Havenith G. Post-warm-up muscle

25.

26.

27.

28.

29.

30.

31.

32.

33.

34.

35.

temperature maintenance: blood flow contribution and external heating optimisation. Eur J Appl Physiol.

2016;116(2):395-404.

Topp R, Winchester LJ, Schilero J, Jacks D. Effect of topical menthol on ipsilateral and contralateral superficial blood flow following a bout of maximum voluntary muscle contraction. Int J Sports Phys Ther.

2011;6(2):83-91.

Topp R, Winchester L, Mink AM, Kaufman JS, Jacks DE. Comparison of the effects of ice and 3.5% menthol gel on blood flow and muscle strength of the lower arm. J Sport Rehabil. 2011;20(3):355-366.

Marieb EN. Human Anatomy and Physiology. 5th ed.

San Fransico: Benjamin Cummings; 2001.

Speakman JR, Selman C. Physical activity and resting metabolic rate. Proc Nutr Soc. 2003;62(3):621-634.

McArdle WD, Katch FI, Katch VL. Exercise Physiology: Nutrition, Energy and Human Performance. Eighth.

Baltimore; 2015.

Frederick Frasch H, Bunge AL. The Transient Dermal Exposure II: Post-Exposure Absorption and Evaporation of Volatile Compounds. J Pharm Sci. 2015;104(4):1499-1507.

Melzack R, Wall PD. Pain mechanisms: a new theory. Science. 1965;150(3699):971-979.

Kwon YS, Robergs RA, Schneider SM. Effect of local cooling on short-term, intense exercise. J Strength Cond Res. 2013;27(7):2046-2054.

Page P, Alexander L. The Clinical Effectiveness of Biofreeze ® Topical Analgesic on Musculoskeletal Pain: A Systematic Review. JPHR J Perform Heal Res. 2017;1(1).

Craighead DH, McCartney NB, Tumlinson JH, Alexander LM. Mechanisms and time course of menthol-induced cutaneous vasodilation. Microvasc Res. 2017;110:43-47.

Dhaka A, Earley TJ, Watson J, Patapoutian A. Visualizing Cold Spots: TRPM8-Expressing Sensory Neurons and Their Projections. J Neurosci.

2008;28(3):566-575.

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IJSPT

ORIGINAL RESEARCH

PITCHING MECHANICS IN FEMALE YOUTH FASTPITCH SOFTBALL Gretchen D. Oliver, PhD1 Hillary A. Plummer, PhD2 Jessica K. Washington, MEd1 Michael G. Saper, DO3 Jeffrey R. Dugas, MD4 James R. Andrews, MD3

ABSTRACT Background: Fastpitch softball is a popular sport for young females. However, data are limited describing youth pitching mechanics. Normative data describing pitching mechanics in the two youngest player pitch leagues are critical to gaining an improved understanding of proper mechanics in an attempt to establish injury prevention programs.

Purpose: The purpose of this study was to examine pitching mechanics in Little League softball pitchers and examine the relationship of these mechanics and participant anthropometrics to ball velocity.

Study Design: Cross-sectional.

Methods: Twenty-three youth softball pitchers (11.4 ± 1.5 years; 154.6 ± 10.5 cm; 51.0 ± 8.0 kg) participated. An electromagnetic tracking system was used to collect kinematic data for three fastball trials for strikes over a regulation distance to a catcher. The pitching motion was divided into three events: top of back swing, stride foot contact, and ball release.

Results: Youth who were older (r=0.745, p < 0.001) and taller (r=0.591, p = 0.003) achieved greater ball velocity.

Trunk kinematics revealed that greater trunk flexion throughout the three throwing events of top of back swing (r=0.429, p=0.041), stride foot contact (r=0.421, p=0.046), and ball release (r=0.475, p=0.022) yielded greater ball velocity. Additionally, greater trunk rotation to the throwing arm side (r=0.450, p=0.031) at top of back swing and greater trunk lateral flexion to the glove side at ball release (r=0.471, p=0.023) resulted in greater ball velocity.

Conclusion: The significant relationships found between pitching mechanics and ball velocity only occurred at the trunk, which may highlight the importance of utilizing the trunk to propel the upper extremity in dynamic movements.

Level of Evidence: Diagnosis, Level 4.

Key Terms: Little League; Mechanics; Shoulder; Pitching

1

Auburn University, Auburn, AL, USA University of Southern California, Los Angeles, CA, USA 3 The Andrews Institute, Gulf Breeze, FL, USA 4 Andrews Sports Medicine & Orthopaedic Center, Birmingham, AL, USA 2

The authors have no conflicts of interest to report.

CORRESPONDING AUTHOR Gretchen D. Oliver PhD, FACSM, ATC, LAT, CES 301 Wire Rd Auburn University Auburn AL 36849 E-mail: goliver@auburn.edu (859) 200-4035

The International Journal of Sports Physical Therapy | Volume 13, Number 3 | June 2018 | Page 493 DOI: 10.26603/ijspt20180493

INTRODUCTION The windmill softball pitch is a dynamic movement in which the athlete rapidly moves their arm in a circular motion to produce an underhand pitch. A common misconception regarding the softball pitch is that it produces less stress on the shoulder than the overhead baseball pitch, however, the literature does not support this notion.1-3 Recent studies have revealed that the windmill softball pitch generates similar forces about the shoulder as those seen in overhand pitching.2,3 Studies examining softball pitching mechanics have focused primarily on kinetics, or forces, about the shoulder and elbow,1-3 ground reaction forces,3-5 and segmental speeds.1-3,5 However, these studies have included wide age ranges and skill levels of participants, and no study, has described the kinematics of the youngest level of competitive softball pitchers.

Approximately 260,000 athletes participate in Little League softball’s four age-based divisions.6 Despite the high number of young athletes participating in the sport, there are limited biomechanical data describing the windmill pitch in the younger divisions of Little League softball. With the high participation in the sport, it is paramount that young athletes are instructed on proper pitching mechanics.6 The current literature contains more data on proper pitching mechanics in baseball compared to softball. Yet, forces about the shoulder and elbow are similar between the baseball and softball pitches despite the fundamental differences in the motions.1-3 The National High School Sports-Related Injury Surveillance Study found that from 2006-2012 injury rates of softball athletes are comparable or exceed those in baseball athletes.7 Studies describing softball pitching kinematics at the younger divisions are warranted in an attempt to educate coaches and sports medicine personnel on proper pitching mechanics in an attempt to reduce injury susceptibility. The purpose of this study was to (1) examine pitching mechanics in Little League softball pitchers and (2) examine the relationship of these mechanics and participant anthropometrics to ball velocity.

METHODS The independent variables in this study were the kinematic parameters (trunk flexion, trunk lateral

flexion, trunk rotation, pelvis anterior/posterior tilt, pelvis lateral flexion, pelvis rotation, shoulder horizontal abduction, shoulder elevation, elbow flexion, stride leg knee flexion, and stride length) and participant anthropometrics (age, height, and weight) and the dependent variable was ball velocity.

Twenty-three female softball pitchers (11.4 ± 1.5 years; 154.6 ± 10.5 cm; 51.0 ± 8.0 kg) were enrolled and reported to the Sports Medicine and Movement Laboratory for data collection. Participants were recruited from local youth fast-pitch softball teams via email contact with their respective coaches.

Selection criteria included being currently active on the playing roster for the position of pitcher to ensure that all participants were competitively active at the pitching position. Potential participants with a history of upper or lower extremity injury within the prior six months were excluded. Participants played Little League softball and had 2.3 + 1.3 years of experience. The Institutional Review Board of Auburn University approved all testing protocols.

Prior to data collection, all testing procedures were explained to each participant and their parent(s)/ legal guardian(s) and informed consent and participant assent were obtained.

Procedures All kinematic data were collected with The MotionMonitorTM (Innovative Sports Training, Chicago, IL) synchronized with an electromagnetic tracking system (Track Star, Ascension Technologies Inc., Burlington, VT). Eleven electromagnetic sensors were attached to the following locations: (1) the posterior/medial aspect of the torso at T1, (2) posterior/ medial aspect of the pelvis at S1, (3-4) bilateral distal/posterior aspect of the upper arm at the deltoid tuberosity, (5) the flat, broad portion of the acromion of the throwing scapula, (6-7) bilateral distal/ posterior aspect of the forearm, (8-9) bilateral distal/lateral aspect of the lower leg centered between the head of the fibula and the lateral malleolus, and (10-11) bilateral distal/lateral aspect of the upper leg (femur).5,8-14 Medial and lateral aspects of each joint were identified and digitized. Joint centers were calculated by the midpoint of the two points digitized.

A link segment model was then developed through digitization of bony landmarks used to estimate the

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joint centers for the ankle, knee, hip, shoulder, thoracic vertebrae 12 (T12) to lumbar vertebrae 1 (L1), and cervical vertebrae 7 (C7) to thoracic vertebrae 1 (T1). The spinal column was defined as the digitized space between the associated spinous processes, whereas the ankle and knee were defined as the midpoints of the digitized medial and lateral malleoli, and the medial and lateral femoral condyles, respectively.5,8-12,15 The shoulder and hip joint centers were estimated using the rotation method as it has been shown to provide accurate positional data.16 The shoulder joint center was calculated from the rotation between the humerus relative to the scapula, and the hip joint center was calculated from the rotation of the femur relative to the pelvis. The point on the humerus or femur that moved the least according to a leastsquares algorithm allowed for the calculation of the joint centers. The variation in the measurement of the joint center had to have a root mean square error of less than 0.001 m in order to be accepted. All kinematic data were sampled at a frequency of 100 Hz. Raw data regarding sensor orientation and position were transformed to locally-based coordinate systems for each respective body segment. Pelvis, torso, and upper extremity kinematics were defined by the standards and conventions of The International Shoulder Group and International Society of Biomechanics.15,17 Stride length was calculated as the distance between bilateral lateral malleoli at the event of foot contact. To enable comparisons between participants, stride length data were normalized to body height.2 Once all sensors were secured, participants were given an unlimited time to perform their own specified pre-competition warm-up (average warm-up time was 8 minutes). Participants were instructed to pitch three fastballs at maximum effort for strikes over a regulation distance to a catcher. As per the standards of the Little League (Major Division), the participants 9-11 years of age threw a distance of 40 ft. (12.19m), while those 12-13 years of age pitched 43ft (13.11m) according to the Junior Division standards.6 Data for each kinematic variable were averaged for the three fastball pitches during data analysis in effort to limit potential variability between pitches. For the purpose of this study, the

arm contralateral to the throwing arm was defined as the glove side. The stride leg was defined as the leg contralateral to the throwing arm. The pitching motion was divided into the events of top of backswing, stride foot contact, and ball release and all variables were analyzed at these events2,3 (Figure 1).

Statistical Analysis Data were analyzed using IBM SPSS Statistics 23 (IBM corp., Armonk, NY). Eleven kinematic parameters (trunk flexion, trunk lateral flexion, trunk rotation, pelvis anterior/posterior tilt, pelvis lateral flexion, pelvis rotation, shoulder horizontal abduction, shoulder elevation, elbow flexion, stride leg knee flexion, and stride length) were analyzed.

Means and standard deviations were calculated for each variable. Pearson product-moment correlations were run to assess the relationships between age, height, weight, and pitching kinematics to ball velocity. The alpha level was set a priori at p â&#x2030;¤ 0.05.

RESULTS Data describing fastball pitching mechanics are presented in Tables 1 and 2.

The results of the correlations between variables and ball velocity are presented in Table 3. Average ball velocity for the examined sample was 40.5 Âą 6.5 mph (18.1 Âą 2.9 m/s). When examining participant demographics of age and height, it was found that youth who were older (r = 0.745, p < 0.001) and taller (r = 0.591, p = 0.003) achieved greater ball velocity. Examining the relationship between pitching kinematic parameters and ball velocity, results revealed that greater trunk flexion throughout the three throwing events of top of back swing (r = 0.429, p = 0.041), stride foot contact (r = 0.421, p = 0.046), and ball release (r = 0.475, p = 0.022) yielded greater ball velocity. Additionally, greater trunk rotation to the throwing arm side (r = 0.450, p = 0.031) at top of back swing and greater trunk lateral flexion to the glove side at ball release (r = 0.471, p = 0.023) resulted in greater ball velocity.

DISCUSSION The purpose of this study was to (1) examine pitching mechanics of youth softball pitchers at the Little League level and (2) examine the relationship of

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Figure 1. Pitching events. TOB= top of back swing; FC= foot contact; BR= ball release.

these pitching mechanics and participant anthropometrics on ball velocity. Regarding pitch mechanics, results from this study are consistent with previous research by Werner et al., which also examined youth softball athletes.3 At the lower extremity, stride knee flexion was approximately 30º from full extension at stride foot contact, and both studies observed 43º of pelvic rotation towards the throwing arm side, resulting in a near closed position at ball release. At the upper extremity, participants in the current study displayed greater shoulder elevation at stride foot contact with approximately 123º versus 109º in the Werner study and again at ball release with 15º versus 3º. Participants in this study had greater elbow flexion of 31º from full extension compared to 20º at ball release. Overall, mean ball velocity of these participants was slower at 18 m/s versus 25 m/s. These subtle discrepancies could be an effect of age, as participants in this study ranged

from 9 to 12 years of age, while participants in Werner et al. ranged from 11 to 19 years.

In analysis of kinematic relationships to ball velocity, youth softball pitchers who were older and taller had greater ball velocity. The relationship between age and ball velocity is not surprising, as strength is generally gained as one matures. It is interesting to note that height was significantly correlated with ball velocity, while stride length was not significant.

Though height is a controlling factor of stride length, it was found that stride length did not play a role in ball velocity. The relationship of height and ball velocity may be the result of maturation, through bone and muscle growth and development, versus stride length. It can be postulated that pitchers who were taller could have longer segments and the potential to generate greater torque during the windmill pitching motion. Furthermore, pitchers in this study displayed

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Table 1. Lower extremity pitching mechanics during the fastball by event of pitching motion.

Table 2. Upper extremity pitching mechanics during the fastball by event of pitching motion.

a stride length of approximately 61% of body height comparable to that of the Werner study at 62%. Longer stride lengths of softball pitchers have been found to increase ball velocity due to the increased propulsive force that leads to a longer stride.4 However, there must be a point of diminishing return with regard to increased stride length, because the body must be in an optimal position to create resistance against which the body can rotate through to ball release.4 Striding too long will cause the pitcherâ&#x20AC;&#x2122;s center of mass to be located closer to the back foot rather than centered within the base of support, thereby decreasing the ability to quickly create enough force for resistance immediately following stride foot contact.

The effects of trunk flexion, lateral flexion and rotation on ball velocity demonstrate that at top of back swing, pitchers with more trunk flexion and trunk rotation towards the pitching arm were able to produce greater ball velocity (Figure 2). This position would have the pitcher with their glove side shoulder pointing to home plate. Then at ball release, those who had greater ball velocity had more trunk forward flexion and their trunk was more laterally flexed to the glove side. The influence of the trunk mechanics on ball velocity reiterates the importance of the lumbopelvic-hip complex as the base for all distal mobility.18 Having a stable lumbopelvic-hip complex allows for optimum force production and

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Table 3. Pearson correlation statistics for ball velocity.

transfer to the most distal segment of the wrist and hand.18 Thus, the trunk kinematics presented by the youth in the current study contributed to the ability to achieve greater ball velocity.

Smith et al.19 recently reported that 38% of the examined softball pitchers (aged 9-18) suffered an injury related to pitching over the course of a competitive season, and of these injuries, 61% involved the shoulder. Previous research in baseball pitching has reported that the greater the ball velocity of a pitch, the greater the forces that occur about the shoulder and elbow. Large forces about the shoulder and elbow may contribute to injury.20 While the current study did not examine forces, ball velocity may be an important indicator of forces at the upper extremity and understanding the variables that are related to ball velocity, including pathomechanics at the

shoulder and elbow, are critical. Ball velocity data are easier to obtain than the sophisticated throwing mechanics data that are currently presented and may be a tool clinicians and coaches can use as a proxy to infer mechanics and forces that youth pitchers incur.

Previously, Kibler has reported that during dynamic overhead movements 63-74% of kinetic energy is generated by the hip/trunk segments.21 The significant relationships, found in the current study, between pitching mechanics and ball velocity only occurred at the trunk, which may highlight the importance of utilizing the lower body and trunk to propel the upper extremity in dynamic movements.18,22 If the hip/trunk have altered movement patterns, then the kinetic energy transferred to the upper extremity may be decreased. In order to compensate for potential decreased energy transfer,

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Figure 2. Trunk positioning for increased ball velocity. (a) Pitcher with greater trunk flexion and rotation towards the throwing arm side, with back slightly towards the target. (b) Pitcher with less trunk flexion and rotation.

the upper extremity must generate greater kinetic energy.23 While this study provides valuable insight into youth softball pitching mechanics, it is important to note that limitations exist. The participants were from a relatively small geographic area. These results may not apply to all youth softball pitchers. A convenience sample of participants were recruited and the sample size was moderate. Additionally, these participants were in Little League softball’s youngest divisional levels that allow youth to pitch. These pitchers generally have the least pitching experience and are still learning how to pitch effectively.

Another limitation to this study is the cross-sectional design that only examined results from a single laboratory session’s pitching performance. A protocol that more closely represents the demands of competitive youth softball may more accurately reflect mechanics during pitching. Future research should aim to characterize the risk of pitching mechanics on upper extremity injury. Other potential factors contributing to injury risk should also be considered, such as muscular performance impairments and range of motion deficits that can enable a comprehensive characterization of risk of injury in youth pitchers.

CONCLUSION Understanding the pitching kinematics of individuals in the youngest division of Little League Softball can be of benefit to not only sports medicine personnel, but also training/conditioning specialist as well as pitching coaches. These data suggest that increased trunk rotation to the throwing arm side at top of back swing, increased trunk flexion throughout the pitch, and increased trunk lateral flexion to the glove side at ball release may improve pitching performance via increasing ball velocity. Using this evidence, sports medicine personnel and coaches can suggest potential improvements in pitching mechanics of the youth population as well as may inform the development of strength and conditioning programs focused on trunk and pelvic stability for greater postural control of the lumbopelvic-hip complex (LPHC). The LPHC is the connecting link of the lower extremity to the upper extremity for efficient transfer of energy. Focus on LPHC stability as well as postural control could ultimately assist in not only pitching performance but also injury prevention in youth softball pitchers.

REFERENCES 1. Barrentine SW, Fleisig GS, Whiteside JA, Escamilla RF, Andrews JR. Biomechanics of windmill softball pitching with implications about injury mechanisms at the shoulder and elbow. J Orthop Sports Phys Ther.

1998;28(6):405-415.

2. Werner SL, Jones DG, Guido JA, Jr., Brunet ME. Kinematics and kinetics of elite windmill softball pitching. Am J Sports Med. 2006;34(4):597-603.

3. Werner SL, Guido JA, McNeice RP, Richardson JL, Delude NA, Stewart GW. Biomechanics of youth windmill softball pitching. Am J Sports Med. 2005;33(4):552-560.

4. Guido JA, Jr., Werner SL, Meister K. Lowerextremity ground reaction forces in youth windmill softball pitchers. J Strength Cond Res. 2009;23(6):1873-1876.

5. Oliver GD, Plummer H. Ground reaction forces, kinematics, and muscle activations during the windmill softball pitch. J Sports Sci. 2011;29(10):10711077.

6. Softball Divisions of Play. 2016; http://www. littleleague.org/media/softball/softballdivisions.htm.

Accessed November 16, 2016, 2016.

7. Schroeder AN, Comstock RD, Collins CL, Everheart J, Flanigan D, Best TM. Epidemiology of overuse

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8.

9.

10.

11.

injuries among high-school athletes in the United States. The Journal of Pediatrics. 2015;166:600-606.

Oliver GD. Relationship between gluteal muscle activation and upper extremity kinematics and kinetics in softball position players. Med Biol Eng Comput. 2013.

Plummer H, Oliver GD. The relationship between gluteal muscle activation and throwing kinematics in baseball and softball catchers. J Strength Cond Res. 2014;28(1):87-96.

Oliver GD, Keeley DW. Pelvis and torso kinematics and their relationship to shoulder kinematics in high-school baseball pitchers. J Strength Cond Res. 2010;24(12):3241-3246.

Oliver GD, Plummer HA. Effects of pitching a simulated game on upper extremity kinematics in youth baseball pitchers. International Journal of Sports and Exercise Medicine. 2015;1(3):1-4.

12. Plummer HA, Oliver GD. Descriptive analysis of kinematics and kinetics of catchers throwing to second base from their knees. J Electromyogr Kinesiol.

2016;29:107-112.

13. Myers JB, Laudner KG, Pasquale MR, Bradley JP, Lephart SM. Scapular Position and Orientation in Throwing Athletes. Am J Sports Med. 2005;33(2):263271.

14. Myers JB, Oyama S, Hibberd EE. Scapular dysfunction in high school baseball players sustaining throwing-related upper extremity injury: a prospective study. J Shoulder Elbow Surg.

2013;22(9):1154-1159.

15. Wu G, van der Helm FCT, Veeger HEJ, et al. ISB recommendation on definitions of joint coordinate systems of various joints for the reporting of human joint motion—Part II: shoulder, elbow, wrist and hand. J Biomech. 2005;38(5):981-992.

16. Veeger HE. The position of the rotation center of the glenohumeral joint. J Biomech. 2000;33(12):1711-1715.

17. Wu G, Siegler S, Allard P, et al. ISB recommendation on definitions of joint coordinate system of various joints for reporting of human joint motion-part I: ankle, hip, and spine. J Biomech. 2002;35(4):543-548.

18. Kibler WB, Press J, Sciascia A. The role of core stability in athletic function. Sports Med. 2006;36(3):189-198.

19. Smith MV, Davis R, Brophy RH, Prather H, Garbutt J, Wright RW. Prospective Player-Reported Injuries in Female Youth Fast-Pitch Softball Players. Sports Health. 2015;7(6):497-503.

20. Fleisig G, Kingsley D, Loftice J, et al. Kinetic comparison among the fastball, curveball, change-up and slider in collegiate baseball pitcher. Am J Sports Med. 2006;34(3).

21. Kibler WB. Biomechanical analysis of the shoulder during tennis activities. Clin Sports Med. 1995;14(1):79-85.

22. Oliver GD, Dwelly PM, Kwon YH. Kinematic motion of the windmill softball pitch in prepubescent and pubescent girls. J Strength Cond Res. 2010;24(9):2400-2407.

23. Kibler WB. The role of the scapula in athletic shoulder function. Am J Sports Med. 1998;26(2):325-337.

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IJSPT

ORIGINAL RESEARCH

REFERENCE VALUES FOR GLENOHUMERAL JOINT ROTATIONAL RANGE OF MOTION IN ELITE TENNIS PLAYERS Catherine Nutt, PT, MSc1 Milena Mirkovic, PT, MMSk, IOC Sports PT2 Robert Hill, MPhty (Sports), MCSP2 Craig Ranson, PhD3 Stephen-Mark Cooper, PhD4

ABSTRACT Background: Due to the repetitive overhead activity involved in playing tennis and the physical demands of the game, shoulder joint injury is common. There is limited research available describing sport specific risk factors for injury in tennis, however, changes in shoulder rotational range of motion (ROM) have been associated with injury in other overhead ‘throwing’ type sports.

Purpose: This study had two purposes: i) to identify reference values for passive glenohumeral joint rotational ROM in elite tennis players, and, ii) to investigate differences in ROM between various age groups of players.

Study design: Cross-sectional analysis.

Methods: Data was collected at national performance camps held at a National Tennis Centre between September 2012 and July 2015. One hundred and eighty-four tennis players aged between 11 and 24 years took part. All had a top eight national ranking within their respective age group. Participants were divided into three age groups; under 14 years, 14-15 years, and 16 years and over. The main outcome measures were dominant and non-dominant internal and external rotation as well as total glenohumeral joint passive ROM. Results: Reduced internal, and greater external rotation passive ROM were identified on the dominant side (p < 0.05), however, no side-to-side differences in total rotation ROM were found (p > 0.05). A glenohumeral joint internal rotation deficit (GIRD) was prevalent on the dominant side, which increased in magnitude with rising player age.

Differences in dominant side internal and external rotation ROM were identified between age groups with the 14-15year olds having less internal and greater external rotation than the under 14-year olds and the over 16-year old athletes (p < 0.05). The total range of motion values were not found to differ between age groups (p > 0.05).

Conclusions: This study provides reference values for glenohumeral joint rotational ROM in elite tennis players and demonstrates age specific differences. Future studies should investigate links between changes in ROM and injury risk.

Level of evidence: 3 Keywords: Glenohumeral joint, overhead athlete, range of motion, tennis

1

Central Health Physiotherapy, Royal Hospital Chelsea, London, UK 2 Department of Sports Medicine and Science, Lawn Tennis Association, National Tennis Centre, London, UK 3 English Institute of Sport, Alan Turing Way, Manchester, UK 4 Cardiff School of Sport & Cardiff School of Education, Cardiff, UK The authors declare that there is no conflict of interest

CORRESPONDING AUTHOR Catherine Nutt Musculoskeletal Physiotherapist Central Health Physiotherapy, Royal Hospital Chelsea, Royal Hospital Road, London, SW3 4SR, UK E-mail: Cknight80@hotmail.com

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INTRODUCTION Participation in tennis at elite levels comes with a risk of musculoskeletal injury,1 due to both the high volume of play and the strenuous physical demands of the sport. Injury rates range between 0.05 to 2.9 injuries per player per year2 with a greater frequency of injury with increased court time.3 Elite junior players (aged 13-19 years) have been found to participate in an average of 2.3 hours of tennis per day over six days per week.4 Despite this, no randomized controlled trials have investigated injury prevention in tennis2 and there is a paucity of sport specific studies linking risk factors and injury rates.

Repeated high force demands placed on the shoulder during tennis have often been associated with gradual onset type injuries.5 A change in glenohumeral joint rotation range of motion (ROM) is a common musculoskeletal adaptation observed in overhead type athletes that may be associated with injury risk.6 In recent tennis literature reduced dominant side internal rotation ROM, larger external rotation ROM and smaller total rotation ROM, (TROM = sum of available internal and external rotation) have been reported.7 Greater losses of both internal ROM and TROM with increasing age and tennis exposure have also been suggested,8 however, it is not clear at which age these changes develop.

A glenohumeral joint internal rotation deficit (GIRD) is thought to develop from a combination of posterior capsular thickening, rotator cuff stiffness and humeral retroversion, which are thought to be adaptations to the stresses occurring during the acceleration and deceleration phases of throwing.9 Increased humeral retroversion is thought to be performance enhancing;10 as the bony adaptations enable an increased external rotation position during the throw.11 This additional ROM theoretically allows for a longer acceleration phase enabling greater upper limb rotational speeds to be achieved.10 Two types of GIRD have been described by Manske et al.15; i) an anatomical type with dominant side internal rotation loss greater than 18-20° but symmetrical TROM bilaterally, and, ii) a pathological GIRD where the internal rotation loss is combined with a greater than 5° loss of dominant side TROM. Ellenbecker et al.7 reported a 10° loss of internal rotation

on the dominant side in 117 tennis players, however, Kibler and Chandler12 found a mean 18° loss in their longitudinal study involving 51 tennis players.

There is also debate as to whether the presence of a GIRD is predictive of injury; it could be an adaptation to the overhead demands of the sport and improve performance or alternatively increase the injury risk.4 Reducing the arc of motion is thought to fatigue the posterior rotator cuff leading to greater force through the posterior capsule13 increasing the likelihood of injury. However, GIRD has not been identified as a specific injury predictor.11 Pluim et al.2 found no evidence that limited glenohumeral joint rotation was related to tennis injury. There are also inconsistencies when describing a clinically significant GIRD. This is supported by Manske et al.15 who stated a GIRD is required to generate sufficient force during serving and does not lead to pathology. In contrast both Kibler & Chandler,12 and Wilk et al.16 suggest the loss of internal rotation ROM is one of the intrinsic risk factors for overhead injury.

Total glenohumeral rotation ROM is also thought to be a useful indicator of shoulder pathology and a decreased TROM was associated with shoulder injury in baseball players.12, 15-17 Wilk et al.16 found a greater than 5° side-to-side difference in TROM which had a two and a half times higher injury risk than those within 5°. The equivalent data is not yet available in tennis. Ellenbecker et al.7 describe side-to-side TROM as equal in baseball players but reduced in tennis players in their study involving 163 athletes. This emphasises why more tennis data is needed, as overhead sports with different musculoskeletal demands cannot be compared.

Glenohumeral joint external rotation changes and their relation to injury risk have not been widely investigated. The concept of an external rotation difference (ERD) has been discussed by Manske et al.15 A difference between the external rotation of the dominant and non-dominant shoulder of less than 5° has been suggested to contribute to an increased injury risk due to the increased stress on the static glenohumeral stabilizers.15 This is consequently an area warranting further research in tennis players.

A few studies describe GIRD in tennis. 5,7 8,14,18 Cools et al.18 investigated age-related shoulder girdle

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adaptations in 59 elite junior players and found reduced internal, increased external, and smaller TROM on the dominant side.18 Despite relatively low participant numbers, the findings were the first to identify age specific differences. However, a clinically relevant correlation between ages was not determined and larger scale research across age groups is warranted.

Elite tennis players often commence high volume training in early childhood, which overlaps the period of rapid skeletal and muscular development.18 The tennis literature has considerable gaps regarding injury risk factors and preventative measures. The determination of age specific reference values for ROM would be valuable for screening, and are prerequisite in determining whether changes in ROM are linked to injury. This study had two purposes: i) to identify reference values for passive glenohumeral joint rotational ROM in elite tennis players, and, ii) to investigate differences in ROM between various age groups of players.

METHODS Participants The glenohumeral joint rotational range of motion (ROM) measurements of 184 elite participants, male (n = 122), and female (n = 62), aged 11 to 24 years, were collected and analyzed by one physiotherapist at performance camps held at a National Tennis Centre between September 2012 and July 2015. Sixteen participants were left hand dominant, and 168 were right hand dominant and all were deemed fit to play at the time of testing. The national performance camps were divided by gender and into eight different age groups of players; under 12 years, 12 years, 13 years, 14 years, 15 years, 16 years, 17 years and 18 years and over. All participants selected to attend had top eight national rankings in their respective age groups and where a top player was unavailable due to either injury, school or tournament commitments, the next available ranked player was invited.

For this research, three sub-groups were created to contrast glenohumeral joint ROM between ages; these were chosen to correlate with the age groups used in other research18. The groups were under 14 years (n = 69 participants), 14-15 years (n = 56), and 16 years and over (n = 59).

Ethical approval was obtained from the Cardiff School of Sport & Health Sciences (Sport) Ethics Sub-committee. All participants were sent information forms detailing the data collection process before attending the camps, and depending on their age, participants or their parents provided written informed consent to participate.

Data collection The participants were tested while supine with the glenohumeral joint positioned in 90° abduction, as suggested by Ellenbecker.19 A universal goniometer was used to measure glenohumeral joint internal and external rotation ROM. The scapula was fixed and the glenohumeral joint passively rotated into full internal and then external rotation. The scapula was fixed to ensure isolated glenohumeral joint movement, and the coracoid process and spine of the scapula were palpated to determine the onset of scapular movement. Measurements were taken at the end of range at the point immediately before scapular movement was appreciated.

The testing order was randomized with some participants tested on their left side first and others on their right. It was not possible to blind the tester; however, the participantsâ&#x20AC;&#x2122; upper limb dominance was not ascertained until after data collection.

Measurements were taken on the first day of each camp before starting any tennis training or gym exercises. Some participants were screened multiple times if they attended several camps. For these participants, their first screening data was used and subsequent measurements were excluded.

Data that could be used to estimate intra-rater reliability was gathered before the experimental data collection and involved the therapist measuring bilateral glenohumeral joint rotational ROM twice (test and retest) on five participants, with 10 minutes between measurements.

Data analysis GIRD was calculated as the difference in glenohumeral joint internal rotation ROM between the dominant and non-dominant sides. Total range of motion (TROM) was calculated as the sum of the internal and external rotation ROM for each side. The total range of motion difference (TROMD) was calculated

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as the difference between the dominant side TROM value and the non-dominant side TROM value. The external rotation difference (ERD) was calculated as the difference between the dominant side ER value and the non-dominant side ER value. The values for GIRD, TROMD and ERD were divided into 10° increments with the number of participants in each counted.

Statistical analyses Test-retest reliability was estimated in terms of: i) the intraclass correlation coefficient (ICC (3,1)), ii) the standard error of measurement [95%SEM = ± 1.96 x (sX x √(1 – ICC (3,1)))] where: sX = sample standard deviation, and, iii) the minimal detectable change [95%MDC = ± (1.96 x √2 x SEM].20 For all the outcome measures a mixed-design analysis of variance (GLM 5 ANOVA) 21 was used to analyze the mean scores due to having repeated measures on the side dominance independent variable (non-dominant vs. dominant) and independent measures on the age groups (under 14 years vs. 14-15-years vs. 16 years and over).21 In all cases, residuals were saved when running the ANOVAs and were confirmed as being drawn from a population that was normally distributed on the variables of interest (AndersonDarling test). Homogeneity of variance about means was confirmed in relevant cases using Levene’s test.

Where main effects were identified for differences between dominant and non-dominant sides, paired t-tests were used as post-hoc tests for the ANOVAs. Where main effects were identified for differences between age groups, two-sample t-tests were used as post-hoc tests for the ANOVAs. To avoid inflating familywise error rates, the level of statistical significance (α) was corrected for each of the paired and two-sample t-tests using the Dunn-Sidák correction (α’): α’ = 1 – (1 – α)1/c, where c = (k(k – 1)/2) and k = the number of comparisons being considered. Statistically significant differences, (α) were described at ≤ 0.05 throughout the data analyses; however, the Dunn-Sidák corrections had the effect of reducing α ≤ 0.05 to an α’ ≤ 0.017 (paired t-tests) and 0.008 (two sample t-tests). To determine the meaningfulness of the effects identified by the t-ratios, Cohen’s d22 was computed for all comparisons. Statistically significant interactions identified between age groups and side dominance were considered with respect

to contrast plots of the estimated marginal means.

Statistical analyses were performed using IBM SPSS Statistics v22. Data are reported as means ± standard deviations unless otherwise highlighted.

RESULTS Reliability of the tester Intraclass correlation coefficients (ICC (3,1)) were calculated for both internal (IR) and external rotation (ER) values. For IR: ICC (3,1) = 0.745, F9,9 = 6.854, p = 0.004, 95%CI = 0.26 – 0.93. For ER: ICC (3,1) = 0.718, F9,9 = 6.10, p = 0.006, 95%CI = 0.21 – 0.92. The standard error of measurement (SEM) and minimal detectable change (MDC) were also calculated for IR: 95%SEM = ±9.0° and 95%MDC = ±12.7°, and for ER: 95%SEM = ±4.5° and 95%MDC = ±12.4°.

Glenohumeral joint internal rotation range of motion (IR ROM) and glenohumeral joint internal rotation difference (GIRD) Table 1 shows that for IR ROM there was a significant main effect for side dominance means (F1,181 = 59.812, p < 0.001), there were also main effect differences between dominant side and non-dominant side IR ROM means for all the three age groups (F2,181 = 5.017, p = 0.008). Dominant side IR ROM was greatest in the under 14-year-olds and this mean was significantly different to that for the 14–15-yearolds (p = 0.005) with a moderate effect size. There were no significant differences for dominant side IR ROM means between the 14-year olds and the over 16-year olds, and between the 14-15 year olds and the over 16 year olds. On the non-dominant side, IR ROM was greatest in the 16 years and over players and this mean was significantly different to that for the 14-15-year olds (p = 0.001) with a moderate effect size. However, there were non-significant differences between the non-dominant side means for, the under 14-year olds and 14-15-year olds, and the under 14-year olds and the 16 years and over players (p > 0.008). Table 1 also shows that there was a significant main effect for the interaction between side dominance and age group means (F2,181 = 4.846, p = 0.009). However, this interaction main effect was only observed between the mean GIRD for the under 14-year olds and the over 16-year olds (p = 0.003), again with a moderate effect size. Interestingly,

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Table 1. Summary data and statistical outcomes for glenohumeral joint internal rotation range of motion (ROM) and glenohumeral joint internal rotation deficit (GIRD) for all age groups. These data are presented in degrees of rotation.

Mean ± SD internal rotation ROM

Differences between means: D vs ND

Glenohumeral joint internal rotation difference (GIRD)

Tdf-ratio (p-value) Age groups (n) Under 14 yrs (69)

a

Dominant side (95% CI)

Non-dominant side (95% CI)

44 ± 11a

47 ± 11

41 to 47

44 to 50

a

b

Mean ± SD (95% CI) Effect size (ES = d) T68 = 2.76 (0.007) 0.33 T55 = 4.84 (< 0.001)

14 – 15 yrs (56)

38 ± 10

35 to 41

42 to 48

0.65

Over 16 yrs (59)

43 ± 13

52 ± 14b

T58 = 5.37 (< 0.001)

40 to 46

49 to 55

0.70

45 ± 10

3 ± 9 (1 to 6)c

6 ± 10 (3 to 9)

9 ± 13 (6 to 12)c

Denotes a difference between age group means: difference between means ± SD = 6 ± 11, 95% CI = 2 to 9, d = 0.55; T123 = 2.84, P = 0.005

b

Denotes a difference between age group means: difference between means ± SD = 7 ± 12, 95% CI = 3 to 12, d = 0.58; T113 = 3.26, P = 0.001

c

Denotes a difference between age group means: difference between means ± SD = 6 ± 11, 95% CI = 2 to 10, d = 0.55; T126 = 2.99, P = 0.003

Figure 1. Percentage of participants against the GIRD (Degrees)

mean GIRD increased with participant age, as it was lowest in the under 14-year-olds and greatest in the 16 years and over group.

The percentage of participants with glenohumeral joint internal rotation differences in each 5° increment is shown in Figure 1.

Glenohumeral joint external rotation range of motion (ER ROM) and external rotation difference (ERD) Outcomes for ER ROM are summarized in Table 2 and show that there was a significant main effect for side dominance means (F1,181 = 56.631, p < 0.001), there were also main effect differences between

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Table 2. Summary data and statistical outcomes for glenohumeral joint external rotation range of motion (ROM) and glenohumeral joint external rotation difference (ERD) for all age groups. These data are presented in degrees of rotation.

Mean ± SD external rotation ROM

Differences between means: D vs ND Difference in external rotation ROM (ERD)

Age groups (n)

Dominant side (95% CI)

Effect size (ES = d)

Mean ± SD (95% CI)

Under 14 yrs (69)

103 ± 8a

100 ± 7

T68 = 3.69 (< 0.001)

3 ± 6 (1 to 4)

101 to 105

99 to 102

0.44

107 ± 9a,b

102 ± 8c

T55 = 4.85 (< 0.001)

105 to 110

100 to 104

0.65

101 ± 10b

97 ± 10c

T58 = 4.16 (< 0.001)

98 to 103

94 to 100

0.55

14 – 15 yrs (56)

Over 16 yrs (59)

Non-dominant side (95% CI)

Tdf-ratio (p-value)

6 ± 9 (3 to 8)

4 ± 7 (2 to 6)

a

Denotes a difference between age group means: difference between means ± SD = 4 ± 8, 95% CI = 2 to 7, d = 0.54; T123 = 3.01, P = 0.003

b

Denotes a difference between age group means: difference between means ± SD = 7 ± 9, 95% CI = 3 to 10, d = 0.78; T113 = 3.86, P = < 0.001

c

Denotes a difference between age group means: difference between means ± SD = 5 ± 9, 95% CI = 1 to 8, d = 0.52; T113 = 2.76, P = 0.007

Figure 2. Percentage of participants against the ERD (Degrees)

dominant side and non-dominant side ER ROM means for all the three age groups (F2,181 = 7.119, p = 0.001). Mean dominant side ER ROM was greatest in the 14-15-year olds, and this was significantly different to the mean value for the under 14-year olds (p = 0.003) with a moderate effect size. Dominant side ER ROM was lowest in the 16 years and over age group, and this mean was also significantly lower than that for the 14-15-year old athletes (p < 0.001).

This difference was characterised with a large effect size. The difference between means for the dominant side ER ROM in the under 14-year olds and the 16 and over athletes was non-significant (p = 0.162).

With reference to the non-dominant side ER means, once again, this was greatest in the 14-15-year olds and it was significantly different to that for the 16 years and over athletes (p = 0.007) with a moderate effect size. The other age group comparisons on the non-dominant side did not differ significantly.

In terms of the interaction between side dominance and age groups main effect, exemplified by the ERD, resulted in a non-significant outcome (F2,181 = 2.237, P = 0.067).

The percentage of participants in each 5° ERD increment is shown in Figure 2.

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Glenohumeral joint total rotation range of motion (TROM) and total range of motion difference (TROMD) The data summarized in Table 3 shows that there were no statistically significant outcomes for all the main effects interrogated in this analysis of the TROM data. For differences between side dominance means, (F1,181 = 0.044, p = 0.835), for differences between age group means (F2,181 = 2.604, p = 0.077), and for the interaction effect between side

dominance and age groups (TROMD) (F2,181 = 2.451 p = 0.089).

The percentage of participants’ TROMD in each 5° increment is shown in Figure 3 with 23% of participants having a difference between 0° and 4°.

DISCUSSION The aim of the present study was to determine reference values for glenohumeral joint rotational range

Table 3. Summary data and statistical outcomes for glenohumeral joint total range of motion (TROM) and glenohumeral joint total ROM difference (TROMD) for all age groups. These data are presented in degrees of rotation.

Mean ± SD total ROM

Age groups (n) Under 14 yrs (69)

14 – 15 yrs (56)

Over 16 yrs (59)

Differences between means: D vs ND Tdf-ratio (p-value)

Difference in total ROM (TROMD)

Dominant side (95% CI)

Non-dominant side (95% CI)

Effect size (ES = d)

Mean ± SD (95% CI)

147 ± 12

147 ± 12

T68 = 0.27 (0.791)

0 ± 11 (-2 to 3)

144 to 150

145 to 150

0.03

146 ± 12

148 ± 12

T55 = 1.68 (0.098)

143 to 149

145 to 151

0.22

140 ± 35

138 ± 34

T58 = 1.68 (0.098)

131 to 149

129 to 147

0.22

2 ± 10 (-0 to 5)

2 ± 9 (0 to 5)

Figure 3. Percentage of participants against the TROMD (Degrees) The International Journal of Sports Physical Therapy | Volume 13, Number 3 | June 2018 | Page 507

of motion (ROM) in elite tennis players, and also to investigate differences in ROM between three age groups, i) under 14 years, ii) 14-15-year olds, and, iii) 16 years and over. These are presented in Tables 1, 2 and 3. As anticipated, there were significant differences in glenohumeral joint ROM on the dominant compared to the non-dominant side with a reduced internal rotation (IR) and increased external rotation (ER) ROM on the dominant side.

Significant between age group differences were found in dominant side IR and ER ROM between the under 14-year olds and the 14-15-year old participants, and also the 14-15-year olds and the 16 and over age group.

The reduced IR ROM in the 14-15-year olds compared to the under 14-year olds suggests the 14-15-year olds should be identified as a potential target for preventative mobility programs if the ROM reaches the levels considered for injury risk.

Reduction in posterior capsule mobility is found in older overhead athletes compared to younger ones; and this could be due to more force travelling through the posterior shoulder resulting in greater thixotropic changes and capsular strain.11 This may explain the lesser degree of IR ROM adaptation in the younger participants and account for the differences between the youngest two age groups in the present study. However, the oldest age group demonstrated the highest IR values. An explanation for this could be that the older players undertake more extensive mobility exercises within their preparation programs than the younger players, thereby contributing to the increased IR ranges found. Assessing the effect of mobility exercises was not carried out in this study, but as these participants had access to high-level support teams, it would be interesting to compare them to other players without such input.

The presence of a glenohumeral joint internal rotation deficit (GIRD) in elite tennis players is supported by the results. However, the 6° mean is lower than the 13° recorded by Cools et al.18 as well as the 18-20° for the anatomical and pathological definitions described by Manske et al.15 In accordance with previous research, in the present study GIRD increased with increased athlete age.8 A higher percentage of participants with larger values of GIRD were identified in the older groups which is relevant

because increased GIRD has been associated with injury in other sports.16 This is also linked to research

by Kibler et al.8 who found the greatest reduction in IR ROM and TROM occurred in those players with less than six or more than nine years of tournament experience. Their study involved 39 tennis players aged between 14 and 21 years. The number of years the present participants had been playing tennis was not assessed as part of this study; however, as greater changes in GIRD were found with increasing participant age, the IR values may have decreased in relation to the increased years of competition in the older players.

Interestingly, the present results also demonstrate differences in both glenohumeral joint IR and ER ROM on the non-dominant side. In particular, there was less non-dominant side IR and greater ER ROM in the 14-15-year olds compared to the 16 years and over age group. Although not measured directly in this study it was observed that the older athletes incorporated more frequent bilateral IR ROM stretches into their program, which may have influenced the IR changes. Alternatively, these changes could be due to the process of normal maturation.

Glenohumeral joint ER stretches were not routinely performed and consequently this additional ER ROM in the 14-15-year olds may not have been maintained in the older age group. Nevertheless, the decrease in humeral retrotorsion, thought to take place during childhood and adolescence,10 may have contributed to the non–dominant side IR ROM increasing and the external rotation ROM decreasing with increased athlete age. It is unclear to what extent changes identified on the non-dominant side could have influenced the calculated values for GIRD in each of the present age groups.

Despite the ER ROM side-to-side differences not being statistically significantly different between the age groups, the results demonstrate a greater than 5° difference in the 14-15-year old age group but less than 5° in both the under 14-year old and the 16 years and over athletes. According to Mankse et al.15 it would be anticipated that both the youngest and oldest age group categories may have a greater likelihood of injury compared to the 14-15-year olds.

As previously described, a side-to-side difference in TROM was not found in the present study. These

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athletes consequently are within the 5° described by Manske et al.15 and would not be considered to be at any increased injury risk.

Study limitations There are several limitations to consider when interpreting the results from this study. Firstly, it cannot be assumed that all participants started to play tennis at the same age and total years of participation was not recorded. Consequently, there may have been greater adaptations in ROM in some participants than in others due to starting playing tennis at different ages. Secondly, the testing was performed during busy training camps, which meant that the time of day the measurements were taken could not be standardized, and the players’ activity levels before testing was not consistent. The volume of training before testing may have altered the ROM and some players could have performed specific posterior capsule stretches thereby impacting on the results. Finally, an important consideration is that it was not possible to blind the tester from the scores as the data was collected at performance camps and needed to be fitted around player and staffing commitments.

Future research This study has highlighted areas for additional research. Reviewing the GIRD results against the retrospective and prospective injury history of the players would be a useful adjunct to the available literature. This knowledge would help ascertain whether restricting match numbers, and training volume, should be introduced to prevent overuse injuries particularly in junior players. It would also guide preventative stretching programs to maintain glenohumeral joint rotational ROM to prevent future shoulder pathology.

This study involved a sample of elite tennis players. However, individuals not involved in overhead type sports may also have a small GIRD because of limb dominance.14 It would be useful, therefore, to compare an elite group to an aged-matched control group to ascertain reference values in non-throwing type athletes.

Future research could also incorporate insight into the skeletal maturity of the players. In this study, it

was not apparent which players had reached skeletal maturity; the addition of radiographs to confirm closure of the individual’s proximal humeral physis would help determine the relative contributions of bony versus soft tissue to adaptations in ROM. Ultrasound measurements of humeral torsion alongside rotational ROM could also be valuable.

A larger scale longitudinal study looking at changes in the glenohumeral rotational arc of individual players over time would be useful. It would be challenging to keep enough athletes over an extensive timeframe but would help exclude some of the limitations discussed previously including standardizing the number of years of play and the skeletal maturity level of the participants.

CONCLUSIONS The results of this study provide reference values for glenohumeral joint rotational range of motion (ROM) specific to elite tennis players. Reduced internal rotation (IR) and increased external rotation (ER) on the dominant, compared to the non-dominant side, of the participants was found. No statistically significant differences in glenohumeral joint total range of motion were identified. Glenohumeral joint IR deficit was present on the dominant side, which increased with rising player age. Trends were also identified across the age groups, with age specific differences in IR and ER ROM found between the under 14 years age group and the 14-15-year-olds, as well as the 14-15-year olds and the 16 years and over athletes. These results provide a baseline for reference of glenohumeral joint rotational ROM values in tennis to be contrasted with other sports. It is important for future studies to correlate changes in glenohumeral joint ROM with injury data, which will be a valuable adjunct to injury prevention programs.

REFERENCES 1. Abrams GD, Renstrom PA, Safran MR. Epidemiology of musculoskeletal injury in the tennis player. Br J Sports Med. 2012; 46: 492 – 498.

2. Pluim, BM, Staal JB, Windler GE, Jayanthi N. Tennis injuries: occurrence, aetiology and prevention. Br J Sports Med. 2006; 40: 415 -423.

3. Hjelm N, Werner S, Renstrom P. Injury risk factors in junior tennis players: A prospective 2-year study.

Scand J Med Sci Sports. 2012; 22: 40 – 48.

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4. Sciascia A, Kibler B. The pediatric overhead athlete: What is the real problem. Clin J of Sport Med. 2006; 16(6): 471 – 477.

5. Ellenbecker TS, Roetert EP, Piorkowski PA, Schulz DA. Glenohumeral joint internal and external rotation range of motion in elite junior tennis players. J. Orthop Sports Phys Ther. 1996; 24: 336 – 341.

6. Van der Hoeven H, Kibler WB. Shoulder injuries in tennis players. Br J Sports Med. 2006; 40 (5): 435 – 440.

7. Ellenbecker TS, Roetert EP, Bailie DS, Davies GJ, Brown SW. Glenohumeral joint total rotation range of motion in elite tennis players and baseball pitchers.

Med Sci Sports Exerc. 2002; 34 (12): 2052- 2056.

8. Kibler WB, Chandler TJ, Livingston BP, Roetart EP. Shoulder range of motion in elite tennis players effect of age and years of tournament play. Am J Sports Med. 1996; 24 (3): 279-285.

9. Bailey LB, Shanley E, Hawkins R, Beattie PF, Fritz S, Kwartowitz D, Thigpen CA Mechanisms of shoulder range of motion deficits in asymptomatic baseball players. Am J Sports Med. 2015; 43 (11): 2783 – 2793.

10. Whiteley RJ, Ginn KA, Nicholson LL, Adams RD. Sports participation and humeral torsion. J Orthop Sports Phys Ther. 2009; 39 (4): 256 – 263.

11. Kibler WB, Sciascia A, Thomas SJ. Glenohumeral internal rotation deficit: pathogenesis and response to acute throwing. Sports Med Arthrosc. 2012; 20 (1): 34 – 38.

12. Kibler WB, Chandler TJ. Range of motion in junior tennis players participating in an injury risk modification program. J Sci Med Sport 2003; 6 (1): 51- 62.

13. Thomas SJ, Swanik CB, Kaminski TW, Higginson JS, Swanik KA, Bartolozzi AR, Nazarian LN. Humeral

14.

15.

16.

17.

18.

19.

retroversion and its association with posterior capsule thickness in collegiate baseball players. J Shoulder Elbow Surg. 2012; 21: 910 – 916.

Torres RR, Gomes JL. Measurement of glenohumeral internal rotation in asymptomatic tennis players and swimmers. Am J Sports Med. 2009; 37: 1017 – 1023.

Manske R, Wilk KE, Davies G, Ellenbecker T, Reinoid M. Glenohumeral motion deficits: Friend or foe? Int J Sports Phys Ther. 2013; 8(5): 537 – 553.

Wilk KE, Macrina LC, Fleisig G, Porterfield R, Simpson CD, Harker P, Paparesta N, Andrews JR. Correlation of glenohumeral internal rotation deficit and total rotational motion to shoulder injuries in professional baseball pitchers. Am J Sports Med. 2011; 39: 329 – 335.

Shanley E, Rauh MJ, Michener LA, Ellenbecker TS, Garrison JC, Thigpen CA. Shoulder range of motion measures as risk factors for shoulder and elbow injuries in high school softball and baseball players.

Am J Sports Med. 2011; 39: 1996- 2006.

Cools AM, Palmans T, Johansson FR. Age- related sport specific adaptations of the shoulder girdle in elite swedish adolescent tennis players. J Athl Train.

2014; 49 (5): 647 – 653.

Ellenbecker TS Musculoskeletal examination of elite junior tennis players. Aspetar Sports Med J. 2014; 548 – 556.

20. Weir JP. Quantifying test-retest reliability using the intraclass correlation coefficient and the SEM. J Strength Condit Res 2005; 19(1): 231–240.

21. Field A. Discovering Statistics Using IBM SPSS Statistics. 4th edition. London: Sage; 2013.

22. Cohen J. Statistical Power Analysis. 2nd edition. New Jersey NY: Lawrence Erlbaum Associates; 1988.

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IJSPT

CASE REPORT

REHABILITATION CONSIDERATIONS FOR AN UNCOMMON INJURY OF THE KNEE: A CASE REPORT Erin Baumann, DPT, OCS, AT1 William Rice, DPT, SCS1 Mitchell Selhorst, DPT, OCS1

ABSTRACT Background and Purpose: Chronic instability of the proximal tibiofibular joint (PTFJ) is an uncommon condition that accounts for <1% of knee injuries. The mechanism of injury is a high-velocity twisting motion on a flexed knee.

Surgical management is controversial due to complications; however, surgeons are now utilizing ligament reconstruction to restore stability. There is a paucity of information in the literature regarding postoperative care and rehabilitation after PTFJ reconstruction. The purpose of this case report is to describe the post-surgical rehabilitation for an adolescent athlete following PTFJ ligament reconstruction using a modified anterior cruciate ligament reconstruction (ACL) post-operative rehabilitation protocol.

Case Description: A 15-year-old female soccer player reported left ankle and knee pain for one year after a contact injury and landing on a hyperflexed knee during a soccer game. The surgeon diagnosed the subject with chronic PTFJ instability and performed reconstruction using an allograft ligament and calcium phosphate bone graft. The subject presented to physical therapy three weeks post-operatively with complete resolution of ankle pain and mild knee pain. The subject’s goal was to return to golf as she reported apprehension with a potential return to soccer. After consulting with the surgeon and because the subject was only allowed to advance weight bearing status by 20 pounds each week (to protect the graft site), the treating therapists progressed the subject using a modified ACL protocol as there is no documented post-operative rehabilitation protocol to treat patients after a PTFJ reconstruction.

Outcomes: Outcome measures for this subject included the patient specific functional scale (PSFS), verbal numeric pain rating scale and ability to participate in golf. The initial PSFS score was 4/30 (activities included walking, jogging and golf) and the subject’s reported pain level was 3/10. Three months after surgery the subject demonstrated significant improvement to 30/30 on the PSFS, 0/10 pain, and had progressed to participation in both golf and jogging.

Discussion: The modified ACL protocol was effective in safely rehabilitating this adolescent athlete following a PTFJ reconstruction. This subject demonstrated some yellow flags which may have slowed her rehabilitation progression.

Use of a modified ACL reconstruction protocol served as a guideline for the rehabilitation of this rare condition. Additional research is necessary to establish evidence-based guidelines for treatment of PTFJ reconstruction.

Level of Evidence: Level 4 Key Words: Lateral knee pain, proximal tibio-fibular joint reconstruction, tibiofibular joint instability

1

Sports and Orthopedic Physical Therapy Department, Nationwide Children’s Hospital, Columbus, OH, USA

Funding: None Conflict of interests: The authors have no conflicts of interest to report.

CORRESPONDING AUTHOR Mitchell Selhorst 6499 East Broad St. Suite 140 Columbus, Ohio 43213.

E-mail: Mitchell.Selhorst@Nationwidechildrens.org

The International Journal of Sports Physical Therapy | Volume 13, Number 3 | June 2018 | Page 511 DOI: 10.26603/ijspt20180511

INTRODUCTION The proximal tibiofibular joint (PTFJ), located distally and laterally to the knee joint, is a plane synovial joint. The PTFJ is between the articular facet on the lateral condyle of the tibia and the facet on the head of the fibula.1 It is designed to rotate a small amount in order to accommodate the rotational stress at the ankle joint that occurs during dorsiflexion.2 It is heavily supported by surrounding ligaments and is rarely injured. The common peroneal nerve travels laterally around the fibular head and can easily be disrupted if instability at this joint is noted. PTFJ instability is extremely rare, accounting for <1% of all documented knee injuries.2 When a PTFJ injury does happen, it typically occurs in athletes. Disruption of the proximal capsular ligaments occurs with sudden internal rotation and plantar flexion of the foot with an externally rotated tibia and flexed knee. Although a rarity, PTFJ instability can cause pain and functional deficits that persist for months after the initial injury.3 The PTFJ has received little attention in the literature. Therefore this condition is often underdiagnosed and the best treatment is unknown. PTFJ instability can be easily mistaken for lateral knee pain syndrome and has only subtle abnormalities on radiographs. Patients with PTFJ instability often complain of lateral knee pain; however, ankle motion can also increase knee symptoms.2 In some cases a bony protrusion is noted at the lateral knee and knee range of motion may also be affected.4 The confusing clinical presentation does not allow a practitioner to clinically diagnosis such an injury so further testing may be necessary to obtain an accurate diagnosis. PTFJ instability is typically missed on unilateral plain radiographs.2 If a clinician is considering PTFJ instability a bilateral radiograph or advanced imaging is suggested. A bilateral radiograph (compared to a unilateral film) allows for easier detection of a displaced fibular head when able to compare to the uninvolved lower extremity.5 PTFJ instability is categorized into four different types; subluxation (type I), anterolateral dislocation (type II), posteromedial dislocation (type III), and superior dislocation (type IV).6 Type II, the most common type of instability, frequently results in ligamentous injury and peroneal nerve palsy due to

the peroneal nerve’s path around the fibular head.

Treatment options for PTFJ instability include conservative care or surgical interventions. In previous cases found in the literature, there has been some success with reduction of the fibular head, casting the leg for one week, then a progression of four weeks to full weight bearing for acute dislocations (type II-IV).5 However, some cases require surgical interventions due to the chronic condition and late diagnosis.11 Surgical management is controversial. Many surgical approaches can cause complications such as lateral knee instability, peroneal nerve palsy, hardware failure, and ankle pain. To avoid the common complications, surgeons are now utilizing ligament reconstruction of either or both the anterior and posterior tibiofibular ligaments to restore knee stability. However, there is little to no information on rehabilitation techniques post-surgery.

There is a distinct lack of treatment guidelines for patients with PTFJ instability. Therefore, the purpose of this case report is to describe the post-surgical rehabilitation for an adolescent athlete following PTFJ ligament reconstruction using a modified anterior cruciate ligament reconstruction (ACL) post-operative rehabilitation protocol.

CASE DESCRIPTION The subject was a 15-year-old female soccer player referred to physical therapy three weeks after PTFJ reconstruction. She sustained a contact injury during a soccer game and reported worsening left ankle and lateral knee pain over the course of a year. There were 13 months between the initial injury and the subject’s surgery. She was seen by multiple providers and had attempted physical therapy without success. The subject continued to have pain and was unable to participate in her usual level of activities.

After magnetic resonance imaging indicated bone barrow edema surrounding the PTFJ the surgeon diagnosed a type I PTFJ injury. The surgeon then completed an allograft ligament and calcium phosphate bone graft for reconstruction.

EXAMINATION A physical therapy examination was performed three weeks after the PTFJ reconstruction. The subject presented partial weight bearing on bilateral axillary

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Table 1. Strength and range of motion testing.

crutches and a left knee hinged brace locked in 0 degrees of extension. The subject reported complete resolution of ankle pain and only mild complaints of lateral knee pain, 3/10 on the verbal numeric pain rating scale (NPRS).

The subject had 1 cm of swelling (compared to noninvolved lower extremity) measured at the joint line and the incision was clean, dry, and healing well.

The physical examination revealed limited active knee range of motion (ROM) and decreased strength.

(Table 1) Manual muscle testing with therapist resistance was deferred at initial examination since the surgeon’s prescription did not indicate if there were any post-surgical precautions or contraindications and the subject’s apprehension. However, she was able to perform 20 straight leg raises without brace and with no extension lag present. The subject also demonstrated symptoms consistent with a sensory peroneal nerve injury due to mild paresthesia at the lateral leg. She completed the Patient Specific Functional Scale (PSFS), centered around three functional activities, walking, jogging, and golf, scoring a 4/30. The subject’s parents reported that she had symptoms consistent with anxiety, but no medical diagnosis had been made. All other screening was negative. The subject’s goal for physical therapy was to return to golf as she did not want to return to soccer.

CLINICAL IMPRESSION The referral to physical therapy had several special instructions and precautions. The subject was

allowed to progress her initial partial weight bearing status by 20 pounds per week and could initiate weight bearing as tolerated by six weeks post-operative. The surgeon also recommended quadriceps activation exercises as tolerated and avoiding excessive hamstring contraction. Therefore the subject was progressed by modifying an anterior cruciate ligament (ACL) reconstruction protocol. The protocol was modified to account for the initial weight bearing restrictions as well to allow for soft tissue healing and to avoid displacement of the PTFJ with excessive contraction of the biceps femoris. The ACL protocol was chosen as it is an established treatment program which reflected the restrictions involved in this case. Excessive hamstring activation was cautioned after reconstruction of the PTFJ due to the biceps femoris attachment onto the fibular head.

Increased stress to the biceps femoris could potentially cause elongation or disruption of the repaired tissue. The chosen ACL protocol limits hamstring activation for six weeks due to tissue grafting of the ipsilateral hamstring in a traditional ACL reconstruction. With the restrictions in hamstring activation and modifications for weight-bearing restrictions contained therein, the ACL protocol was deemed appropriate for modification and use in this subject.

INTERVENTIONS During the first six weeks of physical therapy the subject was seen 1-2 times a week. This depended on her functional and objective progress and compliance with her home exercise program which was measured via subjective report. Initial rehabilitation was focused on gait training (with brace on), weight shifting, passive and active assisted ROM (AAROM) of the left knee as well as ankle, hip and core strengthening. The physical therapists provided gait training with bilateral axillary crutches and practiced transferring weight onto the involved lower extremity (using a scale to measure) to ensure that the weight-bearing restrictions were not exceeded during this protective phase.

Passive and active assisted ROM were applied by the treating physical therapist during the early sessions and the subject was instructed to proceed with ROM exercises without pain to mild discomfort three times per day as a home exercise program. Ankle exercises included ankle 4-way ankle resistance using Theraband. Caution was used during this exercise because

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there was mild lateral knee pain that was reproduced with resisted ankle eversion. Other exercises that were performed during this initial phase of rehabilitation included quadriceps sets, straight leg raises, side-lying hip abduction/adduction, prone hip extension and other non-weight bearing core and hip exercises as tolerated. The physical therapists deferred any exercise that increased pain over the left lateral knee and/or the fibular head.

At six weeks post-surgery, low level hamstring strengthening was initiated beginning with hamstring isometrics and supine bridging exercises which were progressed to single limb Romanian deadlift (RDL) and stool scoots. During weeks 6-12 bilateral hip, knee and ankle strengthening and dynamic balance exercises were progressed per the protocol, increasing the difficulty of each exercise as the subject was able while maintaining proper form.

(Protocol provided in Appendix 1) During this phase of rehabilitation the subject experienced two episodes of syncope. One episode occurred immediately after a physical therapy appointment, the other occurred at home. The subject was seen by a cardiologist who stated no immediate concern and believed this to be secondary to dehydration and deconditioning. Once the clinicians were aware of the subject’s reports of syncope and occasional lightheadedness, the physical therapists adapted the clinical interventions to include multiple timed rest breaks after challenging exercises (up to two minutes in length). After the initial two episodes of syncope, the subject and family denied any other incident. The physical therapists slowly decreased the timed rest breaks during the sessions and the subject did not report any additional episodes of lightheadedness or syncope throughout the rest of the plan of care.

At 12 weeks post-surgery, the subject demonstrated full left knee AROM and full strength throughout the lower quarter with manual muscle testing. Balance was tested using a single limb standing test and the subject was able to hold for over thirty seconds.

The surgeon cleared the subject to begin running and plyometric progression. Examples of plyometric exercises included jump downs, broad jumps, lateral bounding and line jumps. As the subject

demonstrated a moderate amount of dynamic knee valgus bilaterally and faulty landing mechanics, increased time was spent focusing on safe lower extremity mechanics.

The subject was discharged from physical therapy after 15 total sessions. Functional testing per the modified protocol (Appendix 1) on day of discharge included a single limb hop for distance test. The limb symmetry index was 100%. She was pain free with all activity and had successfully returned to playing golf. She demonstrated independence with her home exercise program as well as confidence in ways to progress the program. She was encouraged to call the physical therapists with any questions or concerns with her individualized program. Her parents were in agreement with the plan and all were satisfied with the subject’s current level of function.

OUTCOMES There were three different patient reported outcome measures used during the treatment of this subject which included the PSFS, NPRS and the ability to participate in golf. The PSFS is a self-report measure that has subjects list up to five activities that are difficult for them to complete or that cause a reproduction of pain.7 Although the PSFS can be broadly used with many conditions, the PSFS is a useful tool for measuring knee dysfunction. When using this outcome measure with orthopedic knee conditions the PSFS has a test-retest reliability of 0.84 and good construct validity, and the standard error of measure is 1.0 point.7 The minimal clinically important difference (MCID) is three points.7 The subject in this case report had an initial PSFS score of 4/30. Her listed activities included walking (2/10), jogging (1/10) and golf (1/10) as the subject did not want to return to soccer. The total score on the PSFS increased to 30/30 at discharge which shows a clinically significant change in overall function. (Table 2) The NPRS was also used during the treatment of this subject. The NPRS is an easily administered measure that assesses the subject’s average amount of pain in the last 24 hours. They are asked to rate their pain on an 11-point scale with “0” being no pain and “10” being extreme pain. This can either

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Table 2. Change in outcomes.

be completed via a single 10 cm line or asked verbally. In this subject’s case it was addressed verbally at every treatment session. In patients who have knee pain, it has been suggested that the MCID is 1.2 points.8 Although the subject never complained of high amounts of pain, her initial pain rating was 3/10 and decreased to 0/10 at the left lateral knee at discharge.

DISCUSSION Proximal tibiofibular joint instability is a condition that is rarely encountered by the physical therapist.

This diagnosis receives little attention in the literature, but can cause pain and functional deficits for months after injury due to the fact that it is under recognized and often misdiagnosed.3 Even when correctly diagnosed, management is controversial.6 Conservative options have included avoidance of athletics, taping, bracing, strapping, and strengthening of the hamstrings, gastrocnemius and soleus muscles. Surgical techniques have included arthrodesis of the superior tibiofibular joint, resection of the proximal aspect of the fibula and temporary internal fixation, all of which have early and late complications such as peroneal nerve injury, post-operative ankle pain and instability and knee instability.9 Due to these mixed results, soft tissue reconstruction of the PTFJ ligaments has been recommended for adolescent patients.3,9 This technique has been reported to be safe and effective, however, the post-operative rehabilitation has not been described.

In this case report, the authors demonstrated that using a modified ACL program was safe and effective following soft tissue PTFJ reconstruction for this subject. The treatment program resulted in full functional recovery for this subject and allowed the

subject to return to her desired sport at her final follow up assessment. The modified ACL protocol was chosen because it most closely matched the specific instructions and restrictions provided by the surgeon.

Three months after surgery, the subject demonstrated clinically significant improvement on the PSFS, reporting 0/10 pain on the NPRS, full pain free knee range of motion, and normal lower quarter strength with manual muscle testing. She did not report any instability at her PTFJ. The subject was able to complete a unilateral squat without excessive dynamic valgus and was cleared for jogging and chipping from the physician. Her progress during rehabilitation was slowed down due to her activityrelated fear and two episodes of syncope.

There are several limitations to this case report that limit the strength of the results. This report is only on one individual’s condition and response to treatment and therefore cannot be generalized. Because of the inherent design and limitations of a case report, a cause and effect relationship cannot be inferred from the treatment and the subject’s successful outcomes. Additionally, the subject’s young age and activity level were favorable conditions for a successful outcome.

CONCLUSIONS Although PTFJ instability is rare it is important to have a well-documented and progressive plan for progressions with these patients to achieve best outcomes. These results suggest that using a modified ACL protocol may be a viable treatment option following PTFJ reconstruction for an adolescent athlete. This is a case report on one subject following PTFJ reconstruction, and there is a paucity of literature on this condition. Therefore further research, including controlled clinical trials and documentation of long-term outcome data, are warranted.

REFERENCES 1.

2.

Sarma A, Borgohain B, Saikia B. Proximal tibiofibular joint: Rendezvous with a forgotten articulation.

Indian J Orthop. 2015;49(5):489-495.

Nieuwe Weme RA, Somford MP, Schepers T. Proximal tibiofibular dislocation: a case report and review of literature. Strategies Trauma Limb Reconstr.

2014;9(3):185-189.

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3.

4.

5.

6.

Camarda lA, A; D’Arienzo, M. Proximal Tibiofibular Joint Reconstruction With Augogenous Semitendinosus Tendon Graft. Tech Orthop. 2013;28.

Forster BB, Lee JS, Kelly S, et al. Proximal tibiofibular joint: an often-forgotten cause of lateral knee pain. AJR Am J Roentgenol. 2007;188(4):W359366. van Wulfften Palthe AF, Musters L, Sonnega RJ, et al.

Dislocation of the proximal tibiofibular joint, do not miss it. BMJ Case Rep. 2015;2015.

Ogden JA. The anatomy and function of the proximal tibiofibular joint. Clin Orthop Relat Res. 1974(101):186-191.

7.

8.

9.

Horn KK, Jennings S, Richardson G, et al. The patient-specific functional scale: psychometrics, clinimetrics, and application as a clinical outcome measure. J Orthop Sports Phys Ther. 2012;42(1):30-42.

Piva SR, Gil AB, Moore CG, et al. Responsiveness of the activities of daily living scale of the knee outcome survey and numeric pain rating scale in patients with patellofemoral pain. J Rehabil Med. 2009;41(3):129-135.

Tanner SM, Brinks KF. Reconstruction of the proximal tibiofibular joint: a case report. Clin J Sport Med. 2007;17(1):75-77.

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Appendix 1. ModiďŹ ed ACL Reconstruction Rehabilitation Protocol

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Appendix 1. ModiďŹ ed ACL Reconstruction Rehabilitation Protocol (continued)

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Appendix 1. ModiďŹ ed ACL Reconstruction Rehabilitation Protocol (continued)

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IJSPT

CASE REPORT

THE USE OF SERIAL PLATELET RICH PLASMA INJECTIONS WITH EARLY REHABILITATION TO EXPEDITE GRADE III MEDIAL COLLATERAL LIGAMENT INJURY IN A PROFESSIONAL ATHLETE: A CASE REPORT Michael S. Bagwell, PT, DPT, CMPT1 Kevin E. Wilk, PT, DPT, FAPTA2,3 Ricardo E. Colberg, MD4 Jeffrey R. Dugas, MD5

ABSTRACT Background: Medial collateral ligament (MCL) injuries are one of the most commonly treated knee pathologies in sports medicine. The MCL serves as the primary restraint to valgus force. The large majority of these injuries do not require surgical intervention.

Case Subject Description: A 30-year-old professional wrestling athlete presented to the clinic with acute complaints of right medial knee pain resulting from a traumatic valgus force. Physical exam revealed Grade 3 MCL injury. Magnetic resonance imaging confirmed clinical diagnosis of a Grade 3 proximal MCL tear.

This athlete had sustained a prior grade 3 ACL injury with Grade 3 distal MCL injury which required surgery to reconstruct the ACL and repair the MCL 13 months prior, in November of 2015.

Outcomes: The subject was successfully treated with a series of three sequential Leukocyte Rich Platelet Rich Plasma (LR-PRP) Injections spaced evenly one week apart in addition to an early physical therapy regimen. The total treatment time was cut down from an expected 35-49 days to 31 days.

Discussion: When paired with the appropriate rehabilitation treatment progression, the use of LR-PRP injections in the treatment of an isolated MCL tear was beneficial for this subject.

Conclusion: The results of this case report indicate that the use of LR-PRP and early rehabilitation shows promise in treating an acute grade 3 MCL injury. Future research utilizing randomized controlled trials are needed.

Level of Evidence: Case Report, 4 Key Words: Knee, Leukocyte-Rich PRP, medial collateral ligament

1

Orthopaedic Sports Medicine PT Fellow, Champion Sports Medicine, Birmingham, AL 2 Associate Clinical Director, Champion Sports MedicinePhysiotherapy Associates, Birmingham, AL 3 Director of Rehabilitative Research, American Sports Medicine Institute, Birmingham, AL 4 Non-Operative Orthopaedist, Andrews Sports Medicine & Orthopaedic Center, Birmingham, AL 5 Orthopaedic Surgeon, Andrews Sports Medicine & Orthopaedic Center, Birmingham, AL Conflicts of Interest: The authors of this case report do not have any conflicts of interest to disclose affecting the publication of the case report.

CORRESPONDING AUTHOR Dr. Michael S. Bagwell 805 St Vincent’s Dr., Suite G100 Birmingham, AL 35205 E-mail: msbagwell@gmail.com

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BACKGROUND Medial collateral ligament (MCL) injuries are one of the most commonly treated knee pathologies in sports medicine.1,2 The MCL serves as the primary restraint to valgus force at both 5˚ (57.4%) and 25˚ (78.2%) knee flexion.3 The large majority of these injuries do not require surgical intervention. Furthermore, anatomically, a proximal injury is more favorable than a distal injury in regards to healing rate and regaining stability utilizing a conservative treatment approach.2 Shelbourne et al2 has classified these injuries as follows: Grade 1: No laxity with a solid endpoint, Grade 2: Some medial laxity and a firm endpoint, Grade 3: Complete disruption of the medial collateral ligament with substantial medial opening.2 Conservative care is the standard for grades 1 and 2 injuries. Treatment of grade 3 injuries remains controversial, however good outcomes have been reported with conservative care.5 Additionally, the treatment for distal versus proximal MCL injuries does vary based on the extent of the injury, with distal grade 3 often requiring surgery.2 Holden et al4 reported return after MCL injury in as early as 10 days for Grade 1, and four weeks for a Grade 2. Kim et al.5 reported a five to seven week recovery period for a Grade 3 injury. A general rule of thumb with MCL injury recovery is two weeks off per grade, although time lost from sport can vary significantly depending on lesion location, treatment progression, and demands of the sport.5,6 Platelet rich plasma (PRP) injections are becoming an increasingly popular adjunct to non-operative treatment protocols. PRP is autologous blood drawn with the intent to concentrate platelet levels higher than physiologic levels, in which, the concentration is typically three to five times higher than physiologic baseline.7 Growth factors and other molecules are contained within the alpha granules of platelets that are involved in tissue repair and pain modulation, among other functions.8-11 A few key factors found involved in tissue repair are transforming growth factor-beta 1 (TGF-B1), insulin-like growth factor (IGF), and, thrombospondin-1.11 PRP injections are initiated with intent to facilitate the healing cascade within the MCL due to the presence of growth factors they subsequently introduced to the site.12 The use of ultrasound to guide the PRP injection allows the physician performing the injection to

evaluate the ligament as well as ensure that the PRP is injected within the site of ligament injury. The treatment hypothesis was that the use of a threeinjection series of ultrasound guided leukocyte rich PRP (LR-PRP) injections in combination with an early physical therapy program would expedite the healing of the MCL and overall return to participation. The use of three injections was based on the non-invasive ability to monitor ligamentous healing via ultrasound imaging and the clinical expertise of the surgeon and physician performing the injections.

The rehabilitation focused on immediate motion to facilitate collagen synthesis and alignment,13 preventing further quadriceps muscle atrophy, restoring lower extremity strength, as well as enhancing the neuromuscular stabilization of the knee and full body kinesthetic awareness. Bracing was used to in conjunction to help control valgus stress on the MCL outside of the clinic.

CASE DESCRIPTION A 30-year-old professional male wrestling athlete presented to the clinic 1/31/17 with acute complaints of right medial knee pain resulting from a traumatic valgus force that occurred the previous night 1/30/17. The subject of this case report also trained aggressively with weight lifting exercises, cardiovascular exercise, and in Crossfit. The subject had a pertinent past medical history of a right ACL reconstruction with patellar tendon autograft, medial meniscus repair, and distal MCL repair with suture anchor fixation performed in November of 2015. The subject was ambulating with a modified three point gait utilizing bilateral axillary crutches with antalgia and weight bearing as tolerated in a hinged knee brace locked at 0˚. Clinical exam revealed an active range of motion from 5-120˚, 2 cm of swelling measured at the joint line, a negative Lachman’s exam with firm end feel, and a grade 2+/3 positive valgus stress test at 5˚ and 30˚ of knee flexion. Strength testing and functional testing were deferred due to the acuity of the injury. The magnetic resonance imaging (MRI) depicted a proximal Grade 3 MCL tear in isolation. Due to the proximal location of the isolated injury, non-operative treatment, via an early physical therapy program, was chosen. In combination with the early physical therapy program, serial LR-PRP injections were

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Table 1. Acute Phase rehabilitation following LR-PRP injection to the knee medial collateral Ligament

Figure 1. Right MCL soft tissue integrity at the time of initial Leukocyte Rich-Platelet Rich Plasma injection on 2/1/17. The red arrow pointing towards MCL fibers in disarray.

performed, timed a week apart for three weeks total under the guidance of ultrasound.

TREATMENT PROGRAM The initial LR-PRP injection was performed on 2/1/17. Figure 1 depicts the soft tissue integrity of the MCL at the time of the initial LR-PRP injection (Figure 1). Immediately following the LR-PRP injection the rehabilitation process began in physical therapy.

Weight bearing activity in the clinic was performed under the supervision of the physical therapist (PT) without bracing. Weight bearing activity outside of therapy took place in a hinged knee brace locked at 0˚ until adequate quad control was demonstrated during ambulation, without knee buckling.

The rehabilitation program was separated into three phases, the acute phase, the intermediate, and, the advanced phase. The first three days post-injection consisted of the acute phase rehabilitation (Table 1). The acute phase rehabilitation consisted of ice for pain relief, passive range of motion (PROM) performed on the right knee by the physical therapist (PT). Initial passive range of motion was performed 10-110˚. Neuromuscular electrical stimulation (NMES) was used during quadriceps setting, straight leg raises, and 90-40˚ knee extensions via a hand trigger that allowed the patient to maintain constant muscle stimulus throughout the duration of each exercise repetition. Straight leg adduction raises were avoided in this phase to decrease valgus stress at the knee. Weight shifting was performed in

a staggered stance, shifting in an anterolateral and posterolateral direction on each leg. Partial squats were initiated on a force plate with visual biofeedback to emphasize symmetrical lower extremity loading. Class IV therapeutic laser treatment was also utilized each session for seven minutes at 13.5 Watts (LiteCure,Dover,DE). On day four post-injection, the intermediate phase was initiated for three more days. During this phase the subject was progressed to upright stationary bicycling, isotonic multi-hip machine hip abduction and extension strengthening exercises, seated hip internal and external rotation with elastic band resistance, hip bridging, double leg dynamic balance on an unstable foam surface, and double leg balance on a rocker board with light perturbations (Table 2).

A second injection was performed seven days later (2/8/17) with simultaneous re-assessment of soft tissue integrity with the use of ultrasound imaging (Figure 2). Once again this was followed by the acute phase rehabilitation for three days and again followed by a progression to the intermediate phase rehabilitation up until the next injection. The final injection of the series was performed seven days after (2/15/17) the second injection, with final visual assessment of the MCL (Figure 3). The final injection was followed by the acute phase rehabilitation for three days, then the intermediate phase rehabilitation for five days, followed by a gradual progression into the advanced phase rehabilitation began on day six after the third injection was completed.

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Table 2. Intermediate Phase rehabilitation following LR-PRP injection to the knee medial collateral Ligament

Figure 3. Right MCL soft tissue integrity at the time of the third and final Leukocyte Rich-Platelet Rich Plasma injection on 2/15/17. The arrow pointing to further signs of tissue remodeling.

unstable surfaces. Finally, lower extremity vertical and lateral plyometrics were also introduced during this phase (Table 3.)

Cessation of treatment was determined by a clinical exam, which included improved valgus stability with firm end point, return of normal strength, completion of a functional rehabilitation program, satisfactory physical performance during dynamic functional activity, and close communication between the subject, the referring physician, and the physical therapist.

Figure 2. Right MCL soft tissue integrity at the time of the second Leukocyte Rich-Platelet Rich Plasma injection on 2/8/17, The red arrow pointing to signs of tissue remodeling.

The advanced phase rehabilitation was comprised of a progression into increased dynamic functional activity and strengthening. Cone marching drills were performed going forward, backwards and laterally. Running in the Alter G treadmill (Alter G, Fremont, CA) was introduced, initially with one minute intervals of work and two minutes of rest, to continuous running. A progression of weight resisted single leg strengthening was initiated in this phase along with a progression of dynamic single leg balance on

OUTCOMES The final range of motion measurements were 5-0140˚ on the right knee (affected knee) compared to 5-0-145˚ on the left knee (uninvolved knee). In total, treatment spanned 31 days, with the subject being discharged 32 days after the initial injury. The total treatment time was cut down from the average expected duration of 35 to 49 days5 before return to full activity, to 31 days. The subject demonstrated a non-antalgic symmetrical walking and running gait, negative valgus stress tests at both 5˚ and 30˚, weight bearing symmetry with squatting, and the ability to perform vertical and lateral plyometric jumps and hops without pain or apprehension. The subject was able to return to professional wrestling full time, unrestricted weightlifting, and training for Crossfit competition.

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Table 3. Advanced Phase rehabilitation following LR-PRP injection to the knee medial collateral ligament

use of a series of three, evenly spaced, sequential injections.14 This is the first case report to outline the post-injection rehabilitation. The authors believe the expedited complete recovery of this subject back to high level sport activity was achieved due to several key treatment interventions. It is believed the use of LR-PRP, with laser therapy15-17 and immediate motion created an optimal environment for healing.

In addition, early lower extremity muscle strengthening diminished muscle atrophy, and the use of hip/core control exercises in combination with proprioception and neuromuscular dynamic stabilization drills promoted dynamic joint stability.

Limitations of this case report include, a joint opening measurement, via ultrasound imaging, was not obtained pre or post-treatment to provide further objective evidence of benefit. A validated patient reported outcome questionnaire was not utilized to track progression through rehabilitation. Strength testing via handheld dynamometry was not conducted. A specific return to activity battery of tests such as Biodex testing, single leg press tests, and hop tests were not performed. Finally, this case report reflects a sample size of one and the results cannot be generalized.

DISCUSSION MCL injuries are a commonly treated musculoskeletal pathology seen in orthopedic and sports medicine clinics. A Grade 3 MCL injury is commonly associated with an absence from sport or full athletic participation for five to seven weeks as cited in the literature.5 When paired with the appropriate rehabilitation treatment progression, the use of LR-PRP injections in the treatment of an isolated MCL tear appears to have been beneficial for this subject. In the elite professional athlete, return to participation 4 to 18 days sooner than expected, the cost effectiveness of LR-PRP injections could be significant when lost wages, lost ticket sales, lost advertising costs, lost merchandise sales, and the cost of prolonged treatment are considered. This is the second published case report to the authorsâ&#x20AC;&#x2122; knowledge examining the

CONCLUSION The use of LR-PRP injections is becoming more common place in the orthopedic and sports medicine practice. In this case report, the use of three serial LR-PRP injections in combination with an early rehabilitation program was shown to be beneficial for the treatment of an isolated Grade 3 MCL injury.

Optimal timing of LR-PRP injections, dosing, and long term efficacy remains in question as well as the optimal timing and dosing of the rehabilitation regimen. Future research utilizing LR-PRP should investigate and outline both the injection protocol as well as the rehabilitation protocol used.

REFERENCES 1. Roach CJ, Haley CA, Cameron KL, Pallis M, Svoboda SJ, Owens BD., The epidemiology of medial collateral ligament sprains in young Athletes. Am J Sports Med. 2014;42(5):1103-1109.

2. Shelbourne KD, Patel DV, Management of Combined Injuries of the Anterior Cruciate and Medial Collateral Ligaments, Instruc Course Lect. 1996;45:275-280

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3. Grood ES, Ligamentous and capsular restraints preventing straight medial and lateral laxity in intact human cadaver knees., Bone Joint Surg.

1981;63(8):1257-1269.

4. Holden DL, Eggert AW, Butler JE. The nonoperative treatment of grade I and II medial collateral ligament injuries to the knee. Am J Sports Med. 1983;11:340-344.

5. Kim C, Chase PM, Taylor DC, Return to play after medial collateral ligament injury, Clin Sports Med. 2016;35(4)679-696.

6. Marchant Jr. MH, Tibor LM, Sekiya JK, Hardaker Jr. WT, Garrett Jr WE, Taylor DC, Management of medial-sided knee injuries, part 1. Am J Sports Med 2011;39(5)1102-1112.

7. Marx RE. Platelet-rich plasma (PRP): what is PRP and what is not PRP? Implant Dentistry. 2001;10:225-22.

8. Toumi H, Best T. The inflammatory response: friend or enemy for muscle injury? British J Sports Med. 2003;37:284-28.

9. Blair P, Flaumenhaft R. Platelet α-granules: basic biology and clinical correlates. Blood Reviews.

2009;23:177-189.

10. Leslie M. Beyond clotting: the powers of platelets.

Science. 2010;328:562-564.

11. Leitner G, Gruber R, Neumüller J, et al. Platelet content and growth factor release in platelet–rich plasma: a comparison of four different systems. Vox sanguinis. 2006;91:135-13.

12. LaPrade RF, Geeslin AG, Murray IR, Musahl V, Zlotnicki, Petrigliano F, Mann BJ, Biologic treatments for sports Injuries II think tank-current concepts, future research, and barriers to advancement, part 1. biologics overview, ligament injury, tendionpathy, Am J Sports Med. 44(12):3270-3283.

13. Frank C, Woo SL, Amiel D, Harwood F, Gomez M, Akeson W, Medical collateral healing: a multidisciplinary assessment in rabbits, Am J Sports Med 1983;11(6)379-389.

14. Eirale C, Mauri E, Hamilton B, Use of platelet rich plasma in an isolated complete medial collateral ligament lesion in a professional football (soccer) player: a case report Asian J Sports Med. 2013.

4(2):158-162.

15. Allahverdi A, Sharifi D, Takhtfooladi MA, Hesaraki S, Khansari M, Dorbeh S, Evaluation of low-level laser therapy, platelet-rich plasma, and their combination of achilles tendon in rabbits, Lasers Med Sci. 201.

DOI:10.1007/s10103-015-1733-6.

16. Reddy GK, Stehno-Bittel L, Enwemeka CS, Laser photostimulation of collagen production in healing rabbit achilles tendon, Lasers Surg Med. 1998;22:281287.

17. Tumilty ST, Munn J, McDonough S, Hurley DA, Basford JR, Baxter D, Low level laser treatment of tendinopathy: a systematic review with metaanalysis. Photomed Laser Surg. 2010;28:3-16.

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IJSPT

LITERATURE REVIEW

EVIDENCE-BASED PROCEDURES FOR PERFORMING THE SINGLE LEG SQUAT AND STEP-DOWN TESTS IN EVALUATION OF NON-ARTHRITIC HIP PAIN: A LITERATURE REVIEW Ryan P. McGovern, MS, LAT, ATC1 RobRoy L. Martin, PhD, PT, CSCS1,2 John J. Christoforetti, MD3,4 Benjamin R. Kivlan, PhD, PT, OCS, SCS1

ABSTRACT Background: Functional performance tests are commonly utilized in screening for injury prevention, evaluating for athletic injuries, and making return-to-play decisions. Two frequently performed functional performance tests are the single leg squat and step-down tests.

Purpose: The purpose of this study was to systematically review the available psychometric evidence for use of the single leg squat and step-down tests for evaluating non-arthritic hip conditions and construct an evidence-based protocol for test administration.

Study Design: Review of the Literature Materials/Methods: A search of the PubMed and SPORTSDiscus databases was performed. Psychometric evidence of reliability, validity, and responsiveness to support the use of the both tests were collected. The protocols used for administering these tests were extracted, summarized, and combined.

Results: Of the 3,406 articles that were reviewed, 56 total articles met the inclusion criteria and were included in the review. Evidence for reliability and validity was available to support the use of the single leg squat and step-down tests. Both tests assess for neuromuscular control of the hip and surrounding muscular structures. Evaluation of these functional movement patterns enable the clinician to assess for limitations that may cause an increase in hip pain and dysfunction.

Conclusions: The single leg squat and step-down tests can assess for kinematic and biomechanical deficiencies and may be useful in the evaluation process for individuals with non-arthritic hip pain. The authors of this review present a comprehensive evidence-based protocol for standardized performance of these tests.

Level of Evidence: 2b Keywords: Functional performance testing, non-arthritic hip pain, standardized protocol

1

Duquesne University, Pittsburgh, PA, USA University of Pittsburgh Center for Sports Medicine, Pittsburgh, PA, USA 3 Allegheny Health Network, Pittsburgh, PA, USA 4 Drexel University School of Medicine, Pittsburgh, PA, USA 2

All authors have no conďŹ&#x201A;icts of interest to declare.

CORRESPONDING AUTHOR Ryan P. McGovern, MS, LAT, ATC Doctoral Student 106 Rangos Sr School of Health Sciences Duquesne University Pittsburgh, PA 15282 Phone: 412-396-1811 Fax: 412-396-5554 E-mail: mcgover1@duq.edu

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INTRODUCTION Functional performance tests are used to evaluate basic dynamic movement patterns that are commonly part of more complex activity. Such tests typically combine range of motion, strength, and proprioceptive assessment. They allow for the simultaneous evaluation of movement in all three (frontal, sagittal, and transverse) planes of motion.

These functional performance tests can be useful in sports medicine to screen for injury prevention, evaluate athletic injuries, and help in return-to-play decisions.1-3 The single leg squat test (SLST) (Figure 1) and step-down test (SDT) (Figure 2) are two well-known tests described in the published literature and used in clinical practice.4,5 The SLST and SDT have been used in the evaluation of individuals with lower extremity dysfunction, most commonly among patients with knee pathology.6-15 However, these tests also assess for several deviations in hip, pelvis, and trunk performance that are considered important when assessing individuals with hip pain.16,17 The overall movement pattern during descent for both the SLST and SDT include hip and knee flexion with anterior pelvic tilt, flexion at the trunk, and hip adduction with knee internal rotation and

abduction.17-19 While these two tests are similar, they have been shown to produce different patterns of movement and stresses at the hip.20,21 Therefore, both the SLST and SDT could potentially be used to assess for kinematic and biomechanical deficiencies and be useful in the evaluation process of individuals with hip-related dysfunction. Static measures of range of motion performed standing or supine may not accurately depict the biomechanical demands of dynamic movements. It is currently unclear how the implementation of the SLST and SDT in clinical evaluation of non-arthritic hip patients is best accomplished, but there is promise regarding the potential of routine addition of these tests for advancing the understanding of non-arthritic hip dysfunction.

Additional examination of strength, flexibility, and endurance could be necessary to specifically identify the underlying pathologies, however, the inclusion of the SLST and SDT in clinical practice may be particularly helpful in the examination of patients with non-arthritic sources of hip pain. There is a need for an evidence based standardized protocol for administering the SLST and SDT in individuals with non-arthritic hip pain.

The purpose of this study was to systematically review the literature to identify the psychometric

Figure 1. The Single Leg Squat Test. (A) â&#x20AC;&#x201C; Initial test position. (B) â&#x20AC;&#x201C; Squat position.

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Figure 2. The Step-Down Test. (A) – Initial test position. (B) – Step down position.

evidence to support the use of and the best methods for administration of SLST and SDT in evaluation of patients with non-arthritic hip pain. The results of this study will allow for the development of a standardized protocol for administering the SLST and SDT in clinical practice and future research studies involving non-arthritic hip conditions.

METHODS Search Strategy for Identification of Studies A search of the PubMed and SPORTDiscus databases was performed to include articles from January 1997 to March 2017. Articles were identified that offered psychometric evidence for reliability, validity, and responsiveness regarding the administration of the SLST and SDT for examination of trunk and lower extremity function. The following key words were used in combination for searching the electronic databases: “single leg squat” AND “step down.” The primary author reviewed the abstracts of all references retrieved from the search and duplicates were removed. From this search, full length articles were retrieved and reference lists for these articles were also reviewed for additional relevant articles.

Research articles were included if they met the following criteria: 1) written in English, 2) published in a peer-reviewed journal after 1997, and 3) described the use of the SLST and/or SDT test in evaluation of strength, balance, postural control, or range of motion in the trunk, pelvis, hip, or knee. Studies were excluded if they assessed only the ankle or foot during performance of the tests, or the performance of testing was completed on patients with degenerative disorders (i.e. osteoarthritis).

Data Extraction – Reliability & Validity Statistical analysis of reliability including testretest, intra-rater, and inter-rater, and was recorded from each evaluated research article.2,22,23 Reliability was recorded as an interclass correlation coefficient (ICC) for interval or continuous data and the Cohen’s Kappa statistic for categorical or nominal data.24-26 Both the ICC and Kappa coefficient are valued on a scale of 0.0 to 1.0, with values closer to 1 showing higher reliability.27 A value for either the ICC or Kappa that is equal to or greater than 0.75 is considered excellent, between 0.40 and 0.74 is considered moderate, and less than 0.40 is considered poor.24

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validity, 15 articles addressed reliability, and 14 addressed both reliability and validity. There were no articles that addressed the responsiveness of testing for either the SLST or SDT. There was no evidence of reliability in administration or evaluation procedures for either the SLST or SDT specifically in patients with documented hip dysfunction. Evidence of reliability for the visual assessment of overall quality of movement for both the SLST and SDT in both healthy subjects and those with documented knee injuries is shown in Table 1. Both the SLST and SDT were found to be reliable when the evaluation was based on the evaluators overall impression of test performance as well as evaluation of specific biomechanical deviations for posture and/ or movement of the trunk, pelvis, hip, and knee.29-32

Figure 3. Results of Literature Search for Single Leg Squat and Step-Down Tests. SLST â&#x20AC;&#x201C; single leg squat test; SDT â&#x20AC;&#x201C; stepdown test.

There was no evidence of validity in administration of the SDT specifically in patients with documented hip dysfunction. One study for the SLST demonstrated evidence of validity in administration for patients with hip dysfunction.16 Both tests demonstrated evidence of validity in kinematic and muscle function assessment in healthy patients. Table 2 presents the evidence related to validity in evaluation of hip function for both the SLST and SDT.

Validity for the SLST and SDT was assessed by comparing the performance of individuals with a documented lower extremity condition to healthy individuals and/or comparing performance on another test that shares similar characteristics with the SLST and SDT.28 This relationship is commonly expressed through correlation coefficients, comparing the performance of each clinical test with other values, such as muscle strength and lower extremity range of motion.

Results attained from studies on the SLST2,18,29,33-41 (Table 3) and SDT6,13,29,33,39,40,42-44 (Table 4) were used to create a standardized protocol and scoring criteria for both functional performance tests for use in examination of individuals with non-arthritic hip pain. Evaluation for the proposed protocol was based on an overall impression of the trials (including balance and evaluation of the arm strategy), posture or movement of the trunk, posture of the pelvis, hip joint movement and posture, and knee joint movement and posture.29-32

RESULTS A total of 3,406 research articles were identified in the initial search. After applying the inclusion/ exclusion criteria and subsequent evaluation of reference lists, a total of 56 studies were included in the review. Search results included 37 articles describing the SLST, 14 describing the SDT, and 5 articles describing a combination of the SLST and SDT as shown in Figure 3. A total of 27 articles addressed

DISCUSSION This literature review identified evidence of reliability and validity for the SLST and SDT, with a large proportion of the literature determining these psychometric properties in the healthy population. While there was only one study that offered evidence of validity for the SLST in individuals with non-arthritic hip pain, there was evidence that both tests may be useful in evaluating for range of motion, strength,

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Table 1. Studies offering evidence of reliability in overall quality of movement for SLST and SDT

and proprioceptive deficiencies of the hip and surrounding muscular structures. These tests assess for several deviations in trunk, pelvis, and hip performance that are considered important when assessing individuals with non-arthritic hip pain. From the identified articles, a standardized protocol and scoring criteria was created for administering the SLST and SDT based on the best available evidence.

The SLST demonstrated moderate to excellent reliability for evaluation of test performance. Visual assessment of overall quality of movement for the

SLST showed a 73-87% agreement for inter-rater and intra-rater reliability (Kappa= 0.61 â&#x20AC;&#x201C; 0.80) based on a five-point scoring criteria.29 Moderate to excellent reliability was also present in the inter-tester evaluation of adolescent trunk, hip, and knee postural orientation utilizing a four-point scoring criteria (Kappa = 0.54 â&#x20AC;&#x201C; 0.86).45 Visual observation of dynamic knee valgus and frontal plane projection angle (FPPA) was also shown to be reliable in evaluation of asymptomatic patients during performance of the SLST.4,35,46-49 While the SLST test has been shown effective in the pass/fail evaluation of an individualâ&#x20AC;&#x2122;s trunk, hip,

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Table 2. Studies offering evidence of validity for kinematic evaluation of the trunk, pelvis, hip, and knee.

Table 3. Single Leg Squat Test Protocol

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Table 4. Step-Down Test Protocol

knee, and lower leg movement patterns, a more objective set of criteria is necessary for reliable identification of specific biomechanical deficiencies in multiple planes.30 Kinematic evaluation of the trunk, pelvis, hip, and knee utilizing an electromagnetic tracking system demonstrated excellent intra-rater, intrasession reliability (ICC = 0.83 – 1.00) and intrarater, intersession reliability (ICC = 0.82 – 0.96).50 In addition to evidence of reliability, the SLST was valid in the evaluation of dynamic lower extremity control and hip muscle function.16,29,51 Individuals with documented hip chondropathy were shown to have an overall decrease in balance, as determined by the amplitude and velocity of center of pressure movement when performing the SLST compared to healthy individuals.16 Increased hip external rotation range of motion may also predict balance impairments for those with non-arthritic hip pathologies.16 Moderate, negative correlations between test performance and muscle function of the hip abductors (r = –0.37, p < 0.05).53 Hip abduction (r = 0.466,

p = 0.002), hip external rotation (r = 0.464, p = 0.003), hip extension (r = 0.396, p = 0.012) and core musculature (r = 0.426, p = 0.006) were shown to have moderate, positive correlations to the frontal plane projection angle during performance of the SLST.54 Individuals who were graded as having a “poor” SLST showed weakness and slower activation of the hip abductors specifically the gluteus medius as measured by electromyographic activity,29 with an increase in hip adduction and flexion motions compared to those that were graded as “good” based on visual observation56 Greater strength in the hip abductors and an increase in depth of knee flexion was shown to be related to a decrease in the valgus motion of the knee during the SLST.53 The increase in coactivation of gluteal and hip adductor muscles was shown to also cause a decrease in valgus motion of the knee during the SLST as measured by electromyographic activity and an electromagnetic motion tracking system.57,58 The SLST was shown to induce less hip adduction but more hip external rotation and knee abduction compared to the SDT.17

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Although the evidence for reliability and validity of the SDT is less than that for the SLST, the SDT was shown to have moderate to excellent reliability for test performance. The SDT showed excellent interrater reliability for overall quality of movement (Kappa = 0.81, 0.68 – 0.94), as well as moderate to excellent interrater reliability for trunk alignment (Kappa = 0.72, 0.57 – 0.87), pelvic plane (Kappa = 0.71, 0.52 – 0.90), and knee positioning (Kappa = 0.87, 0.75 – 0.99) during performance in individuals with patellofemoral pain.59,60 Intra-rater reliability for SDT performance in individuals with patellofemoral pain syndrome and healthy subjects was also shown to be excellent (ICC = 0.94, SEM = 0.53).6 The overall movement quality of the SDT has been shown to have moderate (Kappa = 0.67, 80% agreement)43 to excellent inter-tester reliability (Kappa = 0.80, 85% agreement)31 based on a five point scoring criteria in healthy individuals.43 Moderate interrater reliability for the SDT was even shown amongst 142 physical therapists who evaluated 15 healthy subjects on a three level rating criteria (ICC = 0.61, 74% agreement).61 Kinematic evaluation of the trunk, pelvis, hip, and knee utilizing an electromagnetic tracking system demonstrated excellent intra-rater, intrasession reliability (ICC = 0.83 – 1.00) and intra-rater, intersession reliability (ICC = 0.82 – 0.97).50 The available studies demonstrated evidence of validity for evaluation of hip and trunk muscle function. Hip abduction (r = 0.446, p<0.001) and external rotation (r = 0.448, p<0.001) strength were positively correlated with performance of the SDT.42 Those evaluated as having “good” movement quality had significantly stronger hip abductors, increased knee active range of motion, and increased hip adduction range of motion than those with “moderate” movement quality.31 “Moderate” quality of movement patterns also had an increased contralateral pelvic drop (p= 0.01) and increased knee external rotation (p = 0.04) compared to those that were evaluated as “good.”62 The SDT was found to be more biomechanically demanding when compared to the SLST, however, the differences between the two were not statistically significant (p range = 0.36 – 1.00).19 Although similar in performance, when compared to the SLST the SDT demonstrated

significantly greater knee flexion (p<0.001), as well as hip flexion and adduction (p≤0.013) during test performance.17,19 The frontal plane projection angle of the hip was also significantly higher during the SDT than in the SLST (p<.001) as observed with 3-D imaging, surface electromyographic activity, and ground reaction forces.19 Examination of test performance for both functional tests have shown an increase in hip abductor strength and degree of knee flexion to have a significant effect on decreasing hip adduction and valgus motion at the knee.17,54 The SLST and SDT are beneficial in evaluating patients through visual observation of pelvic tilt and rotation as well as trunk stability.42,50,52 This literature review was used to assimilate current evidence to construct standardized protocols for administering the SLST and SDT for use during the examination of individuals with non-arthritic hip pain. The proposed protocols for both the SLST and SDT reflect the authors’ interpretations of best available evidence of reliability and validity extracted from the current peer-reviewed literature. Evaluation was based on an overall impression of each repetition (including balance and evaluation of the arm strategy), posture or movement of the trunk, positioning of the pelvic plane, hip joint movement and positioning, and knee joint movement and posture.29-32 The accumulation of procedures utilized for both the SLST and SDT were extracted and analyzed by the authors from the current peer-reviewed literature in order to assess for reliability and validity.

These results were summarized and combined to create a recommended protocol and evaluation procedure for clinical utilization of the SLST and SDT in individuals with non-arthritic hip pain. The standardized protocol and scoring criteria for both the SLST and SDT can be found in Table 3 and Table 4, respectively.

There are limitations present in the current review that need to be considered when interpreting the results and recommendations. The proposed protocols for administration of the SLST and SDT are based on the authors interpretation of the current peer-reviewed literature. These recommendations may not be the only viable options for administration of the SLST and SDT during assessment of

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individuals with non-arthritic hip pain. Different techniques for test performance as well as differing landmarks for the visual evaluation criteria could be utilized with effectiveness. Other functional performance tests may be beneficial in the evaluation of individuals with intra-articular conditions of the hip.

Caution should also be exercised when generalizing the results of the current review to other populations. Future studies are needed to demonstrate the diagnostic accuracy of the SLST and SDT in evaluation of individuals with non-arthritic hip pain. The use of three-dimensional motion analysis technology and electromyographic assessment could also add quantitative analysis to validate the use of the SLST and SDT in this population.

CONCLUSIONS Evidence was available to support the reliable and valid use of the SLST and SDT. Both tests have been utilized to assess quality of movement in the hip and surrounding structures. These tests are indicative of the weight-bearing demands and dynamic muscular control needed for sports related movements. The best procedures used during research to assess reliability and validity of the tests were extracted, analyzed, summarized, and combined in order to create suggestions for practical, clinical procedures for utilization during administration of the SLST and SDT in examination of individuals with non-arthritic hip pain.

REFERENCES 1. Bird SP, Markwick WJ. Musculoskeletal screening and functional testing: Considerations for basketball athletes. Int J Sports Phys Ther. 2016;11(5):784-802.

2. Kivlan BR, Martin RL. Functional performance testing of the hip in athletes: a systematic review for reliability and validity. Int J Sports Phys Ther.

2012;7(4):402-412.

3. Ardern CL, Glasgow P, Schneiders A, et al. 2016 Consensus statement on return to sport from the first world congress in sports physical therapy, Bern.

Br J Sports Med. 2016;50(14):853-864.

4. Ugalde V, Brockman C, Bailowitz Z, Pollard CD. Single leg squat test and its relationship to dynamic knee valgus and injury risk screening. Phys Med Rehabil. 2015;7(3):229-235; quiz 235.

5. Kline PW, Johnson DL, Ireland ML, Noehren B. Clinical predictors of knee mechanics at return to sport after acl reconstruction. Med Sci Sports Exerc.

2016;48(5):790-795.

6. Loudon JK, Wiesner D, Goist-Foley HL, Asjes C, Loudon KL. Intrarater reliability of functional performance tests for subjects with patellofemoral pain syndrome. J Athl Train. 2002;37(3):256-261.

7. Kulas AS, Hortobagyi T, DeVita P. Trunk position modulates anterior cruciate ligament forces and strains during a single-leg squat. Clin Biomech.

2012;27(1):16-21.

8. Mascal CL, Landel R, Powers C. Management of patellofemoral pain targeting hip, pelvis, and trunk muscle function: 2 case reports. J Orthop Sports Phys Ther. 2003;33(11):647-660.

9. Beutler AI, Cooper LW, Kirkendall DT, Garrett WE, Jr. Electromyographic analysis of single-leg, closed chain exercises: implications for rehabilitation after anterior cruciate ligament reconstruction. J Athl Train. 2002;37(1):13-18.

10. Nakagawa TH, Moriya ET, Maciel CD, Serrao FV. Trunk, pelvis, hip, and knee kinematics, hip strength, and gluteal muscle activation during a single-leg squat in males and females with and without patellofemoral pain syndrome. J Orthop Sports Phys Ther. 2012;42(6):491-501.

11. Nakagawa TH, Serrao FV, Maciel CD, Powers CM. Hip and knee kinematics are associated with pain and self-reported functional status in males and females with patellofemoral pain. Int J Sports Med. 2013;34(11):997-1002.

12. Anderson G, Herrington L. A comparison of eccentric isokinetic torque production and velocity of knee flexion angle during step down in patellofemoral pain syndrome patients and unaffected subjects. Clin Biomech. 2003;18(6):500-504.

13. Souza RB, Powers CM. Differences in hip kinematics, muscle strength, and muscle activation between subjects with and without patellofemoral pain. J Orthop Sports Phys Ther. 2009;39(1):12-19.

14. Lee SP, Souza RB, Powers CM. The influence of hip abductor muscle performance on dynamic postural stability in females with patellofemoral pain. Gait Posture. 2012;36(3):425-429.

15. Levinger P, Gilleard W, Coleman C. Femoral medial deviation angle during a one-leg squat test in individuals with patellofemoral pain syndrome. Phys Ther Sport. 2007;8(4):163-168.

16. Hatton AL, Kemp JL, Brauer SG, Clark RA, Crossley KM. Impairment of dynamic single-leg balance performance in individuals with hip chondropathy.

Arthritis Care Res. 2014;66(5):709-716.

17. Lewis CL, Foch E, Luko MM, Loverro KL, Khuu A. Differences in lower extremity and trunk kinematics between single Leg squat and step down tasks. PLoS One. 2015;10(5):e0126258.

The International Journal of Sports Physical Therapy | Volume 13, Number 3 | June 2018 | Page 534

18. Khuu A, Foch E, Lewis CL. Not all single leg squats are equal: a biomechanical comparison of three variations. Int J Sports Phys Ther. 2016;11(2):201-211.

19. Hatfield GL, Charlton JM, Cochrane CK, et al. The biomechanical demands on the hip during progressive stepping tasks. J Strength Cond Res. 2016.

20. Chinkulprasert C, Vachalathiti R, Powers CM. Patellofemoral joint forces and stress during forward step-up, lateral step-up, and forward step-down exercises. J Orthop Sports Phys Ther. 2011;41(4):241-248.

21. Luque-Seron JA, Medina-Porqueres I. Anterior cruciate ligament strain in ivo: systematic review.

Sports Health. 2016;8(5):451-455.

22. Kim HY. Statistical notes for clinical researchers: Evaluation of measurement error 2: dahlberg’s error, bland-altman method, and kappa coefficient. Restor Dent Endod. 2013;38(3):182-185.

23. Kim HY. Statistical notes for clinical researchers: Evaluation of measurement error 1: using intraclass correlation coefficients. Restor Dent Endod.

2013;38(2):98-102.

24. Andersen EM. Criteria for Assessing the Tools of Disability Outcomes Research. Arch Phys Med Rehabil. 2000;81(Suppl 2 ):S15-S20.

25. Zaki R, Bulgiba A, Nordin N, Azina Ismail N. A systematic review of statistical methods used to test for reliability of medical instruments measuring continuous variables. Iran J Basic Med Sci. 2013;16(6):803-807.

26. Kwiecien R, Kopp-Schneider A, Blettner M. Concordance analysis: part 16 of a series on evaluation of scientific publications. Dtsch Arztebl Int. 2011;108(30):515-521.

27. Bruton A CJ, Holgate ST. Reliability: What is it and how is it measured? Physiotherapy 2000;86(2):94-99.

28. Karras DJ. Statistical methodology: II. Reliability and validity assessment in study design, Part B. Acad Emerg Med. 1997;4(2):144-147.

29. Crossley KM, Zhang WJ, Schache AG, Bryant A, Cowan SM. Performance on the single-leg squat task indicates hip abductor muscle function. Am J Sports Med. 2011;39(4):866-873.

30. Kennedy MD, Burrows L, Parent E. Intrarater and interrater reliability of the single-leg squat test. Athl Ther Today. 2010;15(6):32-36.

31. Park KM, Cynn HS, Choung SD. Musculoskeletal predictors of movement quality for the forward step-down test in asymptomatic women. J Orthop Sports Phys Ther. 2013;43(7):504-510.

32. Herman G, Nakdimon O, Levinger P, Springer S. Agreement of an evaluation of the forward-step-down test by a broad cohort of clinicians with that of an expert panel. J Sport Rehabil. 2016;25(3):227-232.

33. Chmielewski TL, Hodges MJ, Horodyski M, Bishop MD, Conrad BP, Tillman SM. Investigation of clinician agreement in evaluating movement quality during unilateral lower extremity functional tasks: a comparison of 2 rating methods. J Orthop Sports Phys Ther. 2007;37(3):122-129.

34. Weeks BK, Carty CP, Horan SA. Kinematic predictors of single-leg squat performance: a comparison of experienced physiotherapists and student physiotherapists. BMC Musculoskelet Disord. 2012;13:207.

35. Ageberg E, Bennell KL, Hunt MA, Simic M, Roos EM, Creaby MW. Validity and inter-rater reliability of medio-lateral knee motion observed during a singlelimb mini squat. BMC Musculoskelet Disord. 2010;11:265.

36. Stensrud S, Myklebust G, Kristianslund E, Bahr R, Krosshaug T. Correlation between two-dimensional video analysis and subjective assessment in evaluating knee control among elite female team handball players. Br J Sports Med. 2011;45(7):589-595.

37. Graci V, Van Dillen LR, Salsich GB. Gender differences in trunk, pelvis and lower limb kinematics during a single leg squat. Gait Posture.

2012;36(3):461-466.

38. Bremander AB, Dahl LL, Roos EM. Validity and reliability of functional performance tests in meniscectomized patients with or without knee osteoarthritis. Scand J Med Sci Sports. 2007;17(2):120-127.

39. Tijssen M, van Cingel RE, Staal JB, Teerenstra S, de Visser E, Nijhuis-van der Sanden MW. Physical therapy aimed at self-management versus usual care physical therapy after hip arthroscopy for femoroacetabular impingement: study protocol for a randomized controlled trial. Trials. 2016;17:91.

40. Agresta CE, Church C, Henley J, Duer T, O’Brien K. Single leg squat performance in active ddolescents age 8 to 17 years. J Strength Cond Res. 2017;31(5):1187-1191.

41. Perrott MA, Pizzari T, Opar M, Cook J. Development of clinical rating criteria for tests of lumbopelvic stability. Rehabil Res Pract. 2012;2012:803637.

42. Burnham JM, Yonz MC, Robertson KE, et al.

Relationship of hip and trunk muscle function with single leg step-down performance: implications for return to play screening and rehabilitation. Phys Ther Sport. 2016;22:66-73.

43. Piva SR, Fitzgerald K, Irrgang JJ, et al. Reliability of measures of impairments associated with patellofemoral pain syndrome. BMC Musculoskelet Disord. 2006;7:33.

44. Rabin A, Kozol Z. Measures of range of motion and strength among healthy women with differing quality of lower extremity movement during the lateral step-down test. J Orthop Sports Phys Ther.

2010;40(12):792-800.

The International Journal of Sports Physical Therapy | Volume 13, Number 3 | June 2018 | Page 535

45. Junge T, Balsnes S, Runge L, Juul-Kristensen B, Wedderkopp N. Single leg mini squat: an inter-tester reproducibility study of children in the age of 9-10 and 12-14 years presented by various methods of kappa calculation. BMC Musculoskelet Disord.

2012;13:203.

46. Poulsen DR, James CR. Concurrent validity and reliability of clinical evaluation of the single leg squat. Physiother Theory Pract. 2011;27(8):586-594.

47. Raisanen A, Pasanen K, Krosshaug T, Avela J, Perttunen J, Parkkari J. SinglelLeg squat as a tool to evaluate young athletes’ frontal plane knee control.

Clin J Sport Med. 2016;26(6):478-482.

48. Almeida GP, Silva AP, Franca FJ, Magalhaes MO, Burke TN, Marques AP. Relationship between frontal plane projection angle of the knee and hip and trunk strength in women with and without patellofemoral pain. J Back Musculoskelet Rehabil. 2016;29(2):259-266.

49. Tate J, Dale B, Baker C. Expert versus novice interrater and intrarater reliability of the frontal plane projection angle during a single-leg squat. Int J Athl Ther Train. 2015;20(4):23-27.

50. Nakagawa TH, Moriya ET, Maciel CD, Serrao FV. Test-retest reliability of three-dimensional kinematics using an electromagnetic tracking system during single-leg squat and stepping maneuver. Gait Posture. 2014;39(1):141-146.

51. Charlton PC, Bryant AL, Kemp JL, Clark RA, Crossley KM, Collins NJ. Single-leg squat performance is impaired 1 to 2 years after hip arthroscopy. Phys Med Rehabil. 2016;8(4):321-330.

52. Dingenen B, Malfait B, Vanrenterghem J, Verschueren SM, Staes FF. The reliability and validity of the measurement of lateral trunk motion in two-dimensional video analysis during unipodal functional screening tests in elite female athletes.

Phys Ther Sport. 2014;15(2):117-123.

53. Claiborne TL, Armstrong CW, Gandhi V, Pincivero DM. Relationship between hip and knee strength and knee valgus during a single leg squat. J Appl Biomech. 2006;22(1):41-50.

54. Stickler L, Finley M, Gulgin H. Relationship between hip and core strength and frontal plane alignment during a single leg squat. Phys Ther Sport.

2015;16(1):66-71.

55. Shirey M, Hurlbutt M, Johansen N, King GW, Wilkinson SG, Hoover DL. The influence of core musculature engagement on hip and knee kinematics in women during a single leg squat. Int J Sports Phys Ther. 2012;7(1):1-12.

56. Hollman JH, Galardi CM, Lin IH, Voth BC, Whitmarsh CL. Frontal and transverse plane hip kinematics and gluteus maximus recruitment correlate with frontal plane knee kinematics during single-leg squat tests in women. Clin Biomech. 2014;29(4):468-474.

57. Mauntel TC, Begalle RL, Cram TR, et al. The effects of lower extremity muscle activation and passive range of motion on single leg squat performance. J Strength Cond Res. 2013;27(7):1813-1823.

58. Mauntel TC, Frank BS, Begalle RL, Blackburn JT, Padua DA. Kinematic differences between those with and without medial knee displacement during a single-leg squat. J Appl Biomech. 2014;30(6):707-712.

59. Rabin A, Kozol ZVI, Moran U, Efergan A, Geffen Y, Finestone AS. Factors associated with visually assessed quality of movement during a lateral step-down test among individuals with patellofemoral pain. J Orthop Sports Phys Ther.

2014;44(12):937-946.

60. Rabin A, Portnoy S, Kozol Z. The association of ankle dorsiflexion range of motion with hip and knee kinematics during the lateral step-down test. J Orthop Sports Phys Ther. 2016;46(11):1002-1009.

61. Herman G, Nakdimon O, Levinger P, Springer S. Agreement of an evaluation of the forward-stepdown test by a broad cohort of clinicians with that of an expert panel. J Sport Rehabil. 2016;25(3):227-232.

62. Rabin A, Portnoy S, Kozol Z. The association between visual assessment of quality of movement and three-dimensional analysis of pelvis, hip, and knee kinematics during a lateral step down test. J Strength Cond Res. 2016;30(11):3204-3211.

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IJSPT

LITERATURE REVIEW

EVALUATING THE PROGRESS OF MID-PORTION ACHILLES TENDINOPATHY DURING REHABILITATION: A REVIEW OF OUTCOME MEASURES FOR MUSCLE STRUCTURE AND FUNCTION, TENDON STRUCTURE, AND NEURAL AND PAIN ASSOCIATED MECHANISMS Myles Murphy, PT1-3 Ebonie Rio, PT, PhD4,5 James Debenham, PT, PhD1 Sean Docking, PhD4 Mervyn Travers, PT, PhD1,6 William Gibson, PT, PhD1

ABSTRACT Introduction: Alterations in tendon structure and muscle performance have been suggested as mechanisms driving improvement in pain and function with mid-portion Achilles tendinopathy (AT). However, few trials have used consistent outcome measures to track differences in muscle structure and function, tendon structure and neural and pain associated mechanisms.

Objectives: 1) Identify the outcomes measures used in trials utilising loading protocols for mid-portion AT that assess muscle structure and function, tendon structure and neural and pain associated mechanisms in order to report on the reliability of the identified measures, and 2) Propose a summary of measures for assessment of muscle structure and function, tendon structure and neural and pain associated mechanisms in patients with AT. Design: Literature Review Data Sources: Three electronic databases were searched from inception until May 2016 for studies using loading protocols for mid-portion AT. Eligibility Criteria: Randomized and non-randomized trials of loading protocols for mid-portion AT. Results: Twenty-eight studies were included; seven assessed muscle, 21 assessed tendon and two assessed neural and pain associated mechanisms. Evidence suggests that isokinetic dynamometry, eccentric-concentric heel raise tests, single leg drop countermovement jumps or hopping are the most reliable ways to assess muscular adaptation. Assessment of tendon structure is unlikely to have any benefit given it does not appear to correlate to clinical outcomes. The neural and pain associated mechanisms have not been thoroughly investigated.

Conclusion: Further research needs to be done to determine the role of muscle, tendon and neural adaptations using reliable outcome measures during the management of mid-portion AT. Level Of Evidence: Level Five.

Key Words: Achilles; outcome measures; reliability; tendinopathy; tendon structure; tendon function

Acknowledgements:

1

School of Physiotherapy, The University of Notre Dame Australia, Fremantle, Australia 2 SportsMed Subiaco, St John of God Health Care, Subiaco, Australia 3 Sports Science Sports Medicine Department, Western Australian Cricket Association, East Perth, Australia 4 Sports and Exercise Medicine Research Centre, La Trobe University, Bundoora, Australia 5 Australian Collaboration for Research into Injury in Sport and its Prevention (ACRISP), Bundoora, VIC, Australia 6 School of Physiotherapy and Exercise Science, Curtin University, Bentley, Australia The authors report no conďŹ&#x201A;icts of interest.

Myles Murphy would like to acknowledge the support from the Australian Governments Research Training Program Scholarship. Ebonie Rio would like to acknowledge the support from the National Health and Medical Research Councils Early Career Fellowship Scheme.

CORRESPONDING AUTHOR Myles Murphy School of Physiotherapy, The University of Notre Dame Australia, Fremantle, WA, Australia.

Mobile: 0414015434 E-mail: myles.murphy1@my.nd.edu.au

The International Journal of Sports Physical Therapy | Volume 13, Number 3 | June 2018 | Page 537 DOI: 10.26603/ijspt20180537

INTRODUCTION Achilles tendinopathy (AT) is a common runningrelated injury, with a prevalence of 6.2-9.5% in recreational runners.1 AT can present as either mid-portion or insertional tendinopathy. Midportion tendinopathy affects the mid-portion of the tendon approximately 2-4 cm proximal to the insertion whereas insertional tendinopathy affects the tendon insertion onto the calcaneus.2 Clinically, AT is characterised by pain and stiffness with these symptoms affecting athletic function.3,4 Mid-portion and insertional AT are considered different clinical entities,5 and accordingly, the scope of this review focusses purely on mid-portion AT. Both researchers and clinicians are challenged by mid-portion AT.6 Exercise rehabilitation, specifically either eccentric only or isotonic resistance loading protocols, appear to be effective interventions over time.2,7 While these programs appear effective, a proportion of patients who complete loading protocols continue to experience symptoms at five year follow up.8,9 One potential explanation for this relates to the incomplete understanding of the mechanisms underpinning this therapy.10 Several theories have been alluded to in the literature including 1) alterations in tendon structure11 2) alterations in muscle performance12 and 3) alterations in pain mechanisms.13 Evidence supporting these theories however, is either sparse or conflicting and without clear guidance on what outcome measures should be used to assess muscle (structure and function), tendon and neural contributions.

The most commonly cited mechanism underpinning improvements in AT following a loading program is improvements in the material and mechanical properties of the tendon.11,14 This is based on the theory that disorganized fibrillar structure observed within tendinopathic tissue may be responsible for the pain associated with tendinopathy.3,4 For instance in the pathological tendon, a decrease in tendon size and signal on Magnetic Resonance Imaging (MRI) has been proposed to reflect positive improvement in the tendon.11,14 This theory has recently been challenged as the majority of work in this area indicates that changes in tendon structure and volume do not explain improvements in pain and function when

assessed with greyscale ultrasound (US), ultrasound tissue characterisation (UTC) and MRI.15,16 Given the lack of correlation between tendon structure on imaging and improvement in pain and function, recent attention has been directed towards possible adaptations that may occur in either the muscular12 and/ or neural and pain associated mechanisms.13 The muscular system, specifically plantar flexor performance, may act as a â&#x20AC;&#x2DC;stress shieldâ&#x20AC;&#x2122; for the Achilles tendon,17 which is believed to optimize the stretch shortening cycle.18 A growing body of biomechanical literature supports the premise that muscle performance and musculotendinous behaviour are intimately linked, and can be modulated by training. In response to loading, muscle performance improves in timeframes of seconds to weeks, mediated initially by neural mechanisms,19 then subsequently by functional and structural changes within the muscle itself.20 For example, maximal voluntary isometric contraction has been shown to immediately increase following a single bout of isometric loading in patients with patellar tendinopathy and this was associated with a decrease in excess cortical motor inhibition.21 However, these findings have yet to be replicated in mid-portion AT. Medial gastrocnemius fascicles have been shown to have an intimate relationship with the stiffness of the muscle-tendon unit and can be considered in series with the Achilles tendon.22 Longer gastrocnemius fascicle length has also been shown to correlate with improved physical performance in running athletes.23 In healthy individuals, muscle strength improves within days following resistance training.19 These improvements are due to a plethora of suggested neural mechanisms such as increases in motor unit firing rates, double discharges of individual motor units, increased excitability of the motor cortex and cross transfer/ cross education.19 Changes in sensory receptors may also lead to a disinhibition or increased expression of muscle force.19 Despite these early changes in motor output, true muscular hypertrophy appears only after approximately three weeks of a resistance training protocol.20 Given that clinical improvements in response to loading interventions are typically observed prior to this time point, it is likely that other mechanisms driving this improvement are

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involved here also. The early improvement in pain and function without frank adaptation in muscular tissue implicates neural mechanisms as a likely mechanism underpinning this clinical observation.

The drivers of pain in both upper limb and lower limb tendinopathy remain poorly understood, although evidence exists supporting peripheral tendon-based nociceptive contributors as well as input from the central nervous system (CNS).10,24,25 Furthermore, a case control study specific to patellar and AT demonstrated a predominantly peripheral pain state.26 Importantly, immediate improvements in self-reported pain have been demonstrated following exercise rehabilitation for other conditions such as knee osteoarthritis.27 When it comes to measuring pain and function, it has also been highlighted that the reliability and validity of many outcome measures used within intervention studies for midportion AT have not been established.28 This means that the findings of research and clinical assessment may potentially be inaccurate or misleading.28 Thus, it is vital that outcome measures across all assessment domains are valid and reliable in order to produce high quality research which usefully informs our understanding of changes in muscle structure and function, tendon structure, and neural and pain associated mechanisms in mid-portion AT rehabilitation.

One challenge in understanding these mechanisms is that few trials have used consistent outcome measures to quantify the changes in muscle structure, muscle function, and tendon structure. The chosen outcome measures also lack sufficient reliability allow confidence in the results. It is important that clinicians and researchers are familiar with the outcome measures that have been used in clinical trials including their reliability, as suboptimal outcome measures can produce results with questionable utility. However, while reliable measures are important for researchers it is also important for clinicians to know which measures are accessible for everyday practice. This may in turn reduce barriers to implementation of these measures.29 AIMS The objectives of this literature review are: 1) Identify the outcomes measures used in trials utilising

loading protocols for mid-portion AT that assess muscle structure and function, tendon structure and neural and pain associated mechanisms in order to report on the reliability of the identified measures, and 2) Propose a summary of measures for assessment of muscle structure and function, tendon structure and neural and pain associated mechanisms in patients with AT. METHODS Criteria for considering studies for this review Types of studies Both non-randomized cohort studies and randomized controlled trials were included if a loading protocol was used to treat mid-portion AT. Case reports, clinical observations, and systematic reviews were excluded.

Types of participants Physically active and sedentary participants aged 18 years and over identified as having mid-portion AT for greater than three months were included. Studies including participants with insertional AT or other causes of pain (differential diagnoses) anywhere in the Achilles region were excluded from the review.

Types of interventions Intervention studies using either isometric, eccentric, concentric or isotonic (eccentric and concentric) loading protocols were included. Studies that employed an isometric, eccentric, concentric or isotonic loading program in conjunction with a placebo therapy (for example sham laser treatment) were included.

Types of outcomes measures Only studies that used an outcome measure of muscle structure and function, tendon structure, and neural and pain associated mechanisms in mid-portion AT were included.

Search methods for identiďŹ cation of studies Electronic Searches Searches using free text terms (Table 1) were used to identify published articles on the following electronic databases; PUBMED, CINAHL (Ovid) and CINAHL (EBSCO). Only peer reviewed, human, clinical trials and cohort studies were included.

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Table 1. Systematic Review Search Strategy

Searching other Resources Reference lists from reviews and retrieved articles were checked and citation searches on key articles performed. The list of included studies was evaluated by content experts to help identify any additional relevant studies.

Data collection and analysis Selection of Studies One review author (MM) searched and assessed the titles and abstracts of potential studies identified by the search strategy for their eligibility. Studies were exported to reference management software EndNote X8.0.2 (Clarivate Analytics, 2017) and duplicates were removed. If the eligibility of a study was unclear from the title and abstract the full paper was assessed. Studies that did not match the inclusion criteria for this review were excluded.

Studies were not anonymised prior to assessment. A PRISMA study flow diagram was used to document the screening process.30

RESULTS Selection of Studies A total of seven studies were included that contained a measure of muscle structure or function.31-37 A total of 21 studies were included that contained a measure of tendon structure.9,11,14,15,33,38-53 A total of two studies were included that contained a measure of neural and pain associated mechanisms.8,51 Given overlap in some studies a total of 28 studies were included for analysis. The study selection process is demonstrated in the Prisma Flow Diagram (Figure 1).

Data abstraction and management One review author (MM) extracted data from all included studies using a standardized and piloted data extraction form on Microsoft Excel (Microsoft, 2016). The following information was recorded; primary author, year of publication, study design, study population (diagnosis), sample size, loading intervention (e.g. heavy eccentric calf training), outcome measures used, number of follow up points and time (weeks) at each follow up point.

Data synthesis Reliability was reported if provided by the study using the outcome measure. If the study provided a reference to psychometric properties, the referenced study was used to extract the data.

Figure 1. PRISMA Study Flow Diagram.

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Data Extraction Data were extracted from 28 studies, of which some studies assessed a combination of muscle strength and function, tendon structure and neural and pain associated mechanisms. The characteristics of the included studies are presented in Appendix A. MUSCLE STRUCTURE AND FUNCTION Data Synthesis The outcome measures used to assess muscle structure and function are presented in Table 2. Three separate measures are shown to represent muscle function; categorized into those looking at muscle strength, endurance, or power production Structure Ultrasound (US) has been used to examine muscle structure in a single clinical trial.32 US assessment of the calf muscle complex has shown excellent reliability when assessing gastrocnemius thickness (Intrarater ICC=0.96-0.99, Inter-rater ICC=0.97-0.99),55 gastrocnemius fascicle length (Intra-rater ICC=0.91)54 and gastrocnemius pennation angle (Intra-rater ICC=0.69-0.82, Inter-rater ICC=0.70-0.96).55

Strength Isokinetic dynamometry, albeit at different speeds, has been used to measure strength in three clinical trials31,33,36 while the eccentric-concentric toe/ heel raise strength tests have been used in one clinical trial.34 Excluding isokinetic dynamometry at 225 degrees/second, all other speeds tested showed superior (good to excellent) reliability when compared to the eccentric-concentric heelraise tests. Specifically, isokinetic dynamometry at 120deg/s shows excellent reliability (r=0.94).59 The eccentric-concentric heel-raise test also shows good, yet inferior, reliability (ICC= 0.76-0.86)60 when compared to isokinetic dynamometry.

Endurance To measure muscle endurance, isokinetic dynamometry has been used in one clinical trial33 and heel-raise test for endurance have been used in two clinical trials.34,35 The reliability of slow, endurance based isokinetic dynamometry has not been assessed in the ankle, however the heelraise test for endurance shows good reliability (ICC=0.78-0.84).60

Table 2. Outcome measures assessing muscle structure and function

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Power Production Power production has been assessed using a variety of different tests measuring multiple variables (e.g. height, air time etc) with the Sargent jump test being used in one clinical trial,36 the one legged counter movement jump (CMJ) being used in two clinical trials,34,35 the one legged drop CMJ being used in one clinical trial34 and hopping used in two clinical trials.34,37 The Sargent jump test (Test-retest ICC=0.96)62 reported marginally better reliability than one legged CMJ (Test-retest ICC=0.91-0.93),35,60 one legged drop CMJâ&#x20AC;&#x2122;s (r=0.0.88-92)60 and hopping (Test-retest ICC=0.83-0.94).60 TENDON STRUCTURE Data Synthesis The outcome measures used to assess tendon structure are presented in Table Three. Three separate measures are shown; categorised into those looking at structure, para-tendinous substances, and tendon/ paratenon microcirculation.

Structure Tendon structure has been measured using Greyscale US in 10 clinical trials,9,39,41,42,46,48-52 Doppler US has

been used in seven clinical trials,9,39-41,43,47,53 UTC has been reported in two clinical trials15,42 and MRI has been used in two clinical trials.11,14 Excellent intrarater reliability was seen when classifying tendon structure into echo-types using UTC (ICC=0.950.99).65 MRI assessment of tendon volume showed excellent intra-rater (r=0.98-0.99)11 and interrater(r=0.96-0.99)11 reliability. MRI assessment of Mean Achilles Tendon Signal has shown excellent intra-rater (r=0.84-0.97)11 and inter-rater reliability (r=0.78-0.95).11 Grading tendon structure on Doppler US using the Modified Ohberg Score (0 =no vessels visible, 1+ =1 vessel, mostly anterior to the tendon, 2+ =1 or 2 vessels throughout the tendon, 3+ =3 vessels throughout the tendon, or 4+ =more than 3 vessels throughout the tendon) showed good interrater reliability (ICC=0.85).64 Tendon thickness measured by greyscale US has shown good intrarater (ICC=0.78-0.90)67 and inter-rater (ICC=0.720.73)67 reliability.

Para-tendinous substances One clinical trial has measured paratendinous substances using micro-dialysis.45 The variability of assessing interstitial carboxyterminal propeptide

Table 3. Outcome measures assessing tendon structure

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of type I collagen (PIPC) was shown to be good (CV=2.7% at 214μg/L)45 and the variability of assessing interstitial carboxyterminal telopeptide region of type I collagen (ICTP) was also shown to be good (CV=4.9% at 6.1μg/L).45 Tendon/ paratenon microcirculation Tendon and paratenon micro-circulation has been measured by assessing non-invasive combined laser Doppler and flowmetry in one clinical trial. The intra-tester (CV=5%)66 and inter-tester (CV=3237%)66 variability has shown to be good.

NEURAL AND PAIN ASSOCIATED MECHANISMS Data synthesis The outcome measures used to assess domains within the nervous system are listed in Table 4.

Peripheral sensitivity There is a dearth of information assessing the neural and pain associated mechanisms in clinical trials in AT. Mechanosensitivity has been assessed using Pressure Pain Thresholds (PPT) in one clinical trial.51 PPT’s using manual algometry have been shown to have excellent intra-rater reliability (ICC=0.96)68 in the Achilles tendon.

DISCUSSION Muscle structure and function Structure In patients with AT, medial gastrocnemius fascicle length significantly increases within six weeks of beginning an eccentric calf program and correlates with improvements in pain and function.32 However, while US measures of fascicle length are reliable54 these investigators did not establish the reliability of the measure themselves32 leading to potential bias. The role of soleus fascicle length has not been investigated yet in mid-portion AT. Whilst US is reliable for assessing calf muscle architecture,

changes in calf muscle thickness have not been shown to correlate to improvement in pain and function in mid-portion AT leaving questions regarding its utility.32 MRI has not been used in clinical trials to assess muscle structure but it is highly reliable in assessing the muscle volume of the gastrocnemius (Intra-rater ICC=0.99-1.00, Interrater ICC=0.99)70 and soleus (Intra-rater ICC=0.991.00, Inter-rater ICC=0.99).70 US and MRI are appropriate for use in assessing muscle structure in research. However, access to these measures and the training required to report on them is likely a significant barrier to use. Quantification of muscular hypertrophy or architectural changes will not likely occur for at least three weeks following the inception of a loading protocol.20,32 Therefore, any future work investigating these changes require appropriate timeframes for follow-up.

Strength A variety of different assessments have been used to quantify muscle strength in mid-portion AT. Varied speeds for isokinetic dynamometry have been reported and speed of isokinetic dynamometry should therefore be selected based on the role of the muscle to tie into function. The required speed for performing a heel raise is 6.3-6.5 rad/s,71 walking is 4.2 rad/s,72 transitioning from walking to running is 6.6 rad/s,73 running is 8.4-9.0 rad/s74 and jumping is 16 rad/s75 (Figure 2). Given the large angular velocities required in the ankle for function, isokinetic dynamometry at 120 deg/s appears to be the fastest, yet most reliable form of measuring strength. However, even at this velocity it does not mimic functional speeds. More functional strength measures such as the eccentric-concentric heelraise test may better mirror the required angular velocities60 and can be used clinically by recording a three-repetition maximum using weights equipment such as a Smith machine. The eccentric-concentric heel-raise test has also been validated in mid-portion AT and is able to differentiate between participants

Table 4. Outcome measures assessing the neural and pain associated mechanisms

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Figure 2. Peak Ankle Angular Velocity during Functional Tasks.71-75,78

more painful and least/ non painful side (p= 0.001-0.006).60 Isokinetic dynamometry has also only assessed plantar flexor strength in a straight knee position which biases the gastrocnemius.76 To bias the soleus when assessing plantar flexion with isokinetic dynamometry, the knee must be flexed to greater than 45 degrees.77 However, it should be stated that neither of these positions eliminate the other plantar flexor muscles and purely act to selectively bias towards one muscle.77 Further research is needed to determine relevant contributions of the gastrocnemius or soleus in explaining the mechanisms in improvement in pain and function with mid-portion AT. An additional barrier is that isokinetic dynamometry is expensive and often not available in clinical settings. While isokinetic dynamometry remains the gold standard, the eccentric-concentric heel-raise test with its high test-retest reliability and good validity represents a more feasible clinical test.

following the commencement of the loading program may highlight the neural contribution to strength19 whilst testing after this time likely includes the contribution of muscular hypertrophy to strength.20

Given the immediate improvements in pain and function observed in several interventional studies,15,37 performing strength testing at multiple time points may provide information around different contributors to clinical improvement.

Though pain is more complex than this, if we consider strength specifically, testing at four weeks

Power production A systematic review demonstrated sensory and motor deficits are present bilaterally in patients with unilateral tendon pain and disability however, this review only included one paper specifically on AT.24 Functional tasks including jumping and hopping are often the most aggravating tasks in mid-portion AT60

Endurance The heel-raise test for endurance has good reliability60 and given the simplicity of the test it represents the best outcome measure for assessing plantar flexor endurance in both research and clinical practice.

However, significant variability exists in how this test can be performed and this may impact its utility both clinically and in research.76 It is also important to note that no differences were seen when using the heel-raise test for endurance in participants with AT between painful and non-painful/ least painful sides (P=0.077).60 Further research into the reliability of endurance based Isokinetic Dynamometry needs to be performed before it can be recommended for use in research or clinical practice.

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therefore choosing the appropriate measure to assess this functional deficit is important for both clinicians and researchers. In participants with AT, significant unilateral differences during hopping were observed when comparing the painful to the non-painful/ less symptomatic limb; height (p=0.006), plyometric quotient (p=0.001) and visual analogue scale (VAS) pain score (p=0.000).60 Significant differences were also seen during a one-legged drop CMJ task; height (P=0.049), contact time (p=0.008) and VAS pain score (p=0.001).60 However no significant differences were seen with a normal CMJ; height (p=0.665) and VAS pain score (p=0.012).60 Given the significant differences between limbs, unilateral functional tests are likely more sensitive to detecting deficits in function than bilateral tests.

The single leg drop CMJ or hopping appear to be the most appropriate measures of power production given the high test- retest reliability they demonstrate and that they correlate to deficits seen in people with AT.60 For the one-legged drop CMJ and Hopping tests reported by Silbernagel et al.60 a jump mat is required; however, this is expensive. Recently smartphone applications have been validated against jump mats (p<0.001) and been shown to have excellent testretest reliability (ICC=0.997)79 and are more easily accessible for both clinicians and researchers.

Tests of power production represent functional performance and improve due to a combination of muscular and neural factors. These could be assessed as early as four weeks as improvements in muscle strength are potentially correlated to improvements in power production which may be reflected by an increase in the Victorian Institute of Sports Assessment-Achilles (VISA-A). However, due to a test of power likely being correlated to muscle strength and pain it is unlikely to provide specific insight into mechanisms underpinning the improvement patients obtain with loading programs. This distinction may or may not be important for the patient but improvement in functional capacity may encourage rehabilitation adherence. It would also be of great interest to the clinician and the researcher who wish to assess which components or deficits need to be addressed to optimise outcomes in the clinic and in trials.

Tendon structure Structure Both UTC and MRI are not easily accessible for researchers and clinicians. However, these modalities are the most reliable investigations to assess tendon structure and, unlike conventional US, allow for quantification of tendon structure.

These measures have been correlated to symptoms in some studies,11,14,65 however they have also been shown to have a poor relationship to improvement in others.15,42 Doppler US has also been shown to have no correlation to patient symptoms or improvement.16 Given improvements are seen on the VISA-A as early as two weeks following the inception of a loading protocol,15,37 determining whether or not tendon structural adaptations correlate to these improvements would require assessment to be completed when the improvement in pain and function is first seen. Radiological imaging for tendon pathology is known to be highly assessor dependant with poor inter-rater reliability.65 The reliability of grading radiological imaging in tendon pathology has also been demonstrated to be better with more experienced radiologists.80 Given the extent of variation due to different assessors the use of previous reliability studies to justify a new trials reliability should be discouraged and should always be re-examined in an effort to reduce potential bias.

Follow up imaging is not indicated for clinicians treating patients with loading protocols given the poor access, reporting difficulties, patient compliance, and cost. Specifically, differences in tendon structure on imaging do not correlate to improvements in clinical status and therefore are not recommended in the management of mid-portion AT.16 Para-tendinous substances and Tendon/paratenon microcirculation Measures of para-tendinous substance and microcirculation are expensive and can be invasive, but they may provide some insight into the mechanisms playing a role in tendinopathy. However, the authors suggest this would be a research application only due to cost and accessibility.

Neural and pain associated mechanisms Central nervous system mechanisms modulating pain have been shown to be important in chronic

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musculoskeletal pain conditions such as rheumatoid arthritis, osteoarthritis and fibromyalgia,81 yet little research using these outcomes has been performed in AT. A recent systematic review demonstrated nervous system sensitization in persistent tendinopathy, however identified no Achilles tendon studies and only one patellar tendon study out of 16 studies.25 Pressure pain thresholds have been used to assess peripheral and central sensitization,82 however PPTs have also been reported as a potentially poor marker of central and peripheral sensitivity.83 Given the conflicting evidence it is unclear as to how much useful insight PPTs offer into the mechanisms underlying the improvements patients report with loading programs. However, since PPTs have been assessed using manual algometers in one clinical trial and have been shown to have excellent reliability they represent the best (currently available) measure to assess mechanosensitivity of the Achilles tendon.

No clinical trials of loading programs in mid-portion AT have investigated the contribution of different CNS driven mechanisms involved in modulating pain. Three cross sectional studies of patients with AT have identified alterations in 1) endogenous analgesia,68 2) fear of movement8 and 3) altered tactile acuity (as a suggested reflection of somatosensory cortical reorganisation).84 Endogenous analgesia is typically assessed via the conditioned pain modulation paradigm (CPM).

Endogenous analgesia measured via the CPM effect is a centrally driven mechanism that modulates pain.85 Briefly, this requires measurement of the PPT of the Achilles tendon before and during/ after a painful stimulus (e.g. immersion of the participantâ&#x20AC;&#x2122;s hand in cold water) is applied in a remote area from the painful site.68 The change in the PPT is known as the CPM effect and a reduction in mechanosensitivity during/ after the painful conditioning stimulus is regarded as normal.68 One study has demonstrated people with mid-portion AT have deficient CPM compared with controls68 suggesting that further investigation into the role this may play in people with mid-substance AT is needed. However, the pain map provided in this study included people with heel and posterior ankle pain beyond what is

currently considered diagnostic of mid-portion AT5 leading to considerable heterogeneity of the group and likely involving other differential diagnoses. â&#x20AC;&#x2DC;Fear of movementâ&#x20AC;&#x2122; or kinesiophobia is a centrally driven mechanism which may result in restriction of activity and has been shown to be predictive of long term disability in persistent pain conditions, such as chronic low back pain.86 The Tampa scale of Kinesiophobia is one way of measuring fear of movement and has been shown to be have moderate to good test-retest reliability (r=0.64-0.80).69 However, it has only been used in long term follow up of patients with AT and not at baseline8 so it is not possible to make inferences on its prognostic value and therefore future prospective studies quantifying its role in mid-portion AT are needed.

Impaired tactile acuity is theorised to reflect many mechanisms, including altered cortical representation of the painful region.87 A systematic review of 16 studies found that tactile acuity is impaired in persistent pain conditions such as arthritis, complex regional pain syndrome and chronic lower back pain.87 Recently, tactile acuity has been shown to be impaired in mid-portion AT when compared to the unaffected limb and healthy controls.84 Further research is needed to investigate whether alterations in tactile acuity contribute to initiation of the pain experience or are a consequence of it. Given that no investigations of CNS-driven mechanisms of pain modulation, such as the CPM effect or fear of movement, have been completed with loading protocols in mid-portion AT, future investigations should determine if differences occur with loading protocols and what the most optimal timeframes are to assess these differences.

Pressure pain thresholds and the CPM effect can be difficult to assess clinically and therefore may only be plausible for researchers. For clinicians, clinical tools to examine of fear of movement may provide insight into the role of CNS driven mechanisms that modulate pain.

LIMITATIONS The reliability of the tests used to assess muscle structure and function, tendon structure and neural and pain associated mechanisms have been reported for the selected outcome measures in most studies.

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However, a small proportion of assessments used did not have the reliability assessed in a mid-portion AT population. It is unclear whether the reliability of these tests needs to be assessed in this population to remain a valid measure. It is also possible that as a measure of structure and function the tests remain valid across heterogenous populations but as this cannot be certain it may introduce bias.

CONCLUSION Many different outcome measures have been used to assess muscular adaptations, tendon adaptations and neural and pain associated mechanisms in clinical trials treating mid-portion AT with loading protocols.

Isokinetic dynamometry at 120 deg/s and eccentricconcentric heel-raise tests are the suggested best measures of plantar flexor muscle strength, US is capable of measuring muscle architectural properties and the single leg drop CMJ or hopping are the best measures of power production. UTC or MRI are acknowledged as the best ways with which to classify tendon structure and tendon signal. However, given the lack of relationship between tendon structural change and symptoms they are not recommended for clinical use. Endogenous analgesia assessed via the CPM paradigm may be completed simply using a tonic stimulus (such as cold-water immersion) with PPT assessed via manual algometry pre and post application of this tonic stimulus.

It is important for clinicians and researchers to be aware of the outcome measures that have been used as well as the reliability of these measures. By identifying consistent measures that are available to both clinicians and researchers we may be able to gain further insight into the mechanisms responsible for improving pain and function in mid-portion AT. REFERENCES 1. Lopes AD, Hespanhol LC, Yeung SS, et al. What are the main running-related musculoskeletal injuries?

Sports Med. 2012;42(10):891-905.

2. Habets B, van Cingel RE. Eccentric exercise training in chronic mid-portion Achilles tendinopathy: a systematic review on different protocols. Scand J Med Sci Sports. 2015;25(1):3-15.

3. Cook JL, Purdam CR. Is tendon pathology a continuum? A pathology model to explain the clinical presentation of load-induced tendinopathy.

Br J Sports Med. 2009;43(6):409-16.

4. Cook JL, Rio E, Purdam CR, et al. Revisiting the continuum model of tendon pathology: what is its merit in clinical practice and research? Br J Sports Med. 2016;50(19):1187-91.

5. van Dijk CN, van Sterkenburg MN, Wiegerinck JI, et al. Terminology for Achilles tendon related disorders.

Knee Surg Sports Traumatol Arthrosc. 2011;19(5):835-41.

6. Scott A, Docking S, Vicenzino B, et al. Sports and exercise-related tendinopathies: a review of selected topical issues by participants of the second International Scientific Tendinopathy Symposium (ISTS) Vancouver 2012. Br J Sports Med. 2013;47(9):536-44.

7. Murphy M, Travers M, Gibson W, et al. The rate of improvement of pain and function in mid-portion Achilles tendinopathy with loading protocols: A Systematic Review and Longitudinal Meta-Analysis.

Sports Med. 2018; 1-17. [Epub ahead of print] 8. Silbernagel KG, Brorsson A, Lundberg M. The majority of patients with Achilles tendinopathy recover fully when treated with exercise alone: a 5-year follow-up. Am J Sports Med. 2011;39(3):607-13.

9. van der Plas A, de Jonge S, de Vos RJ, et al. A 5-year follow-up study of Alfredson’s heel-drop exercise programme in chronic midportion Achilles tendinopathy. Br J Sports Med. 2012;46(3):214-8.

10. Rio E, Moseley L, Purdam C, et al. The pain of tendinopathy: physiological or pathophysiological?

Sports Med. 2014;44(1):9-23.

11. Shalabi A, Kristoffersen-Wilberg M, Svensson L, et al.

Eccentric training of the gastrocnemius-soleus complex in chronic Achilles tendinopathy results in decreased tendon volume and intratendinous signal as evaluated by MRI. Am J Sports Med. 2004;32(5):1286-96.

12. Allison GT, Purdam C. Eccentric loading for Achilles tendinopathy — strengthening or stretching? Br J Sports Med. 2009;43(4):276-79.

13. Rio E, Kidgell D, Moseley GL, et al. Tendon neuroplastic training: changing the way we think about tendon rehabilitation: a narrative review. Br J Sports Med. 2016;50(4):209-15.

14. Gardin A, Movin T, Svensson L, et al. The long-term clinical and MRI results following eccentric calf muscle training in chronic Achilles tendinosis.

Skeletal Radiol. 2010;39(5):435-42.

15. de Vos RJ, Heijboer MP, Weinans H, et al. Tendon structure’s lack of relation to clinical outcome after eccentric exercises in chronic midportion Achilles tendinopathy. J Sports Rehab. 2012;21(1):34-43.

16. Drew BT, Smith TO, Littlewood C, et al. Do structural changes (eg, collagen/matrix) explain the response to therapeutic exercises in tendinopathy:

The International Journal of Sports Physical Therapy | Volume 13, Number 3 | June 2018 | Page 547

17.

18.

19.

20.

21.

22.

23.

24.

25.

26.

27.

28.

29.

a systematic review. Br J Sports Med. 2014;48(12):966-72.

O’Neill S, Watson PJ, Barry S. Why are eccentric exercises effective for achilles tendinopathy? Int J Sport Phys Ther. 2015;10(4):552-62.

Debenham JR, Gibson WI, Travers MJ, et al.

Eccentric loading of triceps surae modulates stretch shortening cycle behaviour- a possible therapeutic mechanism. J Sports Rehab. 2016:1-22.

Gabriel DA, Kamen G, Frost G. Neural adaptations to resistive exercise: mechanisms and recommendations for training practices. Sports Med. 2006;36(2):133-49.

DeFreitas JM, Beck TW, Stock MS, et al. An examination of the time course of training-induced skeletal muscle hypertrophy. Eur J Appl Physiol.

2011;111(11):2785-90.

Rio E, Kidgell D, Purdam C, et al. Isometric exercise induces analgesia and reduces inhibition in patellar tendinopathy. Br J Sports Med. 2015;49(19):1277-83.

Farcy S, Nordez A, Dorel S, et al. Interaction between gastrocnemius medialis fascicle and Achilles tendon compliance: a new insight on the quick-release method. J Appl Phys. 2014;116(3):259-66.

Kumagai K, Abe T, Brechue WF, et al. Sprint performance is related to muscle fascicle length in male 100-m sprinters. J Appl Phys. 2000;88(3):811-6.

Heales LJ, Lim EC, Hodges PW, et al. Sensory and motor deficits exist on the non-injured side of patients with unilateral tendon pain and disability-implications for central nervous system involvement: a systematic review with metaanalysis. Br J Sports Med. 2014;48(19):1400-6.

Plinsinga ML, Brink MS, Vicenzino B, et al. Evidence of nervous system sensitization in commonly presenting and persistent painful tendinopathies: a systematic review. J Orthop Sports Phys Ther.

2015;45(11):864-75.

Plinsinga ML, van Wilgen CP, Brink MS, et al.

Patellar and Achilles tendinopathies are predominantly peripheral pain states: a blinded case control study of somatosensory and psychological profiles. Br J Sports Med. 2018;52(5):284-91.

Vincent KR, Vincent HK. Resistance exercise for knee osteoarthritis. PM R. 2012;4(5 0):S45-S52.

Murphy M, Rio E, Debenham J, et al. Evaluating the progress of mid-portion Achilles tendinopathy during rehabilitation. A review of outcome measures for self- reported pain and function. Int J Sport Phys Ther. 2018;13(2)283-292 Jette DU, Halbert J, Iverson C, et al. Use of standardized outcome measures in physical therapist practice: perceptions and applications. Phys Ther.

2009;89(2):125-35.

30. Liberati A, Altman DG, Tetzlaff J, et al. The PRISMA statement for reporting systematic reviews and meta-analyses of studies that evaluate healthcare interventions: explanation and elaboration. BMJ. 2009;339:b2700.

31. Alfredson H, Pietila T, Jonsson P, et al. Heavy-load eccentric calf muscle training for the treatment of chronic Achilles tendinosis. Am J Sports Med. 1998;26(3):360-6.

32. Crill MT, Berlet G, Hyer C. Plantar flexor muscle architecture changes as a result of eccentric exercise in patients with Achilles tendinosis. Foot Ankle Spec.

2014;7(6):460-5.

33. Horstmann T, Jud HM, Frohlich V, et al. Whole-body vibration versus eccentric training or a wait-and-see approach for chronic Achilles tendinopathy: a randomized clinical trial. J Orthop Sports Phys Ther.

2013;43(11):794-803.

34. Silbernagel KG, Thomee R, Eriksson BI, et al.

Continued sports activity, using a pain-monitoring model, during rehabilitation in patients with Achilles tendinopathy: a randomized controlled study. Am J Sports Med. 2007;35(6):897-906.

35. Silbernagel KG, Thomee R, Thomee P, et al.

Eccentric overload training for patients with chronic Achilles tendon pain--a randomised controlled study with reliability testing of the evaluation methods.

Scand J Med Sci Sports. 2001;11(4):197-206.

36. Yu J, Park D, Lee G. Effect of eccentric strengthening on pain, muscle strength, endurance, and functional fitness factors in male patients with achilles tendinopathy. Am J Phys Med Rehabil.

2013;92(1):68-76.

37. Brown R, Orchard J, Kinchington M, et al. Aprotinin in the management of Achilles tendinopathy: a randomised controlled trial. Br J Sports Med. 2006;40(3):275-9.

38. Alfredson H, Lorentzon R. Intratendinous glutamate levels and eccentric training in chronic Achilles tendinosis: a prospective study using microdialysis technique. Knee Surg Sports Traumatol Arthrosc.

2003;11(3):196-9.

39. Beyer R, Kongsgaard M, Hougs Kjaer B, et al. Heavy slow resistance versus eccentric training as treatment for Achilles tendinopathy: a randomized controlled trial. Am J Sports Med. 2015;43(7):1704-11.

40. de Jonge S, de Vos RJ, Van Schie HT, et al. One-year follow-up of a randomised controlled trial on added splinting to eccentric exercises in chronic midportion Achilles tendinopathy. Br J Sports Med. 2010;44(9):673-7.

41. de Jonge S, de Vos RJ, Weir A, et al. One-year follow-up of platelet-rich plasma treatment in

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chronic Achilles tendinopathy: a double-blind randomized placebo-controlled trial. Am J Sports Med. 2011;39(8):1623-9.

42. de Jonge S, Tol JL, Weir A, et al. The tendon structure returns to asymptomatic values in nonoperatively treated Achilles tendinopathy but is not associated with symptoms: a prospective study.

Am J Sports Med. 2015;43(12):2950-8.

43. de Vos RJ, Weir A, van Schie HT, et al. Platelet-rich plasma injection for chronic Achilles tendinopathy: a randomized controlled trial. JAMA. 2010;303(2):144-9.

44. Knobloch K, Schreibmueller L, Longo UG, et al.

Eccentric exercises for the management of tendinopathy of the main body of the Achilles tendon with or without the AirHeel Brace. A randomized controlled trial. A: effects on pain and microcirculation. Disabil Rehabil. 2008;30(2022):1685-91.

45. Langberg H, Ellingsgaard H, Madsen T, et al.

Eccentric rehabilitation exercise increases peritendinous type I collagen synthesis in humans with Achilles tendinosis. Scand J Med Sci Sports.

2007;17(1):61-6.

46. Norregaard J, Larsen CC, Bieler T, et al. Eccentric exercise in treatment of Achilles tendinopathy.

Scand J Med Sci Sports. 2007;17(2):133-8.

47. Ohberg L, Alfredson H. Effects on neovascularisation behind the good results with eccentric training in chronic mid-portion Achilles tendinosis? Knee Surg Sports Traumatol Arthrosc. 2004;12(5):465-70.

48. Ohberg L, Lorentzon R, Alfredson H. Eccentric training in patients with chronic Achilles tendinosis: normalised tendon structure and decreased thickness at follow up. Br J Sports Med. 2004;38(1):811.

49. Petersen W, Welp R, Rosenbaum D. Chronic Achilles tendinopathy: a prospective randomized study comparing the therapeutic effect of eccentric training, the AirHeel brace, and a combination of both. Am J Sports Med. 2007;35(10):1659-67.

53. de Vos RJ, Weir A, Cobben LP, et al. The value of power Doppler ultrasonography in Achilles tendinopathy: a prospective study. Am J Sports Med. 2007;35(10):1696-701.

54. Kudo S, Hisada T, Sato T. Determination of the fascicle length of the gastrocnemius muscle during calf raise exercise using ultrasonography. J Phys Ther Sci. 2015;27(12):3763-6.

55. Cho KH, Lee HJ, Lee WH. Reliability of rehabilitative ultrasound imaging for the medial gastrocnemius muscle in poststroke patients. Clin Physiol Funct Imaging. 2014;34(1):26-31.

56. Webber SC, Porter MM. Reliability of ankle isometric, isotonic, and isokinetic strength and power testing in older women. Phys Ther. 2010;90(8):1165-75.

57. Taskiran OO, Gzdugan V, Sepici V, et al. Test-retest and inter-rater reliability of isokinetic ankle dorsiflexor and plantar flexor strength measurement in healthy adults/Saglikli eriskinlerde ayak bilegi dorsifleksor ve plantar fleksor izokinetik kas kuvvet olcumlerinin gozlemci ici ve gozlemciler arasi guvenilirligi. Turk J Phys Med Rehab. 2013;59(1):32.

58. Chester R, Costa ML, Shepstone L, et al. Reliability of isokinetic dynamometry in assessing plantarflexion torque following Achilles tendon rupture. Foot Ankle Int. 2003;24(12):909-15.

59. Karnofel H, Wilkinson K, Lentell G. Reliability of isokinetic muscle testing at the ankle. J Orthop Sports Phys Ther. 1989;11(4):150-4.

60. Silbernagel KG, Gustavsson A, Thomee R, et al.

Evaluation of lower leg function in patients with Achilles tendinopathy. Knee Surg Sports Traumatol Arthrosc. 2006;14(11):1207-17.

61. Moller M, Lind K, Styf J, et al. The reliability of isokinetic testing of the ankle joint and a heel-raise test for endurance. Knee Surg Sports Traumatol Arthrosc. 2005;13(1):60-71.

62. Markovic G, Dizdar D, Jukic I, et al. Reliability and factorial validity of squat and countermovement jump tests. J Strength Cond Res. 2004;18(3):551-5.

50. Rompe JD, Furia J, Maffulli N. Eccentric loading versus eccentric loading plus shock-wave treatment for midportion achilles tendinopathy: a randomized controlled trial. Am J Sports Med. 2009;37(3):463-70.

63. O’Connor PJ, Grainger AJ, Morgan SR, et al.

Ultrasound assessment of tendons in asymptomatic volunteers: a study of reproducibility. Eur Radiol.

2004;14(11):1968-73.

51. Rompe JD, Nafe B, Furia JP, et al. Eccentric loading, shock-wave treatment, or a wait-and-see policy for tendinopathy of the main body of tendo Achillis: a randomized controlled trial. Am J Sports Med. 2007;35(3):374-83.

64. Sengkerij PM, de Vos RJ, Weir A, et al. Interobserver reliability of neovascularization score using power Doppler ultrasonography in midportion achilles tendinopathy. Am J Sports Med. 2009;37(8):1627-31.

52. Tumilty S, Mani R, Baxter GD. Photobiomodulation and eccentric exercise for Achilles tendinopathy: a randomized controlled trial. Lasers Med Sci. 2016;31(1):127-35.

65. van Schie HT, de Vos RJ, de Jonge S, et al.

Ultrasonographic tissue characterisation of human Achilles tendons: quantification of tendon structure through a novel non-invasive approach. Br J Sports Med. 2010;44(16):1153-9.

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66. Ghazanfari M, Vogt L, Banzer W, et al.

Reproduzierbarkeit nicht-invasiver Durchblutungsmessung mit der Laser-DopplerSpektroskopie. Phys Med Rehab Kuror.

2002;12(06):330-36.

67. Johannsen F, Jensen S, Stallknecht SE, et al.

Sonographic measurements of the achilles tendon, plantar fascia, and heel fat pad are reliable: A test-retest intra- and intertester study. J Clin Ultrasound. 2016;44(8):480-6.

68. Tompra N, van Dieen JH, Coppieters MW. Central pain processing is altered in people with Achilles tendinopathy. Br J Sports Med. 2016;50(16):1004-7.

69. Swinkels-Meewisse EJ, Swinkels RA, Verbeek AL, et al. Psychometric properties of the Tampa scale for kinesiophobia and the fear-avoidance beliefs questionnaire in acute low back pain. Man Ther.

2003;8(1):29-36.

70. Commean PK, Tuttle LJ, Hastings MK, et al.

Magnetic resonance imaging measurement reproducibility for calf muscle and adipose tissue volume. J Magn Reson Imaging. 2011;34(6):1285-94.

71. Arai T, Obuchi S, Shiba Y, et al. The feasibility of measuring joint angular velocity with a gyro-sensor.

Arch Phys Med Rehabil. 2008;89(1):95-9.

72. Crowther RG, Spinks WL, Leicht AS, et al.

Relationship between temporal-spatial gait parameters, gait kinematics, walking performance, exercise capacity, and physical activity level in peripheral arterial disease. J Vasc Surg.

2007;45(6):1172-8.

73. Hreljac A. Determinants of the gait transition speed during human locomotion: kinematic factors. J Biomech. 1995;28(6):669-77.

74. Heidenfelder J, Sterzing T, Bullmann M, et al. Heel strike angle and foot angular velocity in the sagittal plane during running in different shoe conditions.

J Foot Ankle Res. 2008;1(1):O16.

75. Bobbert MF, Huijing PA, van Ingen Schenau GJ. A model of the human triceps surae muscle-tendon complex applied to jumping. J Biomech.

1986;19(11):887-98.

76. Hebert-Losier K, Newsham-West RJ, Schneiders AG, et al. Raising the standards of the calf-raise test: a systematic review. J Sci Med Sport.

2009;12(6):594-602.

77. Hebert-Losier K, Schneiders AG, Garcia JA, et al.

Influence of knee flexion angle and age on triceps surae muscle activity during heel raises. Journal Strength Cond Res. 2012;26(11):3124-33.

78. Neptune RR, Sasaki K. Ankle plantar flexor force production is an important determinant of the preferred walk-to-run transition speed. J Exp Biol.

2005;208(Pt 5):799-808.

79. Balsalobre-Fernandez C, Glaister M, Lockey RA. The validity and reliability of an iPhone app for measuring vertical jump performance. J Sports Sci. 2015;33(15):1574-9.

80. Sein ML, Walton J, Linklater J, et al. Reliability of MRI assessment of supraspinatus tendinopathy. Br J Sports Med. 2007;41(8):e9.

81. Lee YC, Nassikas NJ, Clauw DJ. The role of the central nervous system in the generation and maintenance of chronic pain in rheumatoid arthritis, osteoarthritis and fibromyalgia. Arthritis Res Ther.

2011;13(2):211.

82. Jespersen A, Amris K, Graven-Nielsen T, et al.

Assessment of pressure-pain thresholds and central sensitization of pain in lateral epicondylalgia. Pain Med. 2013;14(2):297-304.

83. Kamper SJ, Maher CG, Hush JM, et al. Relationship between pressure pain thresholds and pain ratings in patients with whiplash-associated disorders. Clin J Pain. 2011;27(6):495-501.

84. Debenham J, Butler P, Mallows A, et al. Disrupted tactile acuity in people with Achilles tendinopathy: a preliminary case-control investigation. J Orthop Sports Phys Ther. 2016;46(12):1061-64.

85. Locke D, Gibson W, Moss P, et al. Analysis of meaningful conditioned pain modulation effect in a pain-free adult population. J Pain. 2014;15(11):1190-8.

86. Swinkels-Meewisse IE, Roelofs J, Schouten EG, et al.

Fear of movement/(re)injury predicting chronic disabling low back pain: a prospective inception cohort study. Spine 2006;31(6):658-64.

87. Catley MJ, O’Connell NE, Berryman C, et al. Is tactile acuity altered in people with chronic pain? a systematic review and meta-analysis. J Pain.

2014;15(10):985-1000.

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Appendix A. Individual Study Characteristics

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IJSPT

CLINICAL COMMENTARY

THEORETICAL APPLICATIONS OF BLOOD FLOW RESTRICTION TRAINING IN MANAGING CHRONIC ANKLE INSTABILITY IN THE BASKETBALL ATHLETE John Faltus, DPT, SCS, ATC, CSCS1 Johnny Owens, MPT2 Corbin Hedt, PT, DPT, SCS, CSCS3

ABSTRACT Chronic ankle instability (CAI) is a common dysfunctional state in the basketball population accompanied by pain, weakness and proprioceptive deficits which greatly affect performance. Research evidence has supported the use of blood flow restriction (BFR) training as an effective treatment strategy for improving muscle strength, hypertrophy and function following injury in a variety of patient populations. In managing CAI, it is important to address proximal and distal muscle weakness, pain, and altered proprioception to reduce the likelihood of re-occurring ankle injury. The ability to mitigate acute and cumulative strength and muscle volume losses through the integration of BFR after injury has been supported in research literature. In addition, applications of BFR training for modulating pain, improving muscle activation and proximal muscle strength have recently been suggested and may provide potential benefit for athletes with CAI. The purpose of this clinical commentary is to discuss background evidence supporting the implementation of blood flow restriction training and use a theoretical model for managing CAI as well as to suggest novel treatment strategies using this method.

Key Words: Ankle instability, blood flow restriction, strength training Level of Evidence: 5

1

University Physical Therapy and Sports Medicine at Clemson University, Clemson, SC, USA 2 Owens Recovery Science, San Antonio, TX, USA 3 Houston Methodist, Houston, TX, USA Conflict of interest: Author Johnny Owens is a shareholder of Owens Recovery Science and is a medical consultant for Delfi Medical Innovations Inc. Owens Recovery Sciences has a financial relationship with Delfi Medical Innovations Inc. Johnny Owens is a medical consultant for the Major Trauma Research Consortium (METRC). Other authors declare they have no conflict of interest in the authorship and publication of this manuscript or financial interest in the subject matter discussed in this article.

CORRESPONDING AUTHOR John Faltus, DPT, SCS, ATC, CSCS UPTSM, 205 Fike Rec Center, Clemson University, Clemson SC 29634

The International Journal of Sports Physical Therapy | Volume 13, Number 3 | June 2018 | Page 552 DOI: 10.26603/ijspt20180552

BACKGROUND AND PURPOSE Chronic ankle instability (CAI) consists of characteristic sequelae including recurrent sprain, pain, instability and avoidance of activities1 and is typically defined as mechanical or functional instability.2 Mechanical instability is anatomical laxity in the stabilizing structures around the ankle mortise where functional instability is a subjective feeling of giving away despite the lack of displacement beyond the normal physiological range of talar motion.3 It can be a particularly debilitating condition in the athletic population, with an associated high risk for re-injury.4,5,6 Time loss from sport due to this injury is typically associated with increased pain and crepitus as well as decreased strength, proprioception, range of motion and balance.7,8 Multiple proprioceptive impairments have been linked to persistent functional instability including altered muscle spindle activation of the peroneal musculature, abnormal reflex responses to inversion or supination and proximal kinetic chain deficits as exhibited by presence of neural inhibition and associated weakness in the hip abductors.9,10,11 Furthermore, deficits in postural control and ankle arthro-kinematic motion quality were identified in athletes with CAI using accelerometry.12 Repeat episodes of ankle sprains commonly occur in CAI and appear to further exacerbate instability, associated functional deficits and the ability to maintain a competitive status.5

articular changes and chondral lesions within the ankle joint which can manifest as chronic pain.14 The combination of altered somatosensory afferent signaling and efferent motor control deficits resulting from ankle ligament sprains negatively affects the ability to produce desired protective motor responses in the event of an inversion mechanism.15 The resulting injury pathology then can further exacerbate faulty mechanical patterns and subsequent pain presentation associated with repetitive injury and articular changes.15 Muscle inhibition which occurs following an ankle sprain has been documented.8 Perron et al. have found that significant strength deficits exist up to six months following injury and may contribute to the high recurrence of lateral ankle sprain.16 Furthermore, increased resting motor thresholds have been demonstrated in the peroneus longus muscle, bilaterally, in subjects with CAI.17 This would indicate deficits in corticomotor excitability of the peroneus longus to control subsequent inversion mechanisms which may result in re-injury.17 Decreased corticomotor excitability was also moderately correlated to self-reported function which would indicate that subjectsâ&#x20AC;&#x2122; perceptions of functional limitations likely manifests in resulting neuromuscular deficits and poor motor control.17

The multidirectional and repetitive movement aspects associated with the sport of basketball can predispose these athletes to ankle injuries. While jump landing has been identified as the most common mechanism of injury in this population, change of direction, cutting and pivoting movements also contribute to injury occurrence.5 Over half of total time missed due to injury in this population has been attributed to ankle injury.13 Both elite and recreational basketball players of both genders with a previous ankle injury have also been identified as being at 4.9 times greater risk for subsequent ankle injury.5 Therefore, it appears that CAI leads to significant time lost in sport and previous injury can result in greater re-injury risk.

Altered neuromuscular recruitment and motor control patterns are not strictly isolated to the ankle joint in presentations of CAI. Proximal muscle weakness can contribute to functional deficits which persist following an ankle sprain.9 In particular, weakness of the gluteal musculature can contribute to altered landing mechanics as a result of poor shock absorption and decreased force attenuation throughout the lower quarter.18 In the case of basketball athletes, landing has been identified as a common mechanism of injury for ankle sprains so failing to address these limitations is problematic.5 Therefore, it is important to focus on the entire kinetic chain during the rehabilitation process with strategies which effectively address these underlying neuromechanical deficiencies and altered movement patterns.

Increased pain associated with CAI greatly affects a basketball athleteâ&#x20AC;&#x2122;s ability to return to sport and perform at an elite level. CAI typically presents with

The purpose of this clinical commentary is to discuss background evidence supporting the implementation of blood flow restriction training and

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use a theoretical model for managing chronic ankle instability in the basketball athlete to suggest novel treatment strategies using this method.

DESCRIPTION OF TOPIC: THEORETICAL APPLICATIONS FOR CAI The inability to utilize loads sufficient to induce strength and hypertrophy responses after ankle injury due to pain or healing processes may limit rehabilitation progression. Recently, blood flow restriction (BFR) training has emerged as a novel treatment technique due to its ability to create robust muscle anabolic responses similar to high load training while utilizing very low loads.19 BFR has shown to be an effective treatment strategy for diminishing disuse atrophy and weakness during periods of immobilization as well as increasing strength and hypertrophy in post-op patient populations.20,21,22 Additionally, BFR has been shown to enhance function in blast trauma patients and injured military personnel23 as well as improve performance outcomes as part of a comprehensive strength and conditioning program in the high-performance athlete.24,25 American College of Sports Medicine guidelines recommend utilization of 60-80% of a one rep max (1 RM) load targeting major muscle groups 2-3 days per week in order to achieve strength and hypertrophy gains from resistance training.26 However, similar gains utilizing BFR have been shown within a twoweek training period at loads of much lower intensity (20-30% 1 RM).27,28 Although the exact mechanism is not fully understood, increased muscular fatigue under hypoxia, cellular swelling and upregulation of muscle protein synthesis via mammalian target of rapamycin complex 1 and mitogen-activated protein kinases (MTORC1/MAPK) which are responsible for protein synthesis and cell signaling, have been suggested to play a role.29,30,31 While most of these aforementioned studies focused on the lower extremity in general and post-operative conditions, currently no studies examining the utilization of BFR with CAI have been published.

Chronic Pain Management Chronic pain which results from CAI can be debilitating if not properly managed. Recently published clinical trials that have assessed pain have reported significant reductions in pain if BFR is incorporated

into the intervention. Giles at al found that, when compared to standard quadriceps strengthening, low load exercise with BFR greatly reduced pain in daily living in subjects with patellofemoral pain (PFP) following an eight-week program.32 The conceptual understanding for these changes is that subjects were able to improve quadriceps muscle strength with BFR while tolerating loads lower than those required to make similar gains utilizing traditional quadriceps strengthening activities.32 Given the association of quadriceps muscle weakness and PFP and the increases of knee extensor torque with significantly decreased reported pain in this BFR study group, it has been hypothesized that BFR training can potentially modulate pain through central and neural adaptations which influence strength gains.32 Additionally, subjects with anterior knee pain demonstrated an acute reduction in pain immediately after BFR resisted quad exercises up to 45 minutes post treatment.33 Although, mechanisms behind a potential reduction in pain through the application of BFR have not been elucidated, intensity of exercise may play a role in the endogenous opioid response.34 Despite BFR being performed under low loads, when performed under continuous occlusion (ie..no deflation cycles during rest periods), the metabolic stress produced in the working muscle is similar to exercise at much higher loads.35 This may allow patients in the early stages of rehabilitation or with chronic painful injuries to promote cortical release of opioids to allow for tolerance of rehabilitation programs. Although not directly related to pain inhibition, increases in corticomotor excitability have been demonstrated for up to 60-minutes post continuous BFR exercise possibly due to altered sensory feedback via group III and IV afferents.36 Future BFR studies are warranted that assess pain in clinical populations and the peripheral and central mechanisms of pain modulation that may be involved.

Muscle Inhibition The work by Brandner et al. provides promise as to the applications of BFR as a potential neuromodulator.36 Following an acute bout of upper extremity exercise utilizing BFR, corticomotor excitability of the biceps brachii rapidly increased and remained elevated for up to 60 minutes post exercise.36 It is theorized that these adaptations result from

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increased excitability of corticospinal circuits which results in long-lasting adaptations similar to those which occur following heavy-load resistance training.36 Further research evidence is needed to suggest whether utilization of BFR can potentially improve motor recruitment and neural excitability of inhibited or weak musculature following injury, such as CAI as addressed conceptually in this commentary.

Kinetic Chain Considerations and Proximal Strengthening BFR training would appear to be an effective treatment strategy that can be implemented to improve proximal muscle strength. Abe et al. found significant increases in gluteal muscle strength and hypertrophy following a two-week BFR program compared to a control group, implementing BFR with exercises that included the low load squat and leg curl.37 Despite distal occlusion, proximal gains may result from fatigue of musculature below the cuff requiring more recruitment of synergistic proximal muscles, a backflow effect into musculature above the area of restriction or a potential systemic effect secondary to the anabolic cascade created by BFR.38,39,40,41 Potential benefits of proximal effects from this training strategy may allow safe implementation during both early rehabilitation and return to sport specific exercises which challenge proprioception and balance to incorporate proximal and distal effects.

DISCUSSION: CLINICAL INTEGRATION With a comprehensive understanding of the research evidence behind BFR training, one can then attempt to translate this information into applied clinical practice. Loenneke et al. proposed a clinical integration model which advocates for utilization of BFR throughout various phases of injury rehabilitation.42 The four proposed phases of BFR implementation include: 1) BFR alone during periods of bed rest, 2) BFR combined with low-workload walking exercise, 3) BFR combined with low-load resistance exercise, and 4) low-load BFR training combined with traditional high-load resistance exercise.42 In cases of prolonged immobilization or restricted weightbearing where BFR walking may not be appropriate, low-load, resisted, open kinetic chain exercises, such as ankle ROM, leg lift (Figure 1) and bridge variations may be used safely and effectively with implementation

Figure 1. Open kinetic chain leg lift variation for hip muscle strengthening with BFR (DelďŹ Medical Innovations Inc. Vancouver, BC Canada).

of BFR (Table 1) to attenuate muscle atrophy and weakness commonly associated with disuse.20,21 For optimal motor control in these early stages of rehab, it is important integrate external focus of attention strategies which have been shown to increase muscle excitability.43,44 These strategies may include use of a metronome for repetition pacing or biofeedback, especially during exercises which actively recruit the peroneal and gluteal muscles which have been identified as commonly inhibited and weakened muscle groups in CAI.9,17,43,44 The proprioceptive, balance and motor control deficits associated with CAI have been well documented.8,15,17 Exercises which challenge the proprioceptive system on both stable and unstable surfaces with altered visual and somatosensory feedback have been effective for reducing the recurrence of ankle sprains.45 Examples would include single leg static balance on an unstable surface, multidirectional weight shifting activities and reactive drills (Figures 2 and 3). These exercises can target basketball specific demands by integrating passing (Figure 3), ballhandling and reactive movement drills utilizing verbal or visual cues, with resources such as a light reactive system (Figure 2) or a laser pointer, in order to emphasize an external focus of attention. Exercise progressions would include band-resisted movements replicating basketball specific patterns such as jab steps, close

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Table 1. Integration of BFR with Rehabilitation for Ankle Instability.

Figure 2. BFR static single leg balance on unstable surface with integration of light system (Dynavision D2 -Dynavision International, LLC West Chester Township, OH; Delfi Medical Innovations Inc. Vancouver, BC Canada)

Figure 3. BFR single leg stability with reactive passing component (BOSU® Ashland, OH; Delfi Medical Innovations Inc. Vancouver, BC Canada).

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Figure 4. BFR band resisted drop step squat (DelďŹ Medical Innovations Inc. Vancouver, BC Canada).

out steps, drop step squats and lateral slides (Figure 4). These exercises can be safely integrated with BFR training to further enhance proximal strengthening and neuromuscular control (Table 1).

BFR training can both complement and enhance the conditioning aspects of a return to play rehab program. A BFR treadmill walking protocol, performed six days per week for two weeks, resulted in significant improvements in maximal aerobic capacity, maximal ventilation and anaerobic capacity in male collegiate basketball athletes.46 The protocol consisted of five periods of three-minute working sets at 4-6 km/h and 5% grade with 60 second interset rest.46 Similar findings occurred, in addition to increased size and strength of the leg muscles, following both BFR cycling and low-intensity walking programs.47,48 This indicates that, when utilized as part of a non-impact conditioning program, BFR training can improve overall cardiovascular fitness when combined with aerobic activity. This is especially important during rehab phases where limitations in mobility and dynamic loading do not permit the athlete to run or perform on-court conditioning activities. Athletes with CAI who sustain recurrent ankle injuries would likely benefit from such a program during periods when dynamic loading activities are limited in order to promote tissue healing and recovery from acute injury.

As the athlete progresses back into sport specific activities, BFR training can still play an integral role in developing strength and performance attributes when combined with a traditional strength and conditioning program. Implementation of BFR would follow a high load-low load model whereas BFR exercises would be implemented intra-session in a low-load strategy following traditional high load resistance exercises to enhance hormonal responses and strengthening benefits following the session.49 An example as it applies to the lower extremity would be completing modified bodyweight squats or leg press exercise at 20% maximal load utilizing BFR at the end of a lifting session which consisted of near maximal (80% max) squat and deadlift exercises. This strategy would be especially beneficial in transferring BFR training adaptations which occurred during the rehab process over to individualized strength and conditioning programs that are implemented upon return to play in athletes with CAI. Lastly, nutritional considerations must be addressed in the rehabilitating an athlete using BFR as part of a comprehensive performance enhancement program. Due to the increased protein synthesis response following BFR training, it is important the athlete consume 20-35 grams of protein post-activity for muscle tissue healing and recovery.50 Whey protein is preferred due to both its rapid digestion and absorption as well as greater leucine content which further enhances protein synthesis.50 SAFETY CONSIDERATIONS Safety is of paramount concern when considering rehabilitation programs for injured individuals. BFR utilizes non-traditional methods of building strength and inducing muscle hypertrophy, so reasonable vigilance is required of rehabilitation professionals to maintain safety.

In the instance of tourniquet systems, research on safety and efficacy has consistently been monitored with technological advancements.51,52,53 In the surgical environment, tourniquets are applied for upwards of several hours at a time to provide a bloodless operating field.51 Generally, it is suggested that tourniquet time is minimized as much as possible during surgeries such as total knee arthroplasty (TKA) to mitigate risks such as deep vein thrombosis (DVT), wound infection, hematoma, and

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ecchymosis.53 Similar risks can be expected during BFR training as with the use of tourniquet devices including pneumatic cuffs and straps. However, at lower levels of constriction and reduced tourniquet time, these risks are likely minimal.

Research on safety during BFR and exercise is currently limited, however several measures have been examined with regard to outcomes of exercise with BFR training versus regular exercise. A recent review by Loenneke and colleagues examined peripheral blood flow hemodynamics with BFR and determined that changes in blood flow appear to occur in a “similar fashion as regular exercise”.54 Furthermore, Lida et al observed certain central cardiovascular responses to BFR and found that subjects exhibit elevated cardiac markers (blood pressures, heart rate) in occlusive protocols compared to control groups.55 However, these values are still far less than those performing high intensity exercise, and low-intensity exercise (20% 1RM) with occlusion may be a safe alternative.55 The potential for thrombosis and clotting can be a serious risk when considering patients in a rehabilitative state. Complete vascular occlusion can be experienced with strenuous, high-intensity exercise with tourniquets and has been shown to increase the formation of thrombus.56 However, reported issues of thrombosis with BFR are as little as 0.06% in some studies.57 Others have found that neither prothrombin time (PT) nor D-dimer levels increased following BFR training.58 This may be due to the fact that occlusion levels during most researched BFR protocols do not promote maximal occlusion, given that the device has a means of pressure regulation. suggesting cuff pressures be relative to cuff width and limb circumference to protect the neurovasculature of the extremity.54,59, 60 Nerve conduction velocity (NCV) can be affected significantly by tourniquet pressure, giving rise to further research into electrophysiological changes during BFR.61 The use of wide tourniquets significantly reduces pressures needed for vascular occlusion and has been recommended in clinical settings.62 Additionally, personalized BFR utilizes Doppler technologies to individualize tourniquet pressures for each patient, providing further safety benefit.63 Ultimately, further investigation into BFR protocols and their safety is warranted. However, most protocols

have demonstrated positive efficacy and good safety with very few ill effects. Under skilled supervision and with appropriate equipment, BFR can be used as a safe alternative to traditional high-intensity exercise to develop strength and muscular hypertrophy.

SUMMARY BFR training could theoretically be safely and effectively implemented as part of a rehabilitation program addressing deficits associated with CAI. Benefits of BFR training include minimizing muscle weakness and atrophy associated with the acute phase of injury, potentially modulating pain related to injury conditions, facilitating tissue healing and enhancing muscle hypertrophy and strength gains when combined with low load exercise. Evidence also suggests that BFR training can enhance both aerobic and anaerobic properties when integrated as part of a cycling or walking protocol. These strategies and suggestions provided in this commentary could be especially helpful in cases of CAI where recurrent injury due to both local and proximal weakness, pain, and both decreased proprioception and function contribute to periods of low loading or limited sports specific activities during rehab where tissue healing and recovery is prioritized. Safety of the athlete should be prioritized through utilization of appropriate medical devices by trained medical personnel.

REFERENCES 1. Guillo S, Bauer T, Lee J et al. Consensus in chronic ankle instability: aetiology, assessment, surgical indications and place for arthroscopy. Orthop Traumatol Surg Res. 2013:99:S411-S419.

2. Hong C, Tan K. Concepts of ankle instability: A review. OA Sports Med. 2014;2:3.

3. Freeman M, Dean M, Hanham I. The etiology and prevention of functional instability of the foot. J Bone Jt Surg. 1965;47:678–85.

4. Ekstrand J, Tropp H. The incidence of ankle sprains in soccer. Foot Ankle. 1990;11:41-44.

5. McKay G, Goldie P, Payne W, Oakes B. Ankle injuries in basketball: injury rate and risk factors. Br J Sports Med. 2001;35:103-108.

6. Milgrom C, Shlamkovitch N, Finestone A et al. Risk factors for lateral ankle sprain: a prospective study among military recruits. Foot Ankle. 1991;12:26-30.

7. Yeung M, Chan K, So C, et al. An epidemiological survey on ankle sprain. Br J Sports Med.1994;28:112–16

The International Journal of Sports Physical Therapy | Volume 13, Number 3 | June 2018 | Page 558

8. Willems T, Witvrouw E, Verstuyft J, Vaes P, De Clercq D. Proprioception and muscle strength in subjects with a history of ankle sprains and chronic instability. J Athl Train. 2002;37:487-493.

9. Friel K, McLean N, Myers C, Caceres M. Ipsilateral hip abductor weakness after inversion ankle sprain. J Athl Train. 2006;41:74-78.

10. Bonnel F, Toullec E, Mabit C, et al. Chronic ankle instability: biomechanics and pathomechanics of ligaments injury and associated lesions. Orthop Traumatol Surg Res. 2010, 96:424-32.

11. Gutierrez G, Kaminski T, Douex A. Neuromuscular control and ankle instability. PM&R. 2009;1:359–65.

12. Baczkowicz D, Falkowski K, Majorczyk E. Assessment of relationships between joint motion quality and postural control in patients with chronic ankle joint instability. J Orthop Sports Phys Ther. 2017;47:570-577.

13. McKay G, Payne W, Goldie P, et al. A comparison of the injuries sustained by female basketball and netball players. Aust J Sci Med Sport. 1996;28:12-17.

14. Taga I, Shino K, Inoue M et al. Articular cartilage lesions in ankles with lateral ligament injury: an arthroscopic study. Am J Sports Med. 1993;21:120-127.

15. Hertel J. Sensorimotor deficits with ankle sprains and chronic ankle instability. Clin Sports Med. 2008;28:353-370.

16. Perron M, Moffet H, Nadeau S, Hebert LJ, Belzile S. Persistence of long term isokinetic strength deficits in subjects with lateral ankle sprain as measured with a protocol including maximal preloading. Clin.

Biomech. 2014;29:1151-1157.

17. Pietrosimone B, Gribble P. Chronic ankle instability and corticomotor excitability of the fibularis longus muscle. J Athl Train. 2012;47:621-626.

18. Pollard C, Sigward S, Powers C. Limited hip and knee flexion during landing is associated with increased frontal plane motion and moments. Clin Biomech.

2010:25:142-146.

19. Hughes L, Paton B, Rosenblatt B et al. Blood flow restriction training in clinical musculoskeletal rehabilitation: a systematic review and metaanalysis. Br J Sports Med. 2017;51:1003-1011.

20. Takarada Y, Takazawa H, Ishii N. Applications of vascular occlusion diminish disuse atrophy of knee extensor muscles. Med Sci Sports Exerc. 2000;32:20352039.

21. Kubota A, Sakuraba K, Sawaki K, Sumide T, Tamura Y. Prevention of disuse muscular weakness by restriction of blood flow. Med Sci Sports Exerc.

2008;40:529-534.

22. Ohta H, Kurosawa H, Ikeda H, Iwase Y, Satou N, Nakamura S. Low-load resistance muscular training with moderate restriction of blood flow after anterior

cruciate ligament reconstruction. Acta Orthop Scand.

2003;74:62-68.

23. Hylden C, Burns T, Stinner D, Owens J. Blood flow restriction rehabilitation for extremity weakness: a case series. J Spec Oper Med. 2015;15:50-6.

24. Abe T, Kawamoto K, Yasuda T et al. Eight days KAATSU-resistance training improved sprint but not jump performance in collegiate male track and field athletes. Int J KAATSU Train Res. 2005;1:19-23.

25. Cook C, Kilduff L, Beaven C. Improving strength and power in trained athletes with 3 weeks of occlusion training. Int J Sports Physiol Perform. 2014;9:166-172.

26. ACSM Position Stand. Progression Models in Resistance Training for Healthy Adults. Med Sci Sports Exerc. 2009;41:687-708.

27. Abe T, Yasuda T, Midorikawa T, Sato Y, Kearns C, Inoue K, Koizumi K, Ishii N. Skeletal muscle size and circulating IGF-1 are increased after two weeks of twice daily “KAATSU” resistance training. Int J Kaatsu Training Res. 2005;1:6-12.

28. Yasuda T, Fujita S, Ogasawara R, Sato Y, Abe T. Effects of low-intensity bench press training with restricted arm muscle blood flow on chest muscle hypertrophy: a pilot study. Clin Physiol Funct Imaging. 2010;30:338-343.

29. Fry C, Glynn E, Drummond M, Timmerman K, Fujita S, Abe T, Rasmussen B. Blood flow restriction exercise stimulates mTORC1 signaling and muscle protein synthesis in older men. J Appl Physiol.

2010;108:1199-1209.

30. Fujita S, Abe T, Drummond M, Cadenas J, Dreyer H, Sato Y, Volpi E, Rasmussen B. Blood flow restriction during low-intensity resistance exercise increases S6K1 phosphorylation and muscle protein synthesis.

J Apply Physiol. 2007;103:903-910.

31. Loenneke J, Fahs C, Thiebaud R, et al. The acute muscle swelling effects of blood flow restriction.

Acta Physiologica Hungarica. 2012;99:400-410.

32. Giles L, Webster K, McClelland J, Cook J. Quadriceps strengthening with and without blood-flow restriction in the treatment of patellofemoral pain-a double blind randomized trial. Br J Sports Med. Published online: 12 May 2017. doi: 10.1136.

33. Korakakis V, Whiteley R, Epameinontidis K. Blood flow restriction-induced analgesia in patients with anterior knee pain. J Sci Med Sport. 20 (2017):e100.

34. Saanijoki T, Tuominen L, Tuulari J et al. Opioid release after high-intensity interval training in healthy human subjects. Neuropsychopharmacology. 2017, 1-5.

35, Suga T, Okita K, Takada S. Effect of multiple set on intramuscular metabolic stress during low-intensity resistance exercise with blood flow restriction.

2012;Eur J Appl Physiol. 112:3915-3920.

The International Journal of Sports Physical Therapy | Volume 13, Number 3 | June 2018 | Page 559

36. Brandner C, Warmington S, Kidgell D. Corticomotor excitability is increased following an acute bout of blood flow restriction resistance exercise. Front Hum Neurosci. 2015;9:652.

37. Abe T. Effects of short-term low intensity KAATSU training on strength and skeletal muscle size in young men. J Train Sci Exerc Sport. 2004;16:199-207.

38. Yasuda T, Fujita T, Miyagi Y et al. Electromyographic responses of arm and chest muscle during bench press exercise with and without KAATSU. Int J KAATSU Train Res. 2006;2:15-18.

39. Madarame H, Neya M, Ochi E, et al. Cross-transfer effects of resistance training with blood flow restriction. Med Sci Sports Exerc. 2008;40:258-263.

40. Dankel SJ, Jessee MB, Abe T, Loenneke JP. The Effects of Blood Flow Restriction on Upper-Body Musculature Located Distal and Proximal to Applied Pressure. Sport Med. 2016;46:23-33.

41. Umbel JD, Hoffman RL, Dearth DJ, et al., Delayedonset muscle soreness induced by low-load blood flow-restricted exercise. Eur J Appl Physiol.

2009;107:687-95.

42. Loenneke J, Abe T, Wilson J et al. Blood flow restriction: an evidence based progressive model (review). Acta Physiol Hung. 2012;99:235-250.

43. Leung M, Rantalainen T, Teo W et al. Motor cortex excitability is not differentially modulated following skill and strength training. Neuroscience. 2015;305:99108.

44. Pietrosimone B, McLeod M, Florea D, Gribble P, Tevald M. Immediate increases in quadriceps corticomotor excitability during an electromyography biofeedback intervention. J Electromyogr Kinesiol. 2015;25:316-322.

45. Mohammadi F. Comparison of 3 preventive methods to reduce the recurrence of ankle inversion sprains in male soccer players. Am J Sports Med. 2007;35:922-926.

46. Park S, Kim J, Choi H et al. Increase in maximal oxygen uptake following 2-week walk training with blood flow occlusion in athletes. Eur J Appl Physiol.2010;109:591-600.

47. Abe T, Fujita S, Nakajima T et al. Effects of lowintensity cycle training restricted leg blood flow on thigh muscle volume and VO2 max in young men. J Sport Sci Med. 2010;9:452-458.

48. Ozaki H, Sakamaki M, Yasuda T et al. Increases in thigh muscle volume and strength by walk training with leg blood flow reduction in older participants. J Gerontol A Biol Sci Med Sci. 2011; 66:257-263.

49. Scott B, Loenneke J, Slattery K, Dascombe B. Exercise with blood flow restriction; an updated evidence-based approach for enhanced muscular development. Sports Med. 2015;45:313-325.

50. Tang J, Moore D, Kujbida G, Tarnopolsky M, Phillips S. Ingestion of whey hydrolysate , casein, or soy protein isolate: effects on mixed muscle protein synthesis at rest and following resistance exercise in young men. J Appl Physiol. 2009;107:987-992.

51. Sato J, Ishii Y, Noguchi H, Takeda M. Safety and efficacy of a new tourniquet system. BMC Surg.

2012;12:17.

52. Estebe JP, Malledant Y. Pneumatic tourniquets in orthopedics. Ann Fr Anesth Reanim. 1996;15:162-178.

53. He T, Cao L, Yang D, et al. A meta-analysis for the efficacy and safety of tourniquet in total knee arthroplasty. Zhonghua Wai Ke Za Zhi. 2011;49:551557.

54. Loenneke JP, Fahs CA, Rossow LM, et al. Blood flow restriction pressure recommendations: a tale of two cuffs. Frontiers in Physiology. 2013;4:249.

55. Lida H, Takano H, Meguro K. Hemodynamic and autonomic nervous responses to the restriction of femoral blood flow by KAATSU. Int J KAATSU Training Res. 2005;2:57-64.

56. Strock P, Majno G. Vascular responses to experimental tourniquet ischemia. Surg Gynecol Obstet. 1969;129:309-318.

57. Nakajima T, Kurano M, Lida H et al. Use and safety of KAATSU training: results of a national survey. Int J KAATSU Training Res. 2006;2:5-13.

58. Clark B, Manini T, Hoffman R et al. Relative safety of 4 weeks of blood-flow restricted resistance exercise in young, healthy adults. Scand J Med Sci Sports.

2011;21:653-662.

59. Loenneke JP, Fahs CA, Rossow LM, et al. Effects of cuff width on arterial occlusion: implications for blood flow restricted exercise. Eur J Appl Physiol.

2012;112:2903-2912.

60. Laurentino GC, Loenneke JP, Teixeira EL, Nakajima E, Iared W, Tricoli V. The effect of cuff width on muscle adaptations after blood flow restriction training. Med Sci Sports Exerc. 2016;48:920-925.

61. Mittal P, Shenoy S, Sandhu JS. Effect of different cuff widths on the motor nerve conduction velocity of the median nerve: an experimental study. J Orthop Surg Res. 2008;3:1.

62. Noordin S, McEwen J, Kragh J et al. Surgical tourniquets in orthopedics. J Bone Joint Surg Am. 2009;91:2958-2967.

63. Younger A, McEwen J, Inkpen K. Wide contoured thigh cuffs and automated limb occlusion measurement allow lower tourniquet pressures. Clin Orthop Relat Res. 2004;428:286-293.

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