The Performance Digest - March 2022 (Issue 65)

Study Details

How to Read Me!

Praccal Takeaways from study

Related links to learn more about the topic

Reviewers comments on the st udy

C o nte nts

Research Reviewers

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 Coaching Science,

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.

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.

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 aPhD from Liverpool John Moores University.

Fatigue & Recovery

Matthew is a Physical Therapist and the Clinical Director at a private Physical Therapy clinic in NYC. He has a special interest in the treatment of lower extremity/foot and ankle injuries along with helping runners and walkers to get back to what they love to do.

Fatigue & Recovery

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.

Tom Green MSc UKAD Advisor

James de Lacey MSc

Dr. James Morehen PhD

Cody Roberts MSE

S&C

Matt Klayman’s MSE

Dr. Jordan August DPT, CSFC, SFMA, FMS

H ow co ache s and spo rt scie ntists can use data to the ir advantage

Athlete monitoring strategies, advancements in technology, and simply the research on the human body is more prevalent than ever in the world of sport and athlete development. These opportunities have drastically evolved the field of ‘sport science’, which aims to provide feedback, direction, and support for performance enhancement and athlete management during training and competition. This area has grown so rapidly that it has created a disconnect between the science-based or datadriven opportunities and the practical execution by coaches and athletes on a realistic and daily basis.

There is no doubt sport science is here to stay, but it is going to take some teamwork from both sport scientists and coaches to best understand how to effectively incorporate these methods of data collection, so they seamlessly align and accomplish what they set out to do (i.e. inform coaches, athletes and guide training).

Currently, understanding of how coaches at the NCAA level perceive and approach sport science is limited. Therefore, the aim of this research was to identify widespread themes in how coaches across various sports at a NCAA Division 1 institution handled sport science within their respective programs.

A total of 13 coaches (age 40±8 yr) at a NCAA Division 1 institution were divided into four focus groups. A member of the research team promoted conversation with five specific questions:

“… specific ways that your team would benefit from knowledge gained from collecting data?”

“… specific performance questions you would like answered when it comes to your team?”

“… heard of other university teams in your sport that have successfully used performance data?

“What measures or methods were used…?”

“… throughout the season, what specific questions would you want to see supported by the data?”

§ “How do you think your team would use the data …?”

“… any concerns about collecting data on your team?”

Coaches from 12 men’s and women’s teams (e.g. baseball, basketball, soccer, softball, rowing, volleyball, golf, cross country, track and field, and swimming) were represented, as well as the head strength and conditioning coach for all teams. The focus group conversation lasted about 40 minutes on average and were recorded for thematic analysis, in which key concepts were identified based on similarity and frequency of mention from the coaches.

Results were summarised based on each question and the primary beliefs provided.

P ractical Takeaways

The combination of both objective (i.e. measurements without opinion or judgement) and subjective (i.e. based on perspective of an individual) measures can be used to make training adjustments (e.g. reduced volume or intensity of a session) if signs of fatigue are present. Having athletes rate their fatigue subjectively, combined with an external performance measure such as 10m acceleration time, adds validity to their report and further encouragement to reduce loads.

Tracking data (e.g. session rating of perceived exertion and/or total distance ran) can help coaches optimise their microcycle layout for a competition week - helping ensure that workloads are appropriate during the week and readiness is maximised on gameday Coaches should allow for recovery following a match with reduced workloads, dosing in workloads at opportune times during the days leading up to a competition, and allowing time (e.g. 1-2 days) for recovery prior to a match.

Coaches can use monitoring data to affirm their decisions for training prescription (e.g. volume, intensity, frequency, duration, etc.) - keeping record of this information will help support positive measures of athlete readiness. If athlete readiness is poor, coaches can look back to the workloads they prescribed and make adjustments, if necessary

Coaches should select performance assessments based on important performance qualities needed for success (i.e. key performance indicators). For example, if the ability to accelerate to top speed is important to success in the sport (e.g. baseball, basketball, soccer), coaches should assess acceleration ability (e.g. 20m sprint time), as this is a test that can continuously be measured throughout the year without concern of it negatively impacting performance.

Appreciating an athlete’s perception, especially as it relates to elevated levels of stress or anxiety, is important for a coach, as these can be signs of maladaptation (see ), leading to poor HERE performance or increased injury risk. Coaches can provide athletes with a quick and simple electronic questionnaire, offering athletes the opportunity to rate their stress or anxiety level on a 1-5 scale. This should be done consistently (3-4x per week), with a shared understanding of what each number represents (e.g. 1 being severe stress), with follow up from the coaches when needed.

Athlete readiness is a complex interaction of biopsychosocial influences - coaches should avoid putting too much emphasis on one metric (e.g. vertical jump height) without appreciating other areas as it relates to stress, aerobic capacity, or change of direction ability Coaches should collect multiple performance variables for a more thorough understanding and appreciation of the athlete and their performance potential.

It is important coaches do not fall into the trap of always resorting to doing less and undertraining. Coaches should aim to promote resilience rather than fragility, understanding that fatigue, soreness,

and performance decrements happen at times, but to continue to instil trust and commitment to the training process, as those periods can lead to improvements.

Teamwork (e.g. coaches, scientists, specialists, etc.) and collaboration is vital for success. No coach should aim to run a program by themselves, but should lean on others for support, direction, and involvement. Tap into resources of other professionals and specialists (e.g. researchers, professors, dietitians, biomechanists, etc.) for consultation and education.

From a training perspective, when working with athletes, it is important to equip them with the necessary skills to move well, think, and operate more effectively in competition. Coaches should find a good balance of emphasis on performance, health, safety, and longevity for the best overall development for athletes they work with.

The important thing to remember with data collection is that strategies must be realistic (e.g. cost- and time-effective). Whatever approaches are decided have to fit and flow towards the ultimate goal of improving performance, reducing injury risk, and actionable feedback. Coaches must be judicious in selecting what works best for their program, asking for input from support staff and athletes. Coaches can easily control the workload prescribed, but it is important to also keep a pulse on nutrition and sleep habits to support athlete recovery Assessments initially through questionnaires can be a great starting point for this to identify those in need, with follow-ups, education, and consultation. Remember the goal of these is not aiming to control the athlete, but helping improve health, performance, and recovery (see HERE).

When presenting data to a coach it needs to be simple, easily understood, and actionable. Make sure the data you are collecting is helping to answer the coach’s question. Ensure the time and efforts you are putting toward data collection and presentation are meaningful and understood.

When collecting data from athletes, it is important to involve them in the process, share it with them, explain why you are taking it, how it is going to help, and never make them feel like test subjects. This will help increase buy-in and motivation from the athletes.

Coaches should avoid body composition assessments, but rather focus on objective performance variables and educating athletes on supportive skills related to nutrition, sleep, and stress managementbody composition typically takes care of itself from a foundation of sound psychophysiological practice.

As a coach, it is critical to stay informed as a professional with advancements in the field of science and research so you can help educate the other coaches and athletes you work with. Reading articles like this, attending conferences, and reaching out to other professionals is a great starting point.

Coaches believed collecting data was helpful in tracking an athlete’s performance progress over time and using this information to potentially modify training.

Coaches believed a daily assessment of readiness (e.g. fatigue, recovery, mental state) and sleep and nutrition behaviours was necessary in an effort to understand the athlete on and off the field, as well as a biomechanical analysis.

Coaches believed that data collection would offer confidence for a coach and their respective training methods.

Time-related strategies and requirements, as well as effectiveness, were the two areas that coaches had the greatest concern about regarding data collection and the realistic opportunity to be implemented.

“The important thing to remember with data collection and monitoring is that ‘optimal is not the goal or reality, but rather finding what is feasible based on consistency, opportunity, and effectiveness. When making decisions on what data to commit to collecting, ask yourself: Is this information helpful and actionable? Am I able to collect it frequently through the weeks and months? Does it flow seamlessly with our day-to-day operation and positively influence the training process?”

“Data is feedback to training prescriptions and represents the athletes’ response. Coaches must continue to appreciate the process as it relates to biopsychosocial influences an athlete goes through. In the end, data is simply a compass, not a step-bystep guide on what to do and how to do it.

“Implementing monitoring is not a ‘one-size-fits-all approach, but rather focusing on what is practical and useful is most important. Even the latest and greatest technology has limits, but things can and will continue to improve if conversations between coaches, scientists, and developers continue.”

Stre ngth & C o nditio ning

This month ’ s top research in strength & conditioning.

Is training to failure ne ce ssary to m axim ise hy pe rtro phy ?

A hotly debated topic within the fitness community is whether or not to train to failure. It is often thought that to maximise hypertrophy, you must train to failure to recruit Type II muscle fibres, which are more sensitive to growth. While some studies support this view, the vast majority didn’t match volume between failure and non-failure groups, resulting in failure groups performing more volume. This is a confounding variable since there is a dose-response relationship between volume and hypertrophy (see HERE).

Thus, this study aimed to compare volume equated high load (HL) and low load (LL) resistance training with and without muscle failure on muscle strength and hypertrophy

Thirty-two physically active males (age = 19-34 yr) completed eight weeks of resistance training at low and high loads to and not to failure. Before and after the training intervention, subjects performed a 1RM leg extension for both legs unilaterally and an MRI was taken of the quadriceps to measure cross sectional area (CSA).

Subjects trained twice per week and were randomised into either a high load or low load group. High load used 80% 1RM and low load used 30% 1RM. The limb in the failure condition performed three sets to concentric failure. The non-failure limb (opposite leg) performed the same volume but using 60% of the reps performed over three sets to failure. Therefore, the non-failure protocol had to perform more sets.

Rate of perceived exertion (RPE) was recorded after each training session.

P ractical Takeaways

Practically, the takeaways from this study are simple. When lifting lighter loads (e.g., isolation exercises), effort is the key to maximising hypertrophy When lifting heavier loads, shying away from failure is best, as going to failure confers no additional benefits. How does this translate to the real world?:

§ General population beginners who are training to get stronger may want to avoid training to failure, as a high level of effort could reduce the enjoyment of training. Not to mention the extreme muscle soreness the following day may put them off training all together

§ For athletes who need to get stronger, intensity is the driving factor (see for HERE example) and not volume. Because athletes have many competing demands (e.g., speed, conditioning, technical/tactical), a low volume approach for strength development is a viable solution. For example:

A1) Squat 2-3 x 2-4 @80-85% 1RM

B1) RDL 2-3 x 5-6 @8 RPE

Athletes looking to gain size should avoid taking high load exercises to failure or close to it due to the excessive perceived exertion and residual fatigue. Perform compound exercises far from failure for strength and hypertrophy and use low load isolation or bodyweight exercises to target hypertrophy. For example:

A1) Bench Press 3-4 x 4-6 @80-85% 1RM

A2) Weighted Pull-Up 3-4 x 4-6 @9 RPE

B1) DB Bench Press 3 x 10-12 @8 RPE

B2) Chin-Up 3 x 9 RPE

C1) Push-Ups 2 x failure

C2) Inverted Row 2 x failure

Quadriceps CSA significantly increased from pre to post intervention in high load failure and non-failure, and low load failure conditions with no significant differences between protocols. However, no significant change was seen in the low load nonfailure condition.

Both high load conditions showed significantly greater gains in 1RM compared to the low load conditions. There was no significant difference between failure and non-failure on 1RM within the loading groups.

RPE was significantly greater in all training sessions to failure.

“While this study used untrained subjects, the results fall in line with previous research on loading and strength and hypertrophy When training athletes, having the majority of training well away from failure allows you to prioritise other important aspects of physical and sport preparation.

“My belief is general weight room strength is not as important as we make it out to be, and reducing the perceived exertion during strength training means you can focus on what is more important - technical/tactical training and speed/power development.”

W hich show highe r co rre latio ns to vo lley ball: V e rtical o r ho rizo ntal fo rce -v e lo city re latio nship?

Within volleyball, the main determinants of performance are vertical jump, quick accelerations, and change of direction speed. We know from previous research that the mechanical determinants of sprinting and jumping tend to correlate with explosive activity in the same force vector (e.g. jump mechanical variables correlate with vertical jump but not sprinting). However, no associations have been made between these mechanical variables and volleyball-specific approach jump performance.

Therefore, the study examined the relationship between jump and sprint force-velocity profiles and change of direction (COD), sprinting, and approach jump.

Thirty-seven young male volleyball players (age = 21.8 ± 3.9 yr) performed a battery of tests within the same session. The first test was a vertical force-velocity (FV) profile from the countermovement jump (CMJ), measured on a force plate. The second test was a 25m sprint measured with timing lights at splits of 0-5 m, 0-10 m, 0-15 m, 0-25 m. FV profiles were analysed from these split times. COD performance was measured with the modified T-test and 505 test both measured with timing lights. The approach jump was measured with a measuring tape on a wall with subjects reaching and placing a chalk mark from their fingers.

The mechanical variables measured from the FV profiles were:

F0 – theoretical maximum force

V0 – theoretical maximum velocity

Pmax – maximal power

FV slope – gradient of FV profile

RFmax – ratio of force (sprint only)

Drf – decrement in ratio of force (sprint only)

FVopt – optimal FV profile (jump only)

FV imbalance – percentage difference between optimal and current FV profile (jump only)

Max speed (sprint only)

These mechanical variables were then correlated with COD tests, approach jump height, and split times.

Approach Jump

Moderate correlations were found between vertical F0 and approach jump height, and moderate to high correlations between horizontal F0, Pmax, and RF and approach jump height. 62.2% of the variance in approach jump height could be explained by horizontal Pmax.

Modified T-Test

Modified T-Test was moderately to highly negatively correlated with horizontal F0, Pmax, and RF Meaning the faster the test, the higher the mechanical variables. 34.7% of the variance in the modified t-test could be explained by horizontal Pmax.

505 Test

Left leg 505 had moderate negative correlations with horizontal RF and Pmax. 13.7% of the variance in the 505 test could be explained by Pmax. Right leg 505 test showed no correlations with any FV variables. COD deficit in the left leg was moderately correlated with horizontal F0, FV slope, and RFmax whereas the right leg was moderately to highly correlated with F0, Pmax, FV slope, RF, and Drf. Potentially indicating that COD deficit is a force problem. No vertical FV variables correlated with COD tests.

Sprint Times

5 and 10m sprint was moderately to very strongly negatively correlated with F0, Pmax, RF, FV slope (positive correlation), and Drf (positive correlation). RF alone explained 85.6% and 78.2% of the variance in 5 and 10m sprint times respectively 15 and 25m sprint times were moderately to very strongly negatively correlated with RF, maximum speed, and Pmax. Pmax explained 71.9% and 87 7% of the variance in 15 and 25m sprint times respectively

Practical Takeaways

This is another study that supports the force vector theory. Previous research has shown that jump and sprint force-velocity variables show no relationship (see ) with horizontal sprint HERE mechanical variables showing greater relationships with change of direction performance (see HERE) compared to vertical mechanical variables which supports the current study

One interesting finding is that horizontal mechanical variables had high correlations with approach jump performance in conjunction with vertical mechanical variables. This can potentially be explained by the horizontal approach. A higher approach jump is determined by a longer and more explosive penultimate step which has larger horizontal velocity and momentum (see HERE). Further, the importance of the approach is to create high levels of horizontal force that can be redirected vertically

Very rarely will athletes perform a vertical jump from a stand still position. Most of the time, there is an approach to the jump. For example, heading the ball in soccer, catching a high ball in rugby, or spiking in volleyball - all have some form of approach at various speeds. Therefore, it is potentially important to prioritise horizontal FV profiling for volleyball players as you get more information not only on approach jump performance, but also COD performance.

You can do this simply with the My Sprint app which will give you all of the mechanical variables derived from split times. As RF was a predictor of sprinting ability at all distances, it further confirms the current method I like to group athletes based on horizontal FV profiles. It also automatically tends to rank athletes from higher F0 and Pmax to lower. Here’s how:

1. Place all of the FV data into a spreadsheet for each athlete.

2. Order athletes by RF from high to low

3. Calculate a Z-score ( ) for each player and place anyone one standard this is a great video to help deviation above the mean ratio of force into a ‘velocity deficit’ group. Anyone one standard deviation below can then be placed in a ‘force deficit’ group. The rest are in the ‘well-balanced’ group.

4. Individualise your programs based on these groups to enhance Pmax.

“There is constant debate and conjecture about whether the force vector theory really applies to real world sport. I’d say it does, based on research like this. Further, the ability to orientate force horizontally is a key variable to short sprint performance as further evidenced by this study

“Another interesting finding is that all volleyball subjects had velocity dominant profiles. Previous research in elite volleyball found the same results (see This may be an HERE). adaptation from the high number of jumps, CODs, and short sprints experienced in volleyball training and matches. Therefore, if you do not have the time, space, or know how to create FV profiles, taking a shotgun approach and assuming players are velocity dominant could potentially be a good strategy. In this case, prescribing horizontal force exercises like sled sprints, hip thrusts, and kettlebell swings.”

C an a high fre que ncy e cce ntric training appro ach le ad to gre ate r stre ngth gains?

Training frequency is a hotly debated topic. My recent research review (see summary HERE) adds to the body of literature showing frequency doesn’t play a role in strength & hypertrophy when volume is equated. However, eccentric exercise is associated with increased muscle damage and therefore, training frequency may play a more significant role.

Therefore, this study aimed to investigate the effects of 1 vs. 3-day per week eccentric only isokinetic training on strength and lower body adaptations.

Thirty collegiate men and women (age = 22.6 ± 2 yr) participated, who performed lower body strength training at least three times per month, but no more than two times per week. They were randomly assigned into a high frequency group (three times per week) or a low frequency group (one time per week) of eccentric training. The training intervention lasted four weeks.

Subjects sat on an isokinetic device that was a single-leg leg press, with the high frequency group (HF) performing 2 x 2 minutes of eccentric leg press and the low frequency group (LF) performing 2 x 3 minutes. To match training volume between groups, the low frequency group performed a warm-up and cool down for each set.

Before, midway, and after the intervention, subjects performed three vertical jumps and a maximal six second single leg eccentric leg press.

Soreness and rate of perceived exertion (RPE) were recorded after each session.

Both groups significantly improved maximal eccentric strength with no significant difference between groups even though there was a slight trend in favour of HF (HF = 36.8%; LF = 27.4%).

There was a stronger trend (p = 0.06) for HF (26.2%) to reach higher strength gains at two weeks than LF (13.8%).

Both groups had similar improvements in vertical jump, with the HF group having lower RPE and soreness scores compared to LF

P ractical Takeaways

While not statistically significant, the trend of HF eccentric training leading to greater strength gains, and the fact that all HF subjects had greater strength improvements than LF subjects, a HF approach may have real world application. Specifically with the idea of microdosing, which is how I see this idea fitting within athletic development.

After a cycle of getting an athlete back to training, HF eccentric exercise can be a way to make structural adaptations (e.g., increasing lengthtension relationship and stiffness) without soreness and high subjective training loads so the athlete can get the most from their technical training. It could be something as simple as:

A1) 2 up, 1 down leg press 2 x 5-6 per leg

B1) Rest of gym session

Spending the initial stages of pre-season prioritising eccentric training is essentially a triphasic training approach by Cal Dietz and can be a great way to set up the rest of your pre-season.

wish these studies would use highly trained lifters such as national-level powerlifters and weightlifters. The athletes in this study were general population subjects who would always see large gains with such intense stimulus. But would highly trained athletes, who are capable of tapping into very high outputs, be able to handle a HF approach even if volume is relatively low per session? I believe the results may look much different in this case, making a HF eccentric training approach potentially less effective as an athlete progresses in strength and training age.

“For the general population, eccentric training can be a way to make quick strength gains but is difficult to implement due to complexity, lack of safety, and extreme muscle soreness (e.g., accentuated eccentric squats). A high frequency approach on a leg press machine could be a way for the general population to incorporate eccentric training as there is less soreness.

“In my opinion, general population clients don’t need this intense stimulus and it should be saved for later in their strength development if needed.”

C an spe e d be dev e lo pe d thro ugh so cce r- spe cific training alo ne?

Identifying performance measurements (e.g. sprint performance) helps to identify player readiness, therefore minimising fatigue and guiding training prescription across a competitive season.

Research shows that athletes can be more impactful on the pitch when they can accelerate quickly and have potential to achieve maximum relative velocities (see HERE). Through accurate measurement of velocity-time or displacement data during a maximal sprint (see HERE) coaches are able to examine a comprehensive sprint force-velocity (Fv) profile, determining maximal force, velocity, and power through linear regression.

It is not well understood the changes that a player’s sprint Fv profile goes through during a competitive season, and understanding these changes could aid in enhanced readiness later in the season, improving interventions (training prescription or rest), mitigating injury and improving player performance.

This study attempted to highlight the potential fluctuations in a sprint Fv profile that occur for an elite male soccer player across a full calendar year

Twenty-one male soccer players (age 26.9±3.1) on a professional Spanish soccer team had their 40-m sprint performance assessed a total of six times- beginning in the September 2015 preseason period, every two months following (November, January, March, May, and August) through the season and into the subsequent preseason. These assessments were done at least 48-hr after a friendly (preseason) or competitive match; the fastest of two 40-m sprints was used for analysis.

It is important to note that no additional sprint training was performed beyond soccer-specific practice and competition.

Using a validated method to analyse an athlete’s 40-m sprint to create a Fv profile, calculated metrics included maximal force, -velocity, -power, Fv slope, decrease in the ratio of horizontal-to-resultant force, and maximal ratio of horizontal-to-resultant force (see These HERE). variables were examined for variability over the year for better understanding on how to appropriately manage an athlete s speed qualities.

Practical Takeaways

Having a meaningful performance metric (e.g. 10-m sprint time), and measuring that on a weekly basis, helps to keep a pulse on an athlete’s state of readiness, guiding potential training modifications (e.g. reducing practice time). An assessment like this can be done at the end of a dynamic warm-up, before a high-intensity practice session.

§ Maximal force capability is a critical quality, as an imbalance or weakness is related to increased injury risk, especially in females. Coaches should lean on movements or weight room exercises that they are already performing as assessments and monitoring tools to highlight readiness (e.g. countermovement jump height, broad jump distance, isometric mid-thigh pull, or squat strength).

This research highlights the importance of incorporating specific maximal speed into in-season training, as this quality showed no improvement across the season.

§ To develop maximal sprint ability in-season, approach the inclusion of these 40-60-m sprints with a minimal effective dose mindset, doing as little as 1-2 repetitions per week at the beginning of the most intense practice session of the week, to where athletes are fully recovered from a previous competition (48-72-hr post) and furthest out from the next competition (48-72-hr preceding).

§ Only doing 1-2 repetitions doesn’t seem like much, but doing something has more potential than doing nothing, which all of the athletes in this study experienced. Think of the specific adaptations to imposed demands principle (see HERE).

Prescribing 10-m flying sprints (which would be a gradual build-up, providing as much space as desired (>40-m), and maintaining top speed for 10m) can be another way that reduces the stress of an intense 30-m acceleration. Keeping the dosage to minimal levels (1-2 repetitions) still has potential here as well (see HERE).

§ Ensuring exposure to these maximal speeds is also

beneficial for mitigating hamstring injuries (see HERE)

§ Coaches should prescribe specific volumes of jumping, accelerations, full-speed sprints, and change of direction drills (e.g. 505 agility test) across the week in addition to sport-specific practice, scrimmage, or competitions. This will help to isolate and improve these qualities, so the athlete is more practiced and prepared to incorporate these high-intensity actions during sport-specific activity These can be incorporated into warmups or done during other sport-specific drills during training sessions.

Sled pushing of any load (light to heavy) has shown to have great potential for increasing acceleration ability (see ). Consider incorporating 3-4 HERE maximal sled pushes for a length of 20-m, with 3min rest between repetitions, 1-2 times per week, using a load that causes a 50-75% loss in speed relative to an athlete s maximal unresisted 20-m sprint.

Ÿ This is a specific form of resistance training but incorporating a general form of resistance training using squats, lunges, nordic hamstring curls and hinges at least once per week, performing two sets of 6-10 repetitions for each exercise, can be plenty to maintain strength and maximal force sprinting capacity

Given that performance ability initially maintained, but declined later in the season, this could very well be a case of accumulated fatigue and lack of recovery during a lengthy competitive period. Coaches may need to modify their initial in-season routine in the latter half of the season, reducing practice durations, increasing rest days, and reinforcing supportive recovery habits (e.g. adequate sleep and daily calorie intake, favouring carbohydrates and protein).

The sprint Fv profile measures that showed meaningful changes across the year were maximal force, maximal power, and maximal ratio of horizontal-to-resultant force.

§ These variables peaked in the middle of the competitive season (January and March 2016) and were lowest at the initial preseason test (Sept 2015) and the end of the competition period (May 2016).

§ Measuring 10-m acceleration times followed the same trends as these three sprint Fv profile variables.

Maximal velocity and decrease in the ratio of horizontal-to-resultant force remained constant throughout the year

“An athlete s readiness is a daily measurement that varies based on a biopsychosocial response to their environment. For an in-season athlete, training load and recovery must steadily remain in balance to maximise performance potential and keep injury risk as low as possible. Coaches can better understand the state of this balance (readiness) through consistent measurement and monitoring of performance metrics such as an athlete s acceleration or sprinting ability. Especially for a quality that is so critical to on-field success - sprinting is the most common action that leads to a goal on the pitch (see HERE).

“Knowing that speed is so important to on-field performance and success, as well as learning from this study that only performing soccerspecific training and competition will not adequately develop or improve speed across a season, incorporating sprint work into an inseason microcycle is vital and takes strategic planning to provide the appropriate stimulus at the correct time and in adequate amounts. Don’t leave athletes ill-prepared as championship opportunities present themselves late in the season. The team that is most successful is the one that can best manage and develop players across the entirety of the season.”

Te c hno lo gy & M o nito ring

Is te nsio m yo graphy re ally a re liable to o l to m e asure m uscle functio n?

Tensiomyography (TMG) is a measurement tool that provides feedback on an athlete s muscle function, specifically assessing the displacement and speed of an involuntary (electrically stimulated) isometric muscle contraction using a sensor applied to muscle superficially (see This HERE). measurement can be used to assess muscle symmetry, fatigue, or performance in athletes who are training, helping coaches to understand the tissue s response to stimulus (e.g. sprinting, rehabbing, strength training).

Through this insight, coaches can better prescribe load and remove the uncertainty around neuromuscular readiness; ultimately improving the efficacy of training and reducing injury risk.

The use of TMG to measure muscle function has consistently shown promise and examining an accumulation of research can better confirm the metrics and procedures in providing valid and reliable measures. This study was a systematic review from over 30 years of research, assessing the dependability of TMG measurements and identifying specific strategies to provide the most consistent and trustworthy results.

Peer-reviewed scientific literature published from January 1990 to September 2021 was explored for studies on (TMG), specifically focused on “reliability, reproducibility, and/or measurement error.” For a study to be included, it needed to involve subjects who had no significant musculoskeletal conditions, while the measurement process had to be thoroughly described, as well as the specific metrics and methods for assessing reliability outlined for analysis.

After a thorough quality assessment, a total of 16 articles, involving a total of 356 subjects (7.56% female) were eligible for review The reliability of TMG metrics (displacement (Dm), contraction time (Tc), delay time (Td), contraction velocity (Vc), sustain time (Ts), and half-relaxation time (Tr), (see was HERE) performed within subject, between subjects, days, users, as well as the specific protocols used.

The data from all of these studies was examined statistically in an effort to determine measurement reliability and inform practitioners of best-practice when implementing a TMG assessment.

Practical Takeaways

A TMG measure can be used as an assessment tool before a workout to guide training based on muscle function.

§ If a specific muscle is reading loose (large Dm), loading that specific tissue with targeted contractions (e.g. high speed movement, yielding isometric, or heavier eccentric tension) can help improve muscle stiffness and tone. For example, if hamstrings have a high Dm, sprinting, prone isometric leg curls, or stiff-legged deadlifts would be options.

§ If a muscle is reading tight (small Dm), practitioners can use specific massage techniques to reduce the amount of tension within a muscle and improve the suppleness, as well as avoid any intense (high-force or -velocity) contractions to that given musculature.

§ If a specific muscle is contracting slowly (high Tc), based on comparison with Dm, this may suggest fatigue or detraining. Coaches should consider the previous day’s training, possibly limiting load (intensity) or movements for that given musculature. If training has been minimal in the previous 48-72 hours, this would suggest the muscle needs activation, and coaches should ensure a thorough warm-up as well as targeted isometric exercises to ensure the muscle is functioning properly Then, if logistics allow, performing the TMG again after the warm-up to provide feedback on the efficacy of the exercise in improving muscle function and readiness.

A TMG measure of both left and right sides can help identify asymmetries. Practitioners can use this to ensure one limb is not more fatigued than another. Pairing this with a jump analysis from a dual forceplate, or a more conventional single leg jump distance can help guide training based on the performance and how to improve (train or rest).

A TMG measure is a gauge of muscle readiness and provides practitioners with an objective measure based on recovery-state and load-response. This is helpful when returning from injury or identifying recovery, having a reliable measure to note fatigue or adaptive response, helping to suggest readiness to receive specific loads based on the contractile properties. Leaning on this information can help provide certainty to the 7-14 day window that follows many hamstring injuries, taking the guesswork and emotion out of an athlete’s progressive return to training.

A TMG measure can be taken post-workout to provide feedback on whether the tissue had a response to the session and achieved an overload of work. This can help to guide the efficacy of exercises as well as the volumes of a session. In the off-season, coaches would want to see a response that suggests fatigue, but in-season coaches may want to see as minimal of a response as possible to not create soreness or undue fatigue.

A TMG measure can be taken post-workout to provide feedback on whether the tissue had a response to the session and achieved an overload of work. This can help to guide the efficacy of exercises as well as the volumes of a session. In the off-season, coaches would want to see a response that suggests fatigue, but in-season coaches may want to see as minimal of a response as possible to not create soreness or undue fatigue.

Consistent evidence that TMG provides a reliable assessment of skeletal muscle function in healthy individuals.

Contraction Time (Tc), Dm, and Td were the most reliable metrics.

Half-relaxation time (Tr) was the least reliable metric. Distance between electrodes when placed at the origin and insertion of the muscle ranged from 3 to 10-cm. Using a consistent joint angle, allowing the muscle to be relaxed (e.g. knee flexion 30°), improves reliability

“Given the results of this study, the TMG is a proven tool that can assist coaches in identifying the readiness of an athlete, specifically at the neuromuscular level, examining specific superficial muscles. Many times, when injuries occur, the reconditioning process can become impatient or ill-advised, leading to a recurrence of injury and a cyclical pattern of disappointment and despair TMG removes the emotion from an injury and objectively measures muscle function. With this information, coaches can confidently pair an athlete’s subjective report of feeling good and eager to return with a reliable measure of muscle contractile properties.

“Conversely, TMG can be used as an inseason monitoring tool to keep athletes performing optimally throughout by guiding high-intensity sessions that carry a greater risk of injury. Coaches can use a TMG measure prior to a session to help direct readiness to sprint at maximal velocity Training is necessary, especially high stimulus activities (e.g. sprinting lifting) but the timing of that stimulus matters just as well. It is important to know if an athlete is ready to train or needs more time to recover.”

W hat m o nito ring strate gie s are m o st re liable in e lite yo uth so cce r?

A primary objective in employing monitoring strategies with athletes is to identify fatigue (decreased readiness) that would potentially put the athlete at an increased risk of injury or poor performance, lowering the chance of individual/team success. Options are endless in this space, from subjective wellness questionnaires that inquire about fatigue, soreness, mood, sleep, and soreness to wearable technology, such as the use of micro-electro-mechanical systems (MEMS) equipped with triaxial accelerometers that quantify movement in all planes (e.g. speed, acceleration, deceleration, distance).

Advancements in technology are making measurements more accurate and sensitive, providing useful objective insight and feedback for an athlete s training response. There is uncertainty however around the dependability of wellness questionnaires, especially with the variability in options on what to ask. Ultimately, coaches want to implement monitoring strategies that are time-efficient and effective (reliable in noting change). This study set out to assess test-retest reliability for a subjective wellness questionnaire, a series of jump tests (countermovement (CMJ), squat jump (SJ), and drop jump (DJ)), as well as a movement assessment during a submaximal shuttle run using tri-axial accelerometers in youth soccer players; with specific emphasis on minimising the shuttle run test duration while maintaining adequate reliability

Seventeen soccer players (age 17.4±0.5) participated in two testing sessions that were seven days apart. Athletes were familiarised with the various assessments before testing and both testing windows were preceded by two days of rest to limit interference from training occurring at the start of the 2015-16 season in October

A subjective wellness questionnaire was sent to each athlete (using an app via phone) in the morning and completed privately. Questions were scored on a 5-point Likert scale (1very poor, 5-very good), inquiring about fatigue, sleep quality, muscle soreness, stress, and mood, as well as a summated ‘total wellness score.

Jump performance was assessed using a timing system, three different tests (CMJ, SJ, and DJ) all allowing for four attempts each, hands were on hips across all jumps, the SJ was held for four seconds prior to take-off, and the DJ was done off a 30cm box. Jump height was the target metric for all jumps, as well as contact time and reactive strength index for the DJ

Lastly, a submaximal shuttle run was performed while athletes wore a tri-axial accelerometer, quantifying PlayerLoad (PL) based on rates of change in each of the three planes of motion. The shuttle run was a continuous 20m assessment that lasted five minutes - the first minute was discarded and used as an acclimation phase, and the following minutes were analysed.

The primary object was to assess test-retest reliability for each metric gathered, as well as examination of minimal detectable change across the tests.

Practical Takeaways

Based on the results from this study, coaches could implement a 3-min submaximal shuttle run (continuously running back and forth across a 20-m distance), where after a warm-up, players used the first minute to stabilise work rate, and the final two minutes were used to assess performance.

§ If tri-axial accelerometers are worn, coaches would look for changes in PL greater than 1.4 arbitrary units to denote potential fatigue

§ If wearing heart rate monitors, examining heart rate response following the test could be an avenue to explore to identify fatigue (see HERE).

§ If no technology is available to measure shuttle run performance, coaches can pair the amount of distance covered during the test with a subjective rating of exertion (see ) to denote changes in HERE performance and potential indication of fatigue.

Measuring jump performance prior to the start of a session can be a way to increase energy, effort, and focus by holding athletes accountable to their efforts and promote competition between teammates. Perform these jump tests after a thorough warm-up on a day where high-intensity (e.g. full speed, sprinting activity) is planned.

§ Based on the results in this study, CMJ height must be at least 2.5cm different to be a significant change and SJ height had a minimal detectable change value of 2.3cm.

§ If technology allows to assess contact time and reactive strength index when performing a DJ, changes as small as 0.01-sec and 0.16-m∙s-1 respectively are needed to suggest significant improvement or decrement (fatigue).

§ Although it is time intensive, and not necessaril practical in a large team setting, DJ can be reliably measured using multiple smart phone applications (see and ) if working in an individual or HERE HERE small-group setting.

Although the subjective wellness questionnaire was not reliable between tests in noting fatigue, it still has potential to provide baseline insight that could encourage follow-up conversations related to poor indications of sleep, soreness, fatigue, or mood. These are complex variables and are influenced by more than simply training (e.g. other life stressors, relationships, etc.) and inquiring about them on a consistent basis can help to keep a pulse on an athlete s mental and physical well-being.

§ Specifically, if an athlete notes poor sleep, coaches can inquire why the athlete experienced that and provide suggestions for how to better manage stress, promote a consistent pre-sleep routine or environment, or adjust nutrition (e.g. increasing calories, specifically carbohydrates or tryptophan rich foods) to encourage restful sleep (see HERE).

§ Avoid watering down the measurements by examining them as a summated measure, and possibly increase the Likert scale to be as high as 1-10 to increase the recognition of change.

Based on tri-axial accelerometer data, the only metric that fell below the acceptable range for reliability was the anterior-posterior PL value (noting rate of change in acceleration, (see ), where all other PL values HERE during the submaximal shuttle run proved reliable between tests.

The submaximal shuttle run could be performed for three minutes (1-min stabilisation plus 2-min assessment) and maintain consistent reliability

DJ height was the only jump metric that did not meet reliability standards, whereas all other jump measurements (CMJ and SJ height, DJ contact time, and DJ reactive strength index) were within the threshold for reliability

The wellness questionnaire showed poor test-retest reliability and internal consistency, deeming it unable to note changes in fatigue.

“As performance staff, the objective is to maximise readiness for competition and necessary training sessions where demands are going to be high. This helps to reduce the risk of injury, maximising team success across a season, and provides coaches an accurate opportunity to assess performance ability on the field. This study does a good job in outlining a range of monitoring metrics that ultimately help identify meaningful and reliable change, potentially helping coaches identify fatigue. However, the study only compared data across a week and the reliability, or lack thereof, with assessments goes to show the variance and potential multifactorial influences that change on a weekly basis for an athlete. Reliability is important for measurements, but fatigue is incredibly complex and accuracy is the goal. What I’ve found is that athletes will do their best to mask fatigue, and this seemingly was accomplished with accelerometer and shuttle run data (reliable measures), but unreliable variability was seen with jump performance and questionnaire data. Could these tests be more valid in assessing fatigue and readiness fluctuations?

“Ultimately, coaches must identify ways to accurately assess readiness prior to training, implementing strategies that seamlessly flow into the training or competition environment, the intention is to be supportive and encouraging of the athlete, rather than constantly probing and stressing them through evaluations. Coaches must be sure to explain why assessments or questionnaires are implemented, understanding that consistency and follow-up are vital for these tools to be successful. Monitoring is simply another piece to the training plan that must be marketed and persuaded to the athletes, so they appreciate how it is helpful to the overall progress and process of team success."

Fatigue & Re cove ry

This month ’ s top research on fatigue and recovery

H OW D O S L E E P PAT T E RN S C O M

BE T W E E N E L IT E AT H L E T E S A N

G E N E RA L P O P U L AT IO N ?

E VA LUAT IO N O F LOW E R L IM B A

IN S O C C E R P L AYE RS W IT H A N D

RE C O N ST RU C T IO N S

H ow do sle e p patte rns co m pare betwe e n e lite athlete s and the ge ne ral po pulatio n?

Elite athletes are known to have suboptimal habitual sleep patterns, often due to situational challenges to sleep including travel demands, practice and competition schedules within season. The present study compared the challenges that athletes face with sleeping as compared to agematched subjects in the general population. With this, recovery and quality of sleep were studied to determine any correlation between the location of where sleep took place along with days surrounding competitions.

41 female participants were studied; 11 elite basketball players, 10 elite soccer players and 20 age and sex matched nonathletic controls. Sleep and recovery were monitored over four 7-day periods throughout preseason and competition season for the athletes. The control participants were studied over four 7-day periods as well.

Data collected was taken from the athlete s subjective sleep diary along with a wearable activity monitor to determine when participants were awake and asleep. The sleep diary took information about post-sleep fatigue, sleep quality and perceptual recovery using the Perceived Recovery Status Scale.

The following variables were studied from the activity monitor along with the diary:

Ÿ Bedtime: time when participants attempted to sleep

Ÿ Wake time: time when participants got out of bed

Ÿ Total sleep time: amount of time spent asleep

Ÿ Sleep efficiency: percentage of time asleep while in bed

Ÿ Wake after sleep onset: time spent awake after the onset of sleeping

Ÿ Sleep onset latency: time between bedtime and sleep onset

Ÿ Postsleep fatigue: self rating from fully alert to completely exhausted

Ÿ Sleep quality: self rating from very good to very poor

Ÿ Perceived recovery status: self rating from very poorly recovered to very well recovered

Results showed that both the basketball and soccer players scored worse with the following variables when compared to the control group: wake after sleep onset, sleep efficiency, sleep onset latency, post sleep fatigue and recovery

With competition season, the players had less average sleep time the night before an earlier morning practice. Both groups of athletes had longer sleep durations following home games compared with away games.

Along with this, the athletes slept least the day of the game and the most the day after the game.

§ The present study shows how the elite female athletes suffer from suboptimal sleep patterns when compared to age-matched controls. Some causes contributing to this include competition/practice schedules, unfamiliar sleep locations and stress related to competition.

§ Elite female athletes would benefit from in-season sleep screening and medical assessment to individualise their schedules around competition and improve sleep habits. With this, coaches and trainers can better adapt to this issue by scheduling later practices the day of and after competitions.

§ When able to, teams should go home directly following away games to allow players to sleep in a familiar setting.

§ Coaches and trainers should also encourage napping during the day and protect sleep schedules around competition periods.

§ Avoiding early morning practices and meetings are also good strategies to improve the likelihood of improved sleep.

“Sleep is vital to an athlete's success and is too often pushed aside in season for preparation for competition.

“Coaches can take it upon themselves to do right by their players by adjusting schedules around competition to prioritise sleep. Scheduling later-morning practices, and traveling home following away matches are some of the ways to improve the likelihood of better sleep.

“Continuous monitoring of an athlete's sleep is important to track throughout the season as it can be a strong indicator of performance. Some examples to try may include keeping sleep journals and having weekly check ins with athletes regarding their progress”

E valuatio n of lowe r lim b asy m m etrie s in so cce r play e rs with and witho ut A C L re co nstructio ns

Anterior cruciate ligament (ACL) injuries are common and devastating injuries seen in the athletic population, which often leads to ACL reconstruction (ACLR). Even after reconstruction, there is a high risk of re -injury, where this article states that 20%-25% of athletes will experience a contralateral tear or graft rupture mainly due to persistent deficits seen in the surgical limb well after return to sport.

The purpose of this study was to examine and compare kinetic parameters of performance during the countermovement jump (CMJ) in soccer players with and without ACLR.

Three hundred seventy professional soccer players from were divided into four groups:

1. < 6 months post-ACLR

2. 6-9 months post-ACLR

3. >9 months post-ACLR

4. Healthy matched controls

Participants performed three trials of a CMJ on a force plate system with a 30 second rest period between jumps. Phases of the jump were divided into an eccentric phase (time from initiation of the jump to zero center of mass velocity) and a concentric phase (from zero center of mass velocity to the instant of take-off).

Jump height and phases of the jump were used for analysis.

P ractical Takeaways

After ACLR, athletes appear to develop a compensatory strategy to increase the duration of the eccentric phase of the CMJ

Rehab clinicians working with athletes post-ACLR should incorporate a vertical jump component in a return-to-sport testing battery like the CMJ, as horizontal jumps require lower contribution from the knee joint than vertical tasks.

Rehab clinicians working with athletes post-ACLR should include training to target maximal strength and rate of force development, as deficits are still seen at return-to-sport and may lead to an increased risk for re-injury

Between-limb deficits in key parameters of eccentric and concentric loading are present in athletes post ACLR >9 months, suggesting that full reconditioning and performance at optimal levels most likely takes longer periods of recovery

Jump height increased linearly with greater time postsurgery, however no differences were observed between athletes in the 6-to-9 month group and >9 month group, with performance remaining reduced compared to healthy controls.

Concentric peak force, eccentric deceleration rate of force development, and peak landing were lower on the involved limb for the ACLR groups when compared with the dominant limb of matched controls.

Concentric impulse was also lower on the involved limb in the 6-to-9 month ACLR group compared with non-injured athletes.

Except for eccentric mean force, a trend was evident of reduced asymmetry in athletes who were further away from surgery

Up to six months, lower jump height and heightened concentric impulse asymmetry most accurately differentiated athletes post-ACLR and matched controls, and was still evident greater than nine months post-ACLR.

“Although a criterion-based approach for ACL rehab is superior to a time-based approach, it is evident that a minimum of nine months is recommended for ACL rehab. This is due to the decreased risk of injury from delaying return-to-sport from six months to nine months. However, performance deficits are still present on the surgical limb well after nine months which include off-loading strategies of the surgical limb as well as persistent quadricep weakness.

“It is important that rehab clinicians are precise with their exercise selection and prescription, with emphasis on progressive overload to fully prepare athletes for the demands of their sport but also appreciating the new ACL will continue to remodel over time. Clinically, I like to utilise the ‘My Jump 2’ app in my return-to-sport battery to assess athletes’ CMJ This is a useful tool for clinicians who don’t have access to a force plate and can provide objective data in determining overall readiness.”

Yo uth D eve lo pm e nt

This month ’ s top research on youth development.

C A N A LT E RIN G T H E E XE RC IS E O

T RA IN IN G VO LU M E A F F E C T P E R

A N D IN T E RL IM B A SYM M E T RIE S I AT H L E T E S ?

M A N A G IN G A N D C OA C H IN G YO U T H S : ST RAT E G IE S TO S U P P O RT S M A RT

T RA IN IN G

D O E S ST RE N GT H E Q UA L S P E E D ? A N IN V E ST IG AT IO N O F T H E RE L AT IO N S H IP BE T W E E N T RA IN IN G IN YO U T H S

C an alte ring the exe rcise o rde r and training vo lum e affe ct pe rfo rm ance and inte rlim b asy m m etrie s in yo ung athlete s?

In youth soccer, players are expected to perform numerous sprints, decelerations, jumps and kicks which are not only performed in a multidirectional manner/plane of motion, but are also performed in a unilateral fashion (e.g. predominantly on one leg). While imbalances do exist, excessive imbalances (>15% interlimb asymmetries, ) can cause injury. In HERE addition, these imbalances can force athletes into movement patterns that aren’t optimal or advantageous to a sports-specific situation. For example, if an individual should move left laterally but has a preference to always turn to their right, then this could expose them to mistakes or injury within a game.

Therefore, the aim of the current study was to investigate the role of unilateral combined training on performance testing.

Forty-seven young male soccer players (15yrs) voluntarily took part in this study over a 10-week period. Data was collected for several performance tests, including a lateral squat test, single-leg and single-leg lateral hop test, triple hop test, bilateral and unilateral countermovement jump and a 180⁰ change of direction test. From these tests, interlimb asymmetries were calculated using the following equation: 100/Max Value (right and left) × Min Value (right and left) x − 1 + 100 (1) (HERE).

Once collected, the players were randomly assigned into three training intervention groups:

1. Group 1 – Stronger volume, weaker leg group (n=14)

2. Group 2 – Stronger volume, stronger leg group (n=15)

3. Group 3 – Double volume, weaker leg group (n=16)

All groups performed the same three exercises (lateral squat on vibration-platform, lateral squat and a unilateral side hop). Performance tests were collected pre- and post-training intervention to assess for reductions, indicative of improvement in interlimbasymmetry

P ractical Takeaways

From this study, altering exercise order (i.e. on the weaker leg first), but not training volume had a significant effect on reducing inter-limb asymmetry

As a coach, finding strategies that reduce imbalances is therefore important. Practically, these may include single-leg Romanian deadlifts, rearfoot elevated split squats, and single-leg step-ups at bodyweight. These are excellent introductory exercises and can be seen in the attached video. The single-leg step-up can easily be turned into a ‘step down’, which would be a form of pistol squat. This is an excellent exercise for eccentric control around the knee, which is particularly important for young females around peak height velocity (HERE). An excellent video stating the progressions for this movement can be seen HERE.

When programming the above exercises, developing your coaching eye is essential. When teaching movement patterns, an understanding of the key performance criteria must be taught and understood by the athlete. For example, in a singleleg Romanian deadlift, a list of cues can be seen in the attached article. These state the key movements (e.g. focusing your eyes in front of you, avoid rounding your back, and lower your back in a straight, vertical line). However, children don’t always understand these terms/know what they ‘feel’ like. In practice, getting athletes to mirror each other, match tempo, and draw on the correct

coaching cues is essential. The use of a dowel as an example can be useful to maintain proper head, thoracicspine and hip alignment Once these movements can (HERE). be maintained for 12-15 repetitions, I would instantly look to load this using a kettlebell, dumbbell then barbell, in this order

When interpreting this research, it is important to think about how this may impact other areas of training. For example, in Nathan Kiely’s video on the lateral shuffle it could be (HERE), suggested that starting this drill from the weaker or nondominant leg could have a similar effect. The phenomenon responsible for this is that the limb is less affected by central and peripheral fatigue, allowing an athlete over time to reduce this imbalance by letting one limb “catch-up” with the other

The main finding of this study is that single-leg hop, triple hop, and bilateral countermovement jump improvements were achieved in group 1 (stronger volume on the weaker leg) and group 3 (double volume weaker leg).

Between-group analysis found better results were achieved in group 1 and 3 when compared to group 2 (stronger volume, stronger leg). In addition, the double volume on the weaker leg group (3) achieved better improvements in the countermovement jump in comparison to groups 1 and 2.

Finally, groups that started with the weaker leg seemed to achieve a greater number of significant changes, including reduced asymmetry, than those whose intervention started on the stronger leg. However, performing a double volume programme on the weaker leg didn’t guarantee any further performance benefits when compared to groups 1 and 2.

“This study is a really welcome addition that will be making its way into my practice. Simply programming athletes to start an exercise on their weaker leg first should make an impact over a 10-week period. As a coach, I am now starting to think about all of the other activities I do with my athletes, such as change of direction from a lateral position, split sprint starts, and plyometrics which may also benefit from the same concept (i.e. starting on the weaker leg). However, it is important to note that these have not yet been investigated, but may be interesting to experiment with.

“In the attached podcast, Chris Bishop discusses the role of asymmetry in youth with particular reference to soccer players. Given that a majority of soccer movements have a large unilateral component, Chris suggests targeted interventions, such as those in the practical takeaway section, are really important to program two to three times a week.

“In addition, stage of maturation has previously been found to have no impact on between-limb differences, but a majority of imbalances are developed in early childhood. Therefore, coaches should start to address limb differences prior to peak height velocity (HERE). These could be introduced during warm-up or balance games such as musical floor spots or single-leg squat patterns on a bench (HERE).”

M anaging and co aching yo uths: Strate gie s to suppo rt smart training

Professional soccer clubs invest a significant amount of money in the development of future talent, with the hope that as many youths as possible will reach an elite level of performance. Underpinning a successful transition into this career requires some luck, some talent, and an ability to be robust enough to perform on a weekly basis.

However, youth have many physiological adaptations working both with and against them. For example, maturation status, growth-related issues, and highly specialised practices can lead to many players getting injured. In addition, it is generally acknowledged that many barriers exist when looking to understand best practice.

Therefore, the aim of this review is to provide coaches with an overview of the strengths and weaknesses associated with the Elite Player Performance Plan (EPPP).

As this was a review, there was no formal methodology However, the authors performed a review of all relevant and important research within this topic.

P ractical Takeaways

Programs should strive to ensure players are wellrounded, both as individuals and as athletes. The effective management of this is essential, especially given the risk of early specialisation within this study For example, in the attached article, Mosher and colleagues discuss the risk of early sports specialisation, making a potent argument that both muscular imbalances and a lack of rounded training make for an injury conundrum. Here, coaches and parents should draw attention to the research on longterm athletic development by being secure in the knowledge that a late-specialisation/diversification approach does not hinder elite sports (HERE) participation, allows for wider sports skill development, and increases the athletes’ opportunity to engage in varied motor and cognitive skills.

To prevent injury in youth, eccentric training has previously been shown to be both ethical and effective (HERE). Eccentric training is fantastic for youth, as they are less likely to suffer from delayed onset muscle soreness, fatigue, and report lower session rate of perceived exertion than adults. In one study that I supported the Nordic Hamstring Exercise was (HERE), found to be a great introductory exercise to young football players spanning across varied stages of maturation. This was not only a fantastic way to develop eccentric strength, but could easily be made harder by adding volume (e.g. increasing repetitions), or intensity (e.g. adding a plate to the movement). I would recommend you start with two sets of three repetitions as a starting point for this exercise. Other exercises that can overload the eccentric portion of the muscle include the eccentric push-up and (HERE)

a kettlebell RDL and go some way (HERE) towards building a good program for soccer players. These may require greater capacity, as the load is shared over various muscle groups (i.e. 3-4 sets of 8-12 repetitions).

Another method to prevent injury and specialisation in youth is the introduction of integrative neuromuscular training (INT). INT training incorporates general (e.g. fundamental movements) and specific strength and conditioning tasks (e.g. resistance training, balance work and plyometrics) to improve injury resilience. These movements can be soccerspecific, such as those in the attached video, but can also be tailored around other sports to prevent some of the issues that come with excessive soccer participation. For example, the risk of Osgood Schlatter’s disease and maladaptive morphology is far higher in highly-specialised academy players due to the repeated nature of the sport (i.e. kicking) (HERE). Incorporating catching, throwing and balance may serve to keep a child well-rounded as an athlete.

Finally, in order to understand training load, sports scientists/coaches must make notable attempts to monitor and track individuals over a longitudinal basis. The collection of maturational data four times a year is a great start, as it will highlight sensitive periods for training Secondly, (HERE). daily collection of RPE data can provide ‘readiness’ information for coaches The most important thing (HERE). here is that coaches do adjust their sessions for individuals who are reporting fatigue. Finally, performance scores such as countermovement jumps, sprint testing, and Nordic hamstring strength provide invaluable evidence that your programme is actually developing stronger, and thus more robust athletes for performance.

Talent development pathways in soccer often lead to early specialisation. Individuals participating in the EPPP may be exposed to 20-50% more coaching per-year from the age of 5-16. Early specialisation is common in football due to the pressure placed on youth by parents, coaches, and the expectancy placed on youth from a young age. These types of pathways can increase injury likelihood. This is due to an increased demand on the musculoskeletal system. Chronic overuse injuries, resulting in time away from competing or training can account for 40% of all injuries in youth. Moreover, 20% of these are classed as severe, which is defined as missing over four-weeks of training.

Monitoring and then altering practice for children with a biological difference of 5-6 years in one chronological age bracket can be and is still a challenge. Refining this process is essential so those who benefit from increased performance as a result of muscular and anaerobic maturation are not always selected first in the talent identification process. This would ensure that less talented players slip through the talent identification net as a result of developing later

“From this study, practitioners must utilise the quality information to support their practice. In my opinion, supporting a young athlete must involve all members of staff involved with the athlete, the athlete themselves, and their parents. The involvement of all three develops trust in the process, whilst allowing the coaching staff to manage expectations and training load more adequately When all three parties are involved, the expectancies can therefore be agreed and adhered to.

“In the attached podcast, Skye Eddy, who is the founder of the ‘Soccer Parenting Association believes (HERE), that parental involvement is vital, as they are looking after the athlete for a majority of the day Skye further adds that in order for players to push on professionally, parents need to understand the hard work required to make it at a high level.

“To support a player physically, coaches must look to develop robustness through regularly delivered and monitored training. This is particularly important with youth, when disparities in maturation status and growth place players at risk of injury To support this, coaches must look to monitor maturation through the methods mentioned in the practical takeaways section. In addition, coaches should look to develop holistic qualities such as resilience, organisational and communication skills to ensure that players are wellrounded for other environments, such as school and future employment.”

D o e s stre ngth e qual spe e d? A n inv e stigatio n of the re latio nship betwe e n training in yo uths

Sprinting is one of the key parameters measured in professional soccer and requires an expression of force in both vertical and horizontal vectors.

Several studies have confirmed there is a strong correlation between strength and sprint speed (HERE) and indicating that athletes who can sprint fast (HERE), are also stronger than their peers. Previously, decreases in strength capability and force production have been seen in the off-season (HERE).

Therefore, the aim of this study is to evaluate the possible correlation between strength and speed in the preseason in youth soccer players.

Twenty soccer players (17yrs) at one Spanish professional club were recruited for this study. Inclusion criteria required the participants to be absent of injury for at least five seasons.

To evaluate the aims of this study, the authors used three tests. Explosive strength was measured using the squat jump. Explosive-elastic strength was measured using the Countermovement Jump with and without arm use. Finally, speed was assessed over 10, 20 and 30m.

These tests were completed at the start of the preseason after a thorough warm-up lasting 10 minutes. To verify the correlation between the results, Pearson’s correlation (Pearson r) was used.

Þ

Practical Takeaways

From this study, the authors have highlighted that strength training during the off-season can help to maintain high levels of speed for the successive season. In addition, other studies have found the off-season typically has detrimental effects on body composition and physical fitness (HERE). Therefore, youth coaches are at a difficult crossroads where we must try to balance out sport exposure to prevent early specialisation whilst actively encouraging youth to (HERE), engage in additional training to raise performance for the next season. Therefore, coaches could employ these strategies:

1. Once or twice a week, youth should engage in intense activities lasting between 5-10s which are maximal in nature and can be repeated 4-5 times. Instead of going down the typical route of sprint training, youth could be encouraged to perform maximal efforts in a swimming pool, on a bike, or on a hike. Such alternatives shift the focus from football to developing external experiences which are important for holistic development, whilst driving high anaerobic performance hidden in different tasks. Uphill cycling, for example, has been shown in the attached article to positively enhance breathing frequency and ventilatory rate, leading to improved VO2 performance in youth. Therefore, such training could prevent a loss in ‘fitness’ typically seen in the off-season.

2. A misconception made by many is that bodyweight training may not be sufficient enough to develop true strength. A simple program that can be done from home which will continue to develop/maintain

strength throughout the off-season can be seen in the following text. Bodyweight squats are a fantastic exercise to maintain leg strength. Banded RDL s can be a great (HERE) way to develop a hinge pattern in the off-season, whilst developing lower back and hamstring strength. Adding in some explosive work, such as a lunge catch is an (HERE), excellent method to overload the eccentric component of a landing pattern, which is a common injury in youth footballers. High reps and sets (e.g. 4x8 or 3x12) will offer a good stimulus (HERE).

3. Whilst strength training will do a great job at maintaining force output, stiffness qualities may suffer as a result of the off-season and lack of training. The Rudiment Hop Series by ALTIS is a short injury prevention/maintenance (HERE) program that can be used numerous times throughout a week to develop muscle-tendon unit efficiency. In the attached video, you can see that this takes no longer than five minutes to perform. I would add some extensive plyometrics to this, which are characterised by longer ground contact times such as a broad jump and rotational counter movement jump (HERE).

The main findings of this study were that there was a strong correlation between sprint times and muscle strength measured by the squat and Countermovement Jump.

In addition, the Countermovement Jump with and without arms were found to correlate with strength scores over 10, 20 and 30m, suggesting these may be effective tests to identify speed relationships over short distances.

The squat jump was only found to show a correlation with the 10m sprint distances. However, no statistical relationship was found over 20m and 30m.

“In summary, coaches looking to review their effectiveness in developing short acceleration/sprint performance can use the squat and Countermovement Jump with and without arms to develop a sprint profile of their athletes. The very nature of these tests mimics the fast shift from eccentric to concentric actions as seen in the stretch-shortening cycle which is an underlying sprint mechanism so it is of little (HERE), surprise that this correlation was found. In the attached podcast, Angus Ross, physiologist and strength coach at High Performance Sport New Zealand, explores this relationship to a greater extent, but further, recommends plyometrics and maximal overcoming isometrics as a method to develop stiffness, a quality related to sprint performance. Whilst these are highly effective methods, maximal overcoming isometrics (HERE) require a strong base of strength (>1.5xBW) and technical expertise (e.g. trunk position in relation to lower body) to complete these safely These, with the prior exercises mentioned in the Practical Takeaways section, should give you years of development in a resistance training programme.

“Finally, the sample in this study was relatively small, so future studies should look to increase the sample to numerous teams, but also explore the relationship between season-timing, exposure to training, and access to high quality coaching on speed.”

N utritio n

This month ’ s top research on nutrition

D O E S BE TA- A L A N IN E S U P P L E M E N TAT

T RA N S L AT E TO A N IN C RE A S E IN

P E RF O RM A N C E IN E N D U RA N C E C YC L I

W H O L E BO DY RE S ISTA N C E T RA IN IN G

M AY N OT BE O P T IM A L F O R WO RKIN G

U P A N A P P E T IT E !

S H O U L D S U P P L E M E N TAT IO N IN

F E M A L E F O OT BA L L E RS BE D IF F E RE N T

TO M A L E P L AYE RS ?

D o e s beta- alanine supple m e ntatio n translate to an incre ase in pe rfo rm ance in e ndurance cy cling?

Beta-alanine is a relatively popular supplement within athletic populations. It is a naturally occurring amino acid that is a precursor to carnosine, which itself is an effective intracellular buffer Supplementation of beta-alanine has been previously shown to effectively increase the concentration of carnosine at the muscle and this has been shown to effectively buffer hydrogen ions, reducing the effect of acidosis at the muscle and delaying fatigue. This is detailed within the related article below

These beneficial effects have been observed during exercise activities that are high intensity and of a relatively short duration (0-25 minutes), after supplementation of 4-6g of beta-alanine per day for at least two to four weeks.

The present study looked to investigate the impact beta-alanine supplementation may have on cycling sprints and a 4km time trial within the context of a longer exercise protocol that accurately represents road cycling.

Seventeen participants were included in this placebo controlled double-blind study They were all road cyclists with a minimum of one year experience and a weekly training volume that exceeded 60km, and were also required to have not supplemented with beta-alanine or creatine within the past six months.

The cyclists were randomly assigned to either the beta-alanine (n=11) or placebo group (n=6). All participants visited the lab five times across the course of the study with at least seven days between each visit.

Initially they performed a VO2max ramp test on a bike ergometer, followed by two sessions to familiarise themselves with the protocol. A test prior to supplementation was then completed and another following four weeks of supplementation. Muscle biopsies were taken one hour after the two exercise tests while muscle carnosine content was then measured using a combination of chromatography and a UV detector as described by Mora et al.

The exercise tests consisted of a five-minute warmup, followed by a 120 minute session on a cycle ergometer at standardised power outputs (between 1.5-3 watts.kg BM-1) designed to reflect a road race. A 10 second all-out sprint was carried out every 19 minutes and 50 seconds - cadence was reduced 30s prior to each sprint and at the start of the sprint the cycle ergometer was switched into Wingate mode. At each sprint, mean and peak power output were measured.

Following the end of the simulated road race, the participants transitioned to a road bike on a roller and performed 10 minutes at a constant load before cycling a 4km time trial at a simulated 5% incline. Time to completion of this 4km time trial was measured, as was rate of perceived exertion (RPE) every 400m, and blood lactate was taken immediately before and after the time trial using finger prick samples.

Throughout the protocol, the cyclists ingested 200mls of liquid containing 12g of carbohydrate every 20 minutes to prevent muscle glycogen depletion that may have affected the results.

The supplementation consisted of 6.4g of beta-alanine per day, split into two 800mg capsules taken four times per day The placebo group received the same sized capsules and protocol but containing maltodextrin instead of beta alanine.

All participants were required to take a questionnaire on what they thought they were taking, any potential side effects and if they believed it had improved their training.

Practical Takeaways

Supplementing with beta-alanine has been shown again to be an effective method of increasing muscle carnosine concentration. We know this has benefits as an intracellular buffer for high intensity and relatively short-duration exercise. Thus any practitioner working with athletes who compete in disciplines that are high intensity and shorter than 25 minutes should consider supplementing with betaalanine at 4-6g per day for at least 2-4 weeks.

For athletes who compete in longer endurance events, there may not be any efficacy of beta-alanine and so it may not necessarily be something that you need to trial. However, it may help improve training stimulus for certain periods of high intensity which may carry over to performance, and previous studies have provided evidence of an improvement in sprint cycling in the context of endurance events. This study also did not use intensities based on individual lactate or ventilatory thresholds and so an individual’s training and competition intensities higher than those in this study, resulting in an increased accumulation of hydrogen ions and buffering, may have more of an effect. With all of this

considered, it is likely still worth trialing beta-alanine supplementation with any endurance athletes but as always paying attention to the individual's objective and subjective feedback on performance.

If using beta-alanine with your athletes, ensure the product is batch certified and where possible informed sport tested and thus free from any banned substances.

The side effects of beta-alanine including paraesthesia may be reduced by splitting the dose across the day Overall and consistent intake of the supplement to increase muscle carnosine is the main goal, so timing of beta-alanine does not really matter, however intake with food is advised.

The researchers found no significant difference between mean power output and peak power output during the sprints for either group from before and after supplementation or between groups. Across both tests, both mean and power output decreased from sprint to sprint. There is moderate evidence to suggest the betaalanine group achieved a higher mean power output for the sixth sprint post supplementation compared to the placebo group. Peak power output was also increased across all sprints in the beta alanine group - this result was however not statistically significant. There was no significant difference between each group for time to completion of the 4km time trial. There was also no significant difference within each group pre to post supplementation. The muscle carnosine content of each group was the same pre supplementation. There was a significant increase in muscle carnosine concentration in the beta-alanine group following supplementation - an increase of 9.4 ± 4.0 mmol·kg-1 dry mass was seen compared to a statistically insignificant change of 1.4 ± 1.1 mmol·kg-1 dry mass in the placebo group. There was, however, no correlation between muscle carnosine concentration and time to completion.

There was no group or time effect found for blood lactate levels, however in both groups, blood lactate levels were elevated postexercise for both tests. There was also no significant difference in RPE between groups or across tests for each group.

Two of the individuals supplementing with beta-alanine experienced paraesthesia as a side effect, one of these correctly identified the supplement as beta-alanine, while the other did not know what they were taking. In total, two participants correctly identified beta-alanine and three correctly identified they were taking a placebo. Four participants in each group believed the supplement improved their training.

“In my practice, beta-alanine is perhaps one of the more common recommendations I give. The context of the individual athlete and their sporting discipline should of course always be taken into consideration and it’s not something you should use as a blanket recommendation and as we know, endurance athletes are likely to benefit less from it. However, I believe a significant amount of athletes would benefit from taking it and taking it properly - in my experience a large portion of those who currently use it do so inefficiently, taking acute one-off doses that they believe work because they experience the side effect of paraesthesia but are not increasing muscle carnosine content.

“The risks of beta-alanine supplementation are relatively low and although this present study doesn’t offer evidence that it is beneficial for endurance athletes, it also shows it is not detrimental. Because of the low cost and relative safety of the supplement, provided the correct precautions are taken as when starting any new supplement and the athletes’ health and wellbeing are monitored, then my opinion of beta-alanine is very much one of ‘why not’?”

W ho le bo dy re sistance training m ay not be o ptim al fo r wo rking up an appetite !

Appetite is a relatively complex thing - it’s regulated by neurological pathways in the hypothalamus but is affected by hormonal, psychological and cultural factors as outlined in the related video below We know exercise can impact appetite, with several studies showing it is significantly suppressed following exercise at an intensity greater than 60% of an athlete's Vo2 max (Dorling et al, 2018). Due to negative correlations that have previously been seen between lactate and appetite and lactate and ghrelin, it is currently thought that lactate may play a role in this suppression of appetite (McCarthy, Islam, Hazell 2020), primarily through inhibiting ghrelin secretion.

There is limited evidence on the impact that resistance training has on appetite. This study aimed to quantify the effects of a full body resistance training session vs. split body (upper and lower body) on appetite feeling and leptin release. The authors of the study also sought to identify an involvement of lactate and the autonomic nervous system with regards to exercise induced appetite suppression.

The study used a randomised crossover design. Twelve recreationally resistance trained males, all aged between 2030 and with at least six months’ experience in resistance training, were part of the study. None of the participants were using any dietary supplements, ergogenic aids, or medicine for at least six months prior to the study

A total of six experimental trials were undertaken by each participant. The first visit was to carry out anthropometric measurements, body composition assessments and measure maximal aerobic speed. The second and third visits consisted of one rep max (1RM) testing of upper body movements (including bench press and T bar rows) and lower body movements (including leg press, leg extension and leg curls).

The fourth, fifth and sixth visits consisted of the participants randomly completing either a full body, upper body or lower body workout, with each visit separated by at least seven days.

The workouts were programmed relative to the participants’ 1RM. The full body session consisted of two sets of 10 reps, with another to failure at 65% of movements including leg press, bench press, T bar row, leg extension, leg curls and bicep curls. The upper and lower body sessions consisted of five sets of 10 reps, with another set to failure at 65% of 1RM of just the upper or lower body movements.

Each subject was given the same meal 90 minutes pre training, one consisting of 443 kcal made up of 15-20% protein, 50-60% carbs and 25-30% fat. They were also asked to record food intake three days prior to each trial and consume roughly a similar amount for each trial.

Heart rate variability (HRV) was collected at regular intervals 0-60 mins post workout. Blood samples were also taken via the ear lobe to measure lactate and leptin concentrations. These samples were taken at rest prior to the session, immediately post, five minutes post, and 30 minutes post workout. Subjective levels of hunger were also taken from each subject, using a validated visual analog scale as used by Flint et al (2000). These were taken after breakfast, preexercise, immediately after exercise, one hour after, and two hours after exercise.

Practical Takeaways

Resistance exercise may contribute towards appetite suppression, which is more likely to be seen in sessions that incorporate larger muscle groups and sufficient volume and intensity, such as those that are taken to failure as seen in this present study

This suppression in appetite is likely to be caused in part by the accumulation of lactate which may suppress release of ghrelin.

When looking to overcome appetite suppression to aid recovery, practitioners should use foods and fluids that are less satiating for an athlete. When thinking about the satiety of food, things like taste and ease of digestion should be considered. Liquid calories such as protein smoothies (i.e. whey protein, milk, banana and oats), or high glycemic index carbohydrate drinks are good examples of how recovery can still be achieved but not consuming food.

It’s important that appetite should not necessarily impact an athlete's ability to meet daily fueling requirements - because of this, practitioners should educate athletes on both the impact exercise may have on appetite and ways to get around this that fit in with the athlete s life. Due to the impact on appetite that training intensity has, different fueling strategies can be used for different training sessions to reflect or preempt any potential changes in appetite.

The subjective hunger ratings of the participants for all three workouts were higher one hour post workout compared to post breakfast, pre-exercise and immediately post exercise. Subjective hunger ratings were significantly lower after the full body exercise session compared to the upper body session. There was no significant difference between hunger ratings after the lower body and full body sessions.

Post exercise lactate concentration was found to be significantly greater after full body exercise compared to the two split body sessions, with concentrations peaking above 12 mmol.L-1 immediately after for the full body sessions and only 8 mmol.L-1 for both split body sessions.

Post exercise leptin concentrations were found to not be significantly different between sessions but appeared to decrease 60 minutes post training across all situations. The authors of this study found a significant relationship between subjective hunger ratings and lactate concentration during full body resistance training but not in the upper or lower body exercise sessions.

“As with everything in nutrition, when it comes to appetite, context is king. In the conclusions, the authors of this study have implied that full body resistance training is an effective tool to use to reduce appetite. In my practice when working with elite-level athletes, appetite suppression is more often a barrier than a tool. It’s something that can get in the way of ensuring sufficient intake of carbohydrates and protein to promote recovery

“When I've previously worked with individuals who are looking to reduce appetite, perhaps due to being in a deficit to optimise body composition for their sport, I have always used other methods, such as high fibre and high protein diets to increase satiety for example. Because of the importance of recovery, relying on appetite suppression from exercise to aid a deficit is probably something I would not encourage.”

S ho uld supple m e ntatio n in fe m ale fo otballe rs be diffe re nt to m ale play e rs?

O BJE C TIV E

Supplements are foods, nutrients or non-food compounds that when ingested on top of someone's diet, improve aspects of a person's health or performance. Nutritionists tend to take a ‘food first’ approach when working with athletes, however sometimes this is not possible, and therefore supplements are commonly used by elite athletes.

It has previously been estimated that around 57% of professional male football players regularly use dietary supplements and in a recent position stand, several supplements were recommended for use in this populationsee the related article for more.

Despite this, there are currently no studies on the prevalence or usefulness of supplements in elite female football players. Due to the differences between male and female physiology, it’s reasonable to assume that recommendations for male footballers may not have efficacy in the female population. The present review details multiple supplements with a growing evidence base in the content of supporting an elite female footballers performance.

WHAT THE Y DID

There is no methods section to this paper as it is a review article briefly detailing the evidence of multiple supplements that may be of relevance to this population group.

It includes sections on: macronutrient supplements, omega-3’s, Vitamin D, Iron, Probiotics, Collagen, Creatine, Caffeine, Nitrates, and Beta Alanine.

Practical Takeaways

As with anything in nutrition, there are very few supplements that should be recommended for every member of a population. In the population of elite female footballers, I believe macronutrient supplements, vitamin D, Omega-3s, caffeine and creatine should all at least be considered for athletes, provided sufficient education is provided by the practitioners regarding best timing and dosage. These supplements and others mentioned in this article that may provide a benefit should be individualised to the athlete. The importance of quantifying status for things such as vitamin D before using a supplement cannot be understatedassess the need and meet the need for each individual athlete. Individualised protocols for things such as caffeine should also be considered, as each athlete may have a preferred method of intake, while others may cause issues such as gastrointestinal upset or impact on sleep routines.

Þ The impact of an athlete's menstrual cycle should be considered as outlined above. Ultimately we are unable to provide blanket recommendations on supplementation around the menstrual cycle as there is limited research on this topic, so until more is known it is also something that should be individualised. Practitioners should know their athlete and their cycle and have plans in place to accommodate any changes that may occur due to their cycle. For example, quantifying iron status at various points and supplementing if needed.

Whenever trialling a supplement with an athlete, ensure you have checked the ingredients for prohibited substances and that the substance itself has been batch tested by a third party such as Informed Sport.

The authors looked at macronutrient supplements in the context of energy availability and protein requirements, concluding that protein supplements such as whey protein are a useful tool to help athletes meet daily protein requirements and could be used as a pre-bed protein feed to improve recovery Carbohydrate supplements (i.e. carbohydrate gels or powders) are considered a convenient option for keeping energy availability high and helping to periodise carbohydrate intake in and around training or before or during match-play Omega-3 supplementation was reviewed in the context of muscle recovery and reaction time. It was concluded that chronic use of 5g of omega-3’s per day could improve both reaction time and muscle recovery of female football players. The authors also noted that this may be more beneficial for those on the contraceptive pill due to the potentially protective role of estradiol that those with a normal menstrual cycle would experience.

Vitamin D deficiency is known to negatively impact immune function, bone health and muscle function. Where possible, the authors recommend quantifying vitamin D status via blood samples before supplementing. If this is not achievable then supplementation with 1000-2000 International Units per day is suggested.

A similar stance was taken with regards to Iron supplementation, quantifying the need then supplementing if needed, potentially with vitamin C to improve absorption. It is important to individualise supplementation to the athlete.

Probiotics were discussed as a potential supplement for those who suffer from exercise induced gastro-intestinal upset. It was also suggested they be considered in the winter months to potentially improve immune function. Due to musculoskeletal injuries potentially being more common in female athletes, collagen supplementation was considered. However, collagen synthesis is affected by oestrogen levels and thus the authors recommend taking collagen during the pre ovulatory phase of the menstrual cycle.

Due to creatine being shown to improve repeated sprints and agility in football related tasks the authors suggest supplementation of 5 mg.kg-1.day-1 for elite female athletes. They also mention that the potential for weight gain may put athletes off and there is still limited evidence of efficacy in this population. Despite there being minimal evidence of efficacy of caffeine in this specific population group, it has previously been shown to improve football specific skills and its benefits for sprint performance are well known. Thus it is worth trialling with athletes but dosage and type should be individualised and practiced with the athletes prior to use in a competition setting.

Nitrates have previously been shown to increase nitric oxide levels in the body, leading to improved performance in sub maximal and high intensity exercise in males. Due to females having higher levels of nitrate in the body than males, it was thought they are likely to be less responsive to supplementing with nitrates. Finally, beta-alanine was a supplement worth considering. Beta-alanine works to increase carnosine levels in muscle which acts as a buffer and has been shown to delay the onset of fatigue. Females have less carnosine than males and it’s thought that a lower dose of 2.5 g.day-1 beta-alanine is sufficient to increase carnosine levels in females.

“In my experience, the lack of research of certain supplements within this population group has led to hesitancy when supplementing. This hesitancy comes from both practitioners and athletes, with practitioners not willing to trial supplements that have not been shown to be useful in this population group and athletes being scared to take something they do not necessarily understand.

“This highlights the great need for more research into this population group - there is a huge amount of research into male professional footballers, and with the growth in popularity of female football, hopefully we see a corresponding growth in the body of research too!

“Finally, I honestly believe once you educate the athlete on how each supplement works and its benefits, then many will buy into it and be happy to consume it.”