Thesis helena luginbuehl book 2016 11 30 lvm

PELVIC FLOOR MUSCLE ACTIVATION COMPONENTS in URINARY CONTINENT and STRESS URINARY INCONTINENT WOMEN

Helena Luginbuehl

Pelvic floor muscle activation components in urinary continent and stress urinary incontinent women

Helena Luginbuehl

Faculty of Physical Education and Physiotherapy

Vrije Universiteit Brussel

PELVIC FLOOR MUSCLE ACTIVATION COMPONENTS IN URINARY CONTINENT AND STRESS URINARY INCONTINENT WOMEN

Helena Luginbuehl

THESIS SUBMITTED IN FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR IN REVALIDATIEWETENSCHAPPEN EN KINESITHERAPIE

Brussel 2016

for Dario and Olivia

TODAY’S INNOVATION IS TOMORROW’S TRADITION. Lidia Bastianich (1947- )

Promotor: Prof. Dr. J.-P. Baeyens, Vrije Universiteit Brussel, BE

Co-promotors: Prof. Dr. L. Radlinger, Bern University of Applied Sciences, CH Prof. Dr. med. A. Kuhn, Bern University Hospital and University of Bern, CH

Examination Board: Prof. Dr. med. Hendrik Cammu, Vrije Universiteit Brussel, BE Prof. Dr. Eric Cattrysse, Vrije Universiteit Brussel, BE Prof. Dr. Birgit Schulte-Frei, Hochschule Fresenius Kรถln, D Prof. Dr. Eva Swinnen, Vrije Universiteit Brussel, BE Prof. Dr. Alexandra Vermandel, Universiteit Antwerpen, BE

TABLE OF CONTENTS Preface and acknowledgements .............................................................................. I Abbreviations........................................................................................................... IV Summary ................................................................................................................... V 1

Background and introduction of the thesis ..................................................... 1 1.1

Stress urinary incontinence ........................................................................... 1

1.1.1

Definition ................................................................................................. 1

1.1.2

Prevalence .............................................................................................. 1

1.1.3

Risk factors ............................................................................................. 3

1.1.4

Impact on quality of life ........................................................................... 3

1.1.5

Impact on costs ....................................................................................... 4

1.2

The role of the pelvic floor muscles as regards to guaranteeing urinary

continence ............................................................................................................... 4

2

1.2.1

Terminology, anatomy and physiology of the pelvic floor ........................ 4

1.2.2

Understanding stress urinary incontinence ............................................. 5

1.2.3

Pelvic floor muscle function related to continence and SUI..................... 5

1.2.4

Voluntary versus involuntary PFM contractions ...................................... 7

1.3

Physiotherapy for women with SUI ................................................................ 8

1.4

Aims, related research questions and studies ............................................... 9

Results .............................................................................................................. 13 2.1

Pelvic floor muscle activation and strength components influencing female

urinary continence and stress incontinence: a systematic review ......................... 14 2.2

Intra-session test–retest reliability of pelvic floor muscle electromyography

during running ....................................................................................................... 24 2.3

Pelvic floor muscle electromyography during different running speeds – an

exploratory and reliability study ............................................................................. 33 2.4

Pelvic floor muscle reflex activity during coughing – an exploratory and

reliability study ....................................................................................................... 42 2.5

Continuous versus intermittent stochastic resonance whole body vibration

and its effect on pelvic floor muscle activity ........................................................... 49

2.6

Involuntary reflexive pelvic floor muscle training in addition to standard

training versus standard training alone for women with stress urinary incontinence: study protocol for a randomized controlled trial ..................................................... 55 3

General discussion .......................................................................................... 64 3.1

The influence of PFM activation and strength components on continence and

SUI…………… ...................................................................................................... 64 3.2

PFM activation characteristics of healthy young nulliparous females during

high impact situations typically provoking SUI (running, coughing) ....................... 65 3.3

SR-WBV as an intervention strategy for SUI ............................................... 66

3.4

SUI physiotherapy: Involuntary reflexive pelvic floor muscle training in

addition to standard training .................................................................................. 67 4

General strengths and limitations .................................................................. 70

5

General conclusion and suggestions for further research .......................... 72

6

References ........................................................................................................ 74

7

Publications and conference proceedings .................................................... 80

8

Appendix ........................................................................................................... 85

Preface and acknowledgements

Helena Luginbuehl

Preface and acknowledgements After working eighteen years as a physiotherapist in the Obstetric and Gynecological Clinic, University Hospital Inselspital Bern, I left to become a staff member and later deputy head of the Physiotherapy Bachelor Program at the Bern University of Applied Sciences (BUAS), Health; however, I never gave up working with patients suffering from pelvic floor muscle dysfunction, which I now treat in my own clinical practice.

It was a great piece of luck for me when Prof. Dr. Lorenz Radlinger asked me to participate in pelvic floor muscle research projects as a BUAS staff member, as it gave me the opportunity to close a circle: The projects are in cooperation with the Obstetric and Gynecological Clinic and Department of Physiotherapy, University Hospital Inselspital Bern, involving Prof. Dr. med. Annette Kuhn and the physiotherapists Corinne Lehmann, Regina Gerber, Patricia Spagnuolo, Maja Stoll and Margrit Ackermann, all of whom I know very well. Furthermore, I think it is the greatest privilege to be in research and at the same time a practicing physiotherapy clinician treating the patients involved, and I am very grateful to have had this opportunity.

I soon realized that research is never a solitary occupation - it very much depends on the whole group. Therefore, there are many people involved in this work presented here and I owe them all infinite gratitude:

First and foremost, I would like to express my sincere gratitude to my supervisor, Prof. Dr. Jean-Pierre Baeyens, for his great support, his never ending encouragement, and his patience. Especially in the final phase of writing the thesis, his advice and detailed feedback were invaluable. And I will never forget his and his I

wife Jacint Hendrickx’s hospitality during my stays in Brussels. I would like to thank both of them with heartfelt appreciation.

And to no lesser degree would I like to thank my local supervisor and official cosupervisor Prof. Dr. Lorenz Radlinger. I owe it to him that I dared to tackle a doctorate, which is quite a novelty for physical therapists in Switzerland, as physical therapy education has met the standards of higher education at university level only for the last couple of years. Thanks Lorenz, for all the time you spent with me to introduce me into specific research topics, to discuss our ideas, to give me detailed feedback, to bear up with all my questions, to help me when I was stuck and especially for all the fun we had while working together.

A special thank goes to my second co-supervisor, Prof. Dr. med Annette Kuhn. She acted as my urogynecology expert and was always ready to help. Thanks Annette, for always being there when I needed you, for all the feedbacks and for promoting me. You suggested me as physiotherapy section editor for the International Urogynecology Association Newsletter and therefore opened the doors to the international urogynecology community for me.

My sincere thanks also go to my boss, Eugen Mischler, head of the Bachelor Physiotherapy Program and head ad interim of the Health Department of the University of Applied Sciences Bern. His support and flexibility were of inestimable value for me to balance all my work and especially helpful in making all our conference contributions possible.

II

I would also like to thank my colleagues of the Bern University of Applied Sciences: Jan Taeymans contributed a lot to the systematic review and, in addition, never stopped motivating me; and Irene Koenig, Slavko Rogan and Patric Eichelberger helped greatly with all the many stimulating discussions.

I very much appreciated the collaboration with my physiotherapy colleagues from the Department of Physiotherapy, Obstetric and Gynecological Clinic, Inselspital, Bern, and would like to thank Corinne Lehmann, Regina Gerber, Patricia Spagnuolo, Maja Stoll and Margrit Ackermann for all the discussions and their contributions.

I would like to thank my colleagues Roger Hilfiker, Ida-Maria Maeder, Doro Gruenenfelder, Cécile Greter, Rebecca Naeff, Anna Zahnd, Bettina Oberli and Regula Christen for their specific contributions to the single studies.

I am very grateful to Ron Clijsen who has shared his own experience as a former PhD candidate at the VUB with me and gave me invaluable advice. Many thanks to Sophie Brandt who helped with understanding the Dutch documents of the VUB.

Doris Kruettli helped me regarding administrative matters and I am very grateful for that.

And last but not least, all my gratitude goes to Tino, who was my “hidden” professional and private counselor, himself an internationally well-known researcher in a different field, who encouraged me with endless motivation and love. I am looking forward to all our future projects.

III

Abbreviations EMG

Electromyography

Hz

Hertz

ICC

Intra Class Correlation Coefficient

ICS

International Continence Society

MD

Minimal Difference

ms

Milliseconds

MVC

Maximal Voluntary Contraction

PFM

Pelvic Floor Muscles

RCT

Randomized Controlled Trial

SEM

Standard Error of Measurement

SR-WBV

Stochastic Resonance Whole Body Vibration

SUI

Stress Urinary Incontinence

WBV

Whole Body Vibration

IV

Summary Pelvic floor muscle (PFM) training is effective and therefore recommended as the first line treatment for women suffering from stress urinary incontinence (SUI). Activities such as coughing, sneezing, running or jumping, which typically provoke SUI, are associated with fast and high impacts. Consequently, fast involuntary reflexive PFM stress responses are required to guarantee continence. Despite that, today’s PFM training still focuses on voluntary PFM training only and PFM activity during high impact functional activities or whole body movements and its effects on reflexive PFM muscle activity related to continence have not been investigated so far.

To (partially) fill this research gap, this doctoral thesis generally focused on PFM strength and activation components related to continence and SUI, with emphasis on PFM activation characteristics in high impact situations which typically provoke SUI. The thesis furthered with an exploration of stochastic whole body vibration methodology as an option in SUI physical therapy for PFM reflex training. At last a RCT study protocol was developed integrating PFM involuntary and reflexive training.

The systematic review «Pelvic floor muscle activation and strength components influencing female urinary continence and stress incontinence» found that higher maximal, mean, endured and increase of PFM strength and an earlier onset of PFM activation had a beneficial effect on female urinary continence. However, the rather small number of trials and subjects included, the heterogeneity of terminology and test procedures concerning relevant PFM muscle action or activity, and outcomes made the planned meta-analysis not applicable. As a conclusion, this systematic review underscored the need for a standardized PFM components’ terminology, the use of standardized instructions of patients’ test behavior provoking

V

the respective PFM component, the development of well-matched diagnostic instruments and as a consequence specific PFM training protocols for SUI patients.

The study aim of «Intra-session test-retest reliability of pelvic floor muscle electromyography during running» was to define, describe and test the reliability of PFM electromyography (EMG) activity and time variables during running in healthy young nulliparous women. High and fast PFM activity variables (e.g. PFM activity 50 milliseconds (ms) before the heel strike, minimal EMG activity, maximal EMG activity, time to maximal EMG activity) were found. EMG variables showed good reliability, the time variables however poor reliability.

The aims of the studies «Pelvic floor muscle electromyography during different running speeds» and «Pelvic floor muscle reflex activity during coughing» were to investigate specific, previously defined variables representing PFM pre-activity and reflex activity (during specific time intervals of stretch reflex latency responses) in healthy young nulliparous females during running at different speeds and during coughing, and to test their reliability. The studies’ results showed fast and high PFM activity milliseconds before and after the impact during running and coughing, i.e. revealed PFM pre- and reflex activity during running and coughing. PFM EMG variables during running showed good to excellent reliability, the ones during coughing poor reliability.

The article «Continuous versus intermittent stochastic resonance whole body vibration and its effect on pelvic floor muscle activity» aimed to determine the optimal load modality of stochastic whole body vibration (SR-WBV) for PFM reflex training. This study found PFM activity to be significantly increased during vibration as compared to a rest condition. Neither statistically significant or clinically relevant VI

changes in PFM activity over time nor PFM fatigue was found in neither of the SRWBV modalities within each of the three sets and between the three sets of 60s’ vibration each. No difference was found between the modalities. Therefore, the continuous modality was recommended for its potential training effect in clinical practice due to easier and less time consuming application than the intermittent modality.

The RCT study protocol «Involuntary reflexive pelvic floor muscle training in addition to standard training versus standard training alone for women with stress urinary incontinence» completes this thesis. A training protocol was developed including standard physiotherapy with an additional focus on involuntary reflexive pelvic floor muscle contractions. The aim of the currently conducted RCT (2014-2017: RCT with 6-months follow-up) is to compare this newly developed physiotherapy program (experimental group) with standard physiotherapy (control group) regarding their effect on SUI by means of the “International Consultation on Incontinence Modular Questionnaire Urinary Incontinence short form” (ICIQ-UIsf).

The ICIQ-Ulsf provides a brief and robust assessment of the impact of symptoms of urinary incontinence on quality of life and outcome of treatment. PFM activity during the comprehensive test exercises of running and jumps were secondary study outcomes. Following the results of the studies within this thesis, the authors included running and jumping as exercises for PFM reflex training due to their high impacts and easy and low-cost application as compared to SR-WBV. Should the newly developed therapy program prove more effective than standard PFM training, the clinical impact would be immediate as the implementation of this new therapy protocol could happen at once.

Future studies are definitely needed.

VII

Background and introduction of the thesis

Helena Luginbuehl

1 Background and introduction of the thesis The following introduction shortly overviews the medical condition of stress urinary incontinence (SUI), pelvic floor muscle (PFM) anatomy and physiology, the state of knowledge regarding PFM contraction mechanisms, their influence on continence and SUI, and the current PFM training methods.

1.1 Stress urinary incontinence 1.1.1 Definition SUI, the most prevalent type of urinary incontinence in women [1-3], is defined as involuntary loss of urine during effort or physical exertion (e.g. sporting activities), or upon sneezing or coughing [4, 5]. These activities raise the intra-abdominal pressure and the loading on the PFM [4, 6-8] demanding strong [9, 10], fast [11] and reflexive [6] - i.e. involuntary - contractions of the PFM to guarantee continence. Haylen et al.

[5] prefer the term ‘‘activity related incontinence’’ instead of stress urinary incontinence to avoid confusion with psychological stress.

1.1.2 Prevalence Urinary incontinence is a widely spread medical problem, which affects women four times more than men [3]. The US survey of Minassian et al. [12] presented an overall prevalence of stress, urge and mixed urinary incontinence in women of 23.7%, 9.9% and 14.5% respectively. For Southern Australian women, Botlero et al. [13] provided prevalence data of 16.1% for SUI, 7.5% for urge urinary incontinence and 18.1% for a mixed urinary incontinence pattern. Also Markland et al. [3] reported SUI to be the most common subtype of urinary incontinence in women with a prevalence of 24.8% in the US.

1

Minassian et al. [12] found the highest prevalence of SUI in women in the fifth decade of life (35.7%) and a gradual decrease with older age, whereas the prevalence of mixed urinary incontinence presented a continuous increase throughout life. Botlero et al. [13] showed that SUI was more common among younger women with the highest prevalence of 25.3% found in the age group of 3544 years while urge urinary incontinence was more common amongst older women (24.2% in women over 75 years of age). Variabilities in prevalence outcomes of urinary incontinence may be due to differences in the criteria used (e.g. threshold of incontinence, frequency of incontinence, duration of the reference period) or characteristics of the study populations [14].

For women aged between 45 and 85 years, PFM function was found to be decreasing with age [15]. However, also young and even very young women can be affected by PFM dysfunction and SUI [16-19]. Among these young women presenting SUI problems, young athletes are affected with those participating in “high-impactâ€? sports presenting the highest prevalence [16, 20], which may rise up to 80% [20, 21]. As well as high performance athletes, a significant proportion of young women practicing non-competitive sports are affected by SUI [22]. Nulliparous women with normal weight who attend gym and perform high-impact exercise have a greater prevalence of urine loss than women who do not perform any high-impact exercises [7]. Women who are physically active raise their intra-abdominal pressure more frequently than sedentary women [23]. Therefore, Bo et al. [16] question whether female athletes have strong PFM as a result of their regular training or whether excessive loading of the PFM may overload, stretch and weaken their PFM and cause SUI. Bø & Sundgot-Borgen [24] found that former female elite athletes were not more likely to have more SUI later in life than a control group from the same geographical area. However, their results also indicated that for these elite female 2

athletes urinary incontinence early in life was a strong predictor of urinary incontinence later in life [24].

1.1.3 Risk factors Numerous epidemiologic studies revealed that parity is a risk factor for SUI [2, 12, 25, 26]. Other significant risk factors are age, weight, obesity, chronic pulmonary diseases, white ethnicity, hysterectomy and menopause [2, 12, 25, 26]. Recent genetic studies identified several genes encoding components of the extracellular matrix, which could be related to a predisposition to SUI [27].

1.1.4 Impact on quality of life Urinary incontinence has an impact on the physical, psychosocial, social, personal, and economic well-being of the affected individuals and of their families [28]. SUI patients report a negative impact of this condition on their well-being [29], and present a higher risk for anxiety disorders [30]. Urinary incontinence impairs the physical and social activities and participation [29, 31] and - in order to avoid urine leakage - can lead the affected women to become inactive with refrainment from exercise and recreational activities [20] and abandonment or limitation of sports participation [22].

Despite its high prevalence, SUI remains a taboo with only a minority of incontinent women consulting a medical doctor due to shame and embarrassment, lack of information about the availability of treatment options, fear of surgery and the misconception that urinary incontinence is an inevitable consequence of age or giving birth [29].

3

1.1.5 Impact on costs Due to higher life expectancy and the concomitant increase in prevalence [2, 32] SUI implies a substantial economic impact on the health and social services [28, 33]. In the United States direct female urinary incontinence costs totaled over $12 billion in 1995 - 82% of total costs accounting for SUI -, an amount that continues to grow [33, 34]. The average costs per urinary incontinent women in Germany is calculated approximately 300 Euros within the first year after being diagnosed [35]. Surgical procedures represent 45%, medical aids 28%, drugs 17% and ambulant-medical diagnostics 8% of the total costs. Physiotherapy represents only 2% of total costs [35].

1.2 The role of the pelvic floor muscles as regards to guaranteeing urinary continence 1.2.1 Terminology, anatomy and physiology of the pelvic floor The International Continence Society (ICS) relates the “pelvic floor” to the compound structure which closes the bony pelvic outlet. The pelvic floor comprises different layers, the most cranial being the peritoneum of the pelvic viscera and the most caudal in women being the skin of the vulva and perineum [36]. The term “pelvic floor muscles” refers to the muscular layer of the pelvic floor, comprising the M. levator ani, striated urogenital sphincter, external anal sphincter, ischiocavernosus, and bulbospongiosus [36]. Regarding the PFM there are still controversies regarding terminology. In their literature review, Kearny et al. [37] pointed out that although not perfectly consistent, consensus was found concerning origins and insertions of the M. levator ani, but with great diversity and conflict among the terms chosen. The anatomical structures of the female pelvic floor must prevent incontinence and pelvic organ prolapse during abdominal pressure elevations and motions associated with 4

daily activities. Additionally they must also permit urination and defecation, and allow childbirth [38].

Even though “any understanding of SUI must begin with an accurate appreciation of detailed anatomy of the continence mechanism and pelvic floor� [39] an introduction in pelvic floor anatomy as well as physiology lies beyond the scope of this thesis and therefore related literature is suggested [38, 40].

1.2.2 Understanding stress urinary incontinence DeLancey [39] stated that the understanding of the cause of SUI is still far from complete. Shah et al. [41] presented in their review the following possible rationale to explain SUI: In the pressure transmission theory SUI is related to hypermobility of the bladder neck and urethra as a result of inadequate supporting structures. This inadequacy causes these structures to descend. Consequently, increases of intraabdominal pressure result in SUI due to insufficiency of counteractive PFM and pelvic fascia pressure. Studies have shown stretch related muscular defects in the M. pubococcygeus or M. puborectalis as a result from vaginal births or caesarean delivery. Damaged branches of the pudendal nerves or the pudendal nerve itself close to the ischial spine result in atrophy of the M. levator ani. With the endopelvic fascia and suspensory ligaments taking over the pelvic organ support, this evolves into strain and eventually pelvic organ prolapse. Ashton-Miller & DeLancey [38] emphasize that SUI is caused by problems with urethral support as well as with the urethral sphincter mechanism.

1.2.3 Pelvic floor muscle function related to continence and SUI Of all the striated muscles in the bodies of mammals, only the PFM present myoelectric activity at rest [42]. Normal M. levator ani baseline activity keeps the 5

urogenital hiatus closed at rest by compressing the vagina, urethra and rectum against the pubic bone, the pelvic floor and internal organs in a cephalic direction [38]. This constant baseline tonic activity of the M. levator ani protects the pelvic ligaments and fasciae from constant strain [38].

In addition to this baseline activity, M. levator ani contractions maintain hiatal closure by fast and strongly responding to inertial loads induced by visceral accelerations as well as to intra-abdominal pressure raises during daily activities. These responses are in co-contraction with the abdominal and diaphragm musculature [38, 42, 43].

Primarily caused by the vaginal and rectal parts of the M. levator ani these contractions result in a ventral and cranial movement of the perineum and pelvic organs [36]. The reactive and strong PFM contractions generate an adequate squeeze pressure in the proximal urethra, which maintains a pressure beyond the pressure in the bladder, consequently preventing leakage [44]. With an abrupt rise in the intra-abdominal pressure provoked by coughing, laughing or sneezing, rapid PFM contractions are crucial to maintain continence [45]. As women with no incontinence do not contract voluntarily before coughing or jumping, their PFM contraction must be a quick and strong automatic co-contraction [46].

Zhu et al. [47] found that the muscle fiber diameters of the M. pubococcygeus in a control group (with no SUI and no pelvic organ prolapse) were significantly larger than in the SUI group: 54.9-70.3% of the M. pubococcygeus muscle fibers were type I, 29.7-45.1% type II. In the control group, the diameters of both fiber types decreased significantly with age and menopausal time [47]. In the SUI group 79.697.2% of the M. pubococcygeus muscle fibers were type I and 2.8-21.4% type II [47].

Morin et al. [11] hypothesized that PFM endurance contributes to continence under repeated or prolonged demands of the continence mechanisms such as with jogging or daily living activities. Simultaneous latency measurements indicated a pressure 6

increase in the urethra preceding that of the bladder by approximately 250 ms [48].

Based on that finding and the presence of type II muscle fibers in the M. pubococcygeus [49, 50], Morin et al. [11] suggested that rapid type II fiber contractions anticipate abrupt rises in the intra-abdominal pressure.

Focusing on PFM function, as a first part of this thesis a systematic review [51] was started, accentuating the influence of specific PFM activation and strength components such as endurance, maximal strength or rate of force development etc. on female continence and SUI.

1.2.4 Voluntary versus involuntary PFM contractions Whole body activities typically provoking urine leakage encompass running, jumping or lifting [16, 20]. Related sports activities are, among others, trampoline jumping, soccer, volleyball, basketball and dancing [52] with worse leakage during high-impact activities [16]

and activities involving repetitive jumping and bouncing [52]. This

emphasizes the impact characteristics as a core issue of SUI. (High) impact activities raise the intraabdominal pressure and increase the load on the PFM [7]. Impact loads, which can typically provoke SUI, occur within milliseconds, e.g. the force impact during stair descent follows within 146 ms [53], the expulsive process during sneezing happens within about 150 ms [54] and peak flows arise at 57-110 ms during coughing in women [55]. Consequently, fast involuntary reflexive PFM stress responses are required to guarantee continence [6].

Voluntary PFM contractions in static situations (supine or standing) have been sufficiently investigated [9-11, 46, 56, 57]. In contrast, to the author’s knowledge, the only studies concerning the core issue of involuntary PFM activity are a number of studies related to PFM activity while coughing [8, 58-61]; and one study concerning 7

PFM activity during physical activity [62]: Schaefer & Pannek investigated PFM activity during a standardized horseback riding program (step, trot, gallop) and found that a higher pace led to an increase in pelvic floor EMG activity. However, a) the participants seemed to be convenience sampled with no previously defined inclusion and exclusion criteria and therefore including both continent and incontinent subjects, b) the article did not describe any statistical analyses of the measurements and c) the study compared non-normalized raw surface EMG data, although EMG normalization from a reference contraction is crucial for comparing different individuals [63].

For a deeper insight in PFM function during functional whole body movements and activities with short impacts typically provoking SUI, three exploratory and reliability studies [64-66] were carried out as a second part of this thesis.

1.3 Physiotherapy for women with SUI PFM training is defined as a program of repeated voluntary PFM contractions taught and supervised by a health care professional. It is the most commonly used in physiotherapy to treat women with SUI. The treatment is effective for all types of female incontinence, and therefore recommended as a first-line therapy [67-69].

According to the International Consultation on Incontinence recommendations, PFM training should generally be the first step of treatment before surgery [70]. Despite, the optimal training regimen for achieving continence remains unknown and according to Dumoulin et al. [71] endless questions, such as “how often should women attend PFM training sessions and how many contractions should they perform for maximal effect?� persist. PFM training focuses on voluntary contractions even though the situations provoking SUI such as sneezing, coughing and sporting activities [5] require involuntary fast reflexive PFM contractions [6]. An optimal and 8

well standardized training protocol including involuntary, fast and reflexive PFM contractions still remains unknown.

A promising future training method for PFM involuntary reflex contractions could be whole body vibration (WBV) [72, 73]. Lauper et al. [73] investigated PFM activation of post-partum women with weak PFM (testing score according to the Oxford grading scale [74] of M0-M3) and healthy controls during 5 seconds stochastic resonance WBV (SR-WBV) loads of different intensities (2-12Hz). With increasing vibration intensities, PFM activation increased significantly for both groups and notably led to a peak activation higher than maximal voluntary contraction (MVC) in post-partum women when vibrating with 12 Hz (127.2 EMG%). When the participants performed a MVC during vibration, PFM activation increased with augmenting the vibration intensity for the controls (from 88.3 %EMG to 113.1 %EMG) and for the post-partum women (from 88.0 %EMG to 165.5 %EMG; P < 0.001). However, the SR-WBV training has not yet been investigated regarding its training methodology for PFM, such as duration of intervention, number of sets, rest periods between sets etc.

Therefore, as the third work of this thesis, a study regarding SR-WBV training methodology was carried out [75]. And â&#x20AC;&#x201C; to fill the gap regarding standardized periodized PFM training protocols including involuntary reflexive PFM training â&#x20AC;&#x201C; a physiotherapy RCT protocol was developed, which besides voluntary PFM contractions focuses on involuntary reflexive ones [76].

1.4 Aims, related research questions and studies To (partially) respond to present research gaps, this thesis focuses on the following aims, related research questions and studies:

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1. To systematically review the literature related to PFM activation and strength components influencing continence and SUI in women; activation representing the summation of muscle action potentials, the innervation frequency and muscle fiber recruitment. This aim is related to the research question “What is the influence of PFM activation and strength components on continence and SUI in females?” and is elaborated in the article “Pelvic floor muscle activation and strength

components

influencing

female

urinary

continence

and

stress

incontinence: a systematic review” [51].

2. a) To investigate PFM activation characteristics of healthy young nulliparous females during running in order to determine specific time and activation variables and to test their reliability. This aim is related to the research questions “How are the PFM activated in healthy females during high impact situations, specifically during running at 8km/h? How is the reliability of activity and time variables found?” which furthered in the study and article “Intra-session test–retest reliability of pelvic floor muscle electromyography during running” [65].

b) To investigate specific, previously defined variables of PFM pre- and reflex activity (during specific time intervals of stretch reflex latency responses) in healthy young nulliparous females during running at different speeds and during coughing and to test their reliability. This aim is related to the research questions “How are the PFM activated in healthy females during high impact situations, specifically during running at 7, 9, 11 km/h and during coughing? What is the reliability of those variables of pre- and reflex activity? Regarding running: Is there a speed dependency for these variables?”. The related studies and articles are “Pelvic floor muscle electromyography during different running speeds: an 10

exploratory and reliability study” [66] and “Pelvic floor muscle reflex activity during coughing – an exploratory and reliability study” [64].

3. To investigate the PFM EMG activation characteristics in terms of reactivity and fatigue in response to load duration and/or load modality during whole body vibration loads in women with PFM insufficiency and SUI. Consequently, to determine the load modalities for SR-WBV training methodology as an option for PFM involuntary reflexive muscle training. This aim is related to the research questions “How is the effect of SR-WBV load duration on PFM (activity/ fatigue) of SUI women? Is continuous or intermittent load vibration recommended for SRWBV training in female SUI patients in clinical practice?” and is elaborated in the following study and article “Continuous versus intermittent stochastic resonance whole body vibration and its effect on pelvic floor muscle activity” [75].

4. To develop a new specific standardized and periodized training protocol including fast involuntary reflexive PFM training. To plan and prepare an RCT, which compares two physiotherapy protocols. Both follow the concepts of periodization & exercise sequencing and training of specific muscle strength components. The protocols differ in that one focuses on voluntary PFM contractions (“standard physiotherapy”) and the other one additionally focuses on involuntary reflexive PFM contractions. This aim relates to the research questions “Is there a difference

between

two

self-developed

standardized

and

periodized

physiotherapy programs - involuntary reflexive pelvic floor muscle training in addition to standard training versus standard training alone - regarding their effect on SUI in terms of improvement of continence measured by the “International Consultation on Incontinence Modular Questionnaire Urinary Incontinence (short 11

form)”, and - as to secondary and tertiary outcomes – on PFM activity during SUI provoking activities (running, jumping), pad-test results, quality of life scores (“International Consultation on Incontinence Modular Questionnaire”) and intravaginal muscle strength (digitally tested) from before to after intervention phase in women?”* and to the study protocol “Involuntary reflexive pelvic floor muscle training in addition to standard training versus standard training alone for women with stress urinary incontinence: study protocol for a randomized controlled trial” [76]. *Regarding the completion of this thesis: To come as far as developing the therapy plan and the study protocol (incl. granting and ethics committee approval) and its publication.

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Results

Helena Luginbuehl

2 Results

Pelvic floor muscle activation and strength components influencing female urinary continence and stress incontinence: a systematic review Neurourology and Urodynamics 2015 Aug;34(6):498-506

Intra-session test–retest reliability of pelvic floor muscle electromyography during running International Urogynecology Journal 2013 Sep;24(9):1515-22

Pelvic floor muscle electromyography during different running speeds – an exploratory and reliability study Archives of Gynecology and Obstetrics 2016 Jan;293(1):117-24

Pelvic floor muscle reflex activity during coughing – an exploratory and reliability study Annals of Physical and Rehabilitation Medicine 2016 Jun 2. [Epub ahead of print]

Continuous versus intermittent stochastic resonance whole body vibration and its effect on pelvic floor muscle activity Neurourology and Urodynamics 2012 Jun;31(5):683-7

Involuntary reflexive pelvic floor muscle training in addition to standard training versus standard training alone for women with stress urinary incontinence: study protocol for a randomized controlled trial Trials 2015 Nov 17;16(1):524

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2.1 Pelvic floor muscle activation and strength components influencing female urinary continence and stress incontinence: a systematic review

Neurourology and Urodynamics 2015 Aug;34(6):498-506

Helena Luginbuehl Jean-Pierre Baeyens Jan Teaymans Ida-Maria Maeder Annette Kuhn Lorenz Radlinger

14

Neurourology and Urodynamics 34:498–506 (2015)

Pelvic Floor Muscle Activation and Strength Components Influencing Female Urinary Continence and Stress Incontinence: A Systematic Review Helena Luginbuehl,1,2* Jean-Pierre Baeyens,2 Jan Taeymans,1,2 Ida-Maria Maeder,3 Annette Kuhn,4 and Lorenz Radlinger1 1

Bern University of Applied Sciences, Health, Bern, Switzerland Vrije Universiteit Brussel, Faculty of Physical Education and Physiotherapy, Brussel, Belgium 3 University of Bern, University Library of Bern, Bern, Switzerland 4 Women’s Hospital, Urogynaecology, Bern University Hospital and University of Bern, Bern, Switzerland 2

Aims: A better understanding of pelvic floor muscle (PFM) activation and strength components is a prerequisite to get better insight in PFM contraction mechanisms and develop more specific PFM-training regimens for female stress urinary incontinence (SUI) patients. The aim of this systematic review (2012:CRD42012002547) was to evaluate and summarize existing studies investigating PFM activation and strength components influencing female continence and SUI. Methods: PubMed, EMBASE, and Cochrane databases were systematically searched for literature from January 1980 to November 2013 for cross-sectional studies comparing female SUI patients with healthy controls and intervention studies with SUI patients reporting on the association between PFM activation and strength components and urine loss. Trial characteristics, evaluated PFM components, their definitions, measurement methods, study outcomes, as well as quality measures, based on the Cochrane risk of bias tool, were independently extracted. The high heterogeneity of the retrieved data made pooling of results impossible and therefore restricted the analysis to a systematic review. Results: Cross-sectional studies showed group differences in favor of the continent women compared to SUI patients for PFM activation or PFM maximal strength, mean strength or sustained contraction. All intervention studies showed an improvement of PFM strength and decrease in urine loss in SUI patients after physical therapy.

Conclusions: Higher PFM activation and strength components influence female continence positively. This systematic review underscored the need for a standardized PFM components’ terminology (similar to rehabilitation and training science), standardized test procedures and well matched diagnostic instruments. Neurourol. Urodynam. 34:498–506, 2015. # 2014 Wiley Periodicals, Inc. Key words: electromyography; muscle strength; pressure INTRODUCTION

Pelvic floor muscle (PFM) insufficiency with concomitant stress urinary incontinence (SUI) is a widely spread medical problem, which increased over time as a result of the advancing age of the population.1,2 PFM-training, the most commonly used physical therapy treatment for women with SUI,3 is effective and, therefore, recommended as a first-line therapy.4 However, the optimal training regimen for achieving continence remains unknown.5 To date many questions, such as number of PFM contractions for maximal effect, type of exercises or number of training sessions needed, are still unanswered.5 In their research, where patients, care-givers and clinicians together identified and prioritized important clinical uncertainties in urinary incontinence, Buckley et al.6 identified the question ‘‘what are the optimal PFM-training protocols (frequency and duration of therapy) for the treatment of different patterns of urinary incontinence?’’ was the number one uncertainty. In their systematic review, Price et al.7 found a high variability, for the number of PFM contractions across studies, ranging from 8 to 12 contractions (3/day) or 20 contractions (4/day), up to 200 (or even 500) contractions per day while the contraction duration (‘‘squeeze and hold’’) varied from 4 to 30–40 sec. A Cochrane systematic review confirmed the observed heterogeneity regarding supervision and content of PFM-training programs and concluded that the existent evidence was insufficient to make any strong recommendations about the best approach to PFM-training.8 #

2014 Wiley Periodicals, Inc.

Those results show that complex standardized PFM-training protocols are still lacking, although the specific training principles and methods are well described.9,10 These should be implemented in PFM-training to improve specific PFM components, such as maximal strength, power (starting strength, explosive strength, short, and fast stretch-shortening-cycle), hypertrophy, strength-endurance, and related muscle action forms (concentric, eccentric, isometric, eccentric–concentric).9,10 Such a strategy should additionally follow the model of periodization specifying the optimum frequency, intensity, and type of contraction within training sessions, as an effective conceptualization of a strength training is only possible in consideration of the muscle strength components.9,10 A better understanding of PFM activation, representing the summarization of muscle action potentials, its innervation frequency und following muscle fiber recruitment, and strength components and their characteristics is a prerequisite to develop more specific PFM-training regimens for SUI patients Heinz Koelbl led the peer-review process as the Associate Editor responsible for the paper.

Conflict of interest: none.

Correspondence to: Helena Luginbuehl, Bern University of Applied Sciences Health, Murtenstrasse 10, 3008 Bern, Switzerland.

E-mail helena.luginbuehl@bfh.ch Received 4 February 2014; Accepted 18 March 2014 Published online 9 April 2014 in Wiley Online Library (wileyonlinelibrary.com).

DOI 10.1002/nau.22612

Pelvic Floor Muscle Activation and Strength: A Systematic Review according to the already well elaborated concepts of movement and training sciences.9,10 This would include a differentiated use of training methods well recognized in sports for muscle rehabilitation.9,10 Therefore, the aim of this systematic review was to summarize and evaluate existing studies investigating PFM activation and strength components influencing female continence and SUI. MATERIALS AND METHODS

This systematic review was conducted following the PRISMA guidelines.11 The a priori submitted protocol was reviewed and published (2012:CRD42012002547) by PROSPERO, the international prospective register of systematic reviews in health and social care (www.crd.york.ac.uk/prospero).

Search Strategy and Study Eligibility

The electronic databases PubMed, EMBASE, and Cochrane were searched, covering the time period from January 1980 to November 2013, for studies on the association between PFM activation and strength components and female continence or SUI respectively. The search strategy included strength and activation related terms (e.g., muscle strength, power, rate of force development, etc.) in combination with terms associated with the nomenclature of the muscles involved, the clinical condition (i.e., SUI), and the measurement methods (e.g., electromyography, pressure, force, etc.). The search algorithm was developed in cooperation with an experienced librarian (I.M.) of the University of Bern, and is available online as supplementary data (Table SI). It has been peer reviewed by one academic colleague (SR) according to the guideline developed

by Sampson et al.12 prior to the initial search.

Inclusion and exclusion criteria to assess eligibility of the studies are depicted in Table I. The languages of the studies

499

included in the present review were limited to those understood by the review team: English, German, French, and Dutch.

Two investigators (H.L. and L.R.) independently screened the titles and abstracts of the retrieved studies for eligibility. In case of disagreement, consensus was reached through discussion.

The same researchers independently assessed the full-text articles for eligibility based on the a priori defined inclusion criteria. Again, in case of disagreement, consensus was found by discussion. From the retrieved (systematic) reviews, reference lists were searched manually for possible topic related papers.

In case of questionable study duplicates or when more specific information was needed, the corresponding author was contacted.

Risk of Bias Assessment of the Studies Under Investigation and Data Extraction

The methodological quality of the included articles was assessed according to ‘‘The Cochrane Collaboration’s tool for assessing risk of bias.’’ The criteria list comprised seven items.

Each item was scored with ‘‘þ’’ if the criterion was fulfilled, with ‘‘ ’’ if the criterion was not fulfilled, and with ‘‘?’’ if the information was not provided or was unclear. The same investigators (H.L. and L.R.) independently rated all included papers. Discrepancies were resolved through discussion and by consensus. The results of the risk of bias assessment are summarized in Table II. Data extraction was performed using a customized data extraction form by two researchers (H.L. and L.R.) independently.

The following data were retrieved from the articles: (1) study design; (2) characteristics of the study participants; (3) evaluated PFM component(s); (4) definition of PFM component(s); (5) measurement method(s); (6) outcome(s). In case of disagreements, consensus was reached through discussion. In case of missing data, the corresponding author was contacted for clarification.

TABLE I. Inclusion and Exclusion Criteria for Title, Abstract Screening and Full-Text Evaluation Category

Inclusion

Exclusion

Population

Female adults, with SUI stage I-III, 1 year post-partal, parous, nulliparae, pre-, post-menopausal

Interventions/exposures

Pregnant, <12 month post-partal, prolapse I8, hormone replacement therapy, planned for surgery (gynecological/incontinence), status post-surgery (gynecological/incontinence), urge incontinence, mixed incontinence, fecal incontinence, central nervous disorders, animals, cadavers Urethral/rectal closure force

EMG- and/or strength-measurements of PFM components with different probes and electrodes (a) Healthy (control) group (b) Affected group (SUI) before/after PFM therapy (a) Association/no association between CON/SUI and specific PFM components of women with SUI and healthy women (b) Association/no association between CON/SUI and specific PFM components of women with SUI before/ after PFM therapy Conference abstracts, non peer-reviewed publications, Experimental studies, cross sectional studies, unpublished manuscripts, secondary literature observational studies, systematic reviews (meta

analyses) , RCT’s, case reports, clinical trials, retrospective studies

Comparator Main Outcomes

Type of studies

PFM, pelvic floor muscles; CON, continence; SUI, stress urinary incontinence.

(a): Studies comparing SUI with healthy controls (non-randomized cross-sectional, observational, explorative clinical studies with control), (b): Clinical trial,

intervention study, pre-post design with women suffering from SUI.

No data were extracted from systematic reviews (meta analysis); they were retrieved to check the sources for topic related articles.

Neurourology and Urodynamics DOI 10.1002/nau

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Luginbuehl et al.

TABLE II. Risk of Bias Assessment of Included Articles

Study

Allocation concealed (selection bias)

Blinding of (participants and) personnel (performance bias)

Blinding of outcome assessment (detection bias)

Incomplete outcome data (attrition bias)

Selective reporting (reporting bias)

Other sources of bias

? þ þ ? þ þ þ þ þ

? ? þ ? þ ? ? ? ?

? þ ? ? ? ? ? ? ?

þ ? þ ? ? ? ? þ ?

þ þ þ þ þ þ þ þ þ

?

? ? ? ? ? ? ?

? þ þ

? þ ?

þ

? ? ? ? ?

þ ? ? ? þ

þ þ þ þ þ

? ? ? ? þ

Random sequence generation (selection bias)

Cross-sectional studies Amaro13 Chamochumbi14 Peng15 Sapsford16 Shishido17 Smith18 Smith19 Verelst20 Verelst21 Pre-post designed studies Bo22 Boyington23 Johnson24 Roongsirisangrat25 Turkan26

þ, Criterion was fulfilled (low risk of bias); , criterion was not fulfilled (high risk of bias); ?, the information was not provided or unclear.

Data Synthesis and Analysis

Based on the high heterogeneity of the retrieved articles, the analysis was restricted to a systematic review and an initially planned meta-analysis was not conducted.

RESULTS Selection of Studies

Iden fica on

Figure 1 depicts the study flow diagram. The literature search identified 2,630 abstracts for consideration. Two thousand two

Records iden fied through database searching (n = 2630)

Screening

Duplicates removed (n = 345)

Records screened for tles and abstracts (n = 2285)

Study Characteristics

Eligibility

Records excluded, not mee ng the criteria (n = 2164)

Full-text ar cles assessed for eligibility (n = 121) Ar cles excluded, not mee ng the criteria (n = 107)

Included

hundred and eighty-five records remained after removal of duplicates. After the application of inclusion and exclusion criteria, 2,164 papers were excluded and 121 studies entered the full-text review. From those, 107 were excluded (reasons: one revealed to be an annual meeting abstract, one a published protocol with no following publication, one article was not available while all other studies did not meet the inclusion/ exclusion criteria). No further topic related articles were found by searching the reference lists of the included (systematic) reviews. Fourteen studies were finally included in this systematic review and were divided into two study types: (a) nine studies13–21 comparing SUI with healthy controls (nonrandomized cross-sectional, observational, explorative clinical studies with control) and (b) five studies22–26 concerned clinical trials or intervention studies (non-controlled pre-post design) with females suffering from SUI. Two papers15,17 out of the cross-sectional studies were published based on the same data investigating the physics of a custom-built vaginal probe and considering the clinical interpretation of the gathered data respectively. Two further cross-sectional studies18,19 investigated different research questions on the same sample.

Studies included in final synthesis (n = 14)

Fig. 1. PRISMA flow diagram.

Neurourology and Urodynamics DOI 10.1002/nau

Table III shows the major characteristics of the nine studies referring to the cross-sectional studies. Measurement methods varied among these studies: In six studies13–15,17,20,21 strength measurements were performed (used terminology besides strength were force or pressure and measured units Newton or mmH2O) while in three studies16,18,19 surface EMG amplitude was assessed. The measurements were performed with various probes, that is, with well-established medical devices13,16,18,19 or with custom-built probes.14,15,17,20,21 The measured PFM components and their definitions were highly heterogeneous among studies. All studies except one19 showed group differences of PFM components in favor of the continent women.

The major characteristics of the five studies referring to the pre-post designed studies are summarized in Table IV. In all studies exercise based PFM-training programs were performed.

Two studies22,23 were secondary data analyses while another study26 additionally performed inferential current therapy. The

Muscle strength

Active force, active strength: 1. Anteroposterior (sagittal plane), 2. Left-right directions (frontal plane) Force, closure pressure profile, muscle strength

Resting activity of PFM

Forces in 4 directions and probe position

PFM activity (amplitude) and timing

CON: n ¼ 50; SUI: n ¼ 51; age: 34.0–62.0 years, mean: 42.0 years

CON: n ¼ 16; age: mean ¼ 37.0 years ( 8.0 years); SUI: n ¼ 16; age: mean ¼ 48.0 years ( 7.0 years)

CON: n ¼ 23; age: mean (SE): 39.0 years ( 2.3 years); SUI: n ¼ 10; age: mean (SE): 51.5 years ( 5.3 years)

CON: n ¼ 9; age: mean ¼ 45.0 years; SUI: n ¼ 8, age: mean ¼ 41.8 years

CON: n ¼ 23; age: mean (SE): 39.0 years ( 2.3 years); SUI: n ¼ 10; age: mean (SE): 51.5 years ( 5.3 years)

CON: n ¼ 14; age: mean ¼ 52.5 years ( 12.5 years); SUI: n ¼ 16; age: mean ¼ 49.8 years ( 12.0 years);

Chamochumbi14

Peng15

Sapsford16

Shishido17

Smith18

Evaluated PFM component (variable)

Amaro13

First author, year

Subject characteristics: CON vs.

SUI, sample size (n), age

TABLE III. Data Extraction Form All Cross Sectional Studies

Measurement method

Neurourology and Urodynamics DOI 10.1002/nau Onset of the postural activity (ms) SEMG (periform probe) of the PFM; delayed postural activity (ms) during rapid single arm movements; in

Resting activity in three sitting SEMG (periform probe) postures: slump supported, upright unsupported, very tall supported: mV recording for 10 sec (RMS for 5 sec; average from three trials) Three measurements (N cm 2) at Intravaginal probe (4 force rest and during PFM sensors, diameter adjustor) contraction (at appr. 1/2 MVC with 10 sec rest between contractions) while the probe was pulled through the vagina at a speed of 2 cm sec 1, in supine lithotomy position

PFM active strength was Stainless steel specular evaluated with a 4.9 N of dynamometer passive force: 3 MVC of 4 sec with a 2 min interval in gynecological position Three measurements (N cm 2) at Intravaginal probe (4 force rest and during PFM sensors, diameter adjustor) contraction (at appr. 1/2 MVC with 10 sec rest between contractions) while the probe was pulled through the vagina at a speed of 2 cm sec 1, in supine lithotomy position

Maximal and mean squeeze Perineometer connected to pressure (cmH2O); duration as balloon catheter holding period in s; all tests in supine position

Definition of PFM component (unit)

(continued)

PFM contraction CON > SUI: anterior side: P < 0.05 (4.82 0.5 > 2.61 0.44), posterior side: P < 0.01 (4.18 0.26 > 2.25 0.41), left side: ns (0.56 0.09–0.62 0.12), right side: ns (0.82 0.11–0.83 0.17); maximal values of increment pressure by PFM contraction in CON and SUI: anterior side CON > SUI (P < 0.05) (1.42 0.22 > 0.52 0.23), posterior side: ns (1.98 0.21–1.31 0.3), left side: ns (0.34 0.05–0.45 0.07), right side: ns (0.47 0.08–0.55 0.16) maximal adjusted pressure (¼peak activity pressure) CON > SUI (P ¼ 0.01) (3.29 0.21 > 1.85 0.38) Delayed onset of PFM during rapid arm movements of SUI (P < 0.05); SEMG during period of postural activity: SUI > CON (P ¼ 0.01)

PFM contraction CON > SUI: Anterior side: P < 0.05 (4.82 0.5 > 2.61 0.44), posterior side: P < 0.01 (4.18 0.26 > 2.25 0.41), left side: ns (0.56 0.09–0.62 0.12), right side: ns (0.82 0.11–0.83 0.17); maximal values of increment pressure by PFM contraction in CON and SUI: anterior side CON > SUI (P < 0.05) (1.42 0.22 > 0.52 0.23), posterior side: ns (1.98 0.21–1.31 0.3), left side: ns (0.34 0.05–0.45 0.07), right side: ns (0.47 0.08–0.55 0.16) Raw SEMG activity in slump and upright unsupported sitting position: SUI < CON (P < 0.05). Secondary analysis of subset of subjects (n ¼ 13): SUI ¼ CON in very tall unsupported posture (ns)

Strength: CON > SUI (P < 0.001); maximum peak (38.4 1.33 > 26.1 1.15), mean peak (28.1 1.22 > 15.4 0.62); duration: CON > SUI (P < 0.001) (11.8 0.96 > 8.9 0.17) 1. Anteroposterior active strength CON > SUI (P < 0.01) (0.3 0.2 > 0.1 0.1) 2. Leftright active strength CON/SUI: ns difference (0.43 0.1–0.40 0.1)

Outcome: comparison SUI-CON

Pelvic Floor Muscle Activation and Strength: A Systematic Review 501

First author, year

Neurourology and Urodynamics DOI 10.1002/nau

CON: n ¼ 24; age median (range): Active force 49 years (30–49 years); SUI: n ¼ 21; age median (range): 46 years (27–54 years)

matched age and ¼ BMI CON: n ¼ 14,for age: mean 52.5 PFM activity (raw SEMG) years ( 12.5 years) SUI: n ¼ 16; age: mean ¼ 49.8 years ( 12.0 years); matched for age and BMI CON: n ¼ 26; age median (range): Maximal voluntary force at 41.0 years (30–49 years); SUI: 40 mm diameter, time-ton ¼ 20; age median (range): fatigue 45.0 years (27–54 years)

Evaluated PFM component (variable) Measurement method

standing position Muscle activity (mV) prior to the SEMG (periform probe) loading perturbation (at rest): raw SEMG; muscle activity (mV) during expected and unexpected weight drops Normalized force (adjusted to Intravaginal device (2 semibody weight: N/kg) Maximal circular stiff rods, adjustable maintained PFM contraction diameter) till 10% of contraction force (N) is lost; semilithotomy position Normalized active force (N/kg) at Intravaginal device (2 semidiameter 30, 35, 40, 45, 50 mm circular stiff rods, adjustable always 60 sec after diameter diameter) change: Active force: 3 MVC !0highest force recorded stored for analysis ! maximal active force ¼ total force measured during MVC minus passive force at the corresponding diameter

Definition of PFM component (unit)

Normalized active force at 40 mm diameter: CON > SUI (P < 0.05) (0.168–0.295 > 0.092– 0.181)

Normalized force: CON > SUI, (P < 0.01) (0.14 (0.39–0.43) > 4.9 2 ( 0.06 to 0.20)); timeto-fatigue: SUI-CON: ns (10.5–11.5)

Raw PFM SEMG at rest: CON < SUI (P ¼ 0.011); Raw PFM SEMG response during postural control: SUI > CON (P ¼ 0.034)

Outcome: comparison SUI-CON

Range of means.

Medians (range).

No data available (figures only).

(mean SE).

(mean SD).

significant; y, years.

2 cm sec 1, 2 cm per second; cmH2O, centimeter water; g, grams; ms, milliseconds; mV, millivolt; N, Newton; N/kg, Newton per kilogram; N cm 2, Newton per square centimeter; ns, non-significant; sec, seconds; sign.,

CON, continence/continent; EMG: electromyography; PFM, pelvic floor muscles; RMS, root mean square; SE, standard error; SEMG, surface electromyography; SUI, stress urinary incontinence/stress urinary incontinent.

Verelst21

Verelst20

Smith19

Subject characteristics: CON vs.

SUI, sample size (n), age

TABLE 3. (Continued)

502 Luginbuehl et al.

Secondary data analysis of RCT

Secondary data analysis of 10 randomly selected subjects out of 65

Quasi-experimental, twogroup repeated measures design

Two-armed, quasi randomized controlled, non-blind CT

CT

Boyington23

Johnson24

Roongsirisangrat25

Turkan26

Study design

Bo22

First author, year

Neurourology and Urodynamics DOI 10.1002/nau Muscle endurance, muscle strength

SUI; 2 groups: SCV: n ¼ 16, age: mean ¼ 51 years ( 10.21 years); NMVC: n ¼ 16; age: mean ¼ 49.5 years ( 11.09 years)

Three groups: different intensities of SUI according to 1-hr pad-

PFM strength

Squeezing pressure

Pelvic muscle pressure

Moderate SUI; n ¼ 10; age: mean ¼ 51.7 years ( 10.0 years)

SUI; 2 groups: PFMT: n ¼ 13, age: mean ¼ 49.2 years ( 9.5 years); RBT: n ¼ 13, age: 49.9 years ( 7.7 years)

Muscle strength

Evaluated PFM component (variable)

SUI; 2 groups: IEG: n ¼ 23.

HEG: n ¼ 29; age: 24–64 years, mean ¼ 45.4 years

Subject characteristics: CON vs. SUI, sample size (n), age

TABLE IV. Data Extraction Form Pre-Post Designed Studies

MYOMED 932 Combined Biofeedback device for PFM strength. 1-hr pad-

MYO420 Biofeedback for PFM strength 1-hr padtest, leakage episodes, self-rating scores about quantity of urine leakage

3 vaginal squeezing (best score was recorded) (mmHg)

1. Relaxation PFM ¼ baseline value, 2. ‘‘Strongest

Pressure measurements with air-inflated pneumatic vaginal pressure probe for MMC strength and endurance.

Quantification urine leakage: 10-hr weighed pad-test, daily diaries of leakage episodes

Balloon catheter connected to Microtip transducer; pad-test.

Patients report of improvement, leaking index, social activity index Intravaginal balloon device; 24-hr bladder diary, 24-hr home padtest

Measurement method

Endurance: (a) Number of completed contractions before fatigue. (b) Time in s of sustained contractions. MMC strength (force): pressure (cmH2O): mean of 5 PFM contractions for 5 sec with 5 sec relaxation between each contraction

Actual pressure (mmHg), rate of rise pressure (mmHg sec 1)

Mean of 10 MVC attempts (‘‘as hard as possible’’) (cmH2O); in supine position

Definition of PFM component (unit)

(continued)

After 16 weeks graded PFMT: Actual pressure (P ¼ 0.0009) (18.9 10.4 < 29.5 12.9) and rate of rise pressure (P ¼ 0.004) (32.9 16.6 < 49.0 18.9); urine loss (P ¼ 0.03) (14.1 14.1 > 2.4 1.4) After 6 weeks: endurance: (a) (P < 0.0005) SCV: 5.69 3.42 < 17.25 8.80; NMVC: 5.94 3.62 < 12.00 6.12), (b) (P < 0.0005) SCV: 2.35 2.92 < 9.06 2.20; NMVC: 3.60 3.99 < 9.63 1.15), MMC strength (P < 0.0005) SCV: 4.88 6.68 < 19.19 10.37; NMVC: 8.00 6.72 < 18.38 14.30), 10 hr-pad-test: SVC (P < 0.036) (16.04 27.26 > 3.41 4.79), frequency of leakage (P ¼ 0.0005) SCV: 4.04 3.32 > 1.15 2.55; NMVC: 3.18 1.85 > 0.79 1.65 After 6 weeks exercise program: Vaginal squeezing pressure for both groups (P < 0.05) (PFMT: 14.7 5.8 < 24.6 9.1; RBT: 15.2 10.5 < 24.4 11.0) ; two positive 1-hr pad-tests before intervention, after intervention all negative, improvement leakage episodes and self-rating scores about quantity of urine leakage in both groups (all P 0.05) After 5 weeks of physical therapy and interferential current treatments, PFM strength in

After 6 months of PFMT, positive correlation between " of PFM strength and better pad-test (r ¼ 0.23, P ¼ 0.05) and PFM strength and leakage index (r ¼ 0.34, P < 0.01)

Outcome: comparison before/ after intervention

Pelvic Floor Muscle Activation and Strength: A Systematic Review 503

cmHg, centimeter mercury; cmH2O, centimeter water; g, grams; mmHg, millimeter mercury; mmHg sec 1, millimeter mercury per second; ns, non-significant; hr, hour; sec, seconds; sign., significant; wk, week; y, years; ",

described PFM-training protocols as well as the measurement methods varied strongly among studies. All studies performed strength (terminology: strength, force, pressure) measurements. The probes varied among studies, although they all used well-established medical devices. The measured PFM components and their definitions varied among studies.

Changes in SUI were assessed using pad-tests (various among studies) among other methods. All studies showed an improvement of the PFM component under measurement and a decrease in urine loss after the interventions. The high degree of methodological heterogeneity observed among the eligible trials limited the possibilities for considering pooling the results from the individual studies in order to carry out a meta-analysis.

Risk of Bias

Table II depicts the results of the risk of bias analysis.

All nine cross-sectional studies showed a high risk of random sequence generation, which of course is due to the study design, that is, the group allocation according to presence or absence of SUI. Group allocation, that is, how SUI was diagnosed was described in seven studies. Seven studies provided no information regarding blinding of personnel (participants of course could not be blinded against their diagnoses) and eight did not report who conducted the data analysis and if this person was blinded. Three studies addressed incomplete data while no study showed a reporting bias.

As for the pre-post designed studies two showed a low risk of random sequence generation, two a high risk and one did not provide any information. Regarding allocation concealment, two revealed a low risk, one a high risk and two missed the information. All studies showed a high risk concerning performance bias, due to impossibility of blinding patients and staff against intervention. None of the studies addressed detection bias. Concerning incomplete data addressed, two studies showed a low risk of bias and three studies did not provide sufficient information. All studies showed a low risk of reporting bias.

Over all studies (cross-sectional and pre-post designed), twelve showed unclear information regarding other sources of risk of bias. One had a high risk and one a low risk of other source of bias. The main other source of risk of bias was missing information regarding inclusion and exclusion criteria, especially regarding the presence or absence and degree of prolapse.

DISCUSSION Main Findings

increase; , decrease.

incontinent; VAS, visual analogue scale.

CON, continence/continent; CT, clinical trial; EMG, electromyography; IEG, intensive exercise group; HEG, home exercise group; MMC, mean maximal contractions; NMVC, near-maximal voluntary contraction protocol;

test, n ¼ 48: G1 (0–2 g loss): n ¼ 17, age: mean ¼ 46.4 years ( 10.2 years); G2 (>2– 10 g loss): mild intensity: n ¼ 16, age: mean ¼ 46.3 years ( 10.6 years); G3 (>10 g loss): moderate intensities: n ¼ 15, age: mean ¼ 51.7 years ( 11.5 years)

Neurourology and Urodynamics DOI 10.1002/nau

PFM, pelvic floor muscles; PFMT, pelvic floor muscle training; RBT, rectal balloon training; SCV, submaximal voluntary contraction protocol; SEMG, surface electromyography; SUI, stress urinary incontinence/stress urinary

test (g), number of pads/day; severity of complaint (cm on VAS) contraction of the pelvic floor by pulling the probe’’. ! PFM strength: cmHg ¼ difference between these values.

3. Test repetitions (1 min intervals) ! max. values taken for statistical analysis.

Position: Hook-lying state with feet 30 cm apart

Measurement method First author, year

TABLE 4. (Continued)

Study design

Subject characteristics: CON vs. SUI, sample size (n), age

Evaluated PFM component (variable)

Definition of PFM component (unit)

each group (P < 0.05) (G1: 2.53 0.82 < 4.18 0.95; G2: 2.22 0.93 < 3.91 1.20; G3: 1.53 1.116 < 3.50 1.15) number of pads (P < 0.05) (G1: 1 0 > 0 0; G2: 1.50 0.82 > 0.13 0.34; G3: 3.80þ1.26 > 0.93 0.70), amount of urinary leakage (P < 0.05) (G1: 0.86 0.33 > 0.02 0.08; G2: 2.9 1.4 > 0.31 0.26; G3: 23.64 15.62 > 3.38 3.32)

Luginbuehl et al.

Outcome: comparison before/ after intervention

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In summary, higher maximal, mean, endured and increase of PFM strength and earlier onset of PFM activation were positively associated with female urinary continence. However, a high variation of testing procedures, measurement methods and terminology as well as definitions of the evaluated PFM activation and strength components and their characteristics were found among the selected studies, causing heterogeneity of the results. In addition, the lack of information on the exact intervention given to the study participants and intervention’s standardization, limit the comparison of the outcomes among the studies. Moreover, unclear terminology, test instructions and applications were applied. Maximal contraction tests were well defined while other tests, such as ‘‘3 times squeezing’’25 or ‘‘number of contractions before fatigue’’,24 remained vague regarding the description of

Pelvic Floor Muscle Activation and Strength: A Systematic Review contraction intensity and duration. A clear definition of ‘‘fatigue’’ was lacking.24 The ‘‘rate of rise pressure’’23 may be an interesting parameter for a fast PFM contraction, but was performed as a voluntary contraction, although the continence guaranteeing PFM contraction seems to be a reflexive involuntary type of muscle action.30–32 Balloon catheters have the potential of being adequate for maximal strength testing, but not for rate of rise pressure23 due to the low pass filter characteristic of the elastic component of the balloon. A custom-built dynamometer measuring in Newton14 bears the risk of lever arm artifacts due to a difficult standardization concerning ideal and reproducible insertion depth17 of vaginal application of the dynamometer. All included studies measuring PFM activity16,18,19 used non-normalized raw surface EMG data to compare independent groups (continent, SUI), although EMG normalization from a reference contraction is crucial for comparing different individuals, muscles or after reapplied electrodes.33,34 Strengths and Limitations

To the best of our knowledge this was the first comprehensive systematic review conducted on the topic of PFM activation and strength components influencing female continence and SUI. The thoroughness of the literature search due to the interdisciplinary team comprising an external professional librarian, a medical doctor and physiotherapist both specialized in uro-gynecology, and sports and movement scientists specialized in research methodology, biomechanics, exercise physiology, and PFM diagnostics, is certainly one of the strengths of this systematic review. However, this study has some flaws, such as the rather small number of trials and subjects included, the heterogeneity of terminology, test procedures, and outcomes. Due to these facts the planned meta-analysis was not applicable. Participants of the included studies were aged between the third and the sixth decade only.

This means heterogeneity in age on the one hand and on the other hand data of subjects from the seventh decade on, which typically show a high prevalence of SUI27–29 was missing.

The difference in content validity of outcomes depends on the study type due to the fact that pre-post designed studies may detect cause relationships between SUI and PFM activation and strength components, while cross-sectional studies cannot.

CONCLUSION

Taking into account the limitation of the high methodological variability across the studies under investigation, this systematic review suggests that PFM activation and strength components are associated with female urinary continence and SUI and, therefore generally supports the importance of PFMtraining for SUI patients as improvements of PFM function may be related to improvement in incontinence symptoms.

However, the observed use of different and inconsistent definitions as well as terms for PFM activation and strength components makes it difficult to get a clear-cut picture of SUI mechanisms.

To get a clearer insight into the influence of PFM activation and strength components on continence and SUI, there is a need for more detailed knowledge about physiological and pathophysiological function of the PFM in terms of activation and strength characteristics and their mechanisms, such as muscle metabolism (aerobic, anaerobic alactacid, and lactacid), muscle action forms (isometric, eccentric, concentric, eccentric-concentric: slow or fast stretch shortening cycle), sensorimotor and Neurourology and Urodynamics DOI 10.1002/nau

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muscle fiber recruitment behavior, inhibition, voluntary, and non-voluntary contractions, maximal strength, rate of force development, endurance of rate of force development and a combination of all these aspects.35,36 Especially PFM function has to be clarified for functional movements with short impacts typically provoking SUI37 (e.g., running, jumping, coughing) and not only in non-functional isolated test situations (e.g., maximal voluntary contraction in supine).38,39 On the basis of consistent terminology, standardized instructions of patients’ test behavior provoking the respective PFM component, thereto well-matched diagnostic instruments and based on those findings specific PFM-training protocols could be developed.

ACKNOWLEDGMENTS

We would like to acknowledge Slavko Rogan for peer reviewing the search strategy according to the guidelines by Sampson et al.12 Many thanks also to Jacqueline Buerki for proof reading this article.

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Supporting Information

Additional supporting information may be found in the online version of this article at the publisher’s web-site.

2.2 Intra-session testâ&#x20AC;&#x201C;retest reliability of pelvic floor muscle electromyography during running

International Urogynecology Journal 2013 Sep;24(9):1515-22

Helena Luginbuehl CĂŠcile Greter Doris Gruenenfelder Jean-Pierre Baeyens Annette Kuhn Lorenz Radlinger

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Int Urogynecol J (2013) 24:1515–1522 DOI 10.1007/s00192-012-2034-2

ORIGINAL ARTICLE

Intra-session test–retest reliability of pelvic floor muscle electromyography during running H. Luginbuehl & C. Greter & D. Gruenenfelder & J-P. Baeyens & A. Kuhn & L. Radlinger

Received: 14 June 2012 / Accepted: 20 December 2012 / Published online: 30 January 2013 # The International Urogynecological Association 2012

Abstract Introduction and hypothesis The prevalence of female stress urinary incontinence is high, and young adults are also affected, including athletes, especially those involved in “high-impact” sports. To date there have been almost no studies testing pelvic floor muscle (PFM) activity during dynamic functional whole body movements. The aim of this study was the description and reliability test of PFM activity and time variables during running.

Methods A prospective cross-sectional study including ten healthy female subjects was designed with the focus on the intra-session test–retest reliability of PFM activity and time variables during running derived from electromyography (EMG) and accelerometry.

Results Thirteen variables were identified based on ten steps of each subject: Six EMG variables showed good reliability (ICC 0.906–0.942) and seven time variables did not show good reliability (ICC 0.113–0.731). Time variables (e.g. time difference between heel strike and maximal acceleration of vaginal accelerator) showed low reliability. However, relevant PFM EMG variables during running (e.g., pre-activation, minimal and maximal activity) could be identified and showed good reliability.

Conclusion Further adaptations regarding measurement methods should be tested to gain better control of the kinetics H. Luginbuehl (*) : C. Greter : D. Gruenenfelder : L. Radlinger Bern University of Applied Sciences, Health, Murtenstrasse 10, 3008 Bern, Switzerland e-mail: helena.luginbuehl@bfh.ch H. Luginbuehl : J.-P. Baeyens Vrije Universiteit Brussel, Faculty of Physical Education and Physiotherapy, Brussel, Belgium A. Kuhn Urogynaecology, Women’s Hospital, Bern University Hospital and University of Bern, Bern, Switzerland

and kinematics of the EMG probe and accelerometers. To our knowledge this is the first study to test the reliability of PFM activity and time variables during dynamic functional whole body movements. More knowledge of PFM activity and time variables may help to provide a deeper insight into physical strain with high force impacts and important functional reflexive contraction patterns of PFM to maintain or to restore continence.

Keywords Jogging . Pelvic floor . Reproducibility . Stress urinary incontinence

Introduction Stress urinary incontinence (SUI) is a widespread condition among women of every age, meaning that young female adults are also affected [1]. Brown et al. [2] investigated the prevalence, frequency, and severity of urinary symptoms by questioning nulliparous women aged ≥18 years during pregnancy: 10.8 % of the women reported urinary incontinence according to the authors’ definition, which consisted of experiencing leakage of urine at least once per month during the period of 12 months before pregnancy with their first child.

Among the young women suffering from SUI, young female athletes are also affected, and the highest prevalence is found in those involved in “high-impact” sports [3]. Carls [4] found that 28 % of the 14- to 21-year-old college and high school female athletes responding to a survey assessing the prevalence of SUI and the need for preventative urinary incontinence education reported symptoms of SUI during sports activities. More than 16 % of the responding female athletes with incontinence reported a negative effect on their quality of life that had an impact on their social life or desire to continue participating in sports [4]. Simeone et al. [5] assessed

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the prevalence of lower urinary tract symptoms (LUTS) and incontinence in female athletes. They found a prevalence of urinary incontinence of about 30 % (9.1 % SUI, 7.7 % mixed incontinence, 13.1 % urge incontinence) and also a more frequent association of high-impact sports with incontinence as opposed to low-impact sports with LUTS [5]. Eliasson et al.

[6] investigated trampolining, which exerts extreme forces on the pelvic floor muscles (PFM) with every impact on the trampoline, and found that 80 % of the 35 trampolinists with a mean age of 15 years participating in the National Swedish Trampoline team reported urinary leakage during trampolining. All 28 subjects reporting urine leakage experienced the incontinence during trampoline training, and two subjects also reported leakage during other sports activities. None reported leakage during coughing, sneezing or laughing. However, not only female athletes suffer from SUI; Salvatore et al. [7] found that SUI affects a significant proportion of young women practicing non-competitive sports activities, and that it can cause sufferers to give up the sport or limit its practice.

Women who are physically active raise their intraabdominal pressure more frequently than sedentary women [8], and according to Bø et al. [3] it is therefore debatable whether female athletes have strong PFM as a result of their regular training, thus preventing SUI, or whether excessive loading of the PFM may stretch and weaken them and cause SUI. To guarantee continence, the PFM must be able to contract strongly [9], rapidly, and reflexively [10, 11]. The ability of PFM to generate rapid and strong contractions results in the generation of an adequate squeeze pressure in the proximal urethra, which maintains a pressure higher than that in the bladder, thus preventing leakage [12]. Rapid PFM contractions are crucial for maintaining continence preceding an abrupt rise in the intra-abdominal pressure associated with coughing and sneezing [11, 12]. Several studies showed that the PFM function regarding rate of force development was impaired in incontinent women compared with continent women [10, 11].

According to Hodges et al. [13], it is well known that muscles surrounding the abdominal cavity, such as the diaphragm and abdominal muscles, are active in association with tasks that challenge spinal stability. In their investigation of whether PFM contribute to the pre-programmed postural activity of the trunk muscles prior to predictable challenges to spinal stability, they found a mean onset of the PFM electromyography (EMG) activity of 28.4 ms prior to the onset of EMG activity of the deltoid during single fast arm movements [13]. Sjödahl et al. [14] found even earlier onsets of PFM activity relative to arm lifts and also showed a feed-forward response of the PFM to the start of a leg lift.

To date there have been no such studies investigating PFM activity preceding movements of the whole body, as occurs, for example, during sports activities.

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The highest prevalence of SUI is found in sports involving high-impact activities [3]. Running is one of the most popular physical activities worldwide. Zadpoor and Nikooyan [15], in their systematic review investigating the relationship between lower-extremity stress fractures and the ground reaction force, found peak ground reaction forces between 2.40 and 3.87 times the body weight. With increasing running speed, the ground contact gets shorter and the ground reaction force higher [16].

To date there have been no devices measuring the strength of the PFM during dynamic functional whole body movements. Consequently, EMG measurements are the only available appropriate method and therefore this investigation focuses on PFM activity during running by means of surface EMG. EMG in general is an often used and well-established method of measuring and investigating the voluntary or involuntary activity of skeletal muscles [17]. Electromyography during dynamic functional whole body movements allows the investigation of inter- and intramuscular coordination. Through determination of time variables of muscle activity, critical elements of muscle activity can be examined, e.g., precipitate or lagged activity [13, 14]. To the authors’ knowledge there are no such studies investigating the time parameters of the PFM during dynamic functional whole body movements.

A better understanding of the PFM activity pattern during running would be relevant to the development of more specific diagnostic methods and therapy. Parameters such as PFM activity peak, time to activity peak (“EMG–time curve”), precontraction and time of pre-contraction (anticipation, feed forward), all in relation to the time of the heel-strike, could be crucial for gaining a better insight.

The aim of this study was to investigate PFM activity during running. The specific goals were to describe and test the reliability of the PFM EMG activity and time variables during running.

Materials and methods Study design The current investigation was designed as a prospective crosssectional study to characterize PFM activity during running by means of vaginal EMG. It focuses on the intra-session test– retest reliability of time and activity variables derived from accelerometry and EMG. The study was conducted in accordance with the Declaration of Helsinki, and all subjects gave written informed consent. Following an unwritten agreement with the ethics committee, approval was not required as the investigation concerned a physiotherapy-relevant reliability low-risk study involving healthy volunteer students only and the investigation was a mandatory part of the physiotherapy study program.

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Subjects Ten female subjects from the physiotherapy bachelor program at Bern University of Applied Sciences, Health Section, were included on condition that they were aged between 20 and 35 years, were nulliparae, were anamnestically healthy, had a BMI between 20 and 30 kg/m2 and were physically able to cope with the requirements of treadmill running. Subjects who were pregnant, who were having their period or who had had surgery in the urogenital region as well as those with acute vaginal infection, incontinence, pelvic floor complaints, any pain during jogging, acute back or joint complaints or nickel or latex allergy were excluded. All subjects were familiar with the correct PFM contraction through their urogynecological lessons at the physiotherapy school. For the demographics of the subjects see Table 1.

Instrumentation The running treadmill system used was a Quasar med (h-pcosmos, Traunstein, Germany). All subjects had to perform their running at a velocity of 8 km/h and 1° inclination. A vaginal surface EMG probe (Periform®; Neen UK, Oldham, Lancashire, UK) was used to measure pelvic floor muscle activity. The differential adhesive surface electrode (Nicolet; Viasys Healthcare, Warwick, UK) was fixed on the right iliac crest. EMG was measured with a Tele Myo 2400 G2 device (Noraxon USA; Scottsdale, AZ, USA).

Three accelerometers (Model 317A 3-D accelerometers; Noraxon USA Inc) were attached with double- and singlesided adhesive tape (3 M and 3 M Durapor, Rueschlikon, Switzerland) on the lateral malleolus of the right leg to identify the time point of heel strike (T0), on the sacrum and on the external part of the vaginal probe to identify the vertical impacts at certain time points of the running cycle (see Table 2). The vaginal accelerometer was additionally coated with a latex finger stall (Sanor Lamprecht, Regensdorf, Switzerland).

Procedures After emptying their bladder, receiving the test information and giving their written informed consent, the subjects were Table 1 Subject demographics Parameter

Unit

Included subjects Age Weight Height Body mass index

n Years Kilograms Meters kg/m2

n or mean ± standard deviation 10 24.10±2.77 57.70±5.56 1.67±0.07 20.75±1.66

equipped with the accelerometers and EMG reference electrode. The subjects were instructed in the vaginal insertion of the EMG probe using ultrasound lubrication and then performed the insertion themselves. The subjects wore a loose jogging suit and running shoes.

Electromyography was measured twice for 30 s while the subjects were at rest and totally relaxed, and twice for 5 s during maximum voluntary contraction in both a standing and supine position. Thereafter, the subjects performed a warm-up of walking (5 km/h) for 30 s, then running for 2 min 30 s in a steady state (8 km/h) to get familiar with the treadmill. After a short break of 1 min the treadmill was started again and accelerated up to 8 km/h. When the treadmill and the subject reached the final velocity of 8 km/h and were in a steady state the data acquisition was started: EMG and accelerometry were measured continuously for 60 s and the first 10 steps of these 60 s were analyzed. The subjects were instructed to run and to breathe as normally as possible and not to activate their pelvic floor muscles voluntarily and not to talk for 60 s.

Data reduction Electromyography and accelerometer data were amplified with a gain of 500 and 1,000 and sampled at a rate of 2 kHz using a 12-bit analog-to-digital converter (ME-2600i; SisNova Engineering, Zug, Switzerland) and the software package “Analoge und digitale Signalverarbeitung” (ADS) version 1.12 (uk-labs, Kempen, Germany).

For the sampling frequency of 2 kHz, the sampling interval (dt) was 0.5 ms. The EMG signals were first lowpass filtered with a cut-off frequency of 1 kHz to avoid aliasing and high-pass filtered with 10 Hz (2nd order zero lag Butterworth filter, 24 dB/octave filter steepness).

Second, EMG data were calculated as amplitude (ųV) or as moving average (time window 200 ms) root-mean-square values and normalized to maximum voluntary contraction (MVC; (%) EMG).

One hundred percent of EMG equals the average of the maximum values during the two times 5 s of the MVC. This MVC testing while standing was chosen instead of the usual MVC testing while in a supine position [18] because it seems more functional in comparison with running.

Accelerometer signals were low-pass (2nd order zero lag Butterworth) filtered with a cut-off frequency of 30 Hz. The different time and activity variables are shown in Table 2. All variables were analyzed using the software package “Analoge und digitale Signalverarbeitung” (ADS) version 1.12 (uk-labs, Kempen, Germany).

Electromyography data at rest and at MVC were averaged over the test and retest, as were EMG data during running consisting of ten steps of the right leg for each subject.

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Table 2 Labels, units, and description of time and activity variables derived from accelerometry and electromyography (EMG) Variable (unit)

Description

To identify

T0

Heel strike

The initial time point of the impact and beginning loading phase and strain of the PFM

Tsac (ms)

Time difference between heel strike (T0) and first acceleration of the sacrum accelerator

To identify the time difference (delay) between T0 and Tsac as a more bony part compared with the vaginal accelerator, which is attached to rather less rigid muscle structures

Tvagmin (ms)

Time difference between heel strike (T0) and minimal acceleration of the vaginal accelerator

Periodic characteristics of the acceleration of the vaginal sensor/PFM movements during cyclic running (from minimum to maximum)

Tvagmax (ms)

Time difference between heel strike (T0) and maximal acceleration of the vaginal accelerator

Periodic characteristics of the acceleration of the vaginal sensor/PFM movements during cyclic running (from maximum to minimum)

Temgmin (ms)

Time difference between heel strike (T0) and minimal EMG activity

Temgmax (ms) EMGmin ((%) EMG)

Time difference between heel strike (T0) and maximal EMG activity Minimal EMG activity

Periodic characteristics and an “ON/OFF criterion” of the PFM activity in comparison to rest activity during supine position or standing Periodic characteristics of PFM activity

EMGmax ((%) EMG)

Maximal EMG activity

EMGmin-max ((%) EMG) EMGT-50 ((%) EMG)

Mean EMG activity between EMGmin and EMGmax EMG activity at heel strike (T0) minus 50 ms

EMGT0 ((%) EMG)

EMG activity at heel strike (T0)

EMGT-50-T0 ((%) EMG)

Mean EMG activity between minus 50 ms and T0 Linear regression of EMG activity between EMGmin and EMGmax Linear regression of EMG activity between −50 ms and T0

EMGmin-max (reg) ((%/s) EMG) EMGT-50-T0 (reg) ((%/s) EMG)

Statistical analysis Descriptive statistics were performed for each variable (mean, standard deviation).

The reliability test followed the three steps suggestions of Weir [19]: In order to identify possible systematic errors between the repeated measures, the Wilcoxon rank order test was applied at rest and the MVC tests, and the Friedman test to compare the dependent time and EMG variables over the ten steps. Intra-session test–retest reliability (consistency) was calculated with the intraclass correlation coefficient (ICC 3.1; i.e., relative reliability) and the standard error of measurement (SEM; i.e., absolute reliability). Additionally, the minimal detectable differences (MDDs) using a 95 % confidence interval and the mean absolute differences among all repeated measures were calculated.

Portney and Watkins [20] suggest as a general guideline that ICC values above 0.75 are indicative of good reliability and those below 0.75 of poor to moderate reliability.

Periodic characteristics and an “ON/OFF criterion” of the PFM activity in comparison to rest activity during supine position or standing Periodic characteristics of PFM activity The range of PFM activity The pre-activity of PFM as a regulatory component of anticipation The EMG amplitude at the initial time point of the impact and beginning the loading phase and strain of the PFM The mean pre-activity The gradient of range of amplitude The gradient of pre-activity

The level for significances was set at P<0.05. All statistics were calculated using SPSS 17 for Windows (SPSS; Chicago, IL, USA) as well as Microsoft Excel 2007 (Microsoft, Redmond, WA, USA).

Results Figure 1 shows samples of the amplitude and time variability of EMG–time curves within the ten steps of one subject.

Thirteen variables were selected based on ten steps of each subject. Descriptive statistics and reliability calculations are presented in Tables 3 and 4. All baseline data of EMG during rest or MVC show good reliability. The analysis of systematic errors within repeated measures by Wilcoxon or Friedman tests revealed only nonsignificant values for all variables. ICCs for the time variables (ms) ranged from 0.113 to 0.731. The highest reliability indexes were found for all EMG-amplitude-derived variables

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Fig. 1 Exemplary EMG–time curves derived from the ten steps of subject 1. The curves start and end at the minimum EMG (EMGmin) activity of each step cycle. The dotted line at −50 ms (EMGT-50) represents the start of the pre-activity phase which ends at T0 (dotted line at 0 ms = heel strike). Subsequently, EMG–time curves increase to their activity maximum (EMGmax)

((%) EMG), which were superior to 0.750 and ranged between 0.906 and 0.942. The combined time–amplitude variables ((%/s) EMG) did not reach excellent reliability, with values of 0.542 and 0.704.

Discussion The purpose of this study was to describe and reliability test the variables that characterize PFM activity and time behavior during running. We selected a total of 13 variables (see Table 2), which were tested with regard to their intra-session retest reliability based on ten steps of each subject. Generally, EMG variables showed good time variables and poor reliability.

EMG variables Among the technologies used to study PFM neural control, EMG of the PFM has gained the most attention and clinical relevance [21]. Grape et al. [18] tested the retest reliability of isolated PFM contraction exercise by means of EMG in healthy nulliparae women and showed good reliability

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(ICC=0.82–0.96) of average activity (during a 10-s long squeeze), peak (maximum value), work (the area under the curve), and baseline (resting value); the ICC for speed (peak divided by time taken to reach the peak) was between 0.65 and 0.85. In contrast to our investigation, Gollhofer et al. [22] investigated the EMG reliability in leg muscles during running at constant velocity. They found high reliability coefficients for day-to-day and week-to-week comparisons and also, with regard to qualitative comparisons of EMG, high reproducibility of the shape of the patterns. However, to date there have been no reliability studies concerning vaginal EMG during dynamic functional whole body movements of the subjects.

In our study 6 of the 8 identified EMG variables of PFM activity during running showed good ICC values. Moderate to almost good ICCs of EMG measurements were found for regressions.

The minimal EMG (EMGmin) activity during running shows good reliability. Mean minimal EMG activity during running shows an activity about 24 % higher than mean PFM EMG activity during rest in a standing position. These findings show a constantly increased PFM tone during running, and an aerobic strain of PFM during running could be hypothesized. The increased tonicity of PFM activity was also found in the study of Hodges et al. [13] during repetitive arm movements.

The maximal EMG (EMGmax) activity shows good reliability. The mean activity level was at 124.3 (%) EMG. Hodges et al. [13] found, during repetitive arm movements, bursts of anal and vaginal EMG activity in association with the frequency of arm movement, but they did not provide information about the activity level. These findings suggest a higher PFM activity compared with MVC owing to reflexive and reactive force generation during running.

The mean EMG activity between EMGmin and EMGmax variables shows good reliability and a mean level of 99.2 (%) EMG. These values are about 68 (%) EMG higher than during standing at rest. Schulte-Frei [23] examined PFM activity while subjects stood on stable and unstable ground and during one-leg stands. As her MVC normalization referred to an MVC taken individually during co-contraction while performing a set of other exercises for muscle testing, these values cannot be compared with those found in our study.

Nonetheless, as she found increasing PFM mean activity from standing on stable ground compared with standing on unstable ground and an even higher activity during the one-leg stands, these findings are of interest as, during running a temporary one-leg stand takes place as well.

The variable linear regression of EMG activity between EMGmin and EMGmax shows almost good reliability.

The EMG activity at heel strike (T0) minus 50 ms shows good reliability and an activity level of 72.1 (%) EMG, which is about 40 (%) EMG higher than during rest.

Hodges et al. [13] also found a mean PFM pre-activity of

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Table 3 Descriptive statistics (mean ± SD), reliability indexes (intraclass correlation coefficient, standard error of measurement), minimal detectable difference for variables, and test for systematic error (Wilcoxon, difference) for activity variables Variable

Units

Mean

SD

ICC

Rest supine

(%) EMG

14.2

9.7

0.999a

Rest standing MVC supine MVC standing

(%) EMG ųV ųV

31.3 64.7 57.6

a

4.0 27.4 20.1

0.993 0.867a 0.914a

SEM

MDD

Wilcoxon P value

Difference Mean

3.0 4.0 8.7 6.3

8.3 11.1 24.1 17.6

0.398 0.173 0.445 0.508

0.1 0.7 1.3 1.1

Mean arithmetic mean, SD standard deviation, ICC intraclass correlation coefficient, SEM standard error of measurement, MDD minimum detectable difference, Wilcoxon Wilcoxon signed-rank test; Difference arithmetic mean of test–retest differences a

Indicates ICCs>0.750

28.4 ms prior to arm movements and Sjödhal et al. [14] a median PFM pre-activity of 206 ms prior to the start of a leg lift at a level of 20 (%) EMG. These findings confirm the assumption that the increased PFM activity 50 ms prior to the heel strike could indicate reliable PFM pre-activity during running.

The EMG activity at heel strike (T0) shows good reliability. As the PFM activity shows higher values than the activity at rest in a standing position, this variable confirms the assumption of a PFM pre-activity.

The mean EMG activity between minus 50 ms and T0 shows good reliability. Again, the values are higher compared with the PFM activity during rest in a standing position, which could indicate PFM pre-activity.

The linear regression of EMG activity between −50 ms and T0 before the heel strike shows moderate reliability. This value

((%/s) EMG) cannot be used to investigate PFM pre-activity, as it cannot be compared with the PFM MVC ((%) EMG).

Time variables The time variables show large ranges and therefore low reliability. Four (time difference between heel strike (T0) and minimal acceleration of VagAcc; time difference between heel strike (T0) and maximal acceleration of VagAcc; time difference between heel strike (T0), and minimal EMG activity; time difference between heel strike (T0) and maximal EMG activity) out of five time variables showed low ICC values.

The only variable showing almost good reliability was the time difference between heel strike (T0) and first acceleration of SacAcc. A possible explanation could be a more precise force transmission on bony structures than on less rigid muscle structures.

Table 4 Descriptive statistics (mean ± SD), reliability indexes (ICC, SEM), MDD for variables, and test for systematic error (Friedman, difference) for time and activity variables derived from accelerometry and electromyography Variable

Units

Mean

SD

ICC

SEM

MDD

Friedman P value

Difference Mean

Tsac Tvagmin Tvagmax Temgmin Temgmax EMGmin EMGmax EMGmin-max EMGT-50 EMGT0

ms ms ms ms ms (%) (%) (%) (%) (%)

EMG EMG EMG EMG EMG

72.3 −10.0 75.5 −3.7 214.2 55.0 124.3 99.2 72.1 64.0

14.8 42.3 13.0 57.2 51.8 24.9 99.2 81.6 40.1 27.0

0.731 0.169 0.113 0.452 0.390 0.906a 0.937a 0.942a 0.935a 0.917a

4.7 13.4 6.6 18.1 16.4 7.9 31.4 25.8 12.7 8.5

13.0 37.0 18.4 50.1 45.4 21.8 87.0 71.5 35.2 23.6

0.751 0.628 0.694 0.604 0.517 0.311 0.848 0.796 0.064 0.164

0.4 1.4 3.2 1.9 −2.3 −1.6 5.6 2.9 −1.5 −1.6

EMGT-50-T0

(%) EMG

66.6

31.3

0.942a

EMGmin–max (reg) EMGT-50-T0 (reg)

(%/s) EMG (%/s) EMG

155.9 −34.6

131.7 98.4

0.704 0.542

9.9 41.6 31.1

27.4 115.4 86.3

0.226 0.494 0.709

−1.3 16.7 −13.1

Mean arithmetic mean, SD standard deviation, ICC intraclass correlation coefficient, SEM standard error of measurement, MDD minimum detectable difference, Friedman Friedman test nonparametric repeated measures comparisons; difference arithmetic mean of test–retest differences a

Indicates ICCs>0.750

Int Urogynecol J (2013) 24:1515–1522

To our knowledge, there has been to date no literature published on the time variables of PFM contraction characteristics, and therefore the results of this study can only be discussed in the context of other findings. Leitner et al. [24] were able to show good reliability regarding time variables in stair ascent in the elderly, but clearly lower reliability in stair descent, which seems to be more comparable to impacts during running at slow velocity. Masani et al. [25] investigated the variability of the ground reaction force pattern during walking in relation to different constant speeds. He found an increasing trend in variability with speeds from 3 to 8 km/h; however, the minimum variability speeds of 5.5–5.8 km/h were within the limits of usual walking speeds. This result indicates that the neuromuscular locomotor system was most stable at usual walking speed.

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5 km/h for 30 s and then a running-in of 8 km/h for 2.5 min, both on the treadmill, before the measurements took place.

Shoes According to Maurer et al. [27], the characteristics of human locomotion may change for different boundary conditions such as footwear. In our study, the subjects wore their own running shoes. Wright et al. [28] found no difference between soft and hard shoe impact forces. However, peak rates of loading were greater for the hard shoe than for the soft shoe. Therefore, an influence of footwear on gait and force transmission cannot be excluded. Future studies should require standardized running shoes or running barefoot.

Methodical problems of vaginal probe measurements Conclusion Because vaginal probes cannot be fixed directly onto the muscles, as they use self-adhesive electrodes, minimal shifts of vaginal probes might go unnoticed. In the present study the attachment with tape of the accelerometer to the vaginal probe seemed to be sufficient. However, greater movement of the vaginal probe (EMG and accelerometer) in contrast to the sacral time variables (Tsac) cannot be totally excluded and is supported by the lower ICCs of the vaginal time variables (Tvagmin and Tvagmax). In a future study this issue could be addressed by using a device such as a STIMPON® electrode (Innocept Biobedded Medizintechnik, Gladbeck, Germany).

This electrode adapts its shape to individual vaginal cavities and therefore movement could be avoided.

Cross-talk Electromyography is a reliable method of assessing PFM activity in healthy women [18]. However, Bo and Sherburn [26] conclude in their overview assessing PFM function and strength that the EMG signals must be interpreted with caution because the risk of cross talk from other muscles is high and because of the variability in electrode placement within the vagina. To date, cross-talk during functional dynamic whole body movements for PFM activity has not yet been examined and is therefore difficult to estimate.

To the best of our knowledge, the current study is the first to test PFM activity and time variables during dynamic functional whole body movements with regard to their reliability. It provides a first insight into the PFM activity of healthy women during running. EMG variables of good reliability could be shown, while poor evidence was gained for the reliability of time variables. In particular, further studies should consider adaptations regarding the vaginal probe and footwear. The test application and reliability will likely have to be modified and retested in different populations and given the anatomical changes seen associated with SUI and pelvic organ prolapse. More knowledge of PFM EMG variables and time variables may help to provide a deeper insight into physical strain with high force impacts and functionally important reflexive contraction patterns of PFM to maintain or to restore continence.

A further consequence is support for the development of more sophisticated diagnostic instruments and therapeutic approaches.

Acknowledgements The authors thank Parsenn-Produkte AG (Küblis, Switzerland) for providing the vaginal surface EMG probes.

Conflicts of interest None

Treadmill Some subjects were not familiar with treadmill running, which possibly resulted in a nonphysiological gait compared with running on natural ground at usual individual speeds.

However, running on natural ground at individual speeds would be problematic with regard to speed standardization.

To address the problem of a lack of familiarity with treadmill running, all the subjects performed a warm-up of

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during pregnancy: prevalence, incidence, and associated risk factors. Int Urogynecol J 21:193–202 Bø K (2004) Urinary incontinence, pelvic floor dysfunction, exercise and sport. Sports Med 34:451–464 Carls C (2007) The prevalence of stress urinary incontinence in high school and college-age female athletes in the Midwest: implications for education and prevention. Urol Nurs 27:21–24 Simeone C, Moroni A, Pettenò A et al (2010) Occurrence rates and predictors of lower urinary tract symptoms and incontinence in female athletes. Urologia 77:139–146 Eliasson K, Larsson T, Mattsson E (2002) Prevalence of stress incontinence in nulliparous elite trampolinists. Scand J Med Sci Sports 12:106–110 Salvatore S, Serati M, Laterza R, Uccella S, Torella M, Bolis PF (2009) The impact of urinary stress incontinence in young and middle-age women practising recreational sports activity: an epidemiological study. Br J Sports Med 43:1115–1118 Eliasson K, Edner A, Mattsson E (2008) Urinary incontinence in very young and mostly nulliparous women with a history of regular organised high-impact trampoline training: occurrence and risk factors. Int Urogynecol J 19:687–696 Shishido K, Peng Q, Jones R, Omata S, Constantinou CE (2008) Influence of pelvic floor muscle contraction on the profile of vaginal closure pressure in continent and stress urinary incontinent women. J Urol 179:1917–1922 Deffieux X, Hubeaux K, Porcher R, Ismael SS, Raibaut P, Amarenco G (2008) Abnormal pelvic response to cough in women with stress urinary incontinence. Neurourol Urodyn 27:291–296 Morin M, Bourbonnais D, Gravel D, Dumoulin C, Lemieux MC (2004) Pelvic floor muscle function in continent and stress urinary incontinent women using dynamometric measurements. Neurourol Urodyn 23:668–674 Miller J, Kasper C, Sampselle C (1994) Review of muscle physiology with application to pelvic muscle exercise. Urol Nurs 14:92–97 Hodges PW, Sapsford R, Pengel LHM (2007) Postural and respiratory functions of the pelvic floor muscles. Neurourol Urodyn 26:362–371 Sjödahl J, Kvist J, Gutke A, Öberg B (2009) The postural response of the pelvic floor muscles during limb movements: a methodological electromyography study in parous women without lumbopelvic pain. Clin Biomech 24:183–189

Int Urogynecol J (2013) 24:1515–1522 15. Zadpoor AA, Nikooyan AA (2011) The relationship between lower-extremity stress fractures and the ground reaction force: a systematic review. Clin Biomech 26:23–28 16. Keller TS, Weisberger AM, Ray JL, Hasan SS, Shiavi RG, Spengler DM (1996) Relationship between vertical ground reaction force and speed during walking, slow jogging, and running.

Clin Biomech 11:253–259 17. Merletti R, Parker PJ (2004) Electromyography: physiology, engineering, and non-invasive applications. Wiley, New Jersey 18. Grape HH, Dedering Å, Jonasson AF (2009) Retest reliability of surface electromyography on the pelvic floor muscles. Neurourol Urodyn 28:395–399 19. Weir JP (2005) Quantifying test-retest reliability using the intraclass correlation coefficient and the SEM. J Strength Cond Res 19:231–240 20. Portney LG, Watkins MP (2009) Foundations of clinical research: applications to practice, 3rd edn. Pearson/Prentice Hall, Upper Saddle River 21. Enck P, Vodušek DB (2006) Electromyography of pelvic floor muscles. J Electromyogr Kinesiol 16:568–577 22. Gollhofer A, Horstmann GA, Schmidtbleicher D, Schönthal D (1990) Reproducibility of electromyographic patterns in stretch-shortening type contractions. Eur J Appl Physiol 60:7– 14 23. Schulte-Frei B (2006) Sport- und Bewegungstherapie für den weiblichen Beckenboden. Alltagsrelevanz, Analyse und Therapie unter besonderer Berücksichtigung der neuromuskulären Ansteuerung.

Dissertation, Institut für Rehabilitation und Behindertensport der Deutschen Sporthochschule Köln 24. Leitner M, Schmid S, Hilfiker R, Radlinger L (2011) Test-retest reliability of vertical ground reaction forces during stair climbing in the elderly population. Gait Posture 34:421–425 25. Masani K, Kouzaki M, Fukunaga T (2002) Variability of ground reaction forces during treadmill walking. J Appl Physiol 92:1885–1890 26. Bø K, Sherburn M (2005) Evaluation of female pelvic-floor muscle function and strength. Phys Ther 85:269–282 27. Maurer C, Federolf P, von Tscharner V, Stirling L, Nigg BM (2012) Discrimination of gender-, speed-, and shoe-dependent movement patterns in runners using full-body kinematics. Gait Posture 36:40–45 28. Wright IC, Neptune RR, van den Bogert AJ, Nigg BM (1998) Passive regulation of impact forces in hell-toe running. Clin Biomech 13:521–531

2.3 Pelvic floor muscle electromyography during different running speeds â&#x20AC;&#x201C; an exploratory and reliability study

Archives of Gynecology and Obstetrics 2016 Jan;293(1):117-24

Helena Luginbuehl Rebecca Naeff Anna Zahnd Jean-Pierre Baeyens Annette Kuhn Lorenz Radlinger

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Arch Gynecol Obstet (2016) 293:117–124 DOI 10.1007/s00404-015-3816-9

GENERAL GYNECOLOGY

Pelvic floor muscle electromyography during different running speeds: an exploratory and reliability study Helena Luginbuehl1,2 • Rebecca Naeff1 • Anna Zahnd1 • Jean-Pierre Baeyens2 Annette Kuhn3 • Lorenz Radlinger1

•

Received: 27 April 2015 / Accepted: 3 July 2015 / Published online: 21 July 2015 Ó Springer-Verlag Berlin Heidelberg 2015

Abstract Purpose Stress urinary incontinence (SUI) affects women of all ages including young athletes, especially those involved in high-impact sports. To date, hardly any studies are available testing pelvic floor muscles (PFM) during sports activities. The aim of this study was the description and reliability test of six PFM electromyography (EMG) variables during three different running speeds. The secondary objective was to evaluate whether there was a speeddependent difference between the PFM activity variables.

Methods This trial was designed as an exploratory and reliability study including ten young healthy female subjects to characterize PFM pre-activity and reflex activity during running at 7, 9 and 11 km/h. Six variables for each running speed, averaged over ten steps per subject, were presented descriptively, tested regarding their reliability (Friedman, ICC, SEM, MD) and speed difference (Friedman).

Results PFM EMG variables varied between 67.6 and 106.1 %EMG, showed no systematic error and were low for SEM and MD using the single value model. Applying the average model over ten steps, ICC (3,k) were[0.75 and SEM and MD about 50 % lower than for the single value model. Activity was found to be highest in 11 km/h. & Helena Luginbuehl helena.luginbuehl@bfh.ch 1

Bern University of Applied Sciences, Health, Murtenstrasse 10, 3008 Bern, Switzerland

2

Faculty of Physical Education and Physiotherapy, Vrije Universiteit Brussel, Boulevard de la Plaine 2, 1050 Ixelles, Belgium

3

Women’s Hospital, Urogynaecology, Bern University Hospital and University of Bern, Effingerstrasse 102, 3010 Bern, Switzerland

Conclusion EMG variables showed excellent ICC and very low SEM and MD. Further studies should investigate inter-session reliability and PFM reactivity patterns of SUI patients using the average over ten steps for each variable as it showed very high ICC and very low SEM and MD. Subsequently, longer running distances and other highimpact sports disciplines could be studied.

Keywords Jogging Pelvic floor Reproducibility Sports Stress urinary incontinence

Introduction Stress or ‘‘activity-related’’ urinary incontinence means the complaint of involuntary loss of urine due to effort or physical exertion, e.g., sporting activities, or when sneezing or coughing [1] and affects women of all ages [2]. Sporting activities, which involve high impact, result in the highest prevalence of stress urinary incontinence (SUI) and also affect young athletes [3]. Goldstick and Constantini [4] state in their review that top female athletes report a high prevalence of urinary incontinence, especially during sports but also during daily activities, and that the prevalence of urinary incontinence ranges from 28 to 80 %, with the highest prevalence in high-impact sportswomen such as trampolinists, gymnasts, aerobic gymnasts, hockey players and ballet dancers. Women who attend gym and perform high-impact exercise have a greater prevalence of urine loss than women who do not perform any high-impact exercises [5].

Activities, which typically provoke incontinence, raise the intra-abdominal pressure and the impact loading on the pelvic floor muscles (PFM) [5]. High-impact physical activities, where both feet are off the ground at the same time (e.g., when jumping or running), involve abrupt

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repeated increase in abdominal pressure [5]. To date, few studies are available investigating PFM activity during high-impact loads and hardly any of those concern functional whole-body movement situations, e.g., sports activities. Luginbuehl et al. [6] found PFM electromyography (EMG) pre-activity of 72.1 %EMG [EMG normalized to maximal voluntary contraction (MVC)] at 50 ms prior to the heel strike during running at 8 km/h, which means a PFM activity of approximately 40 %EMG higher than PFM activity during standing without any voluntary contraction. They also found an immediate strong increase up to a mean maximal PFM EMG activity of 124.3 %EMG within 214.2 (±51.8) milliseconds (ms) after the heel strike, which suggests involuntary and therefore PFM reflex activity during running impact loads [6]. Further studies also found PFM pre-activity and reactivity [7, 8], however, those PFM activity measurements all took place in static positions of the subjects (standing or supine).

PFM reflex activity might concern stretch reflexes, i.e., a stretch–shortening cycle muscle function. According to Komi [9], the stretch–shortening cycle proceeds in three phases, namely pre-activity, eccentric lengthening and concentric contraction. Because of the eccentric lengthening a reactive and stronger contraction can follow, which allows the muscle to generate more strength in shorter time [9, 10]. Stretch reflexes can be classified according to their latencies—i.e., reflex peaks—and are characterized by slow, mid and long latency responses and long latency succeeding responses in relation to an impact, e.g., the initial ground contact during running [10].

More knowledge of PFM function is essential to get a better understanding of the pathophysiology of SUI and as a result to develop more precise diagnostic methods regarding PFM activity and contraction components. First and foremost PFM function has to be clarified for functional movements with short impacts typically provoking SUI such as running or jumping [1], and not only for non-functional isolated test situations such as MVC in supine [11, 12].

The aim of the present study was to investigate and describe PFM activity during high-impact sports activities under various conditions. The specific goals were the reliability test of six PFM EMG variables during three different running speeds. The secondary objective was to evaluate whether there was a speed-dependent difference between the PFM EMG variables.

Materials and methods Study design This trial was designed as an exploratory and intra-session retest reliability study to characterize PFM activity during

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running at three different speeds. It focuses on the description and reliability of six previously defined EMG variables of pre-activity and reflex activity and, as a second outcome, on the difference between the three speeds regarding those variables.

The study was conducted in accordance with the Declaration of Helsinki, and all subjects gave written informed consent. Following an agreement with the ethics committee, approval was not required as the investigation concerned a physiotherapy-relevant reliability low-risk study.

Subjects Ten female subjects were recruited from the Bern University of Applied Sciences and were included on condition that they were aged between 20 and 35 years, were nulliparous and anamnestically healthy, had a BMI between 20 and 30 kg/m2, were physically able to cope with the requirements of the testing procedure and were experienced and familiar with treadmill running. Subjects, who had their period or who had had surgery in the urogenital region as well as those with acute vaginal infection, incontinence, pelvic floor complaints, pain during running, acute back or joint pain, acute injury of the lower extremity, or nickel or latex allergy were excluded. All subjects were trained in MVC of their PFM as the learning of a correct isolated (maximal) PFM contraction was part of the practical program of PFM rehabilitation in their professional physiotherapy or midwifery education.

Instrumentation The treadmill was a Kettler Marathon TX1 device (EnseParsit, Germany). All subjects had to perform their running at the speeds of 7, 9 and 11 km/h and 1° inclination. A vaginal surface EMG probe (PeriformÒ, Neen, UK-Oldham Lancashire) was used to measure PFM activity. The single reference adhesive surface electrode (Ambu Blue Sensor N, Ballerup, Denmark) was fixed on the right iliac crest according to the SENIAM recommendations [13]. A force-sensitive resistor footswitch (2-FSR, Noraxon European Service Center, Cologne, Germany) was used to identify the initial contact (T0), i.e., the initial time point of the impact and beginning loading phase and strain of the PFM. The footswitch consists of two FSR sensors, which were fixed with adhesive tape on the right heel and ball of the big toe to optimally capture the initial contact. Electrodes and footswitches were connected to the transmitter by short wire, which was fixed at the back of the subjects.

The signals were sent wirelessly to the receiver (TeleMyo 2400 G2, Noraxon European Service Center, Cologne, Germany).

Arch Gynecol Obstet (2016) 293:117–124

Procedures Demographics (age, weight, height and body mass index) were determined and after emptying their bladder the subjects were equipped with the footswitch and EMG reference electrode. The subjects were instructed in the vaginal insertion of the surface EMG probe using ultrasound lubrication and then performed the insertion themselves. The subjects wore a loose running suit and were barefoot, as the various shock absorption systems of the subjects’ individual running footwear could influence running ground reaction forces and force transmission [6].

PFM EMG was measured twice for 15 s without any voluntary contraction and twice for 5 s during MVC (contraction maximal as possible) in a standing position.

Between the single measurements, a 15-s break was taken.

The MVC testing while standing was chosen instead of the usual MVC testing in a supine position [6, 14] because it seemed more functional in comparison with running.

Thereafter, the subjects performed a warm-up of walking (5 km/h) for 30 s, then running at 7, 9 and 11 km/h consecutively until they reached a steady state. As soon as they reached the steady state at the respective speed, the data acquisition was started: EMG and footswitch signals were measured continuously for 15 s and the first 10 step cycles of the right leg were analyzed. The subjects were instructed to run, to breathe as normally as possible, not to activate their PFM voluntarily and not to talk during the measurements. Between the measurements of the different speeds, the treadmill was stopped, followed by a 1-min break until restarting the same procedure with the next speed.

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variables are described in Table 1. All variables were analyzed using the software package ADS. PFM EMG data during standing without any voluntary contraction and MVC were averaged over test and retest, and PFM EMG data of running over ten steps for each subject.

To determine PFM EMG activity during the initial phase of ground contact, the approach according to Fleischmann et al. [10, 15] was chosen: As basically no clear and reproducible reflex peaks could be determined visually on the rectified EMG of consecutive steps, mean amplitudes for fixed 30-ms intervals covering the phase in which reflex activity is expected to occur were calculated. Therefore, reflex phase amplitudes were calculated between 30 and 60 ms (short latency response), 60–90 ms (mid latency response), 90–120 ms (long latency response) and 120–150 ms (long latency succeeding response). Additionally, pre-activity was computed during the interval between -30 ms and T0 [10, 15].

Following the study protocol of Fleischmann et al. [15], who calculated EMG amplitudes of shank muscles between touchdown to 150 ms of ground contact in 30-ms time windows for lateral jumps from four different distances, the same 30-ms time intervals were calculated for all three running speeds in the present study.

Ten strides of under extremity muscles’ EMG data provide a very high level of stability of a given subject relative to the variability across subjects [17]. Therefore, the analysis of EMG data of 10 steps was also chosen for this study.

Statistical analysis Data reduction EMG and footswitch signals were sampled at a rate of 2 kHz [sampling interval (dt) equals 0.5 ms] using a 12-bit analog-to-digital converter (ME-2600i, SisNova Engineering, Zug, Switzerland) and the software package ‘‘Analoge und digitale Signalverarbeitung’’ (ADS) version 1.12 (uk-labs, Kempen, Germany).

The EMG signals were initially first-order high-pass filtered with a cutoff frequency of 10 Hz by EMG preamplifier leads to reject or eliminate artifacts and later digitally low-pass filtered by ADS software with a cutoff frequency of 1 kHz (second-order zero-lag Butterworth filter, 24 dB/octave filter steepness) to avoid aliasing.

Second, to identify amplitude peaks during MVC, EMG was calculated as RMS (200 ms moving window). 100 % of EMG equals the average of the two peak amplitude values during the two 5-s sessions of MVC. Third, EMG variables were calculated as RMS values within each 30-ms interval [10, 15, 16], averaged over 10 steps and normalized to peak MVC (%EMG). The different activity

A total sample size of N C 9 and an associated actual power of 0.83 were computed as a bivariate normal model by means of G*Power software [18] based on the following assumptions: one-tailed test, correlation coefficient of alternative hypothesis: 0.75; alpha error probability: 0.05; power (1 - beta error probability): 0.80; correlation coefficient of null hypothesis: 0.00.

Descriptive statistics were performed for each variable [mean, standard deviation (SD)].

The reliability test followed the three-step suggestions of Weir [19]: To identify possible systematic errors between the repeated measures, the Friedman test for n-dependent samples to compare EMG variables over the ten steps was applied. Reliability was calculated for single measures (absolute agreement) and average measures (consistency) with the two-way random intraclass correlation coefficients [ICC (3,1) and (3,k)] (i.e., relative reliability) which do not consider systematic error. The absolute standard error of meapffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi surement (SEM ¼ SD 2 1 - ICC; i.e., absolute reliability), the relative SEM related to the mean (SEM%),

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Table 1 Labels, units, and description of activity and time variables derived from electromyography (EMG) and footswitch Variable

Unit

Description

To identify

T-30–0

%EMG

Mean EMG activity between T0 and minus 30 ms

The mean pre-activity between T0 and minus 30 ms as a regulatory component of anticipation

T0–30

%EMG

Mean EMG activity between T0 and 30 ms

The mean EMG amplitude between the initial contact and 30 ms as the initial ground-contact phase, the interval preceding latency responses

T30–60

%EMG

Mean EMG activity between 30 ms and 60 ms after T0

The mean EMG amplitude between 30 and 60 ms to detect short latency response (SLR) as a characterization of reflex activity during a stretch–shortening cycle

T60–90

%EMG

Mean EMG activity between 60 ms and 90 ms after T0

The mean EMG amplitude between 60 and 90 ms to detect mid latency response (MLR) as a characterization of reflex activity during a stretch–shortening cycle

T90–120

%EMG

Mean EMG activity between 90 ms and 120 ms after T0

The mean EMG amplitude between 90 and 120 ms to detect long latency response (LLR) as a characterization of reflex activity during a stretch–shortening cycle

T120–150

%EMG

Mean EMG activity between 120 ms and 150 ms after T0

The mean EMG amplitude between 120 and 150 ms to detect long latency succeeding response (LLR2) as a characterization of reflex activity during a stretch–shortening cycle

additionally the absolute minimal difference pffiffiffi (MD ¼ SEM 1:96 2 2) needed to be considered real, and relative MD related to the mean (MD%) were computed.

SEM and MD were calculated twice, once related to the ICC (3,1) and once to the ICC (3,k).

For the evaluation of relative reliability ICC values benchmarks presented by Shrout and Fleiss [20] were used: Above 0.75 represents excellent, 0.40–0.75 represents fair to good and below 0.40 represents poor reliability.

As to the secondary outcome concerning the differences of the EMG variables between and within the three running speeds, analyses of variance (Friedman test and post hoc Wilcoxon test) were performed.

The level for significances was set to P B 0.05 (Bonferroni correction P \ 0.017 and 0.003). All statistics were calculated with IBM SPSS 20 for Windows (SPSS, Inc; Chicago, IL, USA).

Results The ten included subjects had a mean (±SD) age of 24.9 years (±3.3), weight of 59.5 kg (±7.7), height of 1.7 m (±0.1) and body mass index of 21.6 kg/m2 (±2.7).

Descriptive statistics and reliability calculations of the six EMG variables of the three different running speeds, 7, 9 and 11 km/h are presented in Table 2 and Fig. 1.

PFM EMG during standing without any voluntary contraction showed a mean of 29.6 %EMG. The values of the PFM EMG variables regarding the rather slow running speeds of 7 and 9 km/h are similar and lie between 67.6 and 88.4 %EMG. Only running at 11 km/h leads to higher PFM values rising up to 106.1 %EMG. The means of the PFM EMG variables increase from pre-activity

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(75.4–91.6 %EMG) to T30–60 (84.9–106.1 %EMG) and then decrease to T120–150 (67.6–70.3 %EMG). This increase and decrease was significant for 11 km/h only (P \ 0.001).

The analysis of systematic errors within repeated measures by the Friedman test revealed only non-significant values for all variables.

ICC for single values (3,1) ranged from 0.24 to 0.56 at a speed of 7 km/h, 0.09 to 0.57 at 9 km/h and 0.25 to 0.62 at 11 km/h. SEM (SEM%) based on this ICC (3,1) are generally low and range between 3.5 (4.3) and 4.9 (6.9) %EMG for 7 km/h, 2.7 (3.5) and 5.6 (6.8) %EMG for 9 km/h and 4.6 (5.2) and 6.7 (6.5) %EMG for 11 km/h.

In contrast ICC for averaged values (3,k) ranged from 0.76 to 0.93 at a speed of 7 km/h, 0.49 to 0.93 at 9 km/h and 0.77 to 0.94 at 11 km/h. SEM (SEM%) based on this ICC (3,k) are generally low and range between 1.9 (2.4) and 2.5 (2.9) %EMG for 7 km/h, 1.9 (2.6) and 2.4 (3.2) %EMG for 9 km/h and 2.1 (2.5) and 2.9 (4.1) %EMG for 11 km/h.

Accordingly to SEM (SEM%), the MD (MD%) related to ICC (3,1) were generally higher than related to ICC (3,k). MD (MD%) related to ICC (3,1) ranged from 9.8 (12.0) to 13.5 (19.2) %EMG for 7 km/h, 7.4 (9.8) to 15.5 (18.9) %EMG for 9 km/h and 12.7 (14.4) to 18.6 (18.1) %EMG for 11 km/h. MD (MD%) related to ICC (3,k) ranged from 5.2 (6.6) to 7.0 (7.9) %EMG for 7 km/h, 5.4 (7.1) to 6.6 (9.0) %EMG for 9 km/h and 5.9 (6.8) to 8.0 (11.4) %EMG for 11 km/h.

As to the secondary outcome significant differences (P \ 0.05) were presented for T-30–T0, T0–30, and T30–60, only. In detail, there are no differences for these variables between 7 and 9 km/h, however, between 7 and 11 and 9 and 11 km/h (Fig. 1).

5.0

73.2

70.4

T90–120

T120–150

74.0

67.6

T90–120

T120–150

6.6

7.0

106.1

86.1

80.3

70.3

T30–60

T60–90

T90–120

T120–150

0.52

0.48

0.46

0.62

0.41

0.25

0.55

0.43

0.57

0.55

0.30

0.09

0.56

0.38

0.40

0.24

0.25

0.27

ICC 3,1

0.81

0.90

0.90

0.94

0.87

0.77

0.92

0.87

0.93

0.92

0.81

0.49

0.93

0.86

0.87

0.76

0.77

0.79

ICC 3,k

4.6

5.1

4.8

6.7

5.2

4.8

4.5

5.1

5.4

5.6

4.0

2.7

4.9

3.9

4.6

4.5

3.5

3.7

SEM, ICC 3,1 %EMG

6.5

6.3

5.6

6.3

5.3

5.2

6.7

6.8

6.7

6.6

4.9

3.5

6.9

5.4

5.7

5.1

4.3

4.8

SEM%, ICC 3,1

2.9

2.2

2.1

2.6

2.4

2.7

1.9

2.4

2.2

2.3

2.1

2.0

2.0

1.9

2.2

2.5

2.0

2.0

SEM, ICC 3,k %EMG

4.1

2.7

2.5

2.5

2.5

2.9

2.9

3.2

2.7

2.7

2.6

2.7

2.8

2.5

2.7

2.9

2.4

2.6

SEM%, ICC 3,k

12.7

14.0

13.4

18.6

14.5

13.2

12.6

14.0

14.9

15.5

11.1

7.4

13.5

10.9

12.9

12.5

9.8

10.2

MD, ICC 3,1%EMG

18.1

17.5

15.6

17.5

14.8

14.4

18.6

18.9

18.6

18.3

13.7

9.8

19.2

14.9

15.9

14.2

12.0

13.4

MD%, ICC 3,1

8.0

6.1

5.9

7.3

6.7

7.4

5.4

6.6

6.0

6.4

5.8

5.5

5.5

5.2

6.0

7.0

5.4

5.5

MD, ICC 3,k %EMG

11.4

7.6

6.9

6.9

6.8

8.0

7.9

9.0

7.5

7.5

7.1

7.4

7.8

7.1

7.4

7.9

6.6

7.2

MD%, ICC 3,k

0.082

0.054

0.670

0.359

0.086

0.052

0.312

0.442

0.368

0.091

0.101

0.709

0.253

0.687

0.952

0.115

0.598

0.097

Friedman, P value

Mean arithmetic mean, SD standard deviation, ICC intraclass correlation coefficient, SEM absolute standard error of measurement, SEM% relative standard error of measurement, MD absolute minimal difference, MD% relative minimal difference, Friedman Friedman test non-parametric repeated measures comparison

6.6

10.8

6.8

91.6

97.8

T-30–0

5.5

6.8

6.7

8.2

8.3

4.8

2.8

7.3

5.2

T0–30

11 km/h

84.9

80.3

T30–60

81.1

T60–90

75.4

T-30–0

T0–30

9 km/h

6.0

88.4

80.8

T30–60

T60–90

4.1

76.1

81.8

4.3

SD, %EMG

T-30–0

Mean, %EMG

T0–30

7 km/h

Variable

Table 2 Descriptive statistics (mean ± SD), reliability indexes [ICC (3,1); ICC (3,k)], ICC-related SEM, SEM%, MD, MD%; and test for systematic error (Friedman) for activity variables derived from pelvic floor muscles’ electromyography during running at 7, 9 and 11 km/h

Arch Gynecol Obstet (2016) 293:117–124 121

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Fig. 1 Means and standard deviations of PFM activity variables (time intervals of 30 ms) of three running speeds in %EMG

Discussion Primary outcome All PFM EMG variables of all running speeds show clearly higher values than PFM activity during standing without any voluntary contraction, whose mean of 29.6 %EMG being similar to the findings of Luginbuehl et al. [6] and Lauper et al. [21]. The higher values than during standing without any voluntary contraction suggest a PFM pre-activity and reflex activity during running. There is an increase of activity from T-30–0 to T30–60, and a decrease from T30–60 to T120–150 during 11 km/h. According to the peak activity during T30–60 and the corresponding short latency response, it could be hypothesized that during the highest speed (11 km/h) a fast monosynaptic reflex [22] follows the impact of initial contact.

As the Friedman test revealed only non-significant values for all variables, a systematic error within repeated measures can be excluded. Consequently, ICC (3,1) and (3,k) are correctly chosen tests as they only consider random error [19]. The rather low ICC (3,1) can be considered of little importance as the SEM (SEM%) and MD (MD%) relating to the ICC (3,1) show really low values accounting for high reliability. As expected, average values of ICC (3,k) show higher values, and SEM (SEM%) and MD (MD%) related to ICC (3,k) show lower values as an average over ten steps reduces systematic error [17].

Therefore, the ICC (3,k) shows higher values than the ICC (3,1) and (3,k)-related SEM (SEM%) and MD (MD%)

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approximately 50 % lower values. With the exception of one, all ICC (3,k) are higher than 0.75 and meet the highest benchmarking excellent and the statistical power requirements of [0.8.

Grape et al. [14] showed good to high PFM EMG retest reliability regarding average activity, peak, work and baseline [ICC (2.1) = 0.83–0.96] of isolated PFM contractions for healthy nulliparae aged 20–35 years.

Auchincloss and McLean [23] investigated between-trial and between-day reliability of EMG data (peak EMG amplitudes) recorded from the PFM during the functional task of coughing using two different probes. Overall, they found that between-trial reliability was fair to high for the FemiscanTM [ICC (3,1) = 0.58–0.98] and good to high for the PeriformTM [ICC (3,1) = 0.80–0.98], however, between-day reliability was generally poor for both vaginal probes [ICC (3,1) = 0.08–0.84]. To the authors’ knowledge, the only study investigating the reliability of PFM EMG during functional whole-body movements was conducted by their own research group: Luginbuehl et al. [6] tested eight PFM EMG variables of pre-activity and reflex activity during treadmill running at 8 km/h for reliability. Six EMG variables showed good reliability and two (regression variables) showed moderate to good ICC (3,1) values. Auchincloss and McLean [24] investigated whether vaginal probes may induce changes in PFM recruitment by the very presence of the probes and found that the FemiscanTM and PeriformTM vaginal probes do not influence PFM activation amplitude during a PFM MVC task.

Arch Gynecol Obstet (2016) 293:117–124

Secondary outcome The higher values for the EMG variables of T-30–T0, T0–30, and T30–60 of the faster running speed of 11 km/h rising up higher than MVC related to the slower running speeds could be the response to the higher ground reaction forces and therefore higher impacts during a faster running speed [25] and suggest that the higher PFM activity compared to MVC owes to reflexive and reactive force generation during running.

Future studies should test whether higher running speeds than 11 km/h would lead to even higher PFM EMG activities, i.e., if their values would generally rise above MVC. Limitations Crosstalk Although EMG is a reliable method of assessing PFM activity in healthy women [6, 14], crosstalk can confound the interpretation of EMG recordings using a bipolar surface electrode arrangement [26]. Peschers et al. [27] showed in their investigation that additional contraction of the gluteal muscles together with PFM leads to significantly higher PFM EMG compared to isolated PFM contraction. However, crosstalk for PFM during sports activities such as running has not yet been examined and therefore is difficult to estimate. As there is, among others, muscular activity in the hip adductors and gluteus maximus during running [28], crosstalk cannot be excluded and therefore should be subject to further investigations.

Keshwani and McLean [29] recommend using smaller electrodes and differential electrode configurations to decrease the likelihood of recording crosstalk. The electrodes applied in the current study employ a ‘‘faux differential’’ configuration [29]. However, the only commercially available intravaginal probe with differential electrode configuration is the Femiscan [29], which seems not appropriate for applying during running due to its size and shape. To minimize crosstalk, a 3-pol-STIMPONÒ electrode (Innocept Biobedded Medizintechnik GmbH, Gladbeck, Germany) in a differential configuration could be recommended for future studies. As it has smaller electrodes and is totally inserted into the vagina and adapts its shape individually to the vaginal cavity, this probe could be ideal to minimize crosstalk.

Motion artifacts Movement of the probe relative to the underlying skin temporarily distorts the EMG signal and creates motion artifacts [29]. However, an implemented 10 Hz high-pass filter in the

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preamplifier, using well-fixed short wires between the vaginal electrode and transmitter, and wireless technology minimized motion artifacts induced by the movement of the EMG electrodes while the participants were running on the treadmill. In addition, the raw EMG data was visually controlled (e.g., baseline shifts) by an experienced researcher, who did not identify any abnormal EMG patterns. Spectrum analysis (Fast Fourier Transformation) of the EMG data did not reveal any movement or alternating current hum-related artifacts.

Barefoot running As footwear might influence running and force transmission [30], the subjects ran barefoot. However, from a biomechanical viewpoint, barefoot running can change the landing pattern: Habitually, barefoot runners tend to use the forefoot running pattern, whereas most of the shoed runners use the heel strike pattern [31]. Forefoot strikes lead to a significant reduction in the loading rate [31]. In the present study, most subjects were not used to barefoot running and some subjects repeatedly changed their landing pattern within a measurement period. Therefore, an influence of the landing patterns and the subsequent changes in loading rates [31] and their influence on EMG measurements cannot be excluded. A future study should apply standardized running shoes or, when running barefoot, previously familiarize the subjects with a heel strike running pattern.

Conclusion Up to now, research focused on non-functional isolated test situations such as concentric and isometric voluntary muscle action forms, which lead to lift and squeeze [11, 12] and physical therapy concentrated mainly on muscle hypertrophy training [3]. This study showed excellent intra-session ICC and very low SEM and MD of PFM EMG variables of pre-activation and reflexive function during running. Future research should focus on the intersession reliability of the variables of the present study. A next step would be a similar investigation in women suffering from SUI to get insight in PFM reactivity patterns of the affected. For such investigations, the findings of the current study recommend to average ten steps as a very precise and reliable measure of PFM activity during running. In addition, studies with longer running distances including healthy and affected women to test repetitive strain on the PFM and therefore PFM reactive strength endurance function as well as investigations regarding other high-impact sports disciplines typically provoking SUI such as trampoline jumping, track and field or gymnastics [32] would be of high interest.

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Acknowledgments Many thanks to Daniel Schnyder for his support regarding statistical issues. The authors thank Parsenn-Produkte AG (Ku¨blis, Switzerland) for providing the vaginal surface EMG probes.

Parsenn-Produkte AG had no involvement in the present study. Many thanks also to Jacqueline Buerki for proofreading this article.

Compliance with ethical standards Conflict of interest

None.

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15. Fleischmann J, Gehring D, Mornieux G, Gollhofer A (2011) Task-specific initial impact phase adjustments in lateral jumps and lateral landings. Eur J Appl Physiol 111:2327–2337. doi:10.

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Am J Phys Anthropol 143(4):601–611. doi:10.1002/ajpa.21356 29. Keshwani N, McLean L (2015) State of the art review: intravaginal probes for recording electromyography from the pelvic floor muscles. Neurourol Urodyn 34(2):104–112. doi:10.1002/ nau.22529 30. Wright IC, Neptune RR, van den Bogert AJ, Nigg BM (1998) Passive regulation of impact forces in hell-toe running. Clin Biomech 13:521–531 31. Shih Y, Lin KL, Shiang TY (2013) Is the foot striking pattern more important than barefoot or shod conditions in running? Gait Posture 38(3):490–494. doi:10.1016/j.gaitpost.2013.01.030 32. Bø K (2004) Pelvic floor muscle training is effective in treatment of female stress urinary incontinence, but how does it work? Int Urogynecol J Pelvic Floor Dysfunct 15(2):76–84

2.4 Pelvic floor muscle reflex activity during coughing â&#x20AC;&#x201C; an exploratory and reliability study

Annals of Physical and Rehabilitation Medicine 2016 Jun 2.

[Epub ahead of print]

Helena Luginbuehl Jean-Pierre Baeyens Annette Kuhn Regula Christen Bettina Oberli Patric Eichelberger Lorenz Radlinger

42

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REHAB-988; No. of Pages 6 Annals of Physical and Rehabilitation Medicine xxx (2016) xxx–xxx

Available online at

ScienceDirect www.sciencedirect.com

Original article

Pelvic floor muscle reflex activity during coughing – an exploratory and reliability study Helena Luginbuehl a,b,*, Jean-Pierre Baeyens b, Annette Kuhn c, Regula Christen a, Bettina Oberli a, Patric Eichelberger a, Lorenz Radlinger a a b c

Bern University of Applied Sciences, Health, Discipline of Physiotherapy, Murtenstrasse 10, 3008 Bern, Switzerland Vrije Universiteit Brussel, Faculty of Physical Education and Physiotherapy, Pleinlaan 2, 1050 Elsene, Belgium Department of Gynecology, Division of Urogynecology, Inselspital and University of Bern, Effingerstrasse 102, Switzerland

A R T I C L E I N F O

A B S T R A C T

Article history: Received 21 January 2016 Accepted 18 April 2016

Objectives: Activities that provoke stress urinary incontinence (SUI) rapidly increase the intra-abdominal pressure and the impact loading on the pelvic floor muscles (PFMs). Coughing can cause urinary leakage and is often used to test SUI. However, PFM characteristics during coughing, including their reliability, have not been investigated. Here, we used electromyography (EMG) to describe PFM pre-activity and reflexivity during coughing and examined the reliability of the measurements.

Methods: This was an exploratory and reliability study including 11 young healthy women to characterize EMG reflex activity in PFMs during coughing. We describe 6 variables, averaged over 3 coughs per subject, and tested their reliability (intraclass correlation coefficient 3,1 [ICC(3,1)] and ICC(3,k), related standard error of measurement (SEM) and minimal difference [MD]). The variables represented the mean EMG activity for PFMs during 30-ms time intervals of pre-activity (initial time point of coughing [T0] and minus 30 ms) and reflex activity (T0–30, 30–60, 60–90, 90–120 and 120– 150 ms after T0) of stretch-reflex latency responses.

Results: The mean %EMG (normalized to maximal voluntary PFM contraction) for EMG variables was 35.1 to 52.2 and was significantly higher during coughing than for PFM activity at rest (mean 24.9 3.7%EMG; P < 0.05). ICC(3,k) ranged from 0.67 to 0.91 (SEM 6.1–13.3%EMG and MD 16.7–36.8%EMG) and was higher than ICC(3,1) (range 0.40–0.77; SEM 9.0–18.0%EMG, MD 24.9–50.0%EMG).

Conclusions: PFM activity during reflex latency response time intervals during coughing was significantly higher than at rest, which suggests PFM pre-activity and reflex activity during coughing. Although we standardized coughing, EMG variables for PFM activity showed poor reliability [good to excellent ICC(3,k) and fair to excellent ICC(3,1) but high SEM and MD]. Therefore, coughing is expected to be heterogeneous, with low reliability, in clinical test situations. Potential crosstalk from other muscles involved in coughing could limit the interpretation of our results. ß 2016 Elsevier Masson SAS. All rights reserved.

Keywords: Cough Cross-sectional study Pelvic floor Reproducibility Stress urinary incontinence

1. Introduction The signs of stress urinary incontinence (SUI) are involuntary leakage from the urethra with effort or physical exertion or on sneezing or coughing [1,2]. Stress leakage is presumed to be due to increased abdominal pressure [2]. Activities or efforts that typically provoke SUI rapidly increase the intra-abdominal pressure and the impact loading on the pelvic floor muscles (PFMs) [3–5]. Such impact loads occur within milliseconds (ms);

* Corresponding author. Bern University of Applied Sciences Health, Murtenstrasse 10, 3008 Bern, Switzerland. Tel.: +41 3 184 835 30.

E-mail address: helena.luginbuehl@bfh.ch (H. Luginbuehl).

for example, peak-flow happens within 57 to 110 ms during coughing in women [6].

Fast and high impact loads on the PFMs require reflexive muscle contractions to guarantee continence [5]. Amarenco et al. [7] investigated external anal sphincter electromyography (EMG) during coughing and found that cough intensity was significantly related to EMG activity for the anal sphincter. The authors concluded that the cough anal reflex is not an unambiguous response (response or non-response) but rather a modulated reflex. Deffieux et al. [8] also compared SUI affected with continent women and found a lack of modulated PFM response during successive coughing efforts. Both groups concluded that this gradual PFM adaptation might be one of the main factors

http://dx.doi.org/10.1016/j.rehab.2016.04.005 1877-0657/ß 2016 Elsevier Masson SAS. All rights reserved.

Please cite this article in press as: Luginbuehl H, et al. Pelvic floor muscle reflex activity during coughing – an exploratory and reliability study. Ann Phys Rehabil Med (2016), http://dx.doi.org/10.1016/j.rehab.2016.04.005

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H. Luginbuehl et al. / Annals of Physical and Rehabilitation Medicine xxx (2016) xxx–xxx

contributing to urinary and fecal continence in women [7,8]. Howard et al. [9] investigated vesical neck descent by using ultrasonography during coughing in standing continent nulliparous women and found a mean downward movement of 8.2 4.1 mm. Talasz et al. [10] used real-time dynamic MRI and found a mean PFM downward movement of 7.4 5.8 mm during coughing in healthy nulliparous women in the supine position.

The PFM downward displacement during coughing [9,10], which could mean an eccentric movement, together with the fast impact load on the PFMs during coughing [4,5] suggested that PFM reflex activity during coughing might concern stretch reflexes.

Stretch reflexes can be classified according to their latencies (i.e., reflex peaks), which occur within the first 150 ms after an impact and are characterized by slow, medium and long-latency responses and long-latency succeeding responses in relation to an impact [11,12] (e.g., the impact and beginning loading phase and strain on the PFMs during coughing).

Because coughing rapidly increases the intra-abdominal pressure and typically provokes SUI, it is often used to provoke urine leakage and to test for SUI. Therefore, coughing is used in different pad tests recommended by the International Continence Society [1,13]; during the cough stress test, which is easy to conduct and thus particularly convenient in the clinical setting [14]; and for assessment of urethral sphincters [15] and bladder neck mobility during the Q-tip test [16]. Furthermore, coughing is used to test for the effects of PFM training on SUI symptoms [17].

However, little is known about the PFM behavior or contraction characteristics, muscle action or muscle activity during coughing.

Furthermore, few studies have investigated the reliability of such PFM activity characteristics during coughing. Here, we aimed to characterize PFM pre-activity and reflexivity during coughing measured by EMG and to assess the reliability of the measurements.

2. Materials and methods 2.1. Study design This trial was designed as an exploratory and intra-session retest reliability study to characterize PFM activity during coughing. It focused on the reliability of 6 previously defined EMG variables of pre-activity and reflexivity [11,18,19]. The study was conducted in accordance with the Declaration of Helsinki, and all participants gave written informed consent. According to the Swiss Human Research Act, approval from the Ethics Committee of the Canton of Bern was not required because the investigation concerned a physiotherapy-relevant reliability low-risk study.

2.2. Participants We included 11 female participants from the Bern University of Applied Sciences who were 20 to 35 years old, nulliparous and healthy on the basis of the anamnesis and had a BMI between 18 and 25 kg/m2. Exclusion criteria were menstruation on the measurement day, surgery in the urogenital region, acute vaginal infection, incontinence, pelvic floor complaints, acute back or joint pain, nickel or latex allergy, or chronic cough or acute respiratory disorder.

All participants were familiar with maximal voluntary contraction (MVC) of their PFMs because they had learned about isolated PFM (maximal) contraction as part of the practical PFM rehabilitation program in their professional physiotherapy or midwifery education.

2.3. Instrumentation PFM activity was measured with a vaginal surface EMG probe (Periform1, Neen, UK-Oldham Lancashire: Bipolar stainless steel

electrode, rectangular size of 4.9 cm2 per electrode, mediolateral electrode location with a good vaginal fixation because of the cavity of the electrode, depth of electrode insertion until the retaining ring contacts the internal labia). A single reference adhesive surface electrode (Nicolet; Viasys Healthcare, Warwick, UK) was fixed on the right iliac crest according to the SENIAM recommendations [20]. EMG involved a 16-channel telemetry system (TeleMyo 2400 G2, Noraxon USA Inc., Scottsdale, AZ; digital high pass filter: 10 Hz, digital low-pass filter: 500 Hz; gain: 500). A 3-D accelerometer (22 16 mm; Noraxon European Service Center, Cologne, Germany) was fixed on the processus xiphoideus sterni to identify the onset of acceleration (T0) (i.e., the very beginning of a cough and therefore the impact and beginning loading phase and strain on the PFMs). A Voldyne1 (HUDSON RCI1, Voldyne1 5000 mL) was used to determine the maximal inspiratory volume in milliliters and a peakflow-meter (AsmaPLAN, Vitalograph GmbH, Hamburg, Germany) to measure the cough following maximal inspiration (peak-flow value of at least 250 L/min [4,21]).

2.4. Procedures To familiarize participants with the testing procedure, they were asked to perform 3 test coughs through the peak-flow meter, by maximal inspiration by using the followed Voldyne1. Thereafter the participants were equipped with the accelerometer and the EMG reference electrode and were instructed in how to vaginally insert the EMG probe by using ultrasonography lubrication and then performed the insertion themselves after emptying the bladder. Maximal inspiratory volume measured with the Voldyne1 involved the subject standing (instructions: stand on a marked spot on the floor with feet hip-width apart, hips and knees minimally bent; one hand holding the Voldyne1 tube close to the mouth and the other holding the handle vertically in front of the body and keep the mouth tightly sealed around the mouthpiece of the tube). Two retests were taken, each following a 15-s break.

EMG of the PFMs was performed twice for 30 s at rest (i.e., without any voluntary contraction) and twice for 5 s during maximum voluntary contraction (contraction as fast and maximal as possible) with the participant standing, always taking a 30-s break between measurements. We chose to perform the MVC test with the participant standing instead of the usual supine position [18,22,23] because it seemed more functional for coughing in that the PFMs has to contract against gravity [18,22].

EMG and accelerometer signals were measured continuously during 3 coughs. For coughing, the participants were instructed to stand as relaxed as possible (feet hip-width apart, hips and knees minimally bent) and not perform any voluntary contractions of the PFM, hold the peak-flow-meter with both hands, keep their mouth tightly sealed around the mouthpiece and then perform 3 coughs of maximal expulsion effort through the peak-flow-meter after maximal inspiration without using the Voldyne1 but in the same manner (i.e., with an inspiratory volume as equal as possible) as during Voldyne1 measurements. A 15-s break was taken between coughs.

2.5. Data reduction EMG and accelerometry signals were sampled at a rate of 2 kHz (sampling interval [dt] = 0.5 ms) by using a 12-bit analog-to-digital converter (ME-2600i, SisNova Engineering, Zug, Switzerland) and the software Analoge und digitale Signalverarbeitung (ADS) 1.12 (uk-labs, Kempen, Germany).

The EMG signals were 1st-order high-pass – filtered with a cutoff frequency of 10 Hz ( 10%) and low-pass – filtered with a cut-off frequency of 1.5 kHz by EMG preamplifier leads. EMG variables were

Please cite this article in press as: Luginbuehl H, et al. Pelvic floor muscle reflex activity during coughing – an exploratory and reliability study. Ann Phys Rehabil Med (2016), http://dx.doi.org/10.1016/j.rehab.2016.04.005

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calculated according to existing study protocols as RMS values within 30-ms intervals, representing the reflex latency responses [11,18,19] (See Table 1) with use of Matlab R2013a (The Mathworks, Inc.). To identify amplitude peaks during MVC, EMG was calculated as RMS (200-ms moving window) by using the ADS software. EMG 100% equals the average of the 2 peak amplitude values during the two 5-s sessions of MVC. The EMG variables were averaged over 3 coughs and normalized to peak MVC (%EMG). The EMG activity variables are described in Table 1. EMG data during standing at rest and MVC were averaged over the test and retest, and PFM EMG data for coughing were averaged over 3 coughs per participant.

The variables of pre-activity and variables of slow, medium and long latency and long-latency succeeding responses to characterize reflex activity were chosen from protocols of former studies [11,18,19]. Because basically no clear and reproducible reflex peaks after the initial time point of coughing (i.e., the impact and beginning loading phase and strain of the PFMs) could be determined visually on the rectified EMG for consecutive coughs, we calculated the mean amplitudes for fixed 30-ms intervals covering the phase in which reflex activity is expected to occur.

Therefore, reflex phase amplitudes were calculated from 30 to 60 ms (short latency response), 60 to 90 ms (medium latency response), 90 to 120 ms (long-latency response) and 120 to 150 ms (long-latency succeeding response). Additionally, pre-activity was computed for the interval between –30 ms and T0 [11,18,19].

2.6. Statistical analysis We used G*Power [24] to estimate a sample size of 9 and associated power of 0.83 with a bivariate normal model based on the following assumptions: one-tailed test, correlation coefficient of alternative hypothesis: 0.75; alpha error probability: 0.05; power (1 – beta error probability): 0.80; correlation coefficient of null hypothesis: 0.00. Data are described with mean SD. The reliability test followed the 3-step suggestions of Weir [25]: to identify possible systematic errors between the repeated measures, the Friedman test and Wilcoxon rank order test were applied for participants at rest and the MVC tests, and the Friedman test for n-dependent samples was used to compare EMG over the 3 coughs as well as peak-flow and inspiratory volume. For the PFM EMG variables, reliability was calculated for single and average measures (consistency) with the two-way fixed intraclass correlation coefficients [ICC(3,1) and ICC(3,k)] (i.e., relative reliability), which do not consider systematic error. We computed pffiffiffiffiffiffiffiffiffiffiffiffiffiffi the absolute standard error of measurement (SEM ¼ SD 2 1 ICC ; i.e., absolute reliability), relative SEM related to the mean pffiffiffi (SEM%), and the absolute minimal difference (MD ¼ SEM 1:96 2 2) needed to be considered real, and relative MD related to the mean (MD%). SEM and MD were calculated twice, once for the ICC(3,1) and once for the ICC(3,k). Regarding participants at rest and MVC as well as peak-flow and maximal inspiratory volume,

3

only ICC(3,k) and related SEM and MD values were calculated. To evaluate relative reliability, ICC benchmarks from Shrout and Fleiss [26] were used: > 0.75 excellent, 0.40–0.75 fair to good and < 0.40 poor. P < 0.05 was considered statistically significant.

Statistical analysis involved use of IBM SPSS 22 for Windows (SPSS, Inc., Chicago, IL).

3. Results We included 11 women (mean values for age were 23.8 2.3 years, height 1.67 0.06 m, weight 59.2 5.5 kg and body mass index 21.2 2 kg/m2). The mean maximal inspiration volume was 2693.9 330.3 mL and mean peak-flow 376.8 63.2 L/ min. All measured coughs reached a peak-flow > 250 L/min. Analysis of systematic errors within repeated measures by Friedman test revealed non-significant values for peak-flow and maximal inspiratory volume. The ICC(3,k) for peak-flow was 0.873 (SEM 22.5 L/min and MD 62.4 L/min), whereas the ICC(3,k) for maximal voluntary volume was 0.678 (SEM 187.4 mL and MD 519.5 mL).

The mean PFM EMG with participants standing at rest was 24.9 3.7%EMG. Tests for systematic error showed non-significant results for PFM EMG activity at rest and during MVC, excluding systematic error. The ICC(3,k) for PFM EMG activity at rest was 0.996 (SEM 0.2%EMG and MD 0.6%EMG) and the ICC(3,k) for MVC was 0.986 (SEM 1.8 mV and MD 5.0 mV).

Descriptive statistics and reliability calculations for the 6 EMG variables are in Table 2. The mean values for PFM EMG variables during coughing increased significantly from at rest to between 35.1 and 52.2%EMG (Fig. 1, Table 2). The analysis of systematic errors within repeated measures by Friedman test revealed nonsignificant values for T30–60, T60–90, T90–120, T120–150 but significant values for T–30–0 and T0–30.

The ICC(3,1) (for single values) ranged from 0.40 to 0.77 (SEM [SEM%] 9.0–18.0%EMG [18.3–36.8] and MD [MD%] 24.9–50.0%EMG [50.9–102.0]). In contrast, the ICC(3,k) (for averaged values) ranged from 0.67 to 0.91 (SEM 6.0–13.3%EMG [11.6–27.1] and MD 16.7– 36.8%EMG [32.1–64.7]).

4. Discussion 4.1. Description of variables Values were higher for all PFM EMG variables during coughing than for PFM activity during standing at rest (P < 0.05); the mean value of 24.9 3.7%EMG was similar to findings of Luginbuehl et al.

[18,22]. The higher values for PFM activity during coughing than during standing at rest preceding and following the impact and loading phase and strain on the PFMs within milliseconds suggest PFM pre-activity and reflex activity during coughing.

Table 1 Variables, units, and description of pelvic floor muscle (PFM) activity variables derived from electromyography (EMG).

Variable

Unit

Description

To identify

T–30–0 T0–30 T30–60

%EMG %EMG %EMG

Mean EMG activity between –30 ms and T0 Mean EMG activity from T0 to 30 ms Mean EMG activity from 30 to 60 ms after T0

T60–90

%EMG

Mean EMG activity from 60 to 90 ms after T0

T90–120

%EMG

Mean EMG activity from 90 to 120 ms after T0

T120–150

%EMG

Mean EMG activity from 120 to 150 ms after T0

Representing the pre-activity as a regulatory component of anticipation Representing the interval preceding latency responses Detecting short latency response characterizing reflex activity during a stretch-shortening cycle Detecting medium latency response characterizing reflex activity during a stretch-shortening cycle Detecting long-latency response characterizing reflex activity during a stretch-shortening cycle Detecting long-latency succeeding response characterizing reflex activity during a stretch-shortening cycle

T0 represents the onset of acceleration of the processus xiphoideus sterni accelerator identifying the initial time point of coughing (impact and beginning loading phase and strain of the PFM).

Please cite this article in press as: Luginbuehl H, et al. Pelvic floor muscle reflex activity during coughing – an exploratory and reliability study. Ann Phys Rehabil Med (2016), http://dx.doi.org/10.1016/j.rehab.2016.04.005

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Table 2 Reliability indexes during standing at rest and activity variables during coughing derived from PFM EMG. Variable

Mean %EMG

SD %EMG

ICC(3,1)

ICC(3,k)

SEM ICC(3,1) %EMG

SEM% ICC(3,1)

SEM ICC(3,k) %EMG

SEM% ICC(3,k)

MD ICC(3,1) %EMG

MD% ICC(3,1)

MD ICC(3,k) %EMG

MD% ICC(3,k)

Friedman P value

Rest T–30–0 T0–30 T30–60 T60–90 T90–120 T120–150

24.9 35.1 48.5 49.0 51.7 52.2 44.4

3.6 14.0 19.7 23.7 23.7 19.8 15.3

0.986 0.587 0.403 0.421 0.623 0.766 0.574

0.996 0.810 0.670 0.686 0.832 0.907 0.802

0.4 9.0 15.2 18.0 14.6 9.6 10.0

1.7 25.6 31.4 36.8 28.1 18.3 22.5

0.2 6.1 11.3 13.3 9.7 6.0 6.8

0.9 17.4 23.3 27.1 18.8 11.6 15.3

1.2 24.9 42.2 50.0 40.3 26.5 27.7

4.7 71.1 87.0 102.0 78.0 50.9 62.3

0.6 16.9 31.4 36.8 26.9 16.7 18.9

2.5 48.2 64.7 75.1 52.1 32.1 42.5

0.090 0.035 0.029 0.441 0.913 0.913 0.086

ICC: intraclass correlation coefficient; SEM: absolute standard error of measurement; SEM%: relative standard error of measurement; MD: absolute minimal difference; MD%: relative minimal difference; Friedman: Friedman test non-parametric repeated measures comparison.

4.2. Reliability of variables ICC(3,k) for maximal inspiratory volume was good and peakflow excellent, with standard error small for both. However, the MD was high for maximal inspiratory volume and peak-flow, so reliability must be considered low, even though coughing was standardized in terms of body position, minimal peak-flow and coughing instructions including test coughs. Therefore, coughing may be difficult to standardize.

For PFM EMG variables, ICC(3,1) values were fair to good to excellent and ICC(3,k) values good to excellent. However, because of the high SEM and especially MD, the reliability of PFM preactivity and reactivity time interval variables must be considered poor in general. This observation could be a result of the difficulty in standardizing coughing.

Deffieux et al. [8] tested EMG activity of the external anal sphincter during 4 successive graded coughs (gentle, moderate, strong and very strong) at different bladder fillings in 21 women (4 with urgency and/or frequency without incontinence problems, 6 with isolated SUI and 11 with mixed incontinence) and also tested for repeatability by using, among other tests, the ICC. The ICC comparing 2 repeated measures for all bladder fillings was 0.654 (95% confidence interval 0.487–0.775) for the 21 subjects [8], with no details of ICC type used and no SEM or MD reported. With this missing information, comparison with the present study is difficult. As well, Deffieux et al. [27], who found external anal sphincter pre-activity during coughing in 15 women (all with urgency and/or frequency without urge or stress urinary incontinence problems), reported moderate reliability (ICC 0.46) but again with no ICC type or SEM or MD reported.

Auchincloss and McLean [21] investigated the between-trial and between-day reliability of EMG data (peak EMG amplitudes) recorded from the PFMs during a functional task of coughing by using 2 different probes. The authors found that between-trial reliability was fair to high for the FemiscanTM [ICC(3.1) 0.58–0.98] and good to high for the Periform1 [ICC(3.1) 0.80–0.98], although the between-day reliability was generally poor for both vaginal probes [ICC(3.1) 0.08–0.84] with a mean absolute difference normalized to each subject’s average RMS amplitude of 29.3–48.1% recorded each day. However, the authors studied the reliability of peak EMG amplitudes only, which gave no information on reflex activity because the time of the EMG peak was not the scope of the study. To learn more about reflexive function and reflex type following the impact of coughing, more information on the rate of force development is needed (i.e., the activity increase and time of maximal activity).

Because coughing is commonly used as a test for SUI [1,13–17], in considering our results, it is surprising that the tests were not assessed for reliability. Sensitivity and specificity of the cough stress test compared to urodynamic findings are 90% and 80%, respectively [14]. The pad test showed poorer psychometric properties, with 60% sensitivity and 60% specificity [14]. According to Thomakos et al. [16], the Q-tip test has a sensitivity of 91% and specificity of only 35% as compared with urethroscopy. To date and although widely used internationally, standardization of coughing during SUI tests is still lacking [14,16,28].

In a study of the cough stress test to compare PFM activity in women with and without SUI, Madill et al. [4] required participants to achieve a minimal peak-flow of 250 L/min and gave the instruction, ‘‘When I say go, take a deep breath in and cough once as hard as you can. Be sure to keep your mouth tightly sealed around the peak-flow meter’’. Additionally, the authors ensured a 60-s rest between repetitions [4]. The 250-L/min peak-flow value agreed with some previous work by Auchincloss and McLean [21], who asked subjects ‘‘to cough with maximal effort’’ but only included a 45-s rest between the trials. Other sources assessing or using coughing in the context of SUI mention ‘‘forceful coughs’’ [29] or instructions to ‘‘cough as hard as you can’’ [30]. This diversity in instructions leaves room for interpretation and thus might affect the reliability of the results, particularly for intersubject comparison. Consequently, standardization should be the focus of future work, because it would increase the value of scientific findings.

4.3. Limitations

Fig. 1. Pelvic floor muscle (PFM) activity variables (time intervals of 30 ms) during coughing (in % electromyography [%EMG]). Data are mean SD from 3 coughs. The upper dotted line indicates the 100%EMG activity during maximal voluntary contraction (MVC); the lower dotted line indicates the mean activity while standing during rest (24.9%EMG). T–30–0 = T0 (initial time point of coughing) minus 30 ms.

PFM EMG validity remains questionable because of crosstalk [23], described as the detection by EMG of a signal originating from a neighbouring muscle rather than exclusively from the muscle under investigation [31], which can confound the interpretation of EMG recordings by using a bipolar surface electrode arrangement

Please cite this article in press as: Luginbuehl H, et al. Pelvic floor muscle reflex activity during coughing – an exploratory and reliability study. Ann Phys Rehabil Med (2016), http://dx.doi.org/10.1016/j.rehab.2016.04.005

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[32]. To decrease the likelihood of recording crosstalk, Keshwani and McLean [33] recommend using differential electrode configurations. The electrodes applied in the current study featured a ‘‘faux differential’’ configuration [33]. The commercially available intra-vaginal probe with differential electrode configuration is the FemiscanTM [33], but because of its size and shape, it is not suitable for use during a physically demanding activity such as coughing in an upright position. However, the Periform1 vaginal probe is less prone to shifts during coughing because of its convex shape. To minimize crosstalk, the 3-pol-STIMPON1 electrode (Innocept Biobedded Medizintechnik GmbH, Gladbeck, Germany) in a differential configuration could be an option for future studies [18].

Muscle groups commonly acknowledged to generate crosstalk when recording PFM activity include hip adductors, hip external rotators, gluteals, and abdominal musculature [31,33]. For the present study (i.e., during coughing), contamination of the signal by electrical activity from abdominal musculature may be a problem. Solomonow et al. [34] determined that crosstalk accounted for < 4% to 5% of the recorded surface EMG signal amplitude under optimal conditions. However, when a layer of subcutaneous fat was present underneath the surface electrode, this proportion increased to 16% to 32% [34]. Similarly, suboptimal conditions might affect EMG recordings in the PFM region.

However, crosstalk for PFM during functional activities such as coughing has not been examined, so such crosstalk is difficult to estimate, may be a limitation of the present study and should be further investigated.

Besides crosstalk, motion artifacts are a problem in PFM EMG measurements because movement of the probe relative to the underlying skin may temporarily distort the EMG signal [33]. However, an experienced researcher visually controlled the raw EMG data in the present study and could not identify any abnormal patterns.

5. Conclusions Although we standardized coughing in this study of PFM preactivity and reflexivity during coughing, we found poor reliability of PFM activity time interval variables at milliseconds before and after the impact during coughing. Therefore, urinary leakage provoked by coughing tests should be interpreted carefully in terms of conclusions for PFM activity. To test PFM activity, we need test procedures that provoke higher PFM activity reaction and are more reliable. Cough tests in general, which are widely used in urogynecology, should be tested for their reliability.

Disclosure of interest The authors declare that they have no competing interest.

Acknowledgements Many thanks to Noe´mie Flury for her background search and contribution to the discussion section and to Jacqueline Buerki for proofreading the manuscript. The authors thank Parsenn-Produkte AG (Ku¨blis, Switzerland) for providing the vaginal surface EMG probes. Parsenn-Produkte AG had no involvement in the study design, data collection or analysis, manuscript preparation and decision to publish.

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Please cite this article in press as: Luginbuehl H, et al. Pelvic floor muscle reflex activity during coughing – an exploratory and reliability study. Ann Phys Rehabil Med (2016), http://dx.doi.org/10.1016/j.rehab.2016.04.005

2.5 Continuous versus intermittent stochastic resonance whole body vibration and its effect on pelvic floor muscle activity

Neurourology and Urodynamics 2012 Jun;31(5):683-7

Helena Luginbuehl Corinne Lehmann Regina Gerber Annette Kuhn Roger Hilfiker Jean-Pierre Baeyens Lorenz Radlinger

49

Neurourology and Urodynamics 31:683–687 (2012)

Continuous Versus Intermittent Stochastic Resonance Whole Body Vibration and Its Effect on Pelvic Floor Muscle Activity H. Luginbuehl,1* C. Lehmann,2 R. Gerber,2 A. Kuhn,3 R. Hilfiker,1 J.P. Baeyens,4 and L. Radlinger1 1

Bern University of Applied Sciences, Health, Bern, Switzerland Physiotherapy Institute, Bern University Hospital, Bern, Switzerland 3 Women’s Hospital, Urogynaecology, Bern University Hospital and University of Bern, Bern, Switzerland 4 Vrije Universiteit Brussel, Faculty of Physical Education and Physiotherapy, Brussel, Belgium 2

Aims: To determine the optimal stochastic whole body vibration (SR-WBV) load modality regarding pelvic floor muscle (PFM) activity in order to complete the SR-WBV training methodology for future PFM training with SR-WBV. Methods: The continuous and the intermittent SR-WBV modalities were tested by means of electromyography in two independent groups (27 women 8 weeks to 1-year postpartum and 23 women nulliparae or >1-year postpartum) with self-reported stress urinary incontinence. The change in the PFM activity within a single set and over three sets were calculated for both SR-WBV modalities together (time effect) and for both SR-WBV modalities separately (modality– time interaction). Results: There was no statistically significant or clinically relevant change in PFM activity over time or PFM fatigue in either SR-WBV modality within one or three sets and no difference between the modalities or the groups. Conclusions: The lack of change in PFM activity could be due to a no more than moderate to submaximal PFM activity during SR-WBV, the maintenance of reflexive PFM activity despite PFM fatigue or a compensation of slow red PFM fiber fatigue by an increase of innervation frequency and motor unit recruitment of the fast white fibers.

As there is no SR-WBV modality dependent difference regarding PFM activity, the continuous modality is recommended in clinical practice as it is easier to apply and less time consuming. Neurourol. Urodynam. 31:683–687, 2012. ß 2012 Wiley Periodicals, Inc. Key words: cross-sectional study; electromyography; load normative; stress urinary incontinence

INTRODUCTION

To guarantee continence, sufficient pelvic floor muscles (PFM) must be able to contract strongly,1 rapidly, and reflexively.2,3 Several studies have shown that the PFM function regarding rate of force development is impaired in incontinent women compared to continent women.2,3 PFM training is the most commonly used physical therapy treatment for women with stress urinary incontinence (SUI) and is recommended as a first-line treatment.4 However, the training of reactive and fast contractions seems to be difficult, especially when women have problems in the perception of their PFM; therefore it would be useful to prompt reactive contractions of the PFM. In this context, the application of whole body vibration (WBV) could be interesting.

WBV has a positive effect on muscle strength and rate of force development5,6 and elicits stretch reflexes in the leg extensor muscles.7 The effects from long-term WBV exercise appear to be most beneficial for the untrained people and elderly women.6 Stochastic whole body vibration (SR-WBV) could have the potential to activate PFM and improve their function through better activity patterns and more power.

SR-WBV could cause up to 12 muscle contractions per second in PFM as an equivalent of vibration frequency.8 This contraction frequency cannot be achieved by common PFM exercise.

Until now, WBV training methods have been diverse and more based on empirical experience and practical application than on scientific evidence.9 There is a need for a systematic description of a WBV training procedure concerning training device (sinusoidal or stochastic vibration, vertical or ‘‘seesaw’’ vibration, one footplate or two independent footplates, etc.),

ß 2012 Wiley Periodicals, Inc.

training intensity (Hz, amplitude), load duration (sec), training duration (min), training frequency (per week), etc., and these procedures should be as well known as they are in strength training.10,11 To complete the aspects concerning the described training methods, the question regarding load duration remained to be resolved. Madou and Cronin9 reviewed the WBV loading parameters and found that the most frequently applied intervention time per vibration set was 45–60 sec. The most frequently used rest period between sets of vibrations was 60 sec. We know that PFM tend to fatigue,12,13 that PFM fatigue during strenuous physical activity14 and that in fatigue conditions a lack of the modulation of the PFM contraction can lead to SUI.2 As power or reactivity training should preferably be performed with a low muscular fatigue,10 we wondered whether the PFM fatigues during 60 sec of WBV, namely during 60 sec of continuous9 or 12 times 5 sec of intermittent vibration with short rest periods in between, in accordance with power training methodology.10 Furthermore, the question was whether there would be a difference in PFM

Conflict of interest: none.

Heinz Koelbl led the peer-review process as the Associate Editor responsible for the paper. *Correspondence to: H. Luginbuehl, PT, MME, Bern University of Applied Sciences, Health, Murtenstrasse 10, CH 3008 Bern, Switzerland.

E-mail: helena.luginbuehl@bfh.ch Received 12 September 2011; Accepted 15 November 2011 Published online 6 March 2012 in Wiley Online Library (wileyonlinelibrary.com).

DOI 10.1002/nau.21251

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fatigue between continuous and intermittent vibration load and between the following groups: Group pp (women 8 weeks to 12 months postpartum with self-reported SUI) and group np/pp (nulliparae or >1-year postpartum).

Hence, the aim of this study was to determine the effect of the load duration of SR-WBV stimulation in patients with PFM insufficiency with SUI. The specific aims were to evaluate whether there was a change (decrease) of the PFM activity within one set (1 60 sec) or within three sets (3 60 sec) of continuous or intermittent SR-WBV or whether there was a modality dependant difference (decrease) in the activity between the two groups pp and np/pp.

METHODS Study Design and Subjects

This study was designed as a randomized cross-over trial and was approved by the Ethics Committee of the Canton of Bern (Switzerland, No. 29/08).

Fifty-one subjects were allocated to two groups with selfreported SUI by different inclusion and exclusion criteria: 23 women 8 weeks to 1-year postpartum (group pp) and 28 women nulliparae or >1-year postpartum (group np/pp).

Further inclusion criteria for group pp were 18–45 years old, SUI as main problem, PFM testing score M0–M4 according to the modified Oxford grading system15 and history of positive cough test. Inclusion criteria for women in the group np/pp were nulliparae or >1 year since the last delivery, 18–80 years old, SUI as main problem, PFM testing score M0–M4 according to the modified Oxford grading system15 and history of positive cough test. Pregnancy, menstruation on measurement day, predominant urge incontinence, prolapse 28 (uterus, cystocele, rectocele during valsalva maneuver) and positive pregnancy test were defined as exclusion criteria for both groups, as was a cesarean section for group pp.

Procedures and Data Collection

For the application of the SR-WBV, the SRT-Zeptor1 (Frei Swiss AG, Zurich, Switzerland) was used. The subjects were treated with a vibration frequency of 8 Hz, which has been shown to be a good compromise between maximal effectiveness concerning neuro-muscular activity8 and load tolerance.

During therapy a higher vibration frequency of 10 or 12 Hz is often not tolerated well by the subjects.

Two different load duration modalities were applied: Continuous load duration: three sets of a 60 sec-long SRWBV and a 60 sec rest between the three sets; Intermittent load duration: three sets of a 12 5 sec-long SR-WBV with a 10 sec rest in between and an additional rest of 60 sec between the three sets. During the 10 sec rest in between, subjects were not standing on the vibration platform.

The continuous load duration of 60 sec was chosen in accordance with the results of Madou and Cronin,9 who demonstrated that 60 sec intervention and 60 sec rest periods are historically the most frequent vibratory stimulation loading parameters. In addition, 60 sec are often used to investigate women’s PFM strength endurance.16 The intermittent load duration of 12 5 sec accumulates to a total load duration of 60 sec. This modality with a 10 sec rest after each 5 sec of load was used in accordance with power-training methodology. Here a shorter load duration Neurourology and Urodynamics DOI 10.1002/nau

immediately followed by a rest should lead to a higher rate of force development and inhibit early fatigue during training.

Similarly, intermittent SR-WBV should invoke short time reactive and fast muscle activity with respect to the expected fast muscular exhaustion of the subjects.10 Both vibration modalities were applied on the same test day in random order and with a rest of 15 min between modalities, to be long enough for a full neuromuscular recovery of the subjects according to rest-duration in strength training methods.10 A manual PFM testing was performed and the contraction was graded according to the modified Oxford grading system.15 In order to achieve a high reproducibility and intra-tester reliability, the PFM testing and the modified pad test were carried out by the same experienced physiotherapist for all subjects.

The activity of PFM was measured by electromyography (EMG) in a standing position without any voluntary activity or contraction at rest and during a maximum voluntary contraction test (MVC), each lasting 5 sec. During the SR-WBV modalities EMG was recorded continuously for the whole load duration of each set. Subjects stood on the floor during the rest period or maximum voluntary contraction test (MVC) and on the vibration platform with slightly bent knees and neutral hip position during SR-WBV. Subjects were instructed to perform two maximum voluntary PFM contractions, each lasting 5 sec, with 1-min rest between contractions. MVC was tested 1 min before the first set of SR-WBV. EMG during rest was also measured twice at the beginning.

Afterwards, PFM EMG activity at the vibration intensity of 8 Hz was measured for two different vibration modalities, namely continuous vibration (three sets of 60 sec vibration with 60 sec rest in between) and intermittent vibration (three sets of 12 5 sec with 10 sec rest for three sets with 60 sec rest in between—which also results in a total vibration time of 180 sec). A manual trigger was set to identify the 60 sec continuous load duration as well as the 12 5 sec intermittent load duration in the EMG measurements. The sequence of the vibration modalities was randomized and between the sets a 15-min break was necessary to compensate for possible PFM fatigue.

For EMG, a Periform1 intra-vaginal probe (Parsenn-Produkte AG, Kueblis, Switzerland) similar to the one described by Madill and McLean17 was used, and an EMG device (uk-labs, Kempen, Germany) was used to measure activity of the PFM. The reference electrode (Silver/Silver Chloride, Nicolet Viasys HealthCare, Warwick, UK) was fixed on the osseous anterior part of the tibia.

Data Reduction

The EMG signal was transmitted to a measurement amplifier (UMVE, uk-labs). The cut-off frequency of the low-pass filter was set at 500 Hz in order to avoid aliasing in accordance with the Nyquist–Shannon sampling theorem. Expecting vibration or motion artifacts in EMG during SR-WBV, no highpass filter was applied in order to detect the fundamental frequency of SR-WBV or the harmonic content in the EMG signal.

All data were sampled in sync at a rate of 1 kHz using a 12-bit A/D converter (Meilhaus ME-2600i; SisNova Engineering, Zug, Switzerland) and the ADS software version 1.12 (uk-labs).

Although Ritzmann et al.7 revealed no evidence of motion artifacts during sinusoidal WBV and supported the hypothesis of WBV-induced stretch reflexes in leg muscles instead, this could not yet be shown for PFM and SR-WBV. Consequently,

Stochastic Resonance Whole Body Vibration the fundamental frequency and harmonic content of the SR-WBV EMG’s raw signal parts were spectrum analyzed by Fast Fourier Transformation (FFT) and removed by notch filtering.

The acquired EMG signal was cut according to the manual trigger signal into the following signal parts: Pre-MVC parts 1 and 2 as well as three sets with 12 5 sec SR-WBV parts for the intermittent contractions and another three sets with 12 5 sec SR-WBV parts for the continuous contractions.

Furthermore, the root-mean-square (RMS) values of the EMG-signal parts of MVC and SR-WBV were calculated, and all signals were normalized to the average (mean) of the RMS values of the two MVC signal parts (%EMG). In addition, the SR-WBV signal parts underwent a power spectral analysis using FFT in order to calculate median frequencies (MF).

RMS out of time domain and MF out of the frequency domain are described as relevant parameters of muscular fatigue.18 All data analyses were carried out using a custom LabVIEW program (Ver. 8.5, National InstrumentsTM, Austin, TX).

Statistical Analysis

Descriptive statistics were calculated for groups separately and compared with an independent-samples T-test and a Mann–Whitney U-test for the ordinal Oxford grading scale.

The differences in EMG-amplitude (%EMG) and median frequency (Hz) between the dependent SR-WBV modalities and the change over time within one set as well as between sets were calculated with ANOVA repeated measurements with an in-between interaction approach.

All statistical analyses were carried out with SPSS (Version 16.0.2; SPSS, Inc., Chicago, IL, 1989–2007).

G Power3 was used to calculate the total sample size. To detect a medium effect size (medium effect size for F-tests: f ¼ 0.20) with an a-error probability of 5% (a ¼ 0.05) and a power of 80% (Beta ¼ 0.2), two groups and three repeated measures (correlation among the repeated measures: 0.5) with a total sample size of at least 42 subjects is required. Due to unpredictable exclusions, for example, caused by vibration artifacts or indispositions of the women, we started with 51 subjects.

RESULTS

Fifty-one women in total were initially recruited. One subject in group pp was not able to perform an MVC test and had to be excluded. Descriptive statistics for the included subjects are presented in Table I. As a result of the inclusion criteria, subjects differed significantly in age (P < 0.001).

Amplitude (Fig. 1) and median frequency (Fig. 2) of the EMG during SR-WBV showed no significant decrease or any other TABLE I. Demographic Data

Total recruited subjects Excluded subjects Included subjects Age (years) Weight (kg) Height (m) BMI (kg/m2) Number of births Oxford grading scale Pad test (g)

Group np/pp

Group pp

28 0 28 47.0 9.6 64.0 14.8 1.64 0.06 23.6 4.9 1.7 1.0 3 (IQR 2–4) 6.6 8.8

23 1 22 33.1 4.8 62.6 10.9 1.67 0.05 22.5 3.6 1.7 1.5 3 (IQR 2.75–4) 3.5 8.9

Neurourology and Urodynamics DOI 10.1002/nau

Sign. (P) — — — <0.001 0.707 0.120 0.363 0.866 0.418 0.231

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changes in muscle activity within or among the continuous and intermittent vibration modality, the three sets or the two groups (amplitude: df ¼ 22, F ¼ 0.729, P ¼ 0.813; median frequency: df ¼ 22, F ¼ 0.676, P ¼ 0.866).

DISCUSSION

With regard to our research questions as to whether there is a SR-WBV-modality-independent change (decrease) in the PFM activity within a single set (1 60 sec) or over three sets (3 60 sec), whether there is a SR-WBV-modality-dependent change (decrease) of the activity within a single set or over three sets and whether there is a SR-WBV-modality-dependent difference (decrease) in the activity between the two groups pp and np/pp, we found no statistically significant or clinically relevant change (decrease) or difference (decrease).

WBV is a safe modality to increase physiological responses of reflex and muscle activity and muscle function and has been suggested as an attractive and efficient complement to traditional forms of exercise for athletes, the aged and health compromised individuals.19 Additionally, SR-WBV is safely applied to patients after stroke and the strain caused by SR-WBV is very low and comparable to cardiovascular and metabolic strain between values during rest and aerobic threshold.20 However, little research has been conducted on WBVtraining methodology,9 especially for SR-WBV. The identification of training determinants such as duration of WBV intervention, number of sets, rest periods between sets, loading parameters, number of interventions per week and duration or order of training periods, which have been described for resistance training,11 should be established to design optimal training methodology. Following clarification of these methodological aspects of vibration training, it could be shown in healthy subjects that a WBV device activated PFM at rest.21 A subsequent study8 comparing the PFM response of a postpartum group with the response of healthy volunteers has shown that training on a SR-WBV device leads to higher PFM activity than on a sinusoidal vibration device.

This effect was found particularly in patients with weak PFM contractions postpartum. Regarding training intensity, Lauper et al.8 have demonstrated a substantial peak effect during 6–12 Hz SR-WBV. In this study we were especially interested in the investigation of SR-WBV-load modality; that is, how long and how often a sum of single vibration impulses has to be set during one vibration set.

Madou and Cronin9 reviewed the range of whole bodyvibration loading parameters and found that the most frequently used WBV intervention times were 45–60 sec per set (average approximately 68 sec). The rest period between sets of vibrations was 60 sec in seven of 14 studies. According to studies investigating PFM strength-endurance, such tests are typically performed over a time period of 60 sec.16 Initial reference points regarding PFM fatigue within a minute of contraction were already found in 1975 by Vereecken et al.13 The authors showed that unlike the skeletal muscles of the extremities, the anal sphincter and still more the external urethral sphincter showed marked fatigue within 60 sec of sustained voluntary contraction; fatigue in the levator ani was less pronounced. Peschers et al.22 tested PFM fatigue in a small number of 10 nulliparous females with no history of incontinence. They were unable to demonstrate any fatigue of the PFM using various tasks. The authors hypothesize that their result might show that the PFM in young continent women reacts differently from the PFM in incontinent women. Gunnarsson and Mattiasson16 showed in their study that

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Fig. 1. Means and 95% Cls of MVC-normalized PFM activity (EMG amplitude in %EMG) during continuous and intermittent SR-WBV modality separated into two groups (pp and np/pp) and three sets.

circumvaginal surface EMG activity at maximum contraction of short duration (2 sec) was significantly lower in patients with incontinence compared with healthy volunteers. They also found that the ability to hold a maximum contraction during 1 min was significantly lower in patients with incontinence compared with healthy controls. Deffieux et al.23 conclude in their systematic review that few studies have focused on human PFM fatigue, but several data nevertheless indicate that pelvic neuromuscular fatigue may be involved in the pathophysiology of SUI. Therefore—in anticipation of possible PFM fatigue during SR-WBV—we chose to test the continuous SR-WBV against the intermittent load duration

with short rest periods of 10 sec in-between, in accordance with power-training methodology.10 In our study we found no significant change in the PFM activity during one or over three sets of continuous or intermittent vibration. On the one hand, the lack of a decrease in PFM activity could be due to a PFM activity of only 50–70% during MVC, which means a no more than moderate to submaximal activity. On the other hand, as one of the important findings on vibratory stimulations is an elicitation of reflex responses by direct or indirect stretches of the muscular system,24 it is hypothesized that although the PFM fatigues, the activity is maintained, as this occurs reflexively. A further

Fig. 2. Means and 95% Cls of EMG MF (Hz) of PFM activity during continuous and intermittent SR-WBV modality separated into two groups (pp and np/pp) and three sets.

Neurourology and Urodynamics DOI 10.1002/nau

Stochastic Resonance Whole Body Vibration explanation of the lack of a decrease in PFM activity is as follows: The fatigue of the slow red muscle fibers during vibration could imply an increase of innervation frequency and motor unit recruitment, as the submaximal level of activity has to be kept constant.25 This would show higher amplitudes of activity and mean that other, fast muscle fibers have taken over. This circumstance could cause a compensation of fatigue, although there is no visible fatigue in our measurements. ‘‘This strategy is used frequently during submaximal fatiguing contractions and is evident as an increase in the discharge rate of active motor units and the recruitment of additional units.’’25 However, a systematic increase in median frequency could not be shown in our results.

In theory, there are some arguments in favor of the intermittent vibration modality; that is, that muscle activity might decrease during continuous vibration due to central and peripheral fatigue, as has been shown in strength training.10 This study could show that this was not true for SR-WBV, at least regarding women with self-reported SUI. In conclusion, because there is no relevant difference in the PFM activity between intermittent and continuous SR-WBV, the application of the continuous load duration modality is suggested in clinical practice. This recommendation is based on the fact that the continuous load modality takes less time, that is, only 60 sec compared to 170 sec (12 5 sec vibration and 11 10 sec rest in-between) intermittent vibration per set, and is easier for patients to learn and perform. There is some evidence regarding the most beneficial vibration frequency8; however, many questions regarding WBV methodology remain open and will be answered by future studies.

REFERENCES 1. Shishido K, Peng Q, Jones R, et al. Influence of pelvic floor muscle contraction on the profile of vaginal closure pressure in continent and stress urinary incontinent women. J Urol 2008;179:1917–22.

2. Deffieux X, Hubeaux K, Porcher R, et al. Abnormal pelvic response to cough in women with stress urinary incontinence. Neurourol Urodyn 2008;27: 291–6.

3. Morin M, Bourbonnais D, Gravel D, et al. Pelvic floor muscle function in continent and stress urinary incontinent women using dynamometric measurements. Neurourol Urodyn 2004;23:668–74.

4. Dumoulin C, Hay-Smith J. Pelvic floor muscle training versus no treatment for urinary incontinence in women. A Cochrane systematic review. Eur J Phys Rehabil Med 2008;44:47–63.

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5. Marin PJ, Rhea MR. Effects of vibration training on muscle power: A metaanalysis. J Strength Cond Res 2010;24:871–8.

6. Rehn B, Lidstrom J, Skoglund J, et al. Effects on leg muscular performance from whole-body vibration exercise: A systematic review. Scand J Med Sci Sports 2007;17:2–11.

7. Ritzmann R, Kramer A, Gruber M, et al. EMG activity during whole body vibration: Motion artifacts or stretch reflexes? Eur J Appl Physiol 2010;110: 143–51.

8. Lauper M, Kuhn A, Gerber R, et al. Pelvic floor stimulation: What are the good vibrations? Neurourol Urodyn 2009;28:405–10.

9. Madou KH, Cronin JB. The effects of whole body vibration on physical and physiological capability in special populations. Hong Kong Physiother J 2008;26:24–38.

10. Gu ¨ llich A, Schmidtbleicher D. Struktur der Kraftfa ¨higkeiten und ihrer Trainingsmethoden. Dtsch Z Sportmed 1999;50:223–34.

11. Toigo M, Boutellier U. New fundamental resistance exercise determinants of molecular and cellular muscle adaptations. Eur J Appl Physiol 2006;97: 643–63.

12. Poortmans A, Wyndaele JJ. Preventing fatigue of fast striated muscles of the pelvic floor and slow striated muscles of the limb by manipulating the onoff time of electric stimulation. Arch Phys Med Rehabil 2002;83:550–4.

13. Vereecken RL, Derluyn J, Verduyn H. Electromyography of the perineal striated muscles during cystometry. Urol Int 1975;30:92–8.

14. Ree ML, Nygaard I. Bo K. Muscular fatigue in the pelvic floor muscles after strenuous physical activity. Acta Obstet Gynecol Scand 2007;86:870–6.

15. Bo K, Finckenhagen HB. Vaginal palpation of pelvic floor muscle strength: Inter-test reproducibility and comparison between palpation and vaginal squeeze pressure. Acta Obstet Gynecol Scand 2001;80:883–7.

16. Gunnarsson M, Mattiasson A. Circumvaginal surface electromyography in women with urinary incontinence and in healthy volunteers. Scand J Urol Nephrol Suppl 1994;157:89–95.

17. Madill SJ, McLean L. Relationship between abdominal and pelvic floor muscle activation and intravaginal pressure during pelvic floor muscle contractions in healthy continent women. Neurourol Urodyn 2006;25:722–30.

18. Merletti R, Parker PH. Electromyography—Physiology, engineering and noninvasive applications (IEEE Press Series in Biomedical Engineering). New Jersey: John Wiley & Sons; 2004.

19. Cochrane DJ. Vibration exercise: The potential benefits. Int J Sports Med 2011;32:75–99.

20. Herren K, Holz Ha ¨nga ¨rtner C, Oberli A, et al. Cardiovascular and metabolic strain during stochastic resonance therapy in stroke patients. Physioscience 2009;5:13–7.

21. Bhend J, Born E, Krause K, et al. Ganzko ¨rpervibrationsbelastung und Beckenboden—Querschnittsstudie zur muskula ¨ren Aktivierbarkeit. Physioscience 2007;3:177–80.

22. Peschers UM, Vodusek DB, Fanger G, et al. Pelvic muscle activity in nulliparous volunteers. Neurourol Urodyn 2001;20:269–75.

23. Deffieux X, Hubeaux K, Damphousse M, et al. Perineal neuromuscular fatigue. Ann Readapt Med Phys 2006;49:331–6, 413–7.

24. Haas CT, Turbanski S, Schwed M, et al. Zum Einsatz von Vibrationsreizen in ¨ sterr 2007;4:388–95. der Neurorehabilitation. Psychol O 25. Enoka RM, Stuart DG. Neurobiology of muscle fatigue. J Appl Physiol 1992; 72:1631–48.

2.6 Involuntary reflexive pelvic floor muscle training in addition to standard training versus standard training alone for women with stress urinary incontinence: study protocol for a randomized controlled trial

Trials 2015 Nov 17;16(1):524

Helena Luginbuehl Corinne Lehmann Jean-Pierre Baeyens Annette Kuhn Lorenz Radlinger

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Luginbuehl et al. Trials (2015) 16:524 DOI 10.1186/s13063-015-1051-0

STUDY PROTOCOL

TRIALS Open Access

Involuntary reflexive pelvic floor muscle training in addition to standard training versus standard training alone for women with stress urinary incontinence: study protocol for a randomized controlled trial Helena Luginbuehl1,2*, Corinne Lehmann3, Jean-Pierre Baeyens2, Annette Kuhn4 and Lorenz Radlinger1

Abstract Background: Pelvic floor muscle training is effective and recommended as first-line therapy for female patients with stress urinary incontinence. However, standard pelvic floor physiotherapy concentrates on voluntary contractions even though the situations provoking stress urinary incontinence (for example, sneezing, coughing, running) require involuntary fast reflexive pelvic floor muscle contractions. Training procedures for involuntary reflexive muscle contractions are widely implemented in rehabilitation and sports but not yet in pelvic floor rehabilitation. Therefore, the research group developed a training protocol including standard physiotherapy and in addition focused on involuntary reflexive pelvic floor muscle contractions.

Methods/design: The aim of the planned study is to compare this newly developed physiotherapy program (experimental group) and the standard physiotherapy program (control group) regarding their effect on stress urinary incontinence. The working hypothesis is that the experimental group focusing on involuntary reflexive muscle contractions will have a higher improvement of continence measured by the International Consultation on Incontinence Modular Questionnaire Urinary Incontinence (short form), and — regarding secondary and tertiary outcomes — higher pelvic floor muscle activity during stress urinary incontinence provoking activities, better padtest results, higher quality of life scores (International Consultation on Incontinence Modular Questionnaire) and higher intravaginal muscle strength (digitally tested) from before to after the intervention phase. This study is designed as a prospective, triple-blinded (participant, investigator, outcome assessor), randomized controlled trial with two physiotherapy intervention groups with a 6-month follow-up including 48 stress urinary incontinent women per group. For both groups the intervention will last 16 weeks and will include 9 personal physiotherapy consultations and 78 short home training sessions (weeks 1–5 3x/week, 3x/day; weeks 6–16 3x/week, 1x/day).

Thereafter both groups will continue with home training sessions (3x/week, 1x/day) until the 6-month follow-up.

To compare the primary outcome, International Consultation on Incontinence Modular Questionnaire (short form) between and within the two groups at ten time points (before intervention, physiotherapy sessions 2–9, after intervention) ANOVA models for longitudinal data will be applied.

(Continued on next page)

* Correspondence: helena.luginbuehl@bfh.ch 1 Bern University of Applied Sciences, Health, Discipline of Physiotherapy, Bern, Switzerland 2 Vrije Universiteit Brussel, Faculty of Physical Education and Physiotherapy, Brussels, Belgium Full list of author information is available at the end of the article © 2015 Luginbuehl et al. Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

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Discussion: This study closes a gap, as involuntary reflexive pelvic floor muscle training has not yet been included in stress urinary incontinence physiotherapy, and if shown successful could be implemented in clinical practice immediately.

Trial registration: NCT02318251; 4 December 2014 First patient randomized: 11 March 2015 Keywords: Electromyography, Exercise, Muscle contraction, Pelvic floor, Reflex

Background Stress urinary incontinence (SUI), the most common urinary incontinence subtype in women with a prevalence of 24.8 % [1], is defined as involuntary loss of urine during effort or physical exertion (for example, during sporting activities) or upon sneezing or coughing [2]. Activities typically provoking SUI raise the intra-abdominal pressure and impact loading on the pelvic floor muscles (PFM) and require strong, rapid, and reflexive PFM contractions to maintain continence [3–6]. Fast and strong PFM contractions result in the generation of an adequate squeeze pressure in the proximal urethra, which maintains a pressure higher than that in the bladder, thus preventing leakage [7]. PFM function regarding power (rate of force development) is impaired in incontinent women compared to continent women [4, 6].

PFM training — defined as a program of repeated voluntary PFM contractions taught and supervised by a health care professional — is the most commonly used physiotherapy treatment for women with SUI, is effective with all types of female incontinence, and, therefore, is recommended as a first-line therapy [8, 9]. As endorsed by the International Consultation on Incontinence, PFM training should generally be the first step of treatment before surgery [10]. However, standard SUI physiotherapy concentrates on voluntary contractions even though the situations provoking SUI such as sneezing, coughing, jumping, and running [2] require involuntary fast reflexive PFM contractions [4]. Although training procedures following the concepts of training science and sports medicine are generally well known and widely implemented in rehabilitation and sports [11, 12], an optimal and well-standardized training protocol for involuntary, fast, and reflexive PFM contractions still remains unknown.

Consequently, the research group of the present study developed a standardized therapy program, which includes the standard physiotherapy and additionally focuses on involuntary fast reflexive PFM contractions.

The additional exercises are well known and applied in physiotherapy, however not yet regarding SUI. Therefore, the aim of the present study is to compare two different physiotherapy programs: standard training

plus involuntary reflexive PFM training versus standard training alone, regarding their effect on SUI and the impact of incontinence symptoms on quality of life. Both programs include standard physiotherapy. Both follow the concepts of training science, that is, periodization/ exercise sequence and training of specific muscle strength components [11, 12]. One program focuses on voluntary fast contractions (standard physiotherapy; control group); the other one additionally focuses on involuntary fast reflexive PFM contractions (experimental group). The secondary objective, based on secondary and tertiary outcomes, is a deeper insight into the functioning of the PFM (PFM activity characteristics and muscle action forms) by evaluating their activity measured by electromyography (EMG) in the quality of life of patients with SUI and in patients’ therapy adherence.

Methods/design Study design

The present study is a single-centered, prospective, tripleblinded (participant, investigator, outcome assessor), parallel group, non-inferiority randomized controlled trial with two physiotherapy intervention groups with a 6month follow-up.

Blinding

Participants will be blinded against the type of received physiotherapy (control group, experimental group). The participant information document will not provide any information regarding the differences in the experimental and control therapy protocols in a way that women could find out about their group allocation. All investigators involved in data acquisition, data reduction, data analyses, and statistics will also be blinded against group allocation. The physiotherapists in charge of the therapy cannot be blinded against group allocation and therefore will not be involved in data acquisition, data reduction, data analyses, or statistics.

Participants

With ethics committee approval (Ethics Committee of the Canton of Bern reference number 249/14 on 12 November 2014; Chairperson Prof. Dr. Ch. Seiler), which is

Luginbuehl et al. Trials (2015) 16:524

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Urinary Incontinence short form (ICIQ-UIsf), which provides a brief and robust assessment of the impact of symptoms of urinary incontinence on quality of life and outcome of treatment and is scored on a scale from 0 (not) – 21 (severely affected). Previous research has examined the ICIQ-UIsf questionnaire and found it to have good reliability and constructive validity [14] and to correlate well with urodynamic findings [15]. This questionnaire is validated in the German language [16]. For measurement time points see Table 1.

in accordance with the Declaration of Helsinki and the Swiss Human Research Act, and written informed consent, patients will be included on the condition that they are female adults aged 18–70 years, suffer from SUI (based on the patient’s history) or mixed urinary incontinence (with dominant SUI), are one year post-partal, parous, nulliparous, pre- or post-menopausal, have a BMI of 18–30 kg/m2, are medically and physically fit for the measurement and therapeutic exercises (running, jumps), and, in case of systemic or local estrogen treatment, stable for the past 3 months prior to inclusion.

Exclusion criteria are: urge incontinence or predominant urgency in incontinence; prolapse > grade 1 POP-Q [13] (uterus, cystocele, rectocele during Valsalva maneuver); pregnancy (urine test to accomplish); current urinary tract or vaginal infection, menstruation on the day of examination; lactation period not yet finished; contraindications for measurements or interventions, for example, acute inflammatory or infectious disease, tumor, fracture; de novo systemic or local estrogen treatment (<3 months); de novo drug treatment with anticholinergics or other bladder active substances (tricyclic antidepressants, selective serotonin reuptake inhibitors). Interventions and measurements would be individually modified in case of temporary loss of physical fitness for certain exercises.

Secondary and tertiary outcome measures

The secondary outcome measure will be the EMG activity of the PFM during rest, maximal voluntary contractions (MVCs), voluntary fast contractions (VFCs), and during involuntary contractions during squat jumps (SJs), counter movement jumps (CMJs), drop jumps (DJs), and treadmill running at 7, 9, and 11 km/h [17].

As there is a relation between high impact activities and SUI prevalence [18], those different and comprehensive test exercises will be chosen to represent typical situations of involuntary urine loss and different muscle action forms (isometric-concentric voluntary muscle actions: MVC, VFC; involuntary eccentric-concentric muscle actions: SJ, CMJ, DJ, running).

Additionally, the 20-min pad test [19, 20] and the International Consultation on Incontinence Modular Questionnaire Urinary Incontinence Symptoms Quality of Life (ICIQ-LUTSqol) [21] will be implemented as secondary outcomes. The pad test will provide information

Outcomes Primary outcome measure

The primary outcome measure will be the International Consultation on Incontinence Modular Questionnaire

Table 1 Outcome measures and personal physiotherapy consultation time points Baseline before 16-week intervention phase (1) after randomization into After intervention 6-month intervention phase control group and experimental group phase follow-up Visits

1

2

3

4

5

6

7

8

9

10

11

12

Weeks

−1

1

2

4

6

8

10

12

14

16

16 + 1

16 + 26

PT1

PT2

PT3

PT4

PT5

PT6

PT7

PT8

PT9

x

x

x

x

x

x

x

x

Personal Physiotherapy Consultation (PT) Primary outcome ICIO-UIsf

x

x

Secondary outcomes EMG (rest, MVC)

x

x

x

EMG (VFC, SJ, CMJ, DJ)

x

x

x

EMG (running 7, 9, 11 km/h)

x

x

x

ICIQ-LUTSqol

x

x

x

20-min pad test

x

x

x

ICIQ-UIsf

x

Tertiary outcomes Manual muscle testing Therapy adherence

x x

x

x

x

x

x

x

x

x

x

x

x

ICIQ-UIsf International Consultation on Incontinence Modular Questionnaire Urinary Incontinence (short form), EMG electromyography, MVC maximal voluntary contraction, VFC voluntary fast contraction, SJ squat jump, CMJ counter movement jump, DJ drop jump, ICIQ-LUTSqol International Consultation on Incontinence Modular Questionnaire Urinary Incontinence Symptoms Quality of Life

Luginbuehl et al. Trials (2015) 16:524

regarding the efficacy of the therapy protocols to the UI symptoms (such as changes in the leakage volume) and the ICIQ-LUTSqol evaluates the impact on the participant’s quality of life with reference to social effects. It consists of 20 questions, which lead to a summary score between 19 and 76 points (greater values indicate higher impact on quality of life) and is available in German [22].

As tertiary outcomes PFM strength will be digitally assessed according to the Oxford Grading Scale [23], and adherence to the home exercise program will be assessed, that is, how many of the total therapy sessions will be completed individually. The home exercise adherence data will be collected with a simple training diary questionnaire.

For measurement time points, see Table 1.

EMG procedure, instrumentation, and data reduction Instrumentation

A vaginal surface EMG probe (3-pol-STIMPON® electrode (Innocept Biobedded Medizintechnik GmbH, Gladbeck, Germany) in a differential configuration will be used to measure PFM activity. The STIMPON electrode is a certified device (patent number EP 0 963 217 B1, CE 0482) which is widely applied in pelvic floor rehabilitation. The probe is made of polypropylene and with this soft surface therefore optimally designed to adapt its form to individual vaginal cavities and not to slip out of position during impact loads. The single reference adhesive surface electrode (Ambu Blue Sensor N, Ballerup, Denmark) will be fixed on the right iliac crest.

Running will be conducted on a Kettler Marathon TX1 treadmill device (Ense-Parsit, Germany) at speeds of 7, 9, and 11 km/h and 1° inclination. For the DJ a 20cm step will be used.

To detect events necessary for the parameterization of the time-dependent signals such as heel strike (= initial contact = time point zero (T0)) during running, two load cells (Type KMB52 K 10KN, Megatron, Putzbrunn, Germany) are attached under the treadmill. T0 of SJ, CMJ, and DJ will be identified by using a force plate (Type 9286BA, Kistler Winterthur, Switzerland). Electrodes will be connected to the transmitter by short wire and the signals will be sent wirelessly to the receiver (TeleMyo 2400 G2, Noraxon European Service Center, Cologne, Germany).

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voluntary contraction and twice for 5 s during MVC (contraction maximal as possible), which will be instructed and controlled by intravaginal manual muscle testing before the EMG measurements, and ten times for VFC in a standing position, with a 15-s break between the single measurements. After that they will perform five SJs, five CMJs, and five DJs, again with 15 s between the single measurements, each jump being demonstrated and practiced before EMG recordings.

Thereafter, the subjects will perform a warm-up of treadmill walking (5 km/h) for 30 s, then running at 7, 9, and 11 km/h consecutively until they reach a steady state. As soon as they reach the steady state at the respective speed, the data acquisition will be started: all data will be measured continuously for 10 s and the first ten step cycles of the right leg will be analyzed. Between the measurements of the different speeds the treadmill will be stopped, followed by a 1-minute break until the same procedure is restarted with the next speed [17].

Data reduction

All signals will be sampled at a rate of 3 kHz (sampling interval (dt) equals 0.333 ms) using a measurement amplifier and 1-bit analog-to-digital converter (ME2600i, SisNova Engineering, Zug, Switzerland) and the software package “Analoge und digitale Signalverarbeitung” (ADS) version 1.12 (uk-labs, Kempen, Germany).

The EMG signals will firstly be first order high-pass filtered with a cut-off frequency of 10 Hz by EMG preamplifier leads to reject or eliminate artifacts and later digitally low-pass filtered by Noraxon Receiver Hardware with a cut-off frequency of 500 Hz. Secondly, to identify amplitude peaks during MVC, EMG will be calculated as RMS (200 ms moving window). 100 % of EMG equals the average of the two peak amplitude values during the two 5-s sessions of MVC. Thirdly, EMG variables of preactivity and reflexivity will be calculated as RMS values within 30-ms intervals [24–26], averaged over 10 steps, and normalized to peak MVC (% EMG). The variables of pre-activity and reflexivity (30-ms intervals) will follow former study protocol intervals [17, 24, 25]. All variables will be analyzed using the software package MATLAB (MathWorks, Natick, MA, USA). Outcomes will be averaged over the repetitions of each exercise.

EMG measurement procedures

Statistical methods Hypothesis

The subjects will be instructed in the vaginal insertion of the surface EMG probe using ultrasound lubrication and will perform the insertion themselves after emptying their bladder. They will wear a loose running suit and running shoes of the same type but individual size. PFM EMG will be measured for 30 seconds (s) without any

Alternative hypothesis for primary outcome: It is hypothezised that the experimental group focusing on involuntary pelvic floor muscle contractions will have a statistically higher improvement of continence measured

by ICIQ-UIsf questionnaire from before to after the intervention phase.

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Sample size calculation

Sample size calculation was performed with G*Power software [27], using the statistical model of an ANOVA approach (repeated measures, within-between interactions).

To this day there is no comparable training study (RCT) to estimate sample size based on available data from ICIQ-UIsf. Consequently, sample size was estimated theoretically and an effect size of = 0.1, indicating a small effect [28] will be accepted. The sample size was calculated for the primary outcome ICIQ-UIsf with the following assumptions: α = 0.05, power (1–β error probability) = 0.8, number of groups = 2, number of measurements = 10; correlations among repeated measures were estimated conservatively low with 0.5. Based on these assumptions, a total sample size of N = 80 was estimated. In anticipation of dropouts (10 %: n = 8) or a violation of normality assumption (+10 %: +n = 8), a final sample size of N = 96 (48 participants per group) results.

Statistical analyses

Analysis of the patients will follow the CONSORT flow diagram (see Fig. 1) through the phases of the study

Fig. 1 CONSORT study flow diagram

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(enrollment (assessed, excluded, randomized), allocation (control group, experimental group with received intervention or not received intervention), follow-up (lost to follow-up, discontinued intervention), and analysis (excluded, included)) [29].

The outcomes of the control and experimental group will be analyzed by the repeated measures within-between interactions ANOVA approach and an intention-to-treat analysis (last observation carried forward method). No subgroup analyses are planned.

Primary analysis: For the descriptive analyses means, standard deviations, 95 % confidence intervals, and median, quartiles, minima, maxima will be used.

To compare the primary outcome ICIQ-UIsf between and within the two groups (control group, experimental group) at ten time points (before intervention, physiotherapy sessions 2–9, after intervention), ANOVA models for longitudinal data according to Brunner et al.

[30] will be used. All statistical analyses will be realized after the final measurement of the last patient at the time point after intervention. The statistics will be calculated by SPSS and R software packages in the current

Luginbuehl et al. Trials (2015) 16:524

versions. The repeated measure design with ten time points allows us to monitor how patients change over time, in both short-term (before/during intervention) and long-term situations (before/after intervention).

Secondary and tertiary analyses: All secondary and tertiary outcomes will be analyzed following the same approach and with the same statistical procedures as for primary outcomes. Generally, rational data will be checked for normality using Q-Q-plots. If the normality assumption is not violated, parametric ANOVA models for longitudinal data will be used [31]. As for intrasession retest procedures (EMG amplitude and frequency), data will also be described and checked for their reliability (ICC, SEM, MD, ANOVA).

Detailed study plan Patient recruitment/consent procedure

Patients will be recruited from the urogynecology consultation of the Women’s Hospital, Bern University Hospital and University of Bern, Switzerland. All participants for the study will be provided a participant information sheet and a consent form describing the study and providing sufficient information for them to make an informed decision about their participation in the study.

Each participant will be specifically informed that the participation in the study is voluntary and that she may withdraw from the study at any time and that withdrawal of consent will not affect her subsequent medical assistance and treatment.

Allocation of patients

Patients with written informed consent are randomly allocated to one of the two therapy groups (control group, experimental group). The allocation sequence will be generated by the independent urogynecology secretariat using online randomization software (http://randomization.com); allocation ratio = 1:1 (control group:experimental group). The allocation will be concealed in sealed, opaque, sequentially numbered envelopes, which will be stored at the secretariat and can be opened one at a time for each eligible patient. Physiotherapists treating patients will be informed about enrollment and group allocation of their patient by the independent secretariat.

Outcome measurements

Baseline (before intervention phase), after intervention phase, and 6-month follow-up measurements (of primary, secondary, and tertiary outcomes) will take place at the Bern University of Applied Sciences movement laboratory by two experienced pelvic floor physical therapists, who are blinded regarding group allocation of participants. Measurements during the 16-week

Page 6 of 8

intervention phase (ICIQ-UIsf; primary outcome) will be taken by the treating physiotherapists. However, to guarantee blinding of the outcome, the participant will fill in the questionnaire in the absence of the treating physiotherapist and seal it in an envelope, which will be given to the outcome assessor.

Intervention

Both therapy programs (control group, experimental group) are based on the latest position stand paper of the American College of Sports Medicine [11, 32], PFM motor learning concepts [33, 34], and strength training concepts [11, 12, 32, 35, 36]. The planned progression of training for strength, power, and hypertrophy [11, 32, 33, 35, 36] is shown in Table 2.

Training procedures for motor learning, strength, hypertrophy, and power training phases follow the training principles of variation/periodization, muscle action and velocity of muscle action, loading, volume, exercise selection, rest period, and frequency [11, 12] for both groups. The training program will last 16 weeks and will contain 9 personal physiotherapy consultations and 78 home training sessions of approximately 15 minutes (weeks 1–5 3x/week, 3x/day; weeks 6–16 3x/week, 1x/ day) (Tables 1 and 2). Motor learning and strength and hypertrophy phases are comparable for both groups.

However, the main difference between the programs is the applied type of muscle action (control group: isometric, concentric; experimental group: isometric, concentric, eccentric und eccentric-concentric) and speed of movement (control group: voluntary slow to moderate (to explosive) [33, 35]; experimental group: explosive, reactive, reflexive). After completion of the 16-week training program, the participants will participate in no further personal physiotherapy consultations; however, they will continue home training sessions 3x/week until the 6-month follow-up. During the intervention period participants may continue with their individual activities of daily life.

The personal physiotherapy consultations will take place in the physiotherapy center of the Women’s Hospital, Bern University Hospital and University of Bern, Switzerland. The treating physiotherapists are all specialized and experienced in PFM rehabilitation.

An additional document file presents the intervention (therapy plan of intervention group and control group) in detail [see Additional file 1].

Adverse events

In the current study there are no anticipated risks or inconveniences, as the applied intervention and examinations are well known and widely applied in pelvic floor standard physiotherapy. The additional exercises of the experimental group are also well known and applied in

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Table 2 Time schedule and progression phases of training for motor learning, strength, hypertrophy, and power for experimental and control groups Week

Experimental group

Control group

Training frequency

1–5

Motor learning + power

Motor learning

45 (plus 3 personal physiotherapy consultations)

6–9

Strength + hypertrophy + power

Strength + hypertrophy

12 (plus 2 personal physiotherapy consultations)

10–16

Power

Strength + hypertrophy + power

21 (plus 4 personal physiotherapy consultations)

physiotherapy; however, they have not yet been used with SUI patients.

All the women are asked during every personal physiotherapy and measurement consultation whether they experience any adverse effects.

Trial protocol and updates: see clinicaltrials.gov.

Additional file Additional file 1: Stress Urinary Incontinence Physiotherapy Therapy Plan. (PDF 524 kb)

Ethical approval

The present randomized controlled trial has been approved by the ethics committee of the Canton of Bern (reference number 249/14 on 12 November 2014). The original title of the study approved by the ethics committee of the Canton of Bern, Switzerland and the Swiss National Science Foundation was: “Stress urinary incontinence physiotherapy: study protocol for a randomized controlled trial with 6-month follow-up.”

A summary flow chart is provided in Fig. 1 (CONSORT study flow diagram).

Discussion SUI is increasingly recognized as a health and economic problem which not only troubles the affected women, but also implies a substantial economic burden on health and social services [37]. Physiotherapy, the firstline basic SUI therapy [8, 9], represents only a mere 2 % of total costs [38] and therefore seems to be good value for the money. As activities or efforts typically provoking SUI occur within milliseconds [39, 40], the focus of physiotherapy PFM training protocols on fast and reflexive contractions seems crucial for SUI patients. To the best of the authors’ knowledge, the present study is the first one investigating a PFM protocol focusing on PFM reactivity, that is, investigating involuntary PFM contractions rather than concentrating exclusively on PFM voluntary contractions (standard physiotherapy). Should this newly developed PFM therapy protocol be shown successful, the clinical impact would be high and the application in clinical practice and therefore the benefit for SUI patients immediate. Additionally, the new therapy protocol promises to gain high acceptance by patients as it offers a higher suitability and practicability for daily use, because it has more dynamic whole body movement elements integrated than does standard SUI physiotherapy.

Trial status First patient randomized on 11 March 2015

Abbreviations ADS: software package “Analoge und digitale Signalverarbeitung”; ANOVA: analysis of variance; BMI: body mass index; CMJ: counter movement jump; DJ: drop jump; EMG: electromyography; ICC: intra-class correlation coefficient; ICIQ-LUTSqol: International Consultation on Incontinence Modular Questionnaire Urinary Incontinence Symptoms Quality of Life; ICIQUIsf: International Consultation on Incontinence Modular Questionnaire Urinary Incontinence (short form); MATLAB: Matrix Laboratory; MD: minimal difference; MVC: maximal voluntary contraction; PFM: pelvic floor muscles; RCT: randomized controlled trial; s: seconds; SEM: standard error of measurement; SJ: squat jump; SUI: stress urinary incontinence; VFC: voluntary fast contraction..

Competing interests The authors declare that they have no competing interests.

Authors' contributions LR and AK are responsible for this study. LR, HL, JPB, and AK conceived and developed the study design and drafted and revised the protocol. CL contributed to the study, especially regarding the development of the therapy protocols and is responsible for the physiotherapy interventions. LR and HL are responsible for data acquisition and analyses. HL is responsible for the coordination between the assessing gynecologists and their secretary, the physiotherapists, and the investigators. AK is responsible for patient recruitment. HL prepared the manuscript and is the corresponding author. All authors read and approved the final manuscript.

Acknowledgements Funding: This study is funded by the Swiss National Science Foundation (SNSF; (320030_153424/1). The granting organization Swiss National Science Foundation is not involved in the protocol and conduct of the present study.

Many thanks also to Jacqueline Buerki for proofreading the article.

Author details 1 Bern University of Applied Sciences, Health, Discipline of Physiotherapy, Bern, Switzerland. 2Vrije Universiteit Brussel, Faculty of Physical Education and Physiotherapy, Brussels, Belgium. 3Department of Physiotherapy, Bern University Hospital and University of Bern, Bern, Switzerland. 4Women’s Hospital, Urogynaecology, Bern University Hospital and University of Bern, Bern, Switzerland.

Received: 20 January 2015 Accepted: 11 November 2015

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General discussion

Helena Luginbuehl

3 General discussion The aims of this thesis were: 1) to review the evidences related to the impact of PFM activation and strength on continence and SUI; 2) to investigate activation characteristics of PFM during functional activities which typically provoke SUI; 3) to complement the SR-WBV training methodology for PFM reflex training; and 4) to define a study protocol to investigate the difference between two self-developed physiotherapy programs to cope with SUI, i.e. involuntary reflexive pelvic floor muscle training in addition to standard training versus standard training alone. Three studies for the second and one for each of the other aims and related research questions resulted in six articles, all published in peer reviewed journals [51, 64-66, 75, 76].

This thesis provided new insights in the characteristics of voluntary and involuntary PFM activation to ensure urinary continence, particularly during high impact situations. These insights are of importance to define training protocols for PFM strength and activation (with emphasis on PFM reactivity).

This chapter presents a global discussion concerning the obtained research results furthered with overall limitations and implications for future research.

3.1 The influence of PFM activation and strength components on continence and SUI The systematic review [51], which explored the evidences related to PFM activation and strength components and their contribution to female continence and SUI, provided but limited general conclusions due to the small number of studies included.

This limitation is partly explained by a strict inclusion and exclusion criteria to secure sample homogeneity. One stated conclusion was that â&#x20AC;&#x153;especially PFM function has 64

to be clarified for functional movements with short impacts typically provoking SUI [5] (e.g., running, jumping, coughing) and not only for non-functional isolated test situations (e.g., maximal voluntary contraction in supine) [46, 77]. This requirement was aimed in a first phase of this thesis and resulted in three exploratory and reliability studies concerning PFM activation during running and coughing.

3.2 PFM activation characteristics of healthy young nulliparous females during high impact situations typically provoking SUI (running, coughing) PFM activity was measured using intravaginal surface EMG. In a first step and study [65] the main focus concerned the question whether PFM reflexively reacted to the impacts during running, i.e. whether the PFM showed pre-activity and/ or reflex activity in relation to the heel strike. Variables such as PFM activity 50 ms before the heel strike, minimal EMG activity as well as maximal EMG activity, and time to maximal EMG activity were defined and tested regarding their reliability [65]. As this study found significant PFM pre- and reflex activity during the impacts of running, the subsequent two studies specifically addressed PFM pre- and reflex activity, following the study protocol of Fleischmann et al. [78]. This research team [78] investigated lateral jumps over four different distances on the EMG amplitudes of the shank muscles between touch down up to 150 ms of ground contact in time windows of 30 ms covering the phase in which reflex activity was thought to occur. Also the 30 ms time window preceding initial ground contact was measured. The same 30 ms time windows were calculated regarding PFM activity for the following two studies: One study [66] investigated PFM activity variables (30 ms time windows related to touch down according to Fleischmann et al. [78]) during running at different speeds (7, 9,

65

and 11 km/h) and checked them for reliability and differences in speed. The other study [64] evaluated the same PFM activity variables (30 ms time windows according to Fleischmann et al. [78] related to the initial time point of coughing) and their reliability during coughing.

In both studies, all PFM EMG variables were significantly higher for running and coughing than for standing without any voluntary contraction. Running demonstrated a mean between 68 and106 %EMG and coughing a mean %EMG between 35 and 52 as compared to a rest activity of 30 %EMG in the running study and 25 %EMG in the coughing study. The EMG variables of PFM activity during running showed good to excellent reliability, the ones during coughing poor reliability. During running, the intra class correlation coefficients (ICC) (3,k) for all variables were >0.75 (with one exception) with relatively low standard errors of measurement (SEM) and minimal differences (MD). ICCs of all variables during coughing were between 0.67 and 0.91, however with relatively high SEM and MD.

3.3 SR-WBV as an intervention strategy for SUI Ritzmann et al. [79] demonstrated that the periodic number of peaks per second in the EMG activity on four leg muscles during sinusoidal WBV concurred exactly with the preset vibration frequency. They explained this by vibration induced stretch reflexes and concluded only minor influence of motion artifacts due to shaking cables or electrode displacement. Therefore, it can be hypothesized that SR-WBV would lead up to 12 contractions per second depending on vibration intensity [73]. Lauper et al. [73] extrapolated that during stair descent the PFM need to contract at 6.85 Hz. This is a high frequency which can never be achieved by voluntary PFM exercises.

Consequently, SR-WBV may be an option for PFM reflex training. SR-WBV is a feasible, safe and well tolerable training method even for the untrained elderly [80] 66

with the advantage of a short total intervention time of generally 30 seconds to 5 minutes [81].

In this context, PFM activation characteristics were evaluated in response to duration and modality of the load during SR-WBV in SUI women [75]. No differences were found between the effects of continuous and intermittent SR-WBV load on PFM activity and no PFM activity change, i.e. no fatigue could be demonstrated in either SR-WBV modality within each of the three sets and between the three sets of 60 s vibration in SUI women. An explanation regarding the lack of PFM activity change could be the only moderate to submaximal PFM activity of 50–70 %EMG (normalized to MVC) during vibration. Due to easier and shorter application, continuous vibration is therefore recommended as training modus.

3.4 SUI physiotherapy: Involuntary reflexive pelvic floor muscle training in addition to standard training Standard PFM training is effective for female stress urinary incontinence treatment [67]. Despite its efficiency to control continence, standard PFM training does not embed PFM reflexive training. To train PFM reflex activity, SR-WBV, running or coughing are options because they elicit PFM reflex contractions [64-66, 73]. As a part of the definition of SUI [5], coughing may be of specific interest as a “single impact application” exercise of high amplitude. However, coughing as an exercise is experienced as unpleasant.

Initiating a RCT to compare a standard SUI PFM training against a standard PFM training plus SR-WBV for involuntary reflexive PFM training experienced constraints in terms of high costs with fund raising and the limitation to major therapy centers.

67

Running enables an increase of impact frequency and intensity [65, 66, 82, 83] comparable to SR-WBV [73]. The intensity and frequency of the impacts during running relate to the running velocity [82, 83]. Therefore, running is a free “available for everybody” training modality for PFM reflex activity. For this reason, running as a PFM reflex training method has been included in the newly developed therapy protocol for the RCT study “Involuntary reflexive pelvic floor muscle training in addition to standard training versus standard training alone for women with stress urinary incontinence” [76], which completes this thesis. For the details related to the therapy protocol see Appendix.

Besides running also jumps [84, 85] were included for the experimental group in the RCT study protocol [76]. Jumps are well investigated regarding lower limb muscles, eliciting fast rate of force and activity development due to high impacts and therefore recommended for power and reactivity training [85-87]. Women suffering from SUI have impairment of fast and high PFM activation [11]. Despite, to date PFM activity during jump performances has not been investigated.

To standardize the training program in the RCT many variables have to be considered encompassing exercise selection, repetitions, rest periods, volume, frequency, muscle action (concentric, eccentric, isometric, eccentric–concentric) etc.

The standardization of the therapy plan in the RCT [76] was based on the latest consensus paper of the American College of Sports Medicine [84], PFM motor learning concepts [88, 89], and strength training concepts [84, 85, 90-92]. A strict standardization prohibits adaptation of the training parameters to individual factors and progress status. In case the therapy plan would demonstrate to be effective, criteria need to be defined concerning the termination of each progression phase of training (for motor learning, strength, hypertrophy and power). These criteria can be applied in clinical practice on the individual patient. Initiating an intervention program 68

also encounters the national regulations of health support such as a limitation of sessions or session duration (e.g. nine physiotherapy sessions in Switzerland).

To the authorâ&#x20AC;&#x2122;s knowledge, the proposed therapy protocol and study is the first which focuses on reflexive PFM contractions in SUI women.

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General strengths and limitations

Helena Luginbuehl

4 General strengths and limitations The following inconsistencies and therefore limitations were encountered during this research project. This was partly due to the novel and innovative aspects to investigate the PFM activity characteristics during functional activities or whole body movements, which typically provoke SUI. PFM muscle reflex activity during running was tested and shown in healthy young nulliparous females only but so far not investigated in women suffering from SUI. Logical sequencing would have been to further the project on PFM reflex activity of SUI women during running to support running as a PFM reflex activity exercise in the therapy protocol. This research gap could not be filled due to a non-support in funding. Despite this, running is comparable to SR-WBV in terms of repeatability, frequency and intensity of the impacts whereas SR-WBV showed higher PFM reflex activity in post-partum women with weak PFM than in healthy women [73].

A further limitation applies to jumping, which was neither investigated in healthy nor in SUI women.

To gain insight in the PFM activity characteristics and muscle action, variables of PFM pre-activity and reflex activity [64, 66, 78, 93] during running and jumping were chosen as secondary outcomes about the effect of the therapy protocols. Those PFM variables were only tested regarding their reliability during running in healthy young continent females [66] and not in SUI women and, as to their reliability during jumping they were neither tested in healthy continent females nor in SUI women.

Hence, it was part of the ethics application and its approval (Ethics Committee of the Canton of Bern reference number 249/14 on 12 November 2014; Chairperson Prof.

Dr. Ch. Seiler) that the reliability tests can be accepted retrospectively with the data of the RCT [76]. This procedure is not ideal but chosen due to funding problems concerned.

70

In the first exploratory and reliability study [65] the conclusion of good reliability was based merely on the intra class correlation coefficient values. All variables demonstrated relatively high standard error of measurement and minimal difference values, which were not taken into consideration to discuss reliability [94].

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General conclusion and suggestions for further research

Helena Luginbuehl

5 General

conclusion

and

suggestions

for

further

research This work accentuated on how PFM activation and strength components support female continence and cope with SUI [51], evaluated the PFM pre- and reflex activity during running and coughing [64-66], and dealt with the integration of PFM reflex training in therapy [75, 76]. To the authorâ&#x20AC;&#x2122;s knowledge it was a novelty to investigate functional SUI provoking activities and whole body movements concerning PFM activation and to define and test a standardized PFM training program for SUI women encompassing the training of fast involuntary PFM reflex contractions.

The current guidelines for physical therapy in patients with SUI [95-97] do not contain PFM involuntary reflex training other than PFM involvement in the context of trunk stabilization [95]. Consequently, should the therapy protocol including involuntary reflexive PFM training in addition to standard training be proven to be more effective than standard training alone, this would be of high clinical and practical relevance.

Literature reviews revealed that questions on the specific muscle action of the PFM remain unanswered and that future studies should focus on muscle action to get a deeper insight in physiological and pathophysiological function of the PFM [51, 98].

Within these reviews, no conclusive evidence could be stated to what extent the PFM contractions during high-impact activities represent stretch shortening cycles. It is essential to investigate the PFM displacement during voluntary and reflex activation during functional activities or whole body movements in healthy continent and SUI women. To the authorâ&#x20AC;&#x2122;s knowledge there are no probes available hitherto, which enable PFM strength measurements during functional activities or whole body movements apart from coughing in supine or standing [8]. Therefore, there is a need 72

to develop vaginal probes for PFM active transversal force measurements during functional activities or whole body movements. Of additional interest would be the development of a probe measuring both PFM EMG and strength. This would enable to evaluate PFM maximal strength/ activation, rate of force/ activity development as well as functional PFM strength and activation characteristics [8].

Future research should address functional PFM rehabilitation. Besides SR-WBV [73, 75], running and coughing [64-66] there are other (high) impact situations such as stair climbing [99], jumping on the spot (feet together or feet apart and together) [99], jumps [100], “speaking of hard consonants” (e.g. “ck” in lick-lack-lock or “t”) [101], specific sports activities (e.g. trampoline, gymnastics etc.) or daily activities (e.g. lifting) [16], which could be adequate and feasible as exercises to elicit PFM reflex activity. To the author’s knowledge the only impact situation already proposed as a PFM training exercise is the “speaking of hard consonants” by Tanzberger et al.

[101], which so far has neither been investigated for its effect on PFM activity nor regarding its therapeutic effect for SUI women. The differences in loading and rate of activation could be integrated in progressive levels of a therapeutic intervention protocol (motor learning, strength, hypertrophy and power).

Future research should also explore the coping strategies for SUI in men.

73

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Bernards, A., et al., KNGF Guideline for Physical Therapy in patients with Stress urinary incontinence. Dutch Journal of Physical Therapy, 2011. 121(3 Supplement).

Bernards, A.T., et al., Dutch guidelines for physiotherapy in patients with stress urinary incontinence: an update. Int Urogynecol J, 2014. 25(2): p. 1719.

Qaseem, A., et al., Nonsurgical management of urinary incontinence in women: a clinical practice guideline from the American College of Physicians.

Ann Intern Med, 2014. 161(6): p. 429-40.

Leitner, M., et al., Pelvic floor muscle displacement during voluntary and involuntary activation in continent and incontinent women: a systematic review. Int Urogynecol J, 2015. 26(11): p. 1587-98.

Hahn, I. and M. Fall, Objective Quantification of Stress Urinary Incontinence: A Short, Reproducible, Provocative Pad-Test. Neurourol Urodyn, 1991. 10: p.

475-481.

Bo, K. and J.S. Borgen, Prevalence of stress and urge urinary incontinence in elite athletes and controls. Med Sci Sports Exerc, 2001. 33(11): p. 1797-802.

Tanzberger, R., Physiotherapie in der Kontinenzbehandlung, in Der Beckenboden - Funktion, Anpassung und Therapie: Das TanzbergerKonzeptÂŽ, R. Tanzberger, et al., Editors. 2013, Urban & Fischer: Muenchen. p. 389-91.

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Publications and conference proceedings

Helena Luginbuehl

7 Publications and conference proceedings Peer-reviewed publications Rogan, S., Taeymans, J., Luginbuehl, H., Aebi, M., Mahnig, S., Gebruers, N. Therapy modalities to reduce lymphedema in female breast cancer patients: a systematic review and meta-analysis. Breast Cancer Res Treat. 2016 Aug;159(1):1-14.

Luginbuehl, H., Baeyens, J.-P., Kuhn, A., Christen, R., Oberli, B., Eichelberger, P., Radlinger, L. Pelvic floor muscle reflex activity during coughing – an exploratory and reliability study. Ann Phys Rehabil Med 2016 Jun 2. [Epub ahead of print].

Luginbuehl, H., Naeff, R., Zahnd, A., Baeyens, J.-P., Kuhn A., Radlinger L. Pelvic floor muscle electromyography during different running speeds – an exploratory and reliability study. Arch Gynecol Obstet. 2016 Jan;293(1):117-24. doi: 10.1007/s00404-015-3816-9.

Epub 2015 Jul 21.

Luginbuehl, H., Lehmann, C., Baeyens, J.-P., Kuhn, A., Radlinger, L. Involuntary reflexive pelvic floor muscle training in addition to standard training versus standard training alone for women with stress urinary incontinence: study protocol for a randomized controlled trial.

Trials. 2015 Nov 17;16:524. doi: 10.1186/s13063-015-1051-0.

Luginbuehl, H., Baeyens, J.-P., Taeymans, J., Maeder, I.-M., Kuhn, A., Radlinger, L. Pelvic Floor Muscle Activation and Strength Components Influencing Female Continence and Stress Urinary Incontinence: A Systematic Review. Neurourol Urodyn. 2015 Aug;34(6):498506. doi: 10.1002/nau.22612. Epub 2014 Apr 9.

Luginbuehl, H., Greter, C., Gruenenfelder, D., Baeyens, J.-P., Kuhn, A., Radlinger, L. Intrasession test-retest reliability of pelvic floor muscle electromyography during running. Int Urogynecol J. 2013 Sep;24(9):1515-22. doi: 10.1007/s00192-012-2034-2. Epub 2013 Jan 30.

Luginbuehl, H., Lehmann, C., Gerber, R., Kuhn, A., Hilfiker, R., Baeyens, J.-P., Radlinger, L. Continuous Versus Intermittent Stochastic Resonance Whole Body Vibration and Its Effect on Pelvic Floor Muscle Activity. Neurourol Urodyn. 2012 Jun;31(5):683-7. doi: 10.1002/nau.21251. Epub 2012 Mar 6.

Lauper, M., Kuhn, A., Gerber, R., Luginbuehl, H., Radlinger, L. Pelvic floor stimulation: what are the good vibrations? Neurourol Urodyn. 2009 28(5):405-10. doi: 10.1002/nau.20669.

Non peer-reviewed publications Luginbühl, H., Lehmann, C., Kuhn, A., Radlinger, R. Inkontinenz: Mehr Schnellkraft; Schnellkraft sichert die Kontinenz: Ein Physiotherapieprogramm für die Praxis. med&move.

2014 40-41.

Luginbühl, H., Radlinger, L. Beckenbodendiagnostik und -therapie: Ein Thema für Lehre und Forschung. Frequenz. 2013 Juli:24-25.

80

Radlinger, L., Lehmann, C., Kuhn, A., Luginbühl, H. Aktivierbarkeit Beckenbodenmuskulatur durch Ganzkörpervibration. Kontinenz aktuell, (57):9-13.

der

Peer-reviewed oral presentations Bardill, A., Bachmann, L., Eichelberger, P., Koenig, I., Luginbuehl H., Radlinger, L. Exploring fatigue of pelvic floor muscles with electromyographic measurements during running. International Urogynecological Association IUGA Meeting 2016. Cape Town, South Africa. Int Urogynecol J. 2016 August;27(Suppl 1):593.

Luginbuehl, H., Baeyens, J-P., Kuhn, A., Christen, R., Oberli, B. & Radlinger, L. Pelvic floor muscle electromyography during coughing – an exploratory and reliability study. German Continence Association Congress 2015. Munich, Germany.

Luginbuehl, H., Baeyens, J-P., Kuhn A., Christen R., Oberli B., Zbaeren S., Radlinger, L. Pelvic floor muscle electromyography during coughing – an exploratory and reliability study.

Swiss Association for Gynecology and Obstetrics Congress SGGG 2015. Lugano, Switzerland.

Luginbuehl, H., Naeff R., Zahnd A., Baeyens, J-P., Kuhn A. & Radlinger, L. Pelvic floor muscle electromyography during different running speeds – an exploratory and reliability study. International Conference on Clinical and BioEngeneering for Women’s Health BioMedWomen 2015. Porto, Portugal.

Luginbuehl, H., Baeyens, J-P., Naeff R., Zahnd, A., Kuhn A., Radlinger, L. Pelvic floor muscle electromyography during different running speeds – an exploratory and reliability study. World Confederation for Physical Therapy Congress WCPT 2015. Singapore.

Luginbuehl, H., Baeyens, J.-P., Taeymans, J., Maeder, I.-M., Kuhn, A., Radlinger, L. Pelvic floor muscle activation and strength components influencing female continence and stress urinary incontinence: a systematic review. German Continence Association Congress 2014.

Frankfurt, Germany. The Abstract of this presentation was selected as one of the ten very interesting abstracts and published in the Journal of the German Continence Society. Interessante Vortrags-Abstracts des 26. Kongresses der Deutschen Kontinenz Gesellschaft e.V. kontinenz aktuell 2014 Juli 63(2):18-22.

Luginbuehl, H., Baeyens, J.-P., Naeff, R., Zahnd, A., Kuhn, A., Radlinger, L. Pelvic floor muscle electromyography during three different running speeds – an exploratory and reliability study. German Continence Association Congress 2014. Frankfurt, Germany.

Luginbuehl, H., Baeyens, J.-P., Naeff, R., Zahnd, A., Kuhn, A., Radlinger, L. Pelvic floor muscle electromyography during three different running speeds – an exploratory and reliability study. International Urogynecological Association IUGA and American Urogynecologic Society Joint Meeting 2014. Washington DC, USA. Int Urogynecol J. 2014 July/August;20(4 Suppl):S104-S105.

Luginbuehl, H., Baeyens, J.-P., Taeymans, J., Maeder, I.-M., Kuhn, A., Radlinger L. Pelvic floor muscle activation and strength components influencing female urinary continence and stress incontinence: a systematic review”. International Urogynecological Association IUGA

81

and American Urogynecologic Society Joint Meeting 2014. Washington DC, USA. Int Urogynecol J. 2014 July/August;20(4 Suppl):S105.

Luginbuehl, H., Baeyens, J.-P., Naeff R., Zahnd A., Kuhn A., Radlinger, L. Pelvic floor muscle electromyography during three different running speeds – an exploratory and reliability study. Swiss Association for Gynecology and Obstetrics Congress 2014. Interlaken, Switzerland.

Luginbuehl, H., Greter, C., Gruenenfelder, D., Baeyens, J.-P., Kuhn, A., Radlinger, L. Intrasession test-retest reliability of pelvic floor muscle electromyography during running. German Continence Association Congress 2013. Hannover, Germany.

Luginbuehl, H., Greter, C., Gruenenfelder, D., Baeyens, J.-P., Kuhn, A., Radlinger, L. Intrasession test-retest reliability of pelvic floor muscle electromyography during running. Swiss Association for Gynecology and Obstetrics Congress 2013. Lugano, Switzerland.

Radlinger, L., Lauper, M., Kuhn, A., Gerber, R., Luginbuehl, H. Ganzkörpervibration und Aktivierbarkeit der Beckenbodenmuskulatur. German Continence Association Congress 2011. Köln, Germany.

Luginbuehl, H. , Lehmann, C., Gerber, R., Lauper, M., Hilfiker, R., Kuhn, A., Radlinger L. Stochastische Ganzkörpervibration bei Inkontinenz: Intermittierende versus Kontinuierliche Belastung. National Congress of the Physical Therapy Association Switzerland (physioswiss) 2010. Basel, Switzerland.

Lehmann, C., Luginbuehl, H., Hilfiker, R., Radlinger, L. Konventionelle physiotherapeutische Behandlung der Belastungsinkontinenz der Frau. National Congress of the Physical Therapy Association Switzerland (physioswiss) 2010. Basel, Switzerland.

Lauper, M., Kuhn, A., Gerber, R., Luginbuehl, H., Radlinger, L. Ganzkörpervibration und Aktivierbarkeit der Beckenbodenmuskulatur. 5. Physiokongress Thieme 2009. Stuttgart, Germany.

Invited talks: Luginbuehl, H. [The essential role of pelvic floor power and reactivity for continence].

Symposium der Schweizerischen Gesellschaft für Physikalische Therapie und Rehabilitation. reha schweiz 2015. Bern, Switzerland.

Luginbuehl, H. [Whole body vibration and pelvic floor muscle activation; the essential role of pelvic floor muscle rate of force development and reactivity for continence]. Hirslanden Symposium Zurich 2014. Switzerland.

Peer-reviewed posters: Koenig, I., Luginbuehl, H., Radlinger, L. Intra-session reliability of pelvic floor muscle electromyography tested on healthy women and women with stress urinary incontinence or weak pelvic floor muscle. International Urogynecological Association IUGA Meeting 2016.

Cape Town, South Africa.

82

Luginbuehl, H., Baeyens, J.-P., Kuhn, A., Christen, R., Oberli, B. Radlinger, L. Pelvic floor muscle electromyography during coughing – an exploratory and reliability study. National Congress of the Physical Therapy Association Switzerland (physioswiss) 2016. Basel, Switzerland Luginbuehl, H., Baeyens, J.-P., Kuhn, A., Christen, R., Oberli, B., Radlinger, L. Pelvic floor muscle electromyography during coughing – an exploratory and reliability study. International Urogynecological Association IUGA Meeting 2015, Nice, France.

Luginbuehl, H., Baeyens, J.-P., Taeymans, J., Maeder, I.-M., Kuhn, A., Radlinger, L. Pelvic floor muscle activation and strength components influencing female continence and stress urinary incontinence: a systematic review. World Confederation for Physical Therapy Congress WCPT 2015. Singapore.

Luginbuehl, H., Baeyens, J.-P., Taeymans, J., Maeder, I.-M., Kuhn, A., Radlinger, L. Pelvic floor muscle activation and strength components influencing female continence and stress urinary incontinence: a systematic review. Symposium pelvisuisse 2014. Winterthur, Switzerland. Winner of the poster prize.

Luginbuehl, H., Baeyens, J.-P., Taeymans, J., Maeder, I.-M., Kuhn, A., Radlinger, L. Kontinent oder inkontinent? Der Einfluss von Kraft und Aktivität der Beckenbodenmuskulatur – ein systematisches Review. National Congress of the Physical Therapy Association Switzerland (physioswiss) 2014. Bern, Switzerland.

Mueller, A., Origlia, P., Holzer Gadola, M., Rohrbach, D., Luginbühl, H. Erfolgsfaktor Mentoring. Evaluation bei Dozierenden des Fachbereichs Gesundheit der BFH. Swiss Congress for Health Professions 2014, Bern, Switzerland.

Luginbuehl, H., Greter, C., Gruenenfelder, D., Baeyens, J.-P., Kuhn, A., Radlinger, L. Elektromyographie der Beckenbodenmuskulatur beim Joggen - Parametrisierung und Retest-Reliabilität. National Congress of the Physical Therapy Association Switzerland (physioswiss) 2012. Genf, Switzerland.

Luginbuehl, H., Lehmann, C., Gerber, R., Lauper, M., Kuhn, A., Hilfiker, R., Radlinger, L. Load duration during stochastic whole body vibration in its effects on pelvic floor muscle activation. World Confederation of Physical Therapy Congress WCPT 2011. Amsterdam, Netherlands.

Lauper, M., Kuhn, A., Gerber, R., Luginbuehl, H., Radlinger, L. Acute effects of stochastic and sinusoidal whole body vibration on pelvic floor muscle activation. World Confederation of Physical Therapy Congress WCPT 2011. Amsterdam, Netherlands.

Maurer, D., Radlinger, L., Luginbuehl, H., Lehmann, C., Kuhn, A., Koch, V. Development of intra-vaginal sensors for measuring pelvic floor muscle tone. Swiss Society for Biomedical Engineering - Annual Meeting 2011. Bern, Switzerland.

Maurer, D., Radlinger, L., Luginbuehl, H., Lehmann-Steudler, C., Kuhn, A., Koch, V. Development of an intra-vaginal sensor measuring pelvic floor muscle activation. The 6th International Conference on Microtechnologies in Medicine and Biology 2011. Luzern, Switzerland.

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Schulte-Frei, B., Luginbuehl, H., Lehmann, C., Radlinger, L. Deficit related training strategies for walking and running. Restoring Walking and Running after pelvic floor insufficiency: Assessments and therapy after urinary incontinence. 6th EISCSA-Congress 2010. St. Etienne, France.

Luginbuehl, H., Eigenmann, P. Clinical Reasoning as a Main Educational Strategy Association for Medical Education Europe Congress AMEE 2003. Bern, Switzerland.

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Appendix

Helena Luginbuehl

8 Appendix Study protocol (published in Trials 2015 Nov 17;16(1):524 as additional file)

Stress Urinary Incontinence Physiotherapy â&#x20AC;&#x201C; Therapy Plan (SUIP - Therapy Plan)

1,2

3

2

4

Helena Luginbuehl , Corinne Lehmann , Jean-Pierre Baeyens , Annette Kuhn , Lorenz Radlinger

1

Bern University of Applied Sciences, Health, Discipline of Physiotherapy, Switzerland

2

Vrije Universiteit Brussel, Faculty of Physical Education and Physiotherapy, Belgium

3

Bern University Hospital and University of Bern, Department of Physiotherapy, Switzerland

4

Womenâ&#x20AC;&#x2122;s Hospital, Urogynaecology, Bern University Hospital and University of Bern, Switzerland

85

1

Introduction To date, the focus of research on pelvic floor muscle (PFM) function has been on the concentric and isometric muscle action that leads to the lift and squeeze but so far no light has been shed on the eccentric or eccentric-concentric type of contraction and the related involuntary or reflexive power. â&#x20AC;&#x153;Powerâ&#x20AC;? has to be interpreted as mechanical power (P(t) = F x v ď&#x192;¨ power equals force times velocity) in the sense of rate of force development in the here described context of training.

It can be assumed that the impact loading on the PFM evoked by coughing, running, jumping or any abrupt rise in intra-abdominal pressure provokes involuntary muscle reactivity. Based on the literature review presented in the study protocol the main deficit of an insufficient and incontinent PFM is the lower maximal force and the lower power compared to sufficient PFM. Consequently, the special attribute of the standardized therapy plan for the experimental group introduced here aims at power with voluntary and in contrast to the control group as well as involuntary reactive strength with reflexive PFM contractions as a characteristic of a physiological unconscious and not perceived functioning of PFM during daily life activities or activities with short but intensive impacts (jumps, running, coughing etc.).

Although conventional therapy programs finally also focus on the power, however, fast voluntary PFM contractions are applied only. That means this program of the control group is carried out without the above mentioned involuntary reactive contractions.

Both programs are based on the latest position stand paper of the American College of Sports Medicine (ACSM) [1, 2], PFM motor learning concepts [3, 4], and strength training concepts [1, 2, 5-7]. However, even in these references the training methods vary within a certain range (e.g. repetitions: 8-12; rest intervals: 1-2 minutes, velocity: slow to moderate, etc.). This lack in standardization of training regimens is well known [8]. Therefore, within in these methodological ranges training programs presented her are precisely standardized for the control and experimental group separately and following the references and training principles and methods.

The planned progression of training for strength, power and hypertrophy is shown in Table 1.

Table 1. Time schedule and progression phases of training for motor learning, strength, hypertrophy and power for experimental and control group (compiled following [1-3, 5-7]) Week

Experimental group

Control group

Training Frequency

1-5

Motor learning + power

Motor learning

15 (plus 3 personal physiotherapy consultations)

6-9

Strength + hypertrophy + power

Strength + hypertrophy

12 (plus 2 personal physiotherapy consultations)

10-16

Power

Strength + hypertrophy + power

21 (plus 4 personal physiotherapy consultations)

86

Respected training principles Training procedures for motor learning, strength, hypertrophy and power training phases will follow the below mentioned training principles for both groups.

Variation / periodization. Changes of a therapy program over time allow for the training stimulus remain to be effective and challenging. The here used classical periodization is characterized by the intention to carry out the fundamental aspects (motor learning, strength, hypertrophy, power) to prepare distinct abilities. [1] Table 1 shows a 16 weeks lasting training program with a total number of 78 training sessions with additional 9 personal consultations (= physiotherapy sessions) for both groups.

Motor learning and strength and hypertrophy phases are comparable for both groups, however the main difference between the programs is the applied type of muscle action (control group (CON): isometric, concentric; experimental group (EXP): isometric, concentric, eccentric und eccentric-concentric) and speed of movement (CON: voluntary slow to moderate (to explosive) [3, 5]; EXP: explosive, reactive, reflexive; for details see tables for weekly training below).

Muscle action and velocity of muscle action. All training adaptations are “specific” to the stimulus applied. The relevant factors are the muscle actions involved (CON: concentric; EXP: concentric, eccentric-concentric), the speed of movement (CON: slow – moderate – quick; EXP: explosive – reactive) and the muscle groups trained (CON: PFM; EXP: PFM).

The supra-maximal eccentric actions are known to produce an additional benefit in terms of force generation compared to concentric or isometric contractions.

The recommendations of the ACSM [1] do not bring up the idea of involuntary eccentricconcentric, reactive strength training with maximal explosive contraction velocities as Güllich and Schmidtbleicher [7] propose. However, ACSM recommends jumps with fast repetition velocity for maximal progression in jump performance. This idea will be introduced into the training program of the experimental group aiming on the reactive activation of PFM. The program of the control group uses slow to moderate to quick voluntary contractions instead.

Loads during jumps and running are described as a trigger for incontinence.

Loading. Due to the fact that no external weights are possible it is not possible to carry out a 1 repetition maximum (1RM) like recommended. Therefore it is quite difficult to describe the loading of PFM strength training. Voluntary (and involuntary) contractions of the PFM will be performed in relation to maximal voluntary contraction (MVC). The patients will be familiarized with this maximal loading and submaximal loads will be estimated and performed in relation to 100%MVC. [1] Volume. One to three sets per exercise are recommended to be used by novice individuals.

For progression long term studies indicated multiple sets and a systematic variation of volume over time. [1] Exercise selection. This training program focusses on the voluntary and involuntary PFM contraction. Involuntary PFM contraction will be performed by running or jumping on the spot.

[1] Rest periods. The range of rest periods will be 30 seconds to 120 seconds because the exercises used are with low complexity. [1] Frequency. Besides 9 personal physiotherapy consultations both groups will train 3 times a week (week 1-5 3x/week, 3x/day; week 6-16 3x/week, 1x/day = 78 home training sessions) for 16 weeks to be comparable in training frequency. [1]

87

Basic Therapy The basic therapy will be performed in both groups equally during the 9 intended physiotherapy sessions. Basic therapy represents the usual physiotherapy session contents in the presence of a physiotherapist and patient. Both groups will receive the basic therapy during 9 physiotherapy sessions which homogeneously distributed take place in the weeks 1, 2, 4, 6, 8, 10, 12, 14, and 16.

First, the home exercises and training methods will be instructed, supervised and controlled by the physiotherapist at the 9 physiotherapy sessions only, which is best practice and sufficient [9]. This procedure should also grant a high and sustained adherence over time [10, 11].

Second, each patient will receive the necessary proper basic information and instruction [12] and will be taught to perform a correct voluntary PFM contraction. Basic therapy additionally includes: information regarding anatomical, (patho-)physiological aspects of SUI [13-15], performing an isolated PFM contraction [16], postural control, breathing, and PFM contraction with continuous breathing [17], exercising pre-contraction [18], fluid intake [19], micturition and defecation behavior [20], co-contraction [21] of PFM and M. abdominus transversus [22] during intra-abdominal pressure increase. The 9 personal therapy consultations will not be included into the total amount of 78 therapy units (= 100% of all therapy units).

Third, life style interventions for pelvic floor dysfunction will additionally be given during the therapy and follow-up period following the recommendations of Chiarelli [23].

Therapy plan According to the above discussed training principles and basic therapy a detailed and standardized training program is carried out in the following for each week of training including a short description of the related physiotherapy session 1-9 (aims, basic therapy) and the separate home exercise program for each group with aims of training, exercises used, relevant muscle action type and contraction velocity, description of loading, number of repetitions, volume, duration of rest, training frequency per day/week, and body position applied.

88

st

1 week of exercise program st

1 Physiotherapy session Aims: The patient is able to perform a correct isolated maximal voluntary pelvic floor muscle (PFM) contraction (squeeze around pelvic openings and inward (cranial) lift [24, 25].

Basic therapy: Make an anamnesis and explain the function of the pelvic floor [13-15]. Teach isolated PFM contractions [16] and the home exercise program corresponding to the randomized groups (see below).

Home exercise program Experimental group

Control group

Aims:

motor learning + power

Aims:

motor learning

Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

isolated PFM contractions concentric-isometric, explosive 90-100% of MVC 3x 2-3 seconds hold 3 60s 3x/day & 3x/week supine

Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

isolated PFM contractions concentric, slow 60-70% of MVC 8 1 3x/day & 3x/week sitting on a armchair

nd

2 week of exercise program nd

2 Physiotherapy session Aims: Control and improvement of the home exercise program. Patient knows the interaction between diaphragm and PFM. The patient is able to prevent an interruption of breathing while contracting PFM [17].

Basic therapy: Teach the patient to concentrate on breathing. The patient contracts PFM and counts loudly with continuous breathing to five. Teach the home exercise program corresponding to the randomized groups (see below).

Home exercise program Experimental group

Control group

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

motor learning + power isolated PFM contractions concentric-isometric, explosive 90-100% of MVC 4x 2-3s hold 3 60s 3x/day & 3x/week sitting upright (chair without arm)

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

motor learning isolated PFM contractions concentric, slow to moderate 60-70% of MVC 10 1 3x/day & 3x/week supine

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

motor learning + rate of force development isolated PFM contractions concentric, explosive 90-100% of MVC 3 3 60s 3x/day & 3x/week sitting upright

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

motor learning isolated PFM contractions concentric, slow to moderate 60-70% of MVC 8 1 3x/day & 3x/week sitting upright (chair without arm)

89

rd

3 week of exercise program Home exercise program Experimental group

Control group

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

motor learning + power isolated PFM contractions concentric-isometric, explosive 90-100% of MVC 5x 4s hold 5 60s 3x/day & 3x/week sitting upright (chair without arm)

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

motor learning isolated PFM contractions concentric, slow to moderate 60-70% of MVC 10 2 120s 3x/day & 3x/week supine

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

motor learning + rate of force development isolated PFM contractions concentric, explosive 90-100% of MVC 5 5 60s 3x/day & 3x/week sitting upright

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

motor learning isolated PFM contractions concentric, slow to moderate 60-70% of MVC 8 2 60s 3x/day & 3x/week sitting upright (chair without arm)

th

4 week of exercise program th

3 Physiotherapy Session Aims: Control and improvement of the home exercise program. The patient is able to perform adequate trunk stabilization in functional positions and movements [17].

Basic therapy: Exercise the correct posture in sitting, standing and lifting. Let feel the difference to inadequate trunk stabilization. Teach the home exercise program corresponding to the randomized groups (see below).

Home exercise program Experimental group

Control group

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

motor learning + power isolated PFM contractions concentric-isometric, explosive 90-100% of MVC 4x 2-3s hold 6 60s 3x/day & 3x/week standing upright

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

motor learning isolated PFM contractions concentric, slow to moderate 60-70% of MVC 10 3 60s 3x/day & 3x/week sitting upright

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

motor learning + power isolated PFM contractions concentric, explosive 90-100% of MVC 5 3 60s 3x/day & 3x/week standing upright

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

motor learning isolated PFM contractions concentric, slow to moderate 60-70% of MVC 8 2 2 minutes 3x/day & 3x/week standing upright

90

th

5 week of exercise program Home exercise program Experimental group

Control group

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

motor learning + power isolated PFM contractions concentric-isometric, explosive 90-100% of MVC 5x 3-4s hold 6 60s 3x/day & 3x/week standing upright

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

motor learning isolated PFM contractions concentric, moderate 60-70% of MVC 10 3 60s 3x/day & 3x/week standing upright

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

motor learning + power isolated PFM contractions concentric, explosive 90-100% of MVC 3 5 60s 3x/day & 3x/week standing upright

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

motor learning isolated PFM contractions concentric, moderate 60-70% of MVC 8 2 120s 3x/day & 3x/week standing in a squat position

th

6 week of exercise program th

4 Physiotherapy session Aims: Control and improvement of the home exercise program. The patient is able to contract PFM against the resistance of increased intra-abdominal pressure.

Basic therapy: Training of voluntary contraction immediately before coughing or lifting something (The ÂŤKnackÂť = voluntary PFM pre-contraction) [18]. Teach the exercise program corresponding to the randomized groups (see below).

Home exercise program Experimental group

Control group

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

strength and hypertrophy isolated PFM contractions concentric, explosive 60-85% of MVC 12 3 60s 3x/week standing upright

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

strength and hypertrophy isolated PFM contractions concentric-isometric, moderate 60-70% of MVC 1x 5s hold 3 120s 3x/week sitting on the floor

Aims:

strength and hypertrophy + power running on the spot with pre-contraction concentric-isometric, reactive 15s 3 60s 3x/week standing upright

Aims:

strength and hypertrophy

Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

isolated PFM contractions concentric, quick 60-70% of MVC 8 2 120s 3x/week sitting on the floor

Exercises: Muscle action: Loading: Time: Volume: Rest: Frequency: Position:

91

th

7 week of exercise program Home exercise program Experimental group

Control group

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

strength and hypertrophy isolated PFM contractions concentric, explosive 60-85% of MVC 10 3 15s 3x/week standing upright

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

strength and hypertrophy isolated PFM contractions concentric-isometric moderate, 60-70% of MVC 8x 5s 2 120s 3x/week lying on the floor in a bridging position

Aims:

strength and hypertrophy + power running on the spot with pre-contraction concentric-isometric, reactive 15s 3 60s 3x/week standing upright

Aims:

strength and hypertrophy

Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

isolated PFM contractions concentric, quick 60-70% of MVC 8 3 120s 3x/week lying on the floor in a bridging position

Exercises: Muscle action: Loading: Time: Volume: Rest: Frequency: Position:

Loading = (-): Due to the fact of involuntary contractions the loading cannot be estimated in relation to MVC

th

8 week of exercise program th

5 Physiotherapy session Aims: Control and improvement of the home exercise program. The patient should be able to create and evaluate a micturition-protocol [19].

Basic therapy: Demonstrate an example of a micturition-protocol. Teach that the micturition and the defecation [20] take place without pressing. Teach the home exercise program corresponding to the randomized groups (see below).

Home exercise program Experimental group

Control group

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

strength and hypertrophy isolated PFM contractions concentric, explosive maximal: 90-100% of MVC 3 5 60s 3x/week standing upright

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

strength and hypertrophy isolated PFM contractions concentric-isometric, moderate 60-70% of MVC 8x 5s 2 120s 3x/week lying on forearms and knees

Aims:

strength and hypertrophy + power running on the spot with pre-contraction concentric-isometric, reactive 15s 3 60s 3x/week standing upright

Aims:

strength and hypertrophy

Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

isolated PFM contractions concentric, quick 60-70% of MVC 8 3 120s 3x/week lying on forearms and knees

Exercises: Muscle action: Loading: Time: Volume: Rest: Frequency: Position:

Loading = (-): Due to the fact of involuntary contractions the loading cannot be estimated in relation to MVC

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9 week of exercise program Home exercise program Experimental group

Control group

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

strength and hypertrophy isolated PFM contractions concentric, explosive maximal: 90-100% of MVC 4 5 60s 3x/week standing upright

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

strength and hypertrophy isolated PFM contractions concentric-isometric, moderate 60-70% of MVC 10x 5s 2 120s 3x/week lying on hands and knees

Aims:

strength and hypertrophy + power running on the spot with pre-contraction concentric-isometric, reactive 15s 3 60s 3x/week standing upright

Aims:

strength and hypertrophy

Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

isolated PFM contractions concentric, quick 60-70% of MVC 10 3 60s 3x/week lying on hands And knees

Exercises: Muscle action: Loading: Time: Volume: Rest: Frequency: Position:

Loading = (-): Due to the fact of involuntary contractions the loading cannot be estimated in relation to MVC

th

10 week of exercise program th

6 Physiotherapy session Aims: Control and improvement of the home exercise program. The patient is able to interpret her micturition-protocol.

Basic therapy: Evaluate and discuss the micturition-protocol. Teach the home exercise program corresponding to the randomized groups (see below).

Home exercise program Experimental group

Control group

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

power (voluntary) isolated PFM contractions explosive 10 3 60s 3x/week standing upright, squat position

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

strength and hypertrophy isolated PFM contractions concentric-isometric, moderate 60-70% of MVC 10x 5s 2 120s 3x/week sitting on the floor with legs crossed

Aims: Exercises: Muscle action: Loading: Time: Volume: Rest: Frequency: Position:

power (involuntary) running on the spot (no pre-contraction) reactive 15s 3 60s 3x/week standing upright

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

strength and hypertrophy isolated PFM contractions concentric, quick 60-70% of MVC 12 2 60s 3x/week sitting on the floor with legs crossed

Loading = (-): Due to the fact of involuntary contractions the loading cannot be estimated in relation to MVC

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11 week of exercise program Home exercise program Experimental group

Control group

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

power (voluntary) isolated PFM contractions explosive 10 3 60s 3x/week standing upright, squat position

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

strength and hypertrophy isolated PFM contractions concentric-isometric, moderate 60-70% of MVC 10x 5s 2 120s 3x/week standing upright

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

power (involuntary) squat jumps concentric, explosive 10 3 60s 3x/week standing upright

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

strength and hypertrophy isolated PFM contractions concentric, quick 60-70% of MVC 12 3 60s 3x/week standing upright

Loading = (-): Due to the fact of involuntary contractions the loading cannot be estimated in relation to MVC

th

12 week of exercise program th

7 Physiotherapy session Aims: Control and improvement of the home exercise program. The patient is able to contract isolated transversus abdominus muscle [22, 26].

Basic therapy: Training of voluntary contraction of lower abdominal muscles as the patient would like to zip too tight pants. Important: no movements within the spine region and breathing should be performed. Teach the home exercise program corresponding to the randomized groups (see below).

Home exercise program Experimental group

Control group

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

power (voluntary) isolated PFM contractions explosive 10 4 60s 3x/week standing upright, squat position

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

strength and hypertrophy isolated PFM contractions concentric-isometric, moderate 60-70% of MVC 8x 8s 2 60s 3x/week standing upright in a straddle position

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

power (involuntary) squat jumps concentric, explosive 10 4 60s 3x/week standing upright

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

strength and hypertrophy isolated PFM contractions concentric, quick 60-70% of MVC 12 3 60s 3x/week standing upright in a straddle position

Loading = (-): Due to the fact of involuntary contractions the loading cannot be estimated in relation to MVC

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13 week of exercise program Home exercise program Experimental group

Control group

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

power (voluntary) squat jump concentric, explosive 10 3 60s 3x/week standing upright, squat position

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

strength and hypertrophy isolated PFM contractions concentric-isometric, moderate 60-70% of MVC 8x 5s 2 60s 3x/week single leg standing (left and right)

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

power (involuntary) counter movement jump eccentric-concentric, explosive 10 3 60s 3x/week standing upright

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

strength and hypertrophy isolated PFM contractions concentric, quick 60-70% of MVC 12 3 60s 3x/week single leg standing (left and right)

Loading = (-): Due to the fact of involuntary contractions the loading cannot be estimated in relation to MVC

th

14 week of exercise program th

8 Physiotherapy session Aims: Control and improvement of the home exercise program. The patient is able to contract PFM and transversus abdominus muscle in a co-contraction simultaneously.

Basic therapy: Training of PFM and transversus abdominus muscle co-contraction combined with coughing or other exhaling maneuvers [21]. Teach the home exercise program corresponding to the randomized groups (see below).

Home exercise program Experimental group

Control group

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

power (involuntary) counter movement jumps eccentric-concentric, explosive 12 3 60s 3x/week standing upright

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

strength and hypertrophy isolated PFM contractions concentric-isometric, moderate 60-70% of MVC 8x 10s 2 60s 3x/week standing upright, squat position

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

power (involuntary) drop jump eccentric-concentric, explosive 12 3 60s 3x/week standing upright

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

power isolated PFM contractions concentric-static & concentric quick 60-70% of MVC 8x (5s + 3x) 2 120s 3x/week sitting upright

Loading = (-): Due to the fact of involuntary contractions the loading cannot be estimated in relation to MVC

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15 week of exercise program Home exercise program Experimental group

Control group

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

power (involuntary) counter movement jump eccentric-concentric, explosive 12 4 60s 3x/week standing upright

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

strength and hypertrophy isolated PFM contractions concentric-isometric, moderate 60-70% of MVC 8x 10s 2 60s 3x/week standing upright, squat position

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

power (involuntary) drop jump eccentric-concentric, explosive 12 4 60s 3x/week standing upright

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

power isolated PFM contractions concentric, quick 60-70% of MVC 8x (10s + 3x) 2 60s 3x/week single leg standing (left and right)

Loading = (-): Due to the fact of involuntary contractions the loading cannot be estimated in relation to MVC

th

16 week of exercise program th

9 Physiotherapy session Aims: Control and improvement of the home exercise program. All open questions of the patient relating to SUI and behavior should be resolved. The patient will be informed about the next steps after this training period.

Basic therapy: Give the patient an opportunity to ask questions. Explain the next steps.

Home exercise program Experimental group

Control group

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

power (involuntary) counter movement jump eccentric-concentric, explosive 12 5 60s 3x/week standing upright

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

strength and hypertrophy isolated PFM contractions concentric-isometric, moderate 60-70% of MVC 10x 10s 2 60s 3x/week standing upright, squat position

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

power (involuntary) drop jump eccentric-concentric, explosive 12 5 60s 3x/week standing upright

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

power isolated PFM contractions concentric, quick 60-70% of MVC 8x (10s + 3x) 2 60s 3x/week single leg standing (left and right)

Loading = (-): Due to the fact of involuntary contractions the loading cannot be estimated in relation to MVC

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17 week until 6 months follow-up After the intervention phase the patients receive an information sheet and instruction about the necessary and following home exercise program between the end of therapy and the 6 months followup.

Generally patients should continue performing PFM exercises for years after completing their physiotherapy education sessions [27].

Both groups continue their training as described below Home exercise program Experimental group

Control group

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

power (involuntary) counter movement jump eccentric-concentric, explosive 6 4 60s 3x/week standing upright

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

strength and hypertrophy isolated PFM contractions concentric-isometric, moderate 60-70% of MVC 10x 10s 2 60s 3x/week standing upright, squat position

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

power (involuntary) drop jump eccentric-concentric, explosive 5 3 60s 3x/week standing upright

Aims: Exercises: Muscle action: Loading: Repetitions: Volume: Rest: Frequency: Position:

power isolated PFM contractions concentric, quick 60-70% of MVC 8x (10s + 3x) 2 60s 3x/week single leg standing (left and right)

Loading = (-): Due to the fact of involuntary contractions the loading cannot be estimated in relation to MVC

Further information Take care while you are lifting up something: Donâ&#x20AC;&#x2122;t forget the pre-contraction of the pelvic floor muscle!

Drink about 1½ liter per day and prefer water. 5-6x micturition per day and 0-1x per night are okay.

Be mindful on the correct posture while sitting, standing and lifting.

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Edinburgh, Churchill Livingstone 2007, p. 35-43 Ashton-Miller JA, Howard D, DeLancey JO: The functional anatomy of the female pelvic floor and stress continence control system. Scand J Urol Nephrol Suppl 2001, (207):1-7 Bo K, Larsen S, Oseid S, Kvarstein B, Hagen R, Jorgensen J: Knowledge about and ability to correct pelvic floor muscle exercises in women with urinary stress incontinence. Neurourol Urodyn 1988, 7(3):261-262 Hodges P, Sapsford R, Pengel L: Postural and respiratory functions of the pelvic floor muscles. Neurourol Urodyn 2007, 26(3):362-371 Miller JM, Perucchini D, Carchidi LT, DeLancey JO, Ashton-Miller J: Pelvic floor muscle contraction during a cough and decreased vesical neck mobility. Obstet Gynecol 2001, 97(2):255-260 Stay K, Dwyer PL, Rosamilia A: Women overestimate daytime urinary frequency: the importance of the bladder diary. J Urol 2009, 181(5):2176-2180 Lubowski DZ, Swash M, Nicholls RJ, Henry MM: Increase in pudendal nerve terminal motor latency with defaecation straining. Br J Surg 1988, 75(11):1095-1097 Sapsford R, Hodges P, Richardson C, Cooper D, Markwell S, Jull G: Co‐activation of the abdominal and pelvic floor muscles during voluntary exercises. Neurourol Urodyn 2001, 20(1):31-42 Bo K, Mørkved S, Frawley H, Sherburn M: Evidence for benefit of transversus abdominis training alone or in combination with pelvic floor muscle training to treat female urinary incontinence: a systematic review. Neurourol Urodyn 2009, 28(5):368-73 Chiarelli P: Lifestyle interventions of pelvic floor dysfunctions. In: Bo K, Berghmans B, Morkved S, van Kampen M Eds. Evidence Based Physical Therapy for the Pelvic Floor – Bridging Science and Clinical Practice. Edinburgh, Churchill Livingstone 2007, p. 147-159 Henderson JW, Wang S, Egger MJ, Masters M, Nygaard I: Can women correctly contract their pelvic floor muscles without formal instruction? Female Pelvic Med Reconstr Surg 2013, 19(1):8-12 Kegel AH: Progressive resistance exercise in the functional restoration of the perineal muscles. Am J Obstet Gynecol 1948, 56(2):238-248 Bo K, Sherburn M, Allen T: Transabdominal ultrasound measurement of pelvic floor muscle activity when activated directly or via a transversus abdominis muscle contraction. Neurourol Urodyn 2003, 22(6):582-588 Simard C, Tu le M: Long-term efficacy of pelvic floor muscle rehabilitation for older women with urinary incontinence. J Obstet Gynaecol Can 2010, 32(12):1163-1166

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PELVIC FLOOR MUSCLE ACTIVATION COMPONENTS in URINARY CONTINENT and STRESS URINARY INCONTINENT WOMEN

Helena Luginbuehl

Pelvic floor muscle activation components in urinary continent and stress urinary incontinent women

Helena Luginbuehl

Faculty of Physical Education and Physiotherapy