The Performance Digest - October 2021 (Issue 60)

Study Details

How to Read Me!

Practical Takeaways from study

Related links to learn more about the topic

Reviewers comments on the study

Research Reviewers

Science of coaching

Will is a Lecturer of Sport Coaching at Deakin University, Australia. Prior to this he has worked with Cricket NSW and Cricket Australia in an array of roles ranging from a sport scientist, development coach and a strength and conditioning coach. He completed his PhD at the University of Newcastle, Australia within the area of practice design.

Fatigue & Recovery

Tom is a fitness coach currently working in Premier League football in England. He holds a BSc (Hons) in Sports Science from Liverpool John Moores University and recently completed his PhD titled "An exploration into the assessment of hip extension strength and its importance in professional football".

Injury Prevention & Rehab

Jordan is a Physical Therapist and Strength Coach who currently practices in a Sports & Orthopedic clinic in Bergen County, New Jersey. He is passionate about educating athletes on ways to optimize performance while decreasing the risk of injury.

Youth Development

Tom is the Head of Athletic Development at St Peters RC High School. He holds a Masters in S&C and has previously worked with West Bromwich Albion FC, Gloucester Rugby club, and Great Britain Equine. Tom is our youth research reviewer at Science for Sport.

Strength & Conditioning

James is currently the Head Strength & Conditioning Coach for the Romanian Rugby Union. He has previously worked in America's professional rugby competition Major League Rugby with Austin Elite and the NZ Women’s National Rugby League Team. He is a published author and has completed a MSc in Sport & Exercise Science from AUT, Auckland, NZ.

Technology & Monitoring

Cody is a strength and conditioning coach and adjunct lecturer at the University of Iowa. He has an MSE in Exercise Science from the University of Kansas and also holds a CSCS from the NSCA.

Nutrition

James is a Performance Nutritionist for the English Football Association and works alongside the England national teams (men's and women's). He is also a SENr registered performance nutritionist and holds a PhD from Liverpool John Moores University.

Dr. Will Vickery PhD

Tom Green MSc UKAD Advisor

James de Lacey MSc

Dr. James Morehen PhD

Dr. Jordan August DPT, CSFC, SFMA, FMS

Cody Roberts MSE

Tom King MSc CSCS

The Science of COACHING

What did you say, coach? How asking questions during training can boost performance

OBJECTIVE

When used correctly, the art of questioning is a powerful tool that can be employed by a coach. Unlike more direct forms of communication such as instruction, effective questioning encourages athletes to draw upon their own experiences and knowledge when solving problems.

Many coach education schemes encourage coaches to ask questions of their athletes, although there is limited information available to coaches about what effective questioning involves. The authors of this study set out to document the use of questions by coaches across a range of contexts.

The questioning employed by 19 youth level (U12-16) coaches, who were following the Football Federation Australia National Coaching Curriculum, was observed on two separate occasions. The key details that were coded for each question included:

 Question type (convergent/closed or divergent/open)

 Context asked in (freeze in position, player huddle, activity ongoing)

 Who it was directed towards (individual or team)

 What the question was about (instructional, tactics, technique, problem-solving, general)

 Whether it required higher- (high levels of cognitive processing) or lower-order (low levels of cognitive processing) knowledge

During each session, the frequency and structure of the questions asked by the coaches was measured and compared between the phases (session introduction, individual activities, drills, small-sided games, large games) of a training session.

WHAT THEY FOUND

 Coaches asked 71 questions per session, with more convergent than divergent questions asked.

 When asking a convergent question, it was generally during a freeze in play towards the whole team, instructional and required predominantly lower-order thinking.

 When asking a divergent question, it was typically during a freeze in play towards the whole team, related to tactics, and required a similar amount of lower- and higher-order thinking by the players.

 During drills and small-sided games, coaches tended to ask their athletes instructional convergent questions during a freeze in play. During large games, divergent questions were typically asked while the activity was ongoing and focused on tactics.

Practical Takeaways

 Coaches within the current study tended to rely on lower order thinking questions. Although still beneficial to an athlete’s ability to recall information, in order to develop your athletes’ ability to analyse, synthesise, and evaluate order questions (e.g. “Can you think of a more effective movement that might help you move the bar quickerinformation presented to them, look to include more higher ?”).

 As stated by the authors, the questions asked by a coach should adapt to the context and needs of their athletes. This might mean that you use a combination of questions during training that requires recall and understanding (e.g. “Where should your feet be positioned?”), as well as the analysis of a situation (e.g. What might be the most effective way to get from point A to point B?”) and evaluation of task execution (e.g. Why do you think you weren’t able to beat your opponent?”)

 Consider whether the question being asked is for the whole team or an individual. In this study, most questions were directed towards the team, which presented the problem of a small number of individuals dominating the responses. As recommended by the authors, give the athletes time to think about their answers and then ask a select few to share.

Will Vickery

WHAT THEY DID

Strength & Conditioning

This month’s top research in strength & conditioning.

CAN YOU TRAIN DIFFERENT PARTS OF THE MUSCLE WITH DIFFERENT EXERCISES?

HIIT OR SMALL-SIDED GAMES: WHAT IS BETTER FOR CONDITIONING

IS A TOTAL BODY OR SPLIT ROUTINE BETTER FOR STRENGTH AND HYPERTROPHY

Can you train different parts of the muscle with different exercises?

OBJECTIVE

For decades, bodybuilders have been employing a wide range of exercises for each muscle group to maximise muscular development. The idea behind this is that different exercises ‘work’ different parts of the muscle. This is known as regional hypertrophy and recent research has shown muscle growth to differ among different regions of a single muscle head based on the exercise performed (see HERE).

A recent study found regional hypertrophy to occur following training interventions involving both single and multiple exercises, so authors couldn't conclude which specific exercises targeted which regions. (see HERE).

Therefore, this study aimed to measure regional hypertrophy of the quadriceps muscles by comparing two different quadriceps-focussed exercises.

WHAT THEY DID

Twenty-seven healthy men (age = 25.4 ± 4.8 years) were randomly allocated into a Smith machine squat group (SMITH) or a leg extension group (LEG). Before and after the training intervention, regional cross-sectional area (CSA) and pennation angle were measured for the rectus femoris (RF), and vastus lateralis (VL). Pennation angle was also measured in the vastus medialis (VM). Body mass (kg), body fat (%), and countermovement jump height (CMJ) were also measured.

During the five-week training intervention, the SMITH group performed 4 x 12 deep squats (to failure) in the Smith machine three times a week. The LEG group performed the same set and rep scheme with the leg extension.

Participants were instructed to maintain a protein intake of 2g per kg of bodyweight throughout the intervention.

Practical Takeaways

 If you are training for performance, compound movements such as the Smith machine squat may be a better option than the leg extension as a lower-body strength movement.

 Even better would be performing a barbell squat variation to allow free movement of the body around the barbell.

 Performing multiple exercises may be better for hypertrophy of the quadriceps than performing just one.

 This means leg presses, hack squats and single leg squat exercises should also be part of your quadriceps hypertrophy program to provide enough variety to stimulate each quadricep muscle.

 Although many refer to the squat as the ultimate leg builder, it might not be as effective as a targeted hypertrophy program. Here is an example of a leg session with a quadriceps focus targeting the various quadriceps muscles:

A1) Back Squat Heels Elevated 3-4 x 8-10 (VM emphasis)

B1) Smith Machine Squats 3 x 10-12 (VL emphasis)

C1) Leg Extension 3-4 x 10-15 (RF emphasis)

 A similar approach to the above can be used for regional hypertrophy of the hamstrings. For example, hip extension exercises activate the biceps femoris long head (BFlh) to a greater extent than knee flexion hamstring exercises (see HERE), and exercises such as the Nordic Hamstring curl display greater semitendinosus (ST) activity than BFlh. Conversely, stifflegged deadlifts present similar activity between the two muscles (see HERE). So, a targeted hamstring hypertrophy session may look like this:

A1) Stiff-Legged Deadlift 3-4 x 6-8 (ST & BFlh emphasis)

B1) Nordic Hamstring Exercise 3 x 5-8 (ST emphasis)

C1) Lying Leg Curl 3 x 15-20 (BFlh emphasis)

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WHAT THEY FOUND

 All regions of the RF muscle in the LEG group increased CSA significantly while no significant growth was seen in the SMITH group

 The CSA of the VL central region increased in the SMITH group but not in the LEG group

 There were no changes in the pennation angle of any muscles for either group

 Body mass and jump height both increased in the SMITH group but not in the LEG group

James’ Comments

"If pure hypertrophy is your goal, then ensuring you use a wide variety of movements is important so you can target different regions of the muscle. Interestingly, regional hypertrophy may not only occur at the muscle heads (i.e., VL, VM, RF) but also at the proximal and distal ends of the muscle. For example, this study shows you can target lower or upper rectus abdominus activation during reverse abdominal curls (i.e., reverse crunches) and trunk curls, respectively. The same is seen in hamstrings, where BFlh activity is lowest in the proximal region during Stiff-Legged Deadlifts with no difference between distal and middle region activity.

"On the other hand, the Nordic Hamstring exercise shows the lowest BFlh activity in the proximal region but the highest in the distal region (see HERE).

"Hence, why it may be important to not just “stick with the basics'' and instead, “hit the muscle from all angles ” when it comes to muscle hypertrophy."

HIIT or small-sided games: What is better for conditioning?

OBJECTIVE

Small-sided games (SSG) and high-intensity interval training (HIIT) are two approaches used to develop conditioning for team sport athletes. Both approaches have shown positive adaptations in a variety of sports from soccer to basketball. Sports like basketball consist of many changes of direction and therefore, HIIT should replicate these demands. However, no research to date has compared SSG and HIIT with a change of direction (HIITCOD) within basketball over the short term (<4 weeks).

Thus, this study aimed to compare four weeks of SSG and HIITCOD on physical performance and specific basketball technical skills.

WHAT THEY DID

Nineteen female basketball players (age = 19.9 ± 1.1 years ) from the third division of the Zhejiang University basketball league were assigned to either an SSG or a HIITCOD group, with the study running through the second half of the pre-season. Before and after the intervention, participants completed the 30-15 intermittent fitness test (30-15 ift), repeated sprint ability test (RSA), modified T-test (T-test), counter movement jump (CMJ), and 20 m sprint as physical tests. For technical tests, participants performed the shooting accuracy test, 1 min shooting test, passing test, defensive movement test, and control dribble test. The training intervention ran over four weeks, completing SSG or HIITCOD three times a week.

The SSG group played 2v2 in a 15m x 14m grid with 23min/15-45 sec (work to rest), while the HIITCOD ran 15 sec/15 sec at 90-95% of 30-15 ift velocity (Vift) with a 180° COD. Participants’ heart rate and rate of perceived exertion (RPE) were monitored throughout sessions.

Practical Takeaways

 SSG can potentially provide good use of your training time,improving both physical and technical attributes simultaneously in the short term, at least at this level of basketball.

 For those working in grades of lower skill level, a SSG approach is likely more beneficial than taking a traditional conditioning approachespeciallynear the endof pre-season. In the lower grades, skill level becomes an even bigger differentiate or of performance when compared to the elite, where it’s more consistent among players. By providing more opportunities for your players to develop skills under pressure while simultaneously improving their conditioning, you will gain an advantage over other teams who spend their time simply running up and down the court/field.

 When setting up SSGs for your team, here are a few guidelines you can use to target your desired outcome:

1. Smaller grid + smaller teams = Greater agility manoeuvres; likely increased acceleration/deceleration.

2. Larger grid + smaller teams = Greater distance covered and speed.

3. Smaller grid + larger teams = Much less distance covered at very slow speed; can provide some acceleration/deceleration.

4. Larger grid + larger teams = Quicker transitions; less distance covered. Unbalanced teams = More technical events under pressure.

 My personal preferences with SSGs are as follows:

1. Play games where players are never "out." That means no one is ever sitting on the sideline doing nothing.

2. Use different balls. For example, instead of a basketball, use a tennis ball and other odd-shaped balls. Alternate within the game or between games for variation and developing general hand-eye

3. coordination.

4. Use SSGs in some warm-ups. Start walking in small to moderate-sized grids and expand to larger, running grids with plenty of ball and rule variations. For example,I may play a small grid walking tag game, transition into a moderate grid ball tag game, and then a larger grid running ball game.

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WHAT THEY FOUND

 Average heart rate and RPE were similar between groups during the intervention.

 Both groups improved Vift (SSG = 4.1%; HIITCOD = 4.2%), average RSA time (SSG = -2.2%; HIITCOD = -1.9%), best RSA time (SSG = -2.0%; HIITCOD =2.1%), and T-test time (SSG = -7.2%; HIITCOD = -5.7 %).

 No significant difference was seen in RSA decrement, 20 m sprint, or CMJ for either group.

 Both groups improved their defensive movement (SSG = -5.1%; HIITCOD = -5.8%) and control dribble test times (SSG = -3.4%; HIITCOD = -2.6%).

 The only test to show a difference between groups was the 1-min shooting test, where the SSG improved by 22.4% while the HIITCOD group showed a slight reduction in performance with a -2.6% change.

James

Comments

"This is one of those studies where, at face value, simple 2v2 SSGs are just as effective as HIIT training. However, when you dive deeper into the numbers, the SSG group ran 20 -50% longer in each session. Further, we don't know how much distance was covered in each session between groups.

"In my opinion, SSGs are a great tool for reinforcing technical skills, having some fun, and getting some general conditioning done. However, I don’t think they can be a replacement for targeted conditioning. There are just too many variables to target the adaptations you want or manage the load of the session. Instead, practise drills can be manipulated for a conditioning effect if that is the desired goal. Speeding up play, less rest between drills and stoppages can be one way to increase training density."

Is a total body or split routine better for strength and hypertrophy?

OBJECTIVE

Total body and split routines are two of the most common trainingspl its. Split routines (e.g. upper body/lower body) are usually preferred by bodybuilders , while total body routines are generally preferred by strength athletes. As training adaptations are influenced by training experience, training frequency, and training volume, it is difficult to draw conclusions based on previous literature due to inconsistencies among these variables.

Thus, this study aimed to compare the effects of a total body and split routine on maximal strength and muscle hypertrophy with equated volume, intensity, and exercises used.

WHAT THEY

Twenty-one experienced (at least three years, three times a week), resistance-trained men were randomly split into either a total body (TB) group (age = 24.1 ± 4.4 years) or a split routine (SR) group (age = 24.9 ± 4.2 years).

Before and after the training intervention, participants performed the following tests: isokinetic bench press at 25 m.s-1 (ISOK25) and 75 m.s-1(ISOK75), isometric bench press at a 90° elbow angle, isometric half-squat at a 90° knee angle, and 1RM back squat and bench press.

Ultrasounds of the vastus lateralis, pectoralis major, and trapeziusmuscles were also taken to measure changes in muscle thickness (hypertrophy). Peak force was measured for all isometric tests using a force plate.

The 10-week training intervention consisted of four days a week oftraining, with the same exercises for each group distributed as either a body part split or full-body training. Each exercise was performed forfive sets of six repetitions at an RPE of nine (one repetition in reserve),with two minutes’ rest between sets. Training volume was standardised across both groups.

Practical Takeaways

 Increased training frequency has generally only been associated with greater strength gains when it led to an increased training volume (see HERE ). However, this study indicates that increased training frequency may enhance maximal strength when volume is standardised.

 The trend towards greater strength in TB and greater hypertrophy in SR in this study can potentially influence decisions made around training cycles and periodisation. Both types of training splits can be utilised at different phases of a program. TB can be used during strength phases, while SR can be used during hypertrophy phases. An example of a full-body split could be as follows:



Monday:

A1) Main Lower Body

B1) Main Upper Push

C1) Main Upper Pull



Wednesday

A1) Main Upper Push

B1) Single Leg Lower Body

C1) Main Upper Pull



Friday

A1) Main Lower Body

B1) Upper Push

C1) Upper Pull

 SR may be better for older athletes as it allows more recovery between body parts (e.g. upper/lower split). This could be as simple as:

Monday - Lower body push/quad focused

Tuesday - Upper body horizontal push/pull focus

Thursday - Lower body pull/hamstring focused

Friday - Upper body vertical push/pull focus

 For sporting athletes, I generally recommend an upper/lower split for recovery reasons. Athletes are often training on the field 1-2 times a day most days of the week making total body training less feasible due to the fatigue on the legs. This can be both pre-and in-season. However, a fullbody strength-focused and power-focused day can also be used in-season depending on your personal preference.

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WHAT THEY FOUND

Following the training intervention, ISOK25 increased by 11.5% in the TBgroup and 2.3% in the SR group. No differences were found for ISOK75, isometric bench press, isometric squat, or 1RM squat or bench pressbetween groups, but both groups improved after training.

Although not statistically significant, trends towards greater strength gains were seen in the TB group. A 10% increase in vastus lateralis muscle thickness was found in the SR group compared to a 2.9% increase in the TB group. Additionally, trends towards greater trapeziusmuscle thickness were seen in the SR group, with no diffe rences found for any other muscle group.

"As with systematic reviews on training frequency, I would take the current study with a grain of salt until it is replicated. Many factors could have influenced the outcomes presented. For example , the introduction of a split routine may have provided an additional stimulus for participants, creating more metabolic stress than their usual training, and greater muscle growth. The overall volume may have also been greater than their usual training, resulting in strength and hypertrophy increases in both groups.

"While this is highly speculative, the point is many variables can influence the outcomes of a study like this, so waiting on future research is a smart play."

Technology & Monitoring

This month’s top research on technology and monitoring.

PRACTICAL MONITORING STRATEGIES AT THE AMATEUR LEVEL

GOING OVERBOARD OR JUSTWORK ETHIC? THE IMPORTANCEOF UNDERSTANDING OVERTRAINING

USING OBJECTIVE MEASURES TO SUPPORT A COACH'S PHILOSOPHY

HOW , WHEN AND WHY SHOULD AN ATHLETE USE TECHNOLOGY

Practical monitoring strategies at the amateur level

OBJECTIVE

Training load (TL) is a critical and controllable variable that represents the volume and intensity of work an athlete experiences. Regardless of competition level (professional, amateur, or youth), the goal of TL monitoring is to optimise the physiological stress an athlete experiences on and off the field to improve performance and reduce injury risk.

When resources are limited and implementing the latest technology is not possible, coaches must be creative in how they monitor and manage TL. The objective of this research was to provide a generalised understanding of TL monitoring approaches currently implemented in amateur rugby union.

WHAT THEY DID

An electronic survey was sent to the head strength and conditioning (S&C) coach for each senior first team of the 57 (50 male, seven female) amateur rugby union clubs in Ireland. The survey was initially validated based on its content, purpose, and structure by a review team, with the intent of understanding relative coach education, club demographics, monitoring practices, and use of data.

A total of 33 coaches (31 male, two female ) replied across a four-month span in 2019, and responses were analysed to identify commonalities across the various clubs and create an understanding of load monitoring practices.

Practical Takeaways

Experience and education are vital aspects to implementing effective training load monitoring strategies. Coaches need to seek out education from current research, as well as discuss with other coaches in the industry ways to successfully implement effective monitoring strategies. Lean on others in your network and do not be afraid to fail in the process. In the end, coaching is about learning, growing, and finding what works best.

Obtaining individual sRPE measures from each player (30-min post-training) is a valid and reliable method that can be used to effectively monitor training load (see HERE).

 Collecting subjective feedback (e.g. sRPE, mood, fatigue) from players is a zerocost strategy that encourages open communication within a club.

 When asking for RPE, be clear and consistent (e.g. “how difficult was the session/competition?”), providing simple understanding for what constitutes the respective values on a 1-10 scale (e.g. ‘10’ being maximal or impossible to continue, ‘1’ being hardly any activity) (see HERE).

 Coaches need players to take an active role in their own recovery. However, when sRPE is elevated, providing them with specific strategies and ample opportunity to improve their physical and mental well-being can be helpful (e.g. cold-tubs, meditation, a meal or simple recipe, time off, as well as tactics to improve sleep). Evidence suggests ACWR has potential to reduce injury risk by identifying large spikes in workload

 Calculating ACWR using the exponentially weighted moving average method provides a more appropriate representation of TL as it accounts for time deterioration by weighting more recent sessions as having a greater influence (see HERE).

S&C coaches should focus on building strong relationships with both their athletes and other staff. Mutual respect, trust, and open communication are important factors to focus on (see HERE). This is the foundation to effective teamwork and collaboration in optimising workload and performance

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WHAT THEY FOUND

 73% of the respondents implemented TL monitoring for amateur players, with the primary goal being to reduce injury risk.

 Session rating of perceived exertion (sRPE) (see HERE) and player feedback was the most frequently used method for tracking TL.

 Only 58% of coaches implemented an external workload measure (e.g. total distance), with an even smaller portion collecting data from global positioning systems (17%) or heart rate monitors (4%).

 33% of coaches implemented measures of acute to chronic workload ratio (ACWR, see HERE), sleep quality, and readiness to train.

Cody’ s Comments

Most notably, the theme of these findings centres around the limited resources and time available for S&C coaches working with amateur clubs to implement advanced load monitoring strategies. The key, however, is to not focus on the limitations, but rather the opportunities to prioritise relationships, communication, and cohesion. These aspects can be far more effective and influential to the success of a program than any specific technology or personnel hiring.

Ultimately, the goal of monitoring training load is to reduce the risk of injury and maximise performance. If coaches trust and respect player feedback, the opportunity for consistent monitoring is there for the taking. Be sure that the coaching staff understand the importance of consistently collecting and tracking athlete feedback. This is paramount in building trust and buy-in between athletes and coaches. It is then athletes will know they are being taken care of and understand that their wellbeing is of the utmost importance to their coaches.

Going overboard or just work ethic? The importance of understanding overtraining

OBJECTIVE

Today, opportunities available through digital media (electronic journals and social platforms) have revolutionised the way science and practice interact. The world is well connected and a strong foundation in understanding training and physiology is a requisite for coaches and researchers alike. As we continue to bridge the gap between literature and application, shared definitions and understanding are important across parties to better study and understand how to best optimise the training environment.

One specific area that needs clarification isthe definitions of and differences around overtraining (OT) and overtraining syndrome (OTS). Therefore, the purpose of this study was to understand how strength sport coaches think and work around the topics of OT and OTS when prescribing and managing training.

WHAT THEY DID

The researchers interviewed 14 strength sport (e.g., weightlifting, powerlifting, sprinting, jumping, throwing) coaches (12 males, 2 females) with four to 57 years of experience (mean = 14.4 ± 13.4 years ) from around the world (United Kingdom, Republic of Ireland, United States, and New Zealand) (see Table 1). Backgrounds in education ranged from no formal degree to a Doctor of Philosophy and a range of certifications through governing bodies across strength sports. To best summarise and understand the information collected from the interview process, reflexive thematic analysis was used.

All interviews were conducted by one principal investigator for consistency, and analysis for themes was completed blindly, with neither the investigator nor coach knowing what theme each question pertained to. Emphasis was placed on exploring each coach’s personal experiences rather than identifying similarities between them.

Results were then summarised based on the definitions of OT/OTS, its prevalence, and associated symptoms and recovery time.

Practical Takeaways

 OT and OTS are not well-understood topics, with no mention of either word in articles regarding collaborative research in team sports or evidence-based practice in high performance sport. Regardless, it is a serious and severe state that needs to be prevented and managed appropriately. Coaches must understand this area and work to identify associated signs and symptoms as soon as possible through monitoring fatigue and athlete feedback via conversations or questionnaires.

 When developing a thorough and complete understanding, being able to define and differentiate the differences between function and non-functional overreaching, OT, and OTS is important. Once the effects are fully realised, coaches can better appreciate why it is not productive to push an athlete to these limits. Training harder does not necessarily have a greater return on investment - aim to optimise, not maximise.

 Since a prolonged decrease in performance is the most dependable gauge of overtraining in strength training (see HERE), it is critical to monitor the loads lifted in primary exercises (e.g., squat, deadlift, bench press) across the weeks and months of lifting. Bolster the validity of these lifts by keeping technique solid and consistent, as well as pairing with a subjective rate of effort (e.g., bench pressing 100kg for three repetitions with a rating of perceived exertion of an 8 out of 10) - respecting that it does not always have to be maximal effort. Further, use of velocity-based devices can provide an objective measure of barbell velocity at a given load - if opportunity allows, this can serve as an excellent performance metric to monitor (e.g. back squatting 140kg for three repetitions with an average mean velocity of 0.6 m s-1).

 Coaches must understand that training is not the only stressor an athlete endures on a daily basis. Appreciating social and psychological influences can drastically impact an athlete’s ability to recover and adapt to training. What is a great training plan for one athlete may be far too much for another. So, it is important to respect the individual and their response to the training load and not to ignore warning signs of negative training responses. Be active in asking how athletes feel and observant in looking for non-verbal signs of changes in energy and mood. Make a physical note on these at least weekly for retrospective review, rather than working from memory.

Regular (daily, weekly, or monthly) assessment of an athlete’s physiological response through blood biomarkers/hormone levels or measures around heart rate variability or response can be reliable and effective to provide objective (non-emotional) data of the systemic response of an athlete undergoing an intense or high volume training block. For example, a change of ± 10 beats min-1 in a heart rate measure during sleep or following a bout of activity can be a significant enough variance to note elevated fatigue or stress. With strength training, intensity seems to be the variable that is most stressful, whereas, with endurance training, volume is the variable that can often lead to OT (see HERE).

WHAT THEY FOUND

 Strength sport coaches are unaware of a comprehensive definition of OT or OTS, with understanding on the matter varying.

 Terminology around OT and OTS was inconsistent and broad regarding diagnosis, time course of recovery, and the distinction from planned overreaching. With no mention of functional or nonfunctional overreaching from any coach.

 Coaches seemed unconcerned about the rate at which OT or OTS occurs for their athletes, suggesting their training has room for increases in load (volume or intensity), with no maladaptation expected.

 Overall fatigue or musculoskeletal injury were the most common symptoms that were identified as suggestive of OT or OTS.

 Coaches demonstrated a lack of appreciation for the severity of potential OTS, with many suggesting recovery took only a matter of days (<2 weeks).

Cody’ s Comments

“In my opinion, the lack of evidence and understanding around this topic is rooted in the difficulty (and potential ethical issues) encountered when requiring athletes to push themselves to the stage of OTS for the sake of research. Even within a typical longitudinal observational study, it would be negligent for a coach to continue when noticing signs and symptoms associated with OT. Therefore, much of this information is theoretical and leads to the inconsistencies noted among coaches in this study. As opportunities around monitoring athlete fatigue continue to grow and the appreciation for mental- and physical health is reaching an all-time high, coaches must step up and manage OTS appropriately.

“As practice and research continue to grow closer together, coaches need to learn from the numerous resources shared in this review. Research has previously accepted the inconsistency in definitions, but in order to differentiate and advance this field of understanding, we need clarity and consistency in the verbiage around OT and OTS. That way, when coaches implement overly-aggressive training plans, both athlete health and performance are at the f

Using objective measures to support a coach's philosophy

OBJECTIVE

Monitoring strategies, such as collecting objective measurements via global positioning systems (GPS) (e.g., total or high-intensity distance covered), can provide confidence to coaches when managing their team’s workload accumulation across a season. Comparing metrics in a short (5-7 days) to long-term (3-6 weeks) fashion provides a value known as acute -to-chronic workload ratio (ACWR), which helps in understanding the current state of a team’s volume and intensity relative to previous work.

This study examined GPS-derived workloadsof soccer players across multiple seasons, attempting to find trends between performance metrics, ACWR and injury. Additionally, a coach ’s philosophy on workload management was sought to develop a practical insight on the matter.

WHAT THEY DID

A total of 46 NCAA D1 male soccer athletes (age = 19.4 ± 1.4 years) had GPS (total and highintensity distance (>22 km h-1)) and injury data collected during every match and training session from pre-season to season’s end across three consecutive seasons. Data was separated into preseason and in-season,using weekly (Mon-Sun) averages for total and high-intensity distances to calculate ACWR (the previous seven days relative to the previous three weeks ). An associate headcoach was also interviewed about their workload management approach and the specifics of implementing the ACWR.

ACWR for both total and high-intensity distance covered was analysed for trends and possible relationships to performance and injury incidence.

Practical Takeaways

 ACWR is flexible and should be reflective of the recent (acute) workloads relative to a defined extended (chronic) timeframe. Coaches can adapt their acute and chronic durations based on their training and competition schedule.

 A sport that has a more congested weekly schedule (e.g., baseball or basketball)may operate with a 3-5-day acute range and a 2-3-week chronic range.

 A sport that plays once per week (e.g. football or rugby), may extend out to a 1-2-week acute window and a 4-6-week chronic period.

 Keep ACWR in the 0.8-1.3 range (see HERE). The most important factor in workload management is acclimating athletes to the volume, intensity and frequency experienced during a competition period.

 Coaches need to caution doing too much work too early in the preseason period -especially with higher fatigue often experienced during dense preseason training camps. Preseason workloads should be a gradual transition from the relative

 inactivity of the off-season to the volume and intensity expected for the inseason.Coaches should adjust the volumes and intensities of training to be specific to their relative style of play. The objective in-season is to maintain consistency, limiting drastic fluctuations in workload distance or speeds in a given session or across the week, with an emphasis on being flexible based on previous match workload (e.g., a match with extended minutes or a high volume of sprinting may require adjustments in the subsequent training sessions).

 When identifying speed thresholds to define ‘high-intensity’, coaches should be sure that it is indicative of their athletes’ physical capabilities.

 For example, the speed threshold in this study was set at 22 km h-1 based on the team s relative aerobic capacity performance data (e.g., running one mile in 18 km h-1) and thresholds previously used for adults and professional athletes of similar ability.When support staff are deciding on a workload monitoring strategy to implement,they should take the time to ask and understand the head coach’s philosophy on itsuse within various contexts (e.g., a returning injured player, first year, veteran starter).With this knowledge , the decision on how to best use GPS data to support the athlete s efforts can be made, and confidence can be provided that workload is being managed appropriately relative to their role on the team. These efforts will support the coach and team success by optimising player development and availability.

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WHAT THEY FOUND

ACWR and injury data:

 Players covered a greater total distance on average during the preseason periods compared with in-season.

 Across the three seasons, there were only seven non-contact time-loss injuries (any injury resulting in time away from soccer activity).

 For each of the three seasons, there was a wide range of average acute and chronic total and high-intensity distances. However, ACWR consistently remained similar (0.97-1.15), suggesting this potentially helped to keep non-contact injuries (7) to a bare minimum across three seasons.

Interview with coach:

 For an injured athlete, the coach aimed for a slow return to high-intensity activity.

 For first-year athletes, implementing fitness testing to establish a baseline performance measure was considered important.

 With athletes who have consistently high playing time (starters), the coach’s focus was generally on adjusting conditioning daily and keeping workloads at maintenance levels.

Cody’

s Comments

"The most noteworthy takeaway from this study is the specific insight gained by talking to the coach about their workload management philosophy. This collaboration helps create purpose around monitoring workload data, so that it supports the goals of the coach and needs of the athletes. Rather than treating everyone the same, it is important to respect the different roles and development needed for first year, developmental, or high-level players. Acknowledge that the goal of starters inseason is to maintain their capacity, maximising readiness for gameday. This is accomplished through daily monitoring and adjustments based on recovery and workload , keeping ACWR consistent (close to 1.0).

"Meanwhile, developmental players (e.g., first year or reserves) should start with comparatively reduced volumes and intensities relative to starters, but coaches should allow for higher ACWR values of 1.1-1.3 in order to improve and accommodate their work capacity. Injury risk will rise if training is avoided, but tracking volume and intensity will assist in performance management, improving player availability and team success."

How, when and why should an athlete use technology?

OBJECTIVE

Advancements in technology have exploded over the past decade in the sport performance and athletic development environment. From newage training equipment and wearable technologies to ultra-sensitive measurement devices and portable and readily accessible video feedback, this billion-dollar industry continues to grow and influence the coach-athlete experience.

As coaches, it is critical to have and follow guiding principles for the proper application and effective management of technology within a training environment. Ecological dynamics is a framework that appreciates the whole athlete and environment and the interaction between the two, leading to outcomes based on athlete perception and action. It is a free-flowing, progressive approach that promotes freedom and interaction between coach and athlete for productive learning.

With the misuse of technology among coaches all too common, the authors aimed to use the framework of ecological dynamics to illustrate how it can be best incorporated into a training environment to facilitate athletes’ learning and development.

WHAT THEY DID

The principles of ecological dynamics can be employed to create an interactive and experimental environment for both the coach and athlete. It was suggested that when incorporating any sort of technology into the training process, it should boost the experience and support an athlete’s overall development.

Technologies were broken into four categories (training machinery, tracking technology, performance analysis, and video feedback), discussing the timing of when and how to use each as a facilitator to learning. Additionally, the potential for overuse or mismanagement was reviewed, focussing on instances where the athlete may be overly directed or constrained by the feedback the technology provides.

Ultimately, the authors focussed on considerations and strategies for the conscious use of technology with regard to training pedagogy.

Practical Takeaways

 Coaches can either modify an athlete’s vision (see HERE) or modify equipment (see HERE) to increase the variability in perception, movement solution (the athlete’s physical decision and resultant action), and skill acquisition. The important thing to remember is the specific sport or task should still be the predominant focus of the session, with emphasis on finishing a given session with minimal constraints and maximal specificity for learning and application. More is not better - better is better. Gain feedback from the athletes and note their interest. Then, provide tangible feedback on their progress and development through performance measures (e.g., sprint speed, change of direction ability, jump height).

 The implementation of technology can provide objective measures that are useful ineffectively measuring performance and regulating training in order to mitigate fatigue and optimise performance. Whether it be using global positioning system (GPS) wearables to measure volume and intensity of practice sessions and competitions, looking at heart rate response data to guide training targets, or using a force plate jump results to track readiness, these are tools that offer objectivity to the training process and plan.

 Video can be used to help athletes see, learn, and better understand potential technical or tactical actions through visual feedback, adding support to verbal cueing from a coach. Coaches can use point-of-view cameras, drones, or even clips with a smartphone camera, to provide the opportunity for an athlete to see a movement on the field or in the weight room and another perspective into movement opportunities and strategies that benefit individual and team performance.

 Coaches should understand an athlete s stage of development and readiness to receive the feedback from a specific piece of technology. Rather than being a quick adopter, think about why and how implementing a piece of technology is beneficial (e.g., increased variability, encouraging athlete engagement, monitoring performance).

 Communication and transparency is a vital aspect of incorporating technology in a training environment. All stakeholders (e.g., coaches, support staff and athletes) should be well aware of why any technology is being used, with those implementing it and collecting data being transparent when doing so and able to succinctly explain findings to all. When coaches/staff prioritise their athletes and their understanding as opposed to a machine or metric, it fosters a trusting environment and increases buy-in.

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WHAT THEY FOUND

 Use of technology should enhance coach and athlete interaction, creating opportunities to cooperatively shape training, assess competition, and provide tangible feedback that all support constructive development.

 Technology should be incorporated collectively between staff members, utilising technologies that support training and preparation without distracting or interfering with the process of learning and development.

 Importance was placed on the appreciation and awareness of an athlete ’s needs, stage of development, and how the technology impacts their learning, emphasising caution around the level of influence its feedback had on their performance.

Cody’ s Comments

"Psychologist Wendell Johnson said: 'always and never are two words you should always remember to never use.'

When it comes to using technology, understanding it is neither always nor never, but dependent upon the individual, the goal, and the manner in which it is implemented. The concept of ecological dynamics involves motor learning and cognition (see HERE) and this article highlights the thoughtful approach necessary to support improvements in movement and decision-making. Focusing on the athlete and developing a positive experience is of the utmost importance when training and teaching, facilitating an environment that encourages, engages, and supports progress over time.

"When administered appropriately, technology can really facilitate these ancillary aspects (e.g., experience, motivation, engagement) of athlete development. While most technology provides us with tangible or objective information that we can see and analyse, it’s important that the athlete is also subjectively perceiving it and using it in the way that it is intended. In the words of Bruce Lee, our approach to the use of technology should be like water - flowing and adaptable."

Fatigue & Recovery

This month’s top research on fatigue and recovery.

ASYMMETRY INCREASES IN RESPONSE TO A SOCCER MATCH

Asymmetry increases in response to a soccer match

OBJECTIVE

During soccer, athletes are required to perform repeated high-intensity actions which involve high levels of unilateral force production (see HERE). With the presence of limb dominance in actions such as ball striking and jumping in many team sports, asymmetrical loading is a natural consequence. As a result, inter-limb asymmetries are viewed as likely a byproduct (see HERE).

Asymmetry in soccer is often assessed when players are in a non-fatigued state, with studies investigating this fracture during times of fatigue being scarce. Therefore, this study aimed to investigate the effects of a soccer match on jump performance and inter-limb asymmetries during a 72-hour post-match period.

WHAT THEY DID

Fourteen elite adolescent (academy) male soccer players (age = 17.6 ± 0.5 years) completed three single-leg counter movement jumps (UL CMJ) on each leg separated by 30-seconds rest, before and after completing a match. Jumps were performed two hours pre-match, one-hour postmatch and 24, 48 and 72-hours post-match. The following variables were monitored for each jump with a force plate:

- Eccentric impulse (sum of impulse from the end of the unweighting period until the end of the braking phase)

- Concentric impulse (sum of impulse from the end of the braking phase until take off)- Peak propulsive force (maximum force during the propulsive phase)

- Jump height (cm)

- Peak landing force (maximum force during the landing phase)

- Landing impulse (sum of impulse on landing until peak landing force)

Interlimb asymmetry was then calculated for each variable and reported as a percentage value.

Practical Takeaways

 The reduced performance found for all force-related variables within the study provides important implications for practitioners looking to improve their athletes’ ability to cope with the demands of competitive soccer matches. The reduction in force, velocity and landing mechanics immediately after matches may indicate the inability of athletes to maintain performance in the latter stages of a match,which may have implications on physical performance and injury risk. In addition, the sustained reduction in jump performance up to 72-hours post-match highlights the importance of maximising recovery when training sessions or matches are scheduled on successive days.

 As asymmetry was evidenced to increase post-match, practitioners may wish to spend considerable time and effort in addressing athletes’ baseline asymmetries to enable them to better cope with the demands of a competitive match. Inter limb asymmetry is evidenced to increase injury risk and reduce physical performance(see HERE). Therefore, as mentioned above, the presence of increased asymmetry within the latter stages of a match, or in the following days, may have detrimental effects on overall athlete well-being.

 This study highlights the importance of monitoring several distinct jump variables,as jump height alone was not sensitive enough to show significant changes in jump performance. As inter-limb asymmetries in several variables were sensitive to fatigue post-match, practitioners are urged to look ahead to such metrics in their post-match neuromuscular fatigue monitoring strategies. This will provide a greater insight into athletes’ physical status during recovery, and ensure they are correctly monitored and receive modified training prescriptions where necessary.

 Further to this, monitoring asymmetries more frequently may enable practitioners to determine whether existing imbalances are associated with reduction of physical performance or increased injury risk across the course of a competitive cycle. For instance, when looking at statistical variables like effect size, or smallest worthwhile change, practitioners are able to better understand true change in performance and its subsequent relatedness to the resultant sports performance.

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Time-course of performance changes

 Mean values decreased from baseline at all time points for eccentric impulse, peak propulsive force and landing impulse, and increased at all time points for peak landing force.

 Decreases were also found from one-hour and 24-hours post to 48- and 72-hours post for eccentric impulse and peak propulsive force.

 Further decreases were noted between 48and 72-hours post for eccentric impulse (left side only) and propulsive peak force.

 Jump height was only found to be reduced on the left side between one- and 24-hours post and increased between 24- and 72hours post.

Time-course of asymmetry changes

 Concentric and eccentric impulse, peak propulsive and landing force asymmetry increased from pre- to 24-hours post match.

 Eccentric impulse and peak propulsive and landing force asymmetry decreased from baseline to 1-hour post, and from 24-hours to 48- and 72-hours post..

Tom’ s Comments

It was great to see rigorous detail provided within the methodology section of this paper. Often with papers of this sort, limited information is given on the warm-up and testing procedures, or the procedures provided have very little comprehension – this is something I feel is often overlooked, considering the sensitivity of jump testing. This study presented a relatively comprehensive warm-up procedure (something I feel is key to accurate maximum power readings) and good detail around the jump procedures (e.g. , no swinging of non-jumping leg allowed) to ensure a valid representation of lower-limb power.

The findings presented in this study suggest unilateral jumps are useful markers of the changing nature of jump asymmetry in soccer. Regularly monitoring unilateral jumps may be useful to determine whether an athlete is struggling to cope with the demands of their sport on one side more than the other. Large decrements in unilateral leg strength, stability and power may prove detrimental during fatiguing instances towards the end of a match. Therefore, it would be assumed that interventions to minimise jump asymmetry decrements post-match is desirable.

One thing to keep in mind is the low withinsession reliability of specific jump variables reported in this study. Additionally, scores were presented as means for all variables, with the range at times demonstrating significant variation. Therefore, findings presented for these variables should be interpreted with caution.

Youth Development

This month’s top research on youth development.

THE ROLE OF NEUROMUSCULAR TRAINING IN YOUTH RUGBY PLAYERS

MONITORING GROWTH AND BIOBANDING YOUTH ATHLETES

The role of neuromuscular training in youth rugby players

OBJECTIVE

Rugby is a collision sport requiring players to engage in high-intensity efforts(e.g., tackling andcontact) as well as low-intensity activities (e.g., jogging back into position). When looking to develop young rugby players, ensuring children are strong, powerful and robust is important. In addition, skills such as balance, coordination, and agility are fundamental to enhancing the quality of rugby players. There is evidence to suggest all of these characteristics can be developed through integrative neuromuscular training (INT), which is purposely designed to enhance both skill and health-related components of fitness. However, research exploring the effects of INT on developing young rugby players is sparse.

Therefore, the purpose of this study was to assess the impact of INT on selected physical fitness measures in youth rugby players in different positions and ages.

WHAT THEY DID

One hundred and thirty-eight male rugby players (6-14 years) were divided into the following five groups based on chronological age:

Group 1: N = 20, 7.05 ± 0.58 years

Group 2: N = 27, 8.57 ± 0.49 years

Group 3: N = 31, 11.02 ± 0.56 years

Group 4: N = 33, 13.12 ± 0.58 years

Group 5: N = 27, 14.58 ± 1.53 years

Within these groups, players were identified as being in one of two positional groups (forwards or backs).

Physical fitness measures collected included a Functional Movement Screen (FMS), dominant and nondominant hand-to-eye coordination (tapping test), sprint capacity (5x10m sprint), core muscular endurance (curlup test), and lower (standing long jump) and upper body power (medicine ball throw).

Participants followed an eight-week INT program including progressive strength (e.g., squats, lunges and medicine ball throws), coordination (e.g., throwing, catching, and skipping), and speed exercises (e.g., slalom runs, chasing, and races) performed twice a week, lasting roughly 20 minutes. All data was analysed based on playing position and age, using a simple t-test (HERE).

Practical Takeaways

 When working with children, INT can be a fantastic training approach to adopt as it can help to keep children interested and prevent tedium. One of my favourite ways to structure a session is to superset a strength exercise with a balance and coordination exercise (e.g., a thumbs up body weight squat with a single-leg Romanian deadlift). Both complement each other well due to the demand for control and focus. From here, I would build into some speed (e.g., chasing games) and change of direction work (e.g., 90degree cut relays). A fantastic example of a similar approach can be seen in the attached video.

 Based on the takeaway above, using INT within a programme needs to be a shared vision within your club/organisation. For example, although less structured sessions may be a preference for youth (5-13yrs) (HERE), these may not wield the best physical results in the short term. In the attached article, the authors compared the Fifa 11+ warm-up (HERE) to an INT warm-up. They found that the Fifa 11+ warm-up was more effective. However, the positions and shapes recreated in the Fifa 11+ were far more transferable to the testing battery pre- and post-intervention. With this in mind, coaches need to decide which approach is best by weighing up the performance outcomes against the development priorities of their employer.

 Rugby-specific sessions should incorporate elements that are directly related to sport (e.g., teaching athletes how to ruck) and skill specific (e.g., working on agility). When building a session, the advice above, coupled with the knowledge available to you, should shape how you plan to interact with your athletes. The activate programme (HERE), is a fantastic starting point. Originally developed as a warm-up, the activate programme can be used to form the “strength” portion of your integrative neuromuscular training.

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WHAT THEY FOUND

Eight weeks of INT improved fundamental movement skills and selected physical fitness measures for almost all groups irrespective of chronological age.

With regard to hand-eye coordination, only groups 1 and 3 (younger age groups) failed to show improvement in the tapping test following eight weeks of INT training. Similarly, group 3 showed little improvement in upper and lower body power tests.

Young rugby players equally enhanced their skill and fitness capacities regardless of playing position, with both forwards and backs showing similar improvements.

Results from this study show that irrespective of age, the trainability of fitness components can be achieved in acute periods (8-weeks).

Tom’ s Comments

The results of this study conclude that there can be improvements in as little as eight weeks of INT training. With this in mind, those working with youths may consider the role of FMS and INT within their training sessions to better prepare their athletes for the game of rugby. Although some groups didn’t improve their hand-eye coordination (groups 1 and 3), the authors suggested these were younger participants, whose coaches/educators placed more emphasis on successful skill repetition using the dominant side. As coaches/teachers, it s really important to ensure children are using both feet and hands throughout their development (HERE). To support this, encouraging children to “unlock” their dominant hand/foot (e.g., pass and catch off a wall with your non-dominant hand) could be a great way to do so. In addition, an overreliance on one side of the body can lead to overuse injuries or a skill bias (e.g., a player always wants to use a set pattern for all in-game encounters).

"As this study showed no differences between forwards and back positions in the FMS or physical testing, it is essential we avoid arche typing players (e.g., short and stocky players are more suited as props) in youth. This has been supported in the attached podcast, where cofounder of the Magic Academy, Russel Earnshaw, suggests we must avoid “pigeon-holing” players into positions at a young age, as this can limit their development as a player.

From an S&C perspective, we know the considerable changes that can occur as a result of peak height velocity (HERE) can completely alter the stature of an individual, so we must continue to educate those working with children (e.g., coaches) about this stage of development.

Fortunately, in the UK, the rules of age-grade rugby (HERE) have helped players to get involved in all aspects of the game.

Finally, the limitations of this study, such as a male-only cohort and lack of appreciation for biological age, leave a lot to consider for future research and provide further avenues for exploration."



Monitoring growth and bio-banding youth athletes

OBJECTIVE

Talent identification within youth soccer tends to favour those who are more advanced intheir physical development, as these individuals are typically bigger ,faster, stronger, and more physically fit. To that end, high-level training and competition are happening at earl ier ages and overlap the accelerated growth phase kn own as peak height velocity (PHV) that occurs around 10-16 years of age. The timing of this growth is highly individual,and considerations need to be made to support long-term development by adaptin g training to complement changes before,during, and after PHV. The training process cannot be accelerated an d must be managed accordingly to prevent injury and enhance performance.

As such, the adaptive training method known this review out lined various approaches to est imate growth status in youth athletes and explored methods for adjusting training to best meet developmental stages around PHV.

WHAT THEYDID

The various methods for estimating maturity status were outlined (e.g., x-ray and evaluation of bone development, assessing sexual maturity, and equations that use direct body measurements to approximate growth status),covering the practicality and validity of each,with suggestions provided based on current evidence.

Secondarily, performance capacity relative to PHV was outlined, highlighting the opportunities to best support progress with specific training interventions.

Lastly, the importance of mitigating injury riskthrough management of training loads relativeto maturity status was explained, respecting thebalance of competition and specific training opportunities during these formidable years.

Practical Takeaways

The primary goal when monitoring growth for a youth athlete is to identify PHV - the period of time when growth rate (centimetres per year) is highest. This is best accomplished through repeatable and reliable measurements using a consistent protocol (e.g., the same high-quality devices, time of day, and experienced measurer). Performing measurements at least three times per year (e.g., January, April, September), but increasing measurements to monthly during ages 11-15 years old is important, as is having at least two years of consistent data for reliable interpretation of the transition into PHV.

WHAT THEY FOUND

 A trained radiologist can examine the x-ray of a child’s wrist to estimate biological maturation - the FELS method is the most complete method of analysis in this regard.

 Using measurement equations to calculate maturation status or predict growth is the least invasive and most practical method. Calculating the percentage of final estimated adult stature attainment using the Khamis and Roche equation (currently supported by the English Premier League) or maturity offset (the time before PHV) using either the Fransen et al. or Moore et al. methods are the most common.

 Physical qualities such as strength and speed have increased developmental potential both during and post-PHV but can also be developed pre-PHV at a more gradual rate with appropriate training loads (volume, intensity, and frequency).

 A relationship between maturation rate and injury risk exists, with more severe injuries occurring during PHV. This could be due to the delay in muscle function (e.g., coordination, flexibility, strength) relative to overall structure growth (height and weight), a period known as the ‘adolescent awkwardness’ stage.

Cody’ s Comments



Using equations to calculate growth status can be simple, non-invasive, and helpful in pinpointing a young athlete’s stage of growth, but they do have their associated limitations and errors. Select the equation based on the information available , as some require measurements of the mother and father. When applied consistently, the accuracy and opportunity to individualise is there (see HERE), but no equation has been validated as the ‘best’ because of numerous factors related to gender, ethnicity, etc. So, select the equation that is most valid, reliable, and repeatable over time based on the individual.

 Identifying PHV is important because training needs to be modified to increase the movement capacity (e.g., balance, explosiveness, strength, speed, and agility) of the youth athlete as they go through this period of rapid growth (see HERE). Commonly referred to as ‘windows of opportunity,’ these physical qualities experience accelerated development during this timeframe.

 During PHV, sport-specific activity, especially competitions, should maintain close to a 1:1 ratio when compared to general activities (e.g., movement and strength training or free play). The goal here is to expose the athlete to controlled situations, as opposed to competitive environments, in an attempt to reduce injury risk, control recovery, and enhance overall movement quality. Likewise, it is important to offer at least one complete rest day per week with no structured training, allowing time for rest and recovery.



Systematically implementing resistance training during PHV offers great potential to increase strength, speed, and hypertrophy due to the increased concentrations of anabolic hormones (see HERE). This is vital in aiding the rapid growth rate and reducing the likelihood of severe injury - a risk that is elevated during this period.

 Although there are periods of time (typically during and post-PHV) when progress is accelerated, there is still a possibility to increase coordination, strength, and speed qualities pre-PHV. Training simply needs to be reduced, not avoided prePHV.



From an aerobic capacity development standpoint, it is important to understand it is a quality that simply takes time and cannot be rushed. As a coach, do not focus specifically on developing that quality within training as it is developed in accordance with various means of sport- and non-sport-specific activity (e.g., training drills, games, unstructured play, etc.).

 Flexibility is the most notable quality to manage and train post-PHV, as stiffness increases because tissue length, pennation angles, and recruitment patterns are established. These changes also offer the opportunity to train with more intensity, emphasising force and power production with exercise prescription (e.g., maximal lifts, throws, and jumps).

 It is important to gradually increase training load following a summer or winter layoff period, as September and January have the highest injury rates across the year (see HERE). Coaches should maximise safety and take at least two weeks to reach typical training volumes following a 'Safe Return to Training for Athletes'.

 Collaboration, communication, and education for the sport coaches and parents is paramount. Get all parties on the same page, working together with a common goal and understanding regarding opportunities and risks with youth athletic development. The health, wellbeing, and longevity of the young athlete always takes precedence.

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Although development of speed, strength and endurance can occur for a youth athlete regardless of growth and maturation status, there are notable considerations to make before, during, and after PHV that can mitigate setbacks and optimise development. Most importantly, rate of maturation should not be a limiting factor to long-term sport success and bio-banding athletes can be helpful in this process. Patiently identifying PHV is the primary target that can help group athletes and guide training prescription.

The important thing to remember when training youth athletes is, their bodies are complex and experiencing rapid changes regardless of training stimulus. Being systematic and conservative with volume and intensity is important early on. Similar to training adult athletes, monitoring readiness and managing recovery while identifying and avoiding high-risk situations is important to keep progressing. Be steady with the approach to sport-specific involvement and routine with measurements. Adapting the training to the individual and their maturation status can prevent injury while enhancing performance and building confidence through to adulthood.

Nutrition

This month’ s top research on nutrition.

SOY VS WHEY PROTEIN: WHICH IS THE BEST FOR SOCCER PLAYERS AND RECOVERY

CAN BLOOD FLOW RESTRICTION ENHANCE PROTEINS RELATED TO MUSCLE ENDURANCE AND STRENGTH ?

DO PROFESSIONAL BASKETBALL

ATHLETES CONSUME ENOUGH OMEGA-3S?

Soy vs whey protein: Which is best for soccer players and recovery?

BACKGROUND

Team sports training often incorporates speed-endurance type sessions which involve rapid acceleration, deceleration and changes in direction. These types of movement all have a strong eccentric component which can result in increased muscle damage. The resulting exercise-induced muscle damage can reduce subsequent performance for up to 72 hours during the recovery process.

The role of protein in accelerating muscle recovery is well studied, with whey protein thought to be superior to other protein sources due to its higher leucine content (see video below). However, the continued rise in popularity of vegan and vegetarian diets among athletes warrants further investigation of how plant-based alternatives may also support recovery following muscle damage.

WHAT THEY DID

Ten male soccer players with four or more years of competitive football experience were recruited. The players were assigned to either the whey protein (WP), soy protein (SP) or placebo (PL) groups. During the first seven days, participants adapted to a protein intake of 0.8-1g.kg.day-1. From days 8-14 the players preloaded with either the assigned supplement or maltodextrin placebo each day, which increased daily protein intake to 1.5g.kg.day-1 for those in the WP and SP groups.

On days 15 and 17, all players participated in a speed-endurance training session which lasted 60 min and included a set of 8 x 30s maximum intensity repetitions of a soccer-specific drill. GPS and heart rate monitors were used during each test to assess external and internal loads respectively.

Performance was assessed through isokinetic strength of knee extensors and flexors, maximal voluntary isometric contraction, maximum speed, high-intensity running (distance covered at 1421 km/h), intense decelerations (> 2 m/s2), repeated sprint ability and counter movement jump. Muscle damage was assessed by delayed onset muscle soreness (DOMS) (subjective score) and creatine kinase activity in the blood. Glutathione, total antioxidant capacity and protein carbonyls were used as measures of redox status (the balance between oxidants and antioxidants). Evaluations were taken at baseline, after the first seven days, and during recovery from speed-endurance training.

After the second speed-endurance training session, players completed a seven-day washout period to ensure full recovery before being reassigned to a different protein/placebo group and restarting the trial from day one. This was repeated until each player had completed all three interventions.

Practical Takeaways

 Whey and soy protein are beneficial for aspects of recovery and performance, provided that total protein intake is 1.5 g.kg.day-1 or greater.

 If athletes do opt for plant-based proteins, then they are advised to carefully plan and prepare what plant proteins they will consume at each meal. In particular, it is important to consider the total amino acid profile of each meal to ensure a high intake of the amino acid leucine is consumed.

 Even if the athletes don’t subjectively feel much of a difference by consuming high protein intakes (as evidenced by unaffected DOMS scores in this trial), it is still likely that the mechanistic repair and rebuilding of proteins at the muscle fibre level is far greater when high protein contents are consumed versus low.

 A daily intake of 0.8g.kg.day-1 protein, as per the placebo group, is too low for the vast majority of athletes. If an athlete has a protein intake as low as this, nutrition education may be helpful to encourage them to increase their intake to a more appropriate level. For guidelines on recommended protein intakes see the attached article..

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WHAT THEY FOUND

Concentric and eccentric knee extensor and knee flexor strength from both the dominant and non-dominant limb decreased similarly in all trials at 24 h post-session. Maximal voluntary isometric contraction decreased (compared to pre) only in knee extensors of the non-dominant limb at 1 h (by 12–13%) and 2 h (by 7–7.6%) post-session.

Maximum speed was lower in the second speed-endurance session compared to the first for all groups, but the WP and SP groups slowed slightly less than the PL group, by 2.3% and 2.0% respectively. High-intensity running decreased between the two sessions by 11.2% for the PL group, but only 7.7% for both WP and SP groups. Intense decelerations decreased in the PL group by 5.8 % but did not change in the WP or SP groups.

Repeated sprint ability fatigue index increased (PL: + 20%; WP: + 13%; SP: + 16%) and countermovement jump height decreased (PL: -7%; WP: -5%; SP: -5%) similarly in all trials at 24 h.

Delayed onset muscle soreness increased almost three-fold in all trials at 24 hrs and 48 hrs post-session, without any difference between groups. Similarly, creatine kinase increased almost twofold, 24hrs after the first speed-endurance session compared to pre -trial levels, and stayed elevated until 48 hrs of recovery for all groups.

There was no difference in total antioxidant capacity, although the protein carbonyls were lower in the SP group 48 hrs after training compared to the PL group. Although also lower in the WP group, the change was not statistically significant.

James

Comments

"In this study, the protein supplements were given directly after the training session. However, in practice athletes should aim to have regular protein intakes throughout the day (every threefour hours). Additionally, almost half of the participants’ daily intake of protein was consumed right after the training sessions as per the study protocol.

"Although adequate protein intake certainly plays a key role in recovery, the energy balance of the whole diet, as well as carbohydrate availability, are also important aspects to consider. Similarly, where possible, a food-first approach should be encouraged to ensure an adequate supply of micro nutrients that are vital for the repair and rebuild process, as discussed in the podcast below (i.e., key vitamins and minerals and healthy fats).

"This study focuses on the short-term effects of whey vs soy protein, but in studies of longer duration, it does appear as though animalderived proteins still maintain an advantage when it comes to supporting lean muscle mass and strength. However, some research suggests that when soy protein is matched with whey for leucine content, the advantages of one protein source over the other are negligible. Whether to consume plant-based protein or not is often an emotive topic.

"In my personal practice, the choice comes down to the athlete’s preferences and it is my responsibility to optimise performance within the given parameters."

Can blood flow restriction enhance proteins related to muscle endurance and strength?

OBJECTIVE

Blood flow restriction (BFR) has previously been well-cited to support muscle hypertrophy during low-intensity resistance training, and news of its use hit the media outlets during the 2020Olympic Games in Tokyo. BFR has been adopted by a wide range of populations ranging from healthy Olympic and rehabilitating athletes to the elderly, with the primary goal of increasing muscle hypertrophy.

BFR is typically performed during resistance training sessions. However, it is well-accepted that the adaptive response to exercise training in skeletal muscle takes place in the resting period after that training session itself (related article below). Therefore, there is a strong rationale to use BFR post-training in an attempt to elicit greater adaptive response when the muscle is resting and recovering.

Therefore, the authors of this study aimed to investigate whether BFR applied between sets during resistance training would beneficially impact the effects of a single bout of exercise.

WHAT THEY DID

Seven healthy males (age = 24.5 ± 4.7) completed an acute exercise protocol consisting of a 10-minute warm-up on a cyclingergometer, followed by squatting 10 repetitions at a load one-half their body weight and 4-6 repetitions at total body weight. Participants then completed a one repetition maximum (1RM) test, which was reached in four trials.

All participants then completed seven sets (two-minutes rest between sets) with 10 repetitions of back squatting at 70% of 1RM. During the two-minute rest period, right leg BFR was performed using the Mizuho BFR system at a pressure of 230 mmHg. The left leg served as a control, and blood flow measurement was performed via ultrasound examination of the restricted leg during rest periods.

Muscle biopsy samples were collected from the vastus lateralis muscle of both legs, two hours after the last exercise set to allow assessment of target gene expression levels and protein levels via an Immunoblot assay.

Practical Takeaways

 The mRNA levels of Akt2, NRF1, VEGF and Pax7 increased significantly when BFR was performed during the rest periods of resistance training. This suggests that applying BFR in between working sets may provide a great opportunity for athletes to elicit further gains to their hypertrophy programs in a timeefficient manner.

 This can be especially helpful for injured athletes who first need to minimise muscle mass loss during immobilisation, then gain lean muscle mass as quickly as possible during rehabilitation. This was documented recently with a famous Premier League football player using BFR during his rehab. It is also supported in this article regarding strategies to maintain skeletal muscle mass in the injured athlete.

 Recently, Hytro (a BFR recovery garment) has been used by many professional rugby players, boxers and football players to support return to play, hypertrophy and strength gains and appears to be a quick and efficient way to provide BFR to athletes during both training and rest periods. With this in mind, Hytro could be an easy way for athletes to experience the enhanced gene expression of angiogenesis (forming of new blood vessels), mitochondrial biogenesis, muscle repair and hypertrophy that was evident in this study

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WHAT THEY FOUND

Systolic (pressure when the heart beats) and diastolic (pressure when the heart is resting in between beats) flow velocity were registered before and after cuffing, and with 230 mmHg of pressure, blood fl ow was almost completely blocked. After the fourth and fifth measurements, systolic blood flow increased dramatically when the cuff pressure was released, compared tothe third basal values (fourth measurement: 108.88 ± 28.48 mmHg vs.157.94 ± 13.89 mmHg; fifth measurement:108.88 ± 28.48 mmHg vs.176.81 ± 42.3 mmHg). Pressure dropped back to the initial values five minutes after the cuff pressure was released (86.56 ± 35.79 mmHg).

Levels of microRNA-1, 34a, 133a and 133b did not change with BFR, although the concentration of m icroRNA-206 significantly decreased (1.22 ± 1.02 fold). MicroRNA’s are a class of non-coding RNAs that play important roles in r egulating gene expression.

Resistance exercise with BFR increased key signaling proteins involved in protein synthesis, vascularization, mitochondrial biogenesis, and the antioxidant system. In particular microRNA levels of Akt2 (0.929 ± 0.923 fold), NRF1 (0.457 ± 0.409 fold), VEGF (0.721 ± 0.748 fold), and Ku70 genes (0.929 ± 0.923 fold).

The data also shows an increase in the microRNA levels of Pax7(0.886 ± 0.318 fold). Pax7 is a transcription factor that plays a rolein myogenesis through regulation of muscle precursor cell proliferation.

When assessing for correlations, significant correlations were found between the levels of microRNA-206 and Pax7 (r2 = 0.332,r -0.577). The protein levels of Pax7 (important for myogenesis - forming of new skeletal muscle tissue), NRF1 (a transcription factor important for cell growth), and PGC-1a (a key regulator of energy metabolism) measured two hours after the exercise bouts did not demonstrate differences between the BFR and control legs.

James

Comments

"Although BFR has previously been used as a recovery method during rehabilitation from surgeries or injuries, we are beginning to see more research showing the beneficial effects of BFR for training adaptations and improvements in mechanistic adaptations at the gene and protein level. Indeed, its use has exploded in the last few years with exciting research and practical use, with many Olympians sharing stories of how they have implemented it within their training programmes prior to Tokyo 2020.

"If BFR can be included in an athlete’s training and recovery program as a tool to increase training adaptations and muscular repair and growth, it would be wise for practitioners to consider (see video below). Combine BFR with a high protein diet and a maintenance dose of creatine, and the results could be great!

"This paper does show beneficial effects of BFR, however we must remember this was done in only seven male participants. So, it should not be generalised to other populations."

Do professional basketball athletes consume enough omega-3s?

BACKGROUND

Omega-3s are a family of polyunsaturated fats, so called due to the position of the first double bond in its structure. Examples include eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) - both of which are classed as essential, meaning we cannot synthesise them and must acquire them from outside our body. Omega-3 intake has long been associated with reduced risk of cardiovascular disease (Lee Et al. 2009) and cognitive decline (Fotuhi, Mohassel, Yaffe. 2009).

However, in recent years, focus has shifted towards the potential implications of omega-3s on amplifying training adaptations and improving recovery from exercise, which could have profound impacts on performance and reduction of injury risk. A number of these implications are outlined in the associated article and podcast.

Despite the known benefits of adequate intake, athletes often have a low omega-3 status, consuming less than the recommended two servings of fish per week - the most common source. Additionally, research exploring this among professional athletes is lacking.

As such, this study aimed to quantify the omega -3 status of professional basketball players.

WHAT THEY DID

One hundred and nineteen professional basketball players (age = 23.8 ± 2.0 years) from the minor league of the National Basketball Association (the G league) took part in this study. Blood samples were collected during the pre-season to allow analysis of erythrocyte fatty acids and to calculate an omega-3 index for each athlete. The omega-3 index (O3i) was calculated as the % of EPA and DHA present in the red blood cells. The authors used O3i as a measure of risk for cardiovascular disease with <4% being high risk, 4-8% moderate risk and >8% low risk. O3i has previously been found to be a comparable measurement for predicting cardiovascular risk (Harris. 2008).

Players also carried out a dietary and supplement intake questionnaire to quantify the amount of tuna, salmon, and other nonfried fish they consume per week and current omega-3 supplement protocols, if any.

Practical Takeaways

 Although we don’t necessarily know the optimum omega-3 index for performance, professional athletes will likely benefit from consuming more omega-3s, both from a reduction in cardiovascular risk perspective and amplification of training adaptation and recovery perspective.

 The low consumption of fish and low prevalence of supplementation within this population group is contributing to the low omega-3 status and is discussed more in the video link.

 It appears the recommended amount of two portions of fish per week may still not be enough to result in an omega-3 index of over 8%, and intakes of four servings per week (without supplementation) may be preferred.

 Supplementation could be considered for most athletes as a relatively easy way to increase omega-3 status.

 Vegetarian and vegan athletes will likely benefit more from supplementation due to the lack of fish within their diet.

 Education on the benefits of omega-3s from a performance perspective and how to increase omega-3s into diets will likely help increase buy-in from athletes.

 The omega-3 index is a relatively non-invasive way of assessing the omega-3 status of an athlete. Monitoring this will likely be more useful than questionnaires on intake in this setting, as the athletes are likely to respond well to objective, measurable data.

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WHAT THEY FOUND

The mean omega-3 index of the athletes was 5.0%, ranging from 2.8 to 9.8% with only two athletes having an O3i above 8.0%.

77.0% were found to be within the moderate risk category (4-8%), and 21.0% were found to have an O3i of less than 4.0%, thus putting them at high risk of cardiovascular disease. Very few athletes (8.0%) reported consuming two or more servings of fish per week, with most (61.0%) reporting consumption of one serving per week and just under a third of players (31.0%) consuming no fish each week.

Only 12 out of the 119 subjects reported supplementing with omega-3s, the frequency of which varied from daily to three times per week. Nine of these 12 reported doses of 0.53.0 g, with the other three not reporting a dosage.

When those who supplement were excluded from the analysis, a significant correlation was found between dietary fish intake and omega-3 index. However, omega-3 indexes of less than eight were still found in those consuming two-to-four servings of fish per week.

James’ Comments

"The novel aspect of this study was the fact it was carried out within a professional setting. To some, the low consumption of fish and low prevalence of supplementation may come as a surprise.

Unfortunately, I believe it is unsurprising that omega-3 status within this population is low. In my own practice, I have often found that even when clients consume two servings of oily fish per week, their omega-3 status is low. This is reflected here, and I believe poses the question: Is two servings per week enough? To which the answer may be no.

"Although a food-first approach is often preferred, in some scenarios, it is simply not possible. This population already fails to consume the recommended number of fish per week, and if the recommended amount should be higher, it will be increasingly difficult to bring the intakeup to where it needs to be. I believe supplementation of omega-3s is a relatively easy and frictionless approach to correcting this.

"However, education on the potential benefits of omega-3s on performance and recovery, along with education on how to increase intake through diet, would also be a beneficial approach. Although health is a priority, it is likely professional athletes will engage more with an intervention if it is shown to improve performance.

Future research should look to find the most effective way to increase the omega-3 status of athletes and look to quantify the potential

Injury Prevention & Rehab

This month’s top research on injury prevention and rehabilitation.

HOW DOES THE CONTRIBUTIONS OF THE KINETIC CHAIN INFLUENCE HOP TEST PERFORMANCE?

How does the contributions of the kinetic chain influence hop test performance?

OBJECTIVE

Hop testing has been well utilised in the rehabilitation setting during the return to play clinical decision-making process Current practice aims to achieve 90% limb symmetry during hop testing as a marker to determine overall readiness to return to sport, although some research suggests that it can overestimate knee function (see HERE). The horizontal hop test has been the most commonly used of all the current tests available however the vertical hop test may be more indicative of true knee function. The purpose of this study was to examine the biomechanical influence of the hip ankle and knee joint during the vertical and horizontal hop in active adults.

WHAT THEY DID

Twenty male adults performed the vertical and horizontal hop tests during a single session where the motion of each participant was captured using reflexive markers placed on each individual, and ground reaction forces were collected by a force plate.

Four successful trials were used for analysis when the participant landed inside the border of the force plate and held the landing for at least 2-sec. The data was used to calculate the internal moments and contributions of the hip, knee, and ankle joint during the hop tests.

Practical Takeaways

 Physical therapists should utilise both the horizontal and vertical hop tests when rehabilitating athletes with knee injuries as the landing phase of the horizontal hop and peak knee power generation of the vertical hop is most indicative of knee function.

 Physical therapists should also choose the vertical hop test as it may be more useful in determining knee asymmetry than the horizontal hop. This is because the hip, knee, and ankle joints each contribute roughly equally during the propulsive phase, indicating a higher performance contribution from the knee joint.

 Practitioners should also utilise both bilateral and single-leg functional performance tests as they likely involve different motor strategies and different joint contributions representing total lower extremity function rather than performance at one particular joint.

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WHAT THEY FOUND

 During the propulsive phase of the horizontal hop, peak ankle power was greater than both hip and knee peak power. Work generation from the hip and ankle joint did not differ but was greater than knee work.

 During the propulsive phase of the vertical hop, peak ankle power was greater than hip and knee peak power.

 During the landing phase of the horizontal hop, peak knee power absorption was greater than both the hip and the ankle. The work contribution of the knee joint in landing was greater than both the hip and ankle.

 During the landing phase of the vertical hop, peak power absorption did not differ between the ankle and hip, however, peak knee power absorption was less than both the hip and ankle.

 Peak hip and ankle power were greater in the horizontal hop compared with the vertical hop.

 Peak knee power generation was less in the horizontal hop compared with the vertical hop.

“

It was interesting to see the breakdown of biomechanics as the horizontal hop is most commonly used as a return to sport measure for the knee joint by measuring single-leg hop distance, however, this study shows that the knee joint contributed very little to the propulsive phase.

Hop testing in just one piece of the return to sport battery and is insufficient in fully assessing knee function. Other objective measures including movement screening, landing mechanics, force production, muscular endurance, and the psychological domain, should all be assessed to truly determine an athlete’ s readiness.”

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