The Performance Digest - November 2022 (Issue 73)

P E RFORM A N C E

Study Details

How to Read Me!

Praccal Takeaways from study

Related links to learn more about the topic

Reviewers comments on the st udy

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.

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.

Technology & Monitoring

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

Coaching Science, S&C, Equality, diversion & inclusion

Tom is currently an assistant professor in applied sports sciences and has worked in elite sport for over 10 years. Previous roles include working as a sports scientist at Liverpool FC, where he completed his PhD, and working across a number of other sports. He is passionate about physiology and has published papers on strength and conditioning, nutrition and youth development

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.

Nutrition

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

Tom Green MSc UKAD Advisor

James de Lacey MSc

Cody Roberts MSE

Tom Brownlee PhD

Matt Klayman’s MSE

Dr. James Morehen PhD

C OA C H IN G

C an V R be used to co m bat pre ssure and anxiety in cricket?

Pressure can lead to anxiety and reduced performance in all walks of life. In the sporting realm this has been manipulated experimentally by involving live audiences, competing against, or being evaluated by an expert, or public display of scores on a leaderboard. These scenarios allow pressure to be manipulated in a way that leads to anxiety to be better understood. One challenge with these approaches is the ability to have a controlled environment, and level of pressure.

If the skill being tested could be preserved in virtual reality (VR) then the performers may be able to practice under reproducible training demands. It is important though that the quality of the VR used be able to distinguish between the level of individuals (i.e., high- and low-skill player) taking part to ensure its realism.

The aim of this study was to first see whether a VR batting task was representative of a batting task in real life by determining whether better players scored better than less good ones. Secondly, it would consider whether pressure manipulations would influence anxiety ratings and whether this would show a difference between levels.

Male participants were split into a high (n = 14, age 23 ± 5 yrs.) and low (n = 14, age 24 ± 10 yrs.) skill group. They then completed a batting task where they faced balls that were described as short, good, full, or deceptive in length. The aim was to score runs without losing their wicket (which they could do by being bowled out or caught).

They began with a 15 min familiarisation with the technology followed by 24 balls in a low pressure situation, 24 balls at high pressure and 24 balls again at low pressure. They believed that each of the three sets were being bowled by different bowlers. Actually, participants faced eight different ball deliveries from the same virtual international level bowler, presented three times throughout each of the three conditions. A random number generator was used to randomise the order of deliveries, with an additional rule applied to ensure that no delivery could be presented more than once within any set of three trials.

They were told the first set was being bowled by a club bowler, before switching to an international bowler, then back to the club bowler They were also told the club bowler balls would be recorded for the researchers and they would have to score as well as possible.

For what they thought was the world-class bowler they were told it would be livestreamed to some university students critiquing technique as part of their master’s programme. They were also told this recording would go to all participants accompanied with a leaderboard for the task.

P ractical Takeaways

The findings of this study suggest that a VR batting simulation can be used to measure the impact of pressure, and subsequent anxiety, in tasks involving dynamic skills such as batting in cricket.

This manipulation of pressure and anxiety could be further enhanced via the ease of adding crowds and the accompanying noise. This study only allowed the participant to face 8 different balls though in time it is positive that this could be increased to add to the realism of the environment.

Ultimately, when looking to simulate pressure, realism is key. It is a positive of this study that participants experienced increased competition anxiety as a result of the intervention. This could lead to effective tools for understanding expertise differences in terms of decisions and action responses.

To meet their first aim, they found that high skill participants not only scored higher run rates than low skill participants, but they outperformed the low skill group in all performance measures including higher incidences of correct foot placements that reflect better anticipatory responses.

Having established that the test was sensitive to ability level it was subsequently seen that anxiety was greater for both groups in the high-pressure condition compared to the two low-pressure conditions.

The size of this effect was greater in the low skill group for both cognitive and somatic anxiety. Despite anxiety levels increasing in the high-pressure condition, no negative changes to batting performance were found for either group, with both groups actually showing performance improvements.

Tom’s C o mme nts

“Historically, it has been challenging to measure the variables of pressure and anxiety in these kinds of dynamic situations. It is a real positive that this study has found positive results, especially with some of the cricket-specific aspects used here.”

“Having said that, the sports specific nature used here still has a long way to go before it feels truly immersive. Companies such as Rezzil though are beginning to close these gaps with research such as this highlighting where applications may be heading.”

“This study gives us confidence that in time such technology will be useful for psychological interventions to target specific issues including handling pressure and anxiety.”

W hat do we know abo ut e lite athlete dev e lo pm e nt?

The amount of research around talent identification, skill acquisition, early sport specialisation and athlete development has increased dramatically in recent years. This has occurred in tandem with those working in high performance settings having an increased pressure to create evidence based programmes to aid the development of these young athletes.

Recent reviews have highlighted how there are still gaps in our knowledge around how best to achieve this. This editorial sought to emphasise five key research limitations that destabilise the evidence around elite athlete development and discuss the associated implications.

The researchers involved in this editorial considered that survivorship bias, cohort effects, understanding selection, focusing on false dichotomies, and there being a lack of foundational theories were the main criticisms of current research.

P ractical Takeaways

The idea of this editorial was to provoke thoughtful discussion around our actual understanding of athlete development. They encouraged researchers to highlight the limitations they listed in future work in order to allow consideration and potential subsequent control of them moving forwards.

They also hoped that future research would consider these limitations by moving away from traditional research approaches. They suggested better capturing the complexity and nuance of this area of research, by perhaps taking part in larger, multi-centre studies.

Taking each point in turn they highlighted that survivorship bias was an important consideration in current research as often we are left looking at those who made it through a particular system. We don’t know what happened to those who didn’t come through and potentially whether the systems in place played a part in their exiting of the system.

Cohort effects exist when athletes experience different systems or regimes, perhaps due to changes in funding, coaches, or philosophies. This means that sometimes it can be hard to know how the changes from one cohort to the next may have influenced findings.

Another enigma they highlighted is how poorly we understand selection. We know that as athletes progress they may or may not progress to the next age group. Our true understanding of this is limited though. We know it may involve sport specific traits or characteristics of their personality, but the true blend of these things is still somewhat of a mystery

They highlighted that focusing on false dichotomies may also be oversimplifying our understanding around elite athlete development. For example, it is unlikely to be as black and white as ‘is it nature or nurture?’ or ‘should we specialise or sample many sports?’ They suggest that this simplicity may hinder our understanding.

Finally, lacking foundational theories, unlike in other disciplines such as physics, they say may be limiting our progression. They suggested searching for these ‘universals’ of human development may improve our understanding as a whole when working with athletes.

“This is not only a very tricky problem to solve but also the main goal in working with your high-standard athletes. If we’re able to understand how to optimise these programmes we will ensure more enjoyment and fewer injuries for those involved but also will produce higher numbers of more capable individuals.”

“This is a real challenge and the limitations listed in this editorial can help us to move things in the right direction by improving the research that is scrutinising current practice. Whether it is through longer term studies that might help to prevent cohort effects influencing results, working with larger cohorts, or addressing the other issues presented here there is much we can do.”

Stre ngth & C o nditio ning

W hat is the thre sho ld fo r the num be r of sprints pe r we e k be fo re e cce ntric ham string stre ngth re duce s?

Hamstring injuries are the most common injury in soccer and sprinting is the most common cause (see HERE). Hence the huge emphasis by practitioners to reduce the injury risk throughout a season.

Unfortunately, the game is only getting faster, and schedules more congested. For example, high-velocity running and sprinting increased 24-36% between the 2006/07 and 2012/13 seasons in the English Premier League and is continuing to rise (see HERE).

Eccentric hamstring strength and frequent exposure to high-velocity sprinting has been identified as an important metric to reduce the risk of injury Therefore, this study aimed to investigate the relationship between eccentric force output during the Nordic Hamstring Exercise (NHE) and total weekly sprint volume, and number of exposures to sprints >90% maximum velocity (Vmax).

Fifty-eight male professional soccer players (age = 21 ± 5 years) who were competing in the Scottish Premier League, Reserve League, and U18 League were measured over half to one-and-a-half football seasons. Players were categorised as defenders, midfielders, and attackers. Goalkeepers were omitted from the study

All subjects were full-time professionals. They were monitored with Catapult GPS devices during training and matches. Sprint distance (m), maximum velocity (m/s), and number of sprints at >90% and >95% Vmax were recorded.

The NHE was performed weekly on match day +2 (2 days after a match) for one set of three reps on the NordBord. Peak bilateral force (N) and between limb strength imbalances were recorded.

Practical Takeaways

In this particular cohort, exceeding eight sprints above 90% Vmax per week could potentially increase the risk of hamstring injury due to the reduction in eccentric strength. The sample size was far too small for sprints above 95% to show any effects on hamstring eccentric strength. How can this be used in practice?

§ Exceed 7-8 sprints per week in the pre-season. If 7-8 sprints really are the threshold before eccentric hamstring strength starts to deteriorate, then exposing the body to these higher volumes of high-velocity running will prepare the athlete for congested periods of sprinting within the season.

§ Keep regular exposure to sprinting. This could mean varying the number of sprints or highvelocity exposures week to week. For example, matches scheduled once per week can afford more sprints within training. When playing twice per week, then removing planned sprint training may be necessary

Maintain/develop hamstring strength year-round. Nordics aren’t the only method for overloading the hamstrings. Further, it’s not a fix-all exercise as it only overloads the hamstrings in a shortened position. Hip hinges work the hamstrings eccentrically through longer muscle lengths. However, these must be performed at low volumes due to extreme muscle soreness. Another option is isometrics at long muscle lengths, e.g. single leg hamstring bridges. We potentially see similar structural adaptations to the muscle as we would when performing eccentrics such as adding sarcomeres in series which is the primary adaptation practitioners want to achieve. It shifts the angle of peak torque to longer muscle lengths, shifting the length-tension relationship up and to the right, improving force generating capabilities when at long muscle lengths such as sprinting.

Over the course of the study, subjects completed 209,139m of sprint distance (all distance above >90% Vmax), 947 efforts >90% Vmax and 16 efforts >95% Vmax. Per week, this equalled 212 m of sprint distance consisting of 0.96 efforts >90% Vmax and 0.02 efforts >95% Vmax Mean percentage change in eccentric hamstring strength was significantly influenced by weekly efforts >90% Vmax. Specifically when 78 weekly exposures were hit but not with <6 weekly exposures >90% Vmax.

Mean percentage change in eccentric hamstring force was not significantly influenced by weekly sprint distance.

“It’s important to note that players in this study averaged one sprint over 90% Vmax per week. This is interesting, as the authors introduce this paper stating frequent exposure to high-velocity running is important for reducing the risk of injury To me, this is a recipe to undercook your athletes, risking potential hamstring problems especially in congested periods of competition (e.g. playing twice a week). Seven or eight runs above 90% Vmax may be on the low end of the threshold because of this. If you are regularly sprinting, this number might be much higher. Style of play may also play a role where some players may be required to sprint more often than others due to their roles within a playing structure.

“Further, whether this reduction in eccentric hamstring strength drastically increases the risk of injury remains unknown since injuries were not recorded within this study.”

C an back squat and ov e rhe ad pre ss pre dict split je rk 1RM pe rfo rm ance?

One rep max (1RM) testing is an easy-to-implement field test allowing monitoring of maximal strength and providing numbers to program from using percentages.

However, performing multiple 1RM tests is not feasible in most athletes' programs due to time constraints and fatigue. Therefore, to reduce time issues it may be possible to predict 1RM for specific exercises if you know the 1RM of other exercises if there is a strong association (see HERE).

To date, the relationship of upper body strength on Olympic Weightlifting performance has been studied once, with the overhead press being strongly related to split jerk 1RM (see HERE). Currently, no research has investigated upper and lower body strength relationships with split jerk performance. Thus, this study aimed to determine the relationship between upper and lower body strength measured by the overhead press and back squat to the split jerk.

Twenty males (age = 28.9 ± 6.6 yr; relative back squat = 1.9 ± 0.2; relative overhead press = 0.9 ± 0.1; relative split jerk = 1.4 ± 0.1) and 13 females (age = 27 7 ± 4.4 yr relative back squat = 1.5 ± 0.3; relative overhead press = 0.6 ± 0.1; relative split jerk = 1.1 ± 0.1) performed 1RM tests for the back squat, overhead press, and split jerk on separate days.

Correlation calculations were performed between all lifts to determine the relationship between upper and lower body strength and weightlifting performance. Regression analysis was conducted to see if split jerk performance could be predicted from upper and lower body strength tests.

Very strong and significant correlations were found between the overhead press and split jerk 1RM (r = 0.92) and back squat and split jerk 1RM (r = 0.97). When separated by sex, men (r = 0.75) and women (r = 0.72) showed strong and significant correlations between the overhead press and split jerk. Very strong and significant correlations were found for the back squat and split jerk 1RM in men (r = 0.91) and women (r = 0.89).

Split jerk 1RM could be predicted using the back squat and overhead press with the following equations:

Men

Split jerk 1RM = -0.4566 + 0.6558 x back squat (kg) + 0.2100 x overhead press (kg)

Women

Split jerk 1RM = -3.617 + 0.5814 x back squat (kg) + 0.4809 x overhead press (kg)

Whether you’re looking to improve split jerk performance as a competitive weightlifter or for athletic performance, I’m sure many of you are already developing lower and upper body strength. However, this study highlights the importance of overhead pressing strength, which can often be lower down the priority list in favour of leg strength.

Where this study shines is the equation to predict split jerk 1RM performance. If you work in a team setting, you likely already test the back squat in some capacity Testing the overhead press can give you the opportunity to prescribe loads for the split jerk if this is one of your lifts.

However, not everyone programs the split jerk as there are easier jerk variations to teach that provide the same benefits. For example, the power jerk. According to Commonwealth medallist and weightlifting coach Mona (Pretorius) de Lacey, lifters will typically be able to power jerk 85-90% of the split jerk 1RM. Now the equation allows you to estimate power jerk 1RM. Some lifters will be able to power jerk closer to their split jerk 1RM but these can be managed on an individual basis.

Mona has also used split jerk 1RM to prescribe loads for the push press. She uses 6080% of split jerk 1RM for 1-3 reps of the push press and 55-65% 1RM for 4+ reps.

“For anyone who programs plenty of overhead work with weightlifting derivatives, this paper provides a simple way to prescribe percentages and loads without needing to test every lift. Having back squat and overhead press data can allow you to prescribe loads for the overhead press, push press, power jerk, and split jerk.”

“This is helpful in a team setting if you don’t have fancy equipment like velocity tracking devices. Personally, I’m not a fan of programming the split jerk for non-weightlifting athletes but I’m very fond of the push press and power jerk to train the sequencing of force generation from the legs through to the arms.”

“If you are hell bent on using the split jerk it’s nice to know that you can estimate percentage of 1RM from the findings of this study Additionally, a variation I’ve found easier to teach is the landmine split jerk. It doesn’t require a lot of technical proficiency or overhead mobility.”

C an te am spo rt athlete s accurate ly hit sub- m axim al running v e lo citie s witho ut o bje ctiv e fe e dback?

As physical performance coaches, we often outline percentages of maximum velocity for our athletes to hit as they warm-up, so they can safely build up to a full sprint.

However, evidence is lacking regarding whether team sport athletes can accurately run at sub-maximal velocities without objective feedback. Therefore, this study investigated the ability of team sport athletes to accurately hit sub-maximal running velocities with only verbal instruction.

Twelve male professional rugby union players (19.7 ± 0.9 yrs) performed two days of testing, separated by one week. Participants performed 3 x 40m sprints on day 1 on synthetic turf to determine their maximum velocity (Vmax) using Catapult GPS units.

The second day consisted of performing 3 x 40 m runs at subjective intensities of 60%, 70%, 80%, and 90% of Vmax. These were performed in randomised order, with all three runs at the prescribed intensity completed before moving to the next intensity

Mean bias, prediction error and Pearson correlations were calculated.

Practical Takeaways

As players tended to overestimate 60% Vmax, it may be pertinent to perform some movement before starting the gradual increase in intensity when running. Things I like to use are various sprint drills to reinforce the ‘pop’ with ground and switching of the legs. Or walking to jogging games.

Players underestimated their 90% Vmax, which means you may want to use an extra warmup run at a subjective 95% to get closer to maximal effort.

I don’t believe it is practical to provide objective feedback to every player on the field when performing their warm-up accelerations. Players will autoregulate their intensity by how they feel and often won’t push too fast if they don’t feel like they can ‘open up. I haven’t had any issues using some of the methods below:

§ One method I like to use to safely increase intensity during the warm-up is to use a ‘gear change.’ Every 10m, increase intensity. For example, 50%, 60%, 70%, 75% for the first warm-up run. Essentially increasing intensity into a tempo run, and you’re covering 40m. This can be progressed to 70%, 80%, 90% or 80%, 90%, 100% for your first sprint.

§ This one I got when talking with legendary athletic performance coach Vern Gambetta (see ) when I was concerned about our team constantly playing on changing HERE surfaces in the middle of winter due to snow After sufficient warm-up, have players build to approximately 90% Vmax and whenever they feel ready, hit 100% for 8-12 steps before coasting out of the sprint. Give them 50m of space to do this so there’s plenty of time. It ensures athletes only hit full speed when they feel comfortable in their stride.

Here were the average speeds achieved at each percentage:

§ 60% (73 ± 8%)

§ 70% (77 7 ± 7%)

§ 80% (81.8 ± 5.2%)

§ 90% (86.1 ± 4.3%)

The speeds run at 70% and 80% were statistically similar but different to speeds run at 60% and 90%. The largest range of speeds run was at 60% (57.1 – 88%) and smallest at 90% Vmax (76.8 – 94.8%).

Running at 60% resulted in very to extremely large mean bias and very large prediction error. Pearson correlation between criterion and observed velocity was large.

Running at 70% Vmax resulted in large to very large mean bias, prediction error and Pearson correlation.

Running at 80% Vmax resulted in small mean bias, large prediction error, and very large correlations.

Running at 90% Vmax resulted in moderate mean bias, moderate to large prediction error, and very large to nearly perfect correlations.

“There are a couple of issues I have with this study:

It’s not feasible to provide objective feedback to a squad of 30+ players during a warm-up. Plus, I don’t believe it’s something that will make your session better

The sub-maximal runs were performed in a randomised order. I understand why this would be done within a study design, but on the field we always use a graded exposure. E.g., start at 60% and move up.

“On the first point, I don’t believe it makes your session any better than allowing athletes to selfregulate even if they are under or over estimating their percentages. Based on these findings, you could potentially count the last warm-up sprint at 90% as the first sprint of the session.

“On the second point, accuracy of each submaximal effort may improve when gradually increasing intensity, as you can base the next run off the previous. This is complete speculation on my part but I’ve never had issues with gradually improving.”

D o e s re petitiv e he ading in so cce r im pact sho rt te rm le arning?

Repetitive head impacts (RHI) and concussion are common in soccer, as well as many other sports. Soccer heading, in particular, has been independently associated with adverse profiles of brain microstructure and cognitive performance. The severity of these effects is modest and clinical levels of impaired function have not been reported among the younger healthy players that have been studied to date.

It is well-established that although women, depending upon age, are less likely to experience traumatic brain injury (TBI), including concussion, they sustain worse outcomes. In this study, it was investigated whether heading over 12-months would be adversely associated with short-term learning on a test of working memory, to a greater degree among women compared to men.

Forty five women and 60 men had their heading exposure assessed using “HeadCount”, a validated structured questionnaire at the baseline visits. The short-term rate of learning of each individual was quantified using the twoback test (a task designed to measure working memory, or the ability to hold information temporarily while completing a complex task demand). This was then compared two weeks later

A linear regression model was used to test the association of heading exposure with rates of learning, including age, sex, years of education and history of concussion as covariates, as well as variables describing soccer play and heading within the two-week period. This was then used to determine how heading exposure over the last 12 months impacted their abilities.

The women were found to head the ball less than men (median of 661 compared with 1089 times). Despite this, greater 12-month heading was associated with lower rates of learning among women but not among men during the two week period investigated.

PThe study identified evidence for an adverse, albeit subclinical, effect of soccer heading on brain function among young adult players, which selectively affects women in this particular sample.

They proposed that further study is required to understand the longer-term implications of this research. They considered this would also be useful to understand how particular attributes of those studied (such as gender and age) might relate to the findings.

Despite not being clear on the mechanisms causing this difference between men and women they proposed that weaker neck musculature may play a role

“Our need to understand the repercussions of brain injury caused during sporting activity is more important than ever This study is important in showing that in the females in the group learning tasks were impacted by typical heading during soccer play.”

“The idea that lower neck strength may play a role in this issue is something that perhaps should be considered by all S&C coaches working with athletes who may experience brain injuries during training and play.”

“Beyond this, straightforward actions to be taken from this study are not simple to come by but this study serves to add another piece to the puzzle in helping us to understand the broader picture. As legislation begins to change and further evidence builds hopefully in time our understanding will also grow This should allow us a better idea of how to protect those playing sport from such brain injuries both in an acute and longer-term sense.”

Te c hno lo gy & M o nito ring

A pro po sed m o de l fo r co m paring exte rnal and inte rnal training lo ads

O BJE C TIV E

The purpose of effective monitoring is to go beyond getting a general sense of an athlete's or team's psychophysiological readiness and also to identify individuals who are in need of training modifications (e.g.changes to intensity, volume, or exercise prescription itself) due to decrease in performance, increase in fatigue, or any sort of indication of maladaptation (e.g. illness, increased stress, concerning soreness).

Monitoring variables can be categorised into external training load (ETL) and internal training load (ITL). External training loads (ETL) are objective measurements of outputs (e.g. performances, distances, speeds, etc.) performed or accomplished, often captured using global positioning system [GPS] devices (e.g. distance covered, speeds achieved, energy expenditure). Internal training load, which represents an athlete’s response to their environment (e.g. heart rate variability, session rating of perceived exertion (s-RPE), or endocrine markers via saliva or blood sample) provide an explanation or context for subsequent performances. Although s-RPE is a simple and valid option (see ), a direct HERE comparison between ETL and ITL variables provides a more accurate representation of athlete readiness.

With the numerous opportunities to monitor both ETL and ITL, there is currently not one specific metric that provides coaches with a current representation of both performance ability, and identifying potential fatigue (see ). Therefore, the HERE objective of this study was to identify specific monitoring variables (both external and internal) that would provide an appropriate representation of an athlete s readiness. With these variables, a potential model was proposed that is reactive to current training loads and current performance potential that coaches could use to help identify an athlete’s response to training.

WHAT THE Y DID

Training and match data (warm-up included) was analysed for 20 professional (Italian first division club) male soccer players (age 25.8±4.1-yr). There were four athletes from each position (central defender, wide defender, central midfielder, wide midfielder, and attacker) included, but no goalkeepers.

Session rating of perceived exertion (session duration multiplied by RPE, taken using a 10-point scale about 20 minutes after each session or match, see ) was used as an HERE ITL metric, and was compared with energy expenditure (kJ∙kg1) as the ETL metric (calculated via software, accounting for change of direction and running speed, see HERE).

Data was collected in two phases - initially during the 2016 season (Oct-Dec), examining the correlation between ITL and ETL. Subsequent data was collected during the pre-season (July to Aug 2017) and divided into three phases (10 training sessions each). Following a model proposed by Borresen and Lambert (see ), the authors used standard error of HERE estimate to indicate high, average, or low fitness levels based on the regression line created when comparing s-RPE and energy expenditure.

Since this comparison between ITL and ETL was ongoing, the proposed model was titled the Relation of Ongoing Monitored Exercise in Individual (‘ROMEI’) and results were presented on an individual athlete basis looking for a strong correlation between metrics.

Practical Takeaways

The ROMEI model is useful for monitoring the interaction between ITL and ETL, accounting for the athletes’ subjective perception (s-RPE), as well as their physical output (energy expenditure). These are two variables that coaches and athletes can easily understand and the variables can improve the opportunity for support from other members of the organisation.

This model has the potential to identify an athlete’s fitness level without additional or maximal testing (see ), as HERE well as noting any potential changes that would either provide confidence for the coaches and athlete or suggest a modification in training or recovery strategies.

Important steps when employing the ROMEI model:

Coaches need to first apply this model to identify outliers (e.g. low fitness), but then appreciate the interaction between fitness and fatigue. If fitness is noted as low, that could be a sign that fatigue is masking performance and strategies that offer more rest and recovery (reducing training volume and intensity, increasing sleep, improving nutrition) could be the best avenue to help to improve fitness.

External training load data collection is straightforward, as 20-Hz global position technology has shown to be valid and reliable (see ). However, the process of collecting subjective data requires consistency Athletes need to HERE understand the scale they are using, information needs to be collected and handled in a supportive fashion, and at a consistent time-point and circumstance following the training (e.g. privately off the field).

This study and the ROMEI model are a great reminder for coaches to pair multiple metrics (subjective and objective, internal and external) to provide full context and understanding as it relates to the psychophysiological readiness of an athlete. Avoid getting tunnel-vision on one metric, but rather, looking at multiple metrics can provide clarity in the feedback and direction forward with training prescription.

WHAT THE Y FO U N D

Consistent with previous research (see and HERE, HERE, HERE), a reliable relationship between ITL and ETL was found to be lacking.

When there is a poor relationship (low correlational value) across the team with regards to s-RPE and energy expenditure, that is a sign of a discrepancy in fitness capacity and reason to examine ITL and ETL on an individual level.

Likewise, the relationship between ITL/ETL (s-RPE/kJ∙kg-1) will vary based on fitness status, as this changed per player and improved across the three phases of the preseason period for active players.

“Monitoring can be an incredibly complex endeavour but reducing the potential complication or misunderstanding between fellow coaches and athletes is important for adherence and efficacy. Monitoring is a way of obtaining measurable feedback regarding the stresses that are being endured by athletes and their ability to cope with the demands.”

“The best monitoring strategies are practical, sustainable, and understandable; allowing coaches to make actionable decisions and identify potential negative influences that fatigue can have on fitness. Therefore, monitoring is an invaluable process that requires communication, helps strengthen relationships between coworkers and athletes, enhances a sense of belonging and involvement, and adds immense amounts of confidence to the overall training process and experience.

“Effective monitoring helps coaches answer the question of whether or not what they are doing is enough, too much, and actually working to get us closer to where we want to be. Most importantly, when employing a strategy like the ROMEI model, it is a fluid, continuous, and ongoing effort by coaches and athletes.”

D o e s high- spe e d running during pre seaso n im prov e te chnical pe rfo rm ance?

O BJE C TIV E

Research often tries to identify cause-effect relationships, and in the realm of sport performance, research findings can help guide the process of training and managing athlete preparedness. One specific and popular area of cause-effect is the impact preseason training has on in-season performance (see and ). HERE, HERE, HERE, HERE

The preseason period is a demanding but critical time that prepares athletes for the demands of a rigorous competitive season. There appears to be a dose-response relationship between workload and availability in Australian football and rugby league, but like most things, more is not always better, and there comes a point of diminishing returns. This is why monitoring training load (TL) can help to properly progress work and effectively manage the higher volume periods of time so that risk of injury and overtraining are minimised.

Further, although important, physical development is merely one aspect to performance, and technical ability does not always correlate directly with preseason TL (see ). For HERE rugby league specifically, research has yet to explore the relationship that preseason TL has on physical preparation and in-season performance. Therefore, the purpose of this study was to examine the interaction between preseason TL and subsequent in-season physical outputs, as well as quantifying technical performance for professional rugby league players.

WHAT THE Y DID

Twenty-two professional rugby league players (age 24.7±4.0-yr) from the same club had a total of 1,576 training sessions (fieldand gym-based) and 329 match data files (across 21 matches) analysed across a pre- and in-season period. While field-based training involved speed development, conditioning, tactical and technical development, the gym-based training involved strength and power development with resistance training, as well as wrestling sessions.

Wearable microtechnology (triaxial accelerometer and gyroscope) collected on-field movement data for in-season matches and on-field training sessions. Researchers looked specifically at relative total distance (m.min-1) and high-speed running distance (defined as a speed relative to an estimated first ventilatory threshold) based on the reliability and validity of those measures. Noting the relationship between end-stage velocity and high-speed running (see ), the first ventilatory HERE threshold was estimated by having players run the 30-15 intermittent fitness test (see ) twice during the preseason HERE period (beginning and end).

Internal TL for all sessions (field- and gym-based) was measured using the session rating of perceived exertion (sRPE) method, multiplying an athlete’s subjective report of intensity by the session duration (HERE).

Technical match performance was quantified using a customdesigned model of performance known as “NRL Fantasy” which has been used previously (see ). This scoring system HERE considers 19 technical statistics that accounts for key performance indicators (e.g. number of errors, missed tackles, and hit-up metres (metres travelled with possession of the ball, see ). The scoring is based on a point system that rewards HERE players for positive play (e.g. try assist is +5 points) and deducts points for negative actions (e.g. missed tackle -2 points), indicating match performance, with higher values being more favourable and indicative of positive performance, and presented as a relative score based on playing time (points.min-1).

The preseason training and in-season match data was compared, exploring a potential relationship between preseason TL, technical match performance, and physical match activities.

P ractical Takeaways

Most notably, coaches must remember the SAID principle (Specific Adaptations to Imposed Demands), in that running at high-speed makes you better at running at high-speed, or in order to improve the ability to tackle or pass the ball, an athlete needs numerous context-specific repetitions that expose them to the intensity (e.g. speeds and heart rates) that are associated with these actions.

The results of this research are a great reminder that technical and physical development are both necessary for an athlete, but at the same time they are task-specific qualities to train. Therefore, coaches must consider the physical demands (e.g. cardiorespiratory fitness, speed, strength, etc.) and technical abilities (e.g. tackling, passing, catching, ball possession skills, etc., see ) that need to HERE be developed. These necessary abilities are known as key performance indicators, and improvements can directly increase performance potential.

§ Fitness is arguably best improved through exposure to periodised high TL (see ), which is a critical quality for rugby athletes HERE (see ) and their durability (see ), but exposure and development of this general physical quality should occur early in HERE HERE the off-season. This allows for improvements in technical and tactical proficiency to be the primary focus of the preseason period.

§ Coaches should consider this development as it relates to the off-season calendar, where early in the off-season period, general physical fitness is the primary focus. However, as the athlete transitions to the preseason period, there is an emphasis placed on sport-specific technical development. This utilises the improved general physical ability (e.g. running, accelerating, or changing direction) to achieve higher volumes and intensities of specific activities (e.g. on-field drills or small sided games).

One strategy for coaches to experiment with is identifying ways to assess technical ability through a specific drill that involves definite success and failure of a task (e.g. scoring, tackling), or rating of performance (e.g. percentage of success during a specific time period).

Another strategy is gaining feedback from athletes rating their perception of difficulty and charting improvements over time (see HERE). The aim with either strategy is to quantify technical performance.

Testing fitness in season is not completely necessary as fitness has been shown to be maintained across the season (see ). To HERE boost confidence and quiet any doubts related to this, coaches can use external and internal training data obtained each week to note the same speeds, distances, heart rates, or s-RPE over time.

Coaches should consider the limitations of RPE (see ) as it relates to drastic shifts in external load, recognising the importance of having HERE objective measures from training to pair with subjective data for further context and explanation (e.g. heart rate as an internal measure or relative speed volumes (distances) as an external measure) for comparison.

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WHAT THE Y FO U N D

Although a relationship was found between high-speed running distance during the preseason and increased highspeed activity during in-season competition, there was a negative relationship with technical performance.

Results indicated poor technical performance scores and less hit-up m.min-1 during matches for athletes with higher volumes of high-speed running during the preseason.

The relationship between high-speed running during the preseason and greater high-speed match activity was consistent across all stages of the season (early-, mid-, and late-season), noting a sustained fitness potential throughout the competitive period.

No relationship was found between preseason s-RPE and technical performance, suggesting a lack of cause-effect relationship between the two variables.

“One foundational concept that emerges from this research is that ‘more is not better,’ and aspects of training have a threshold for development (law of diminishing returns). Training prescription is about appropriate application of volume and intensity across the off-season in preparation for success during the competitive season. However, the only way these efforts and values can be properly managed for each athlete is through consistent data collection and monitoring.”

“Another foundational concept is the principle of specificity (SAID) mentioned in the first ‘Practical Takeaway’ - these results are not suggesting highspeed running is not important, rather the likelihood that high-speed running and the training transfer is arguably more important than the overall volume. Coaches should not prioritise running to improve technical abilities - the best way to improve technical skills is task-specific activities (e.g. on-field training drills or small sided games).”

“Therefore, continuing to identify consistent means and methods for assessing technical performance and identifying the skills necessary to enhance the chances of match success is paramount. These are the training means that become the priority late in the pre-season as competition approaches.”

C o nside ratio ns aro und assessing and m o nito ring ham string stre ngth

Injury prevention is a bit of a fallacy, but with proper assessments and monitoring, injury risk can be mitigated (see HERE). Identifying the athletes at greatest risk is the first step, which allows training interventions to be prescribed appropriately in hope time lost due to injury is reduced.

Due to the combination of sprinting under fatigue, hamstring injuries are the most common injury in professional soccer and require proper assessment and training to prepare for the demands of play (see ). Practitioners can measure HERE hamstring strength using a NordBord, where the athlete has maximal eccentric strength assessed for individual legs while performing a Nordic hamstring exercise (NHE) to identify weakness or imbalance. This device has been proven to be reliable in early research (see ), and a lack of or HERE asymmetry in strength (>15-%) is a recognised risk factor for injury (see and ). HERE HERE

It can be difficult to derive immediate conclusions from assessments without appropriate familiarisation or awareness of reliability in the measurement device or procedures. Ultimately, an assessment is a snapshot value that can vary between sessions, especially during demanding training periods such as preseason. However, using this time period to identify athletes who are at a high risk of injury due to weakness or asymmetry is essential to longevity during the season. Therefore, this study examined the reliability of peak force when performing a NHE and investigated potential asymmetry when comparing peak force of the right and left leg between multiple sessions.

Fourteen UK-based male professional soccer players (27.5±4.4yr) had their hamstring strength measured weekly during a sixweek preseason period. Athletes performed six repetitions of a NHE on a NordBord device following specific warm-up and instructions on how to perform the test.

The first two weeks of testing were considered familiarisation sessions, and the following four weeks of data identified the maximum force capable for each athlete (measuring right and left legs individually), as well as the average for each limb across all six repetitions.

Data was analysed for reliability between sessions, as well as examination of the size and side (right or left dominance) of asymmetry when comparing limbs

P ractical Takeaways

Incorporating performance measurements on a weekly basis within training can be a great monitoring strategy to help identify readiness and prevent an over-accumulation of fatigue in season. This starts with capturing baseline values early in the preseason and using tests or exercises that are already occurring in training sessions in order to save time. Likewise, this is where valid and reliable objective measures using technology are helpful (e.g. force plates for measuring jumps, laser timing gates for sprints, global positioning system for measuring speed and distances, or linear position transducers to measure barbell velocity).

When performing any assessment, reliability can be improved when instructions and circumstances are consistent and comparable across the week. Researchers in this study did this by testing on a consistent day of the week and readiness was comparable for the athletes relative to their training load (e.g. a rest day and on-pitch training prior).

§ Also, instructions on performing the test (e.g. “gradually lean forward, maintaining the slowest possible speed resisting through both lower limbs with the trunk and hips in a neutral position throughout and with hands held across your chest”) were given before performing the NHE exercise.

Following performance assessments and monitoring, conducting individual analysis of the results is critical to identifying the individuals at high risk and need of intervention (e.g. modified training loads or supplementary training). Coaches should avoid averaging out performance data across the team if the goal is to mitigate injury

When collecting data that compares right to left sides, it is important to note the direction of the asymmetry This can be accomplished if we consider a left-sided dominance as a negative value and a right side dominance as a positive value. Take caution when using bilateral (double-leg) activities to identify single leg asymmetry There is research that suggests a higher prevalence of compensation when performing bilateral tasks such as jumps, as opposed to the unilateral (singleleg) option(see ). This makes sense since sprinting, although cyclic, is single-leg in nature. HERE

§ Regarding testing using the NHE, this is a good reminder to utilise other single leg tasks to help identify a potential weakness or asymmetry in the hamstrings. The bilateral assessment can be used as a starting point, but further testing using an isokinetic dynamometer may be a more thorough option (see HERE).

Lastly, coaches can use research like this to develop normative values or standards for a specific population. For example, this group of professional male soccer players had peak forces of ~421 ± 84 N with their dominant leg and ~385 ± 70 N in their nondominant leg across the four weeks of testing. Therefore, a value below 300 N may be suggestive of inadequate hamstring strength in such populations.

Following two familiarisation sessions, the NHE proved to have acceptable reliability between weekly sessions when using the Nordbord to assess hamstring strength. A reduction in the force produced by the nondominant limb was greater than reductions in dominant limb across testing during the preseason period, suggesting potential signs of fatigue accumulating.

Likewise, the variability of degree of asymmetry across the group was substantial, noting the importance of individual analysis and comparison between athletes (see HERE).

“With the prevalence of hamstring injuries in soccer, the thought process around implementing a measure of hamstring strength is a great way to guide training intervention (e.g. programming and prescription) for athletes in need. This provides purpose to their training, and the objective feedback provided with the NordBord gives the athlete feedback that can be encouraging as numbers noticeably improve. The NHE is a repeatable and reliable measurement of eccentric hamstring strength, which isolates the capacity of that high-risk musculature.”

“Likewise, the NHE is an exercise that helps to develop eccentric strength. This should be the goal of any time-effective assessment and monitoring battery, in that ‘training is testing’ and ‘testing is training’ - the two are occurring simultaneously Making the frequency of the assessment a practical option for coaches who are looking for direction and feedback on the performance abilities of an athlete and identifying their needs when the opportunity to work with them is allowed. Especially in-season, time to perform supplementary training in the weight room is limited, and those sessions need to be effective and efficient.”

M anaging pe rfo rm ance during co nge ste d in- seaso n co m petitio ns

TIV

The primary objective of training is to prepare athletes for the demands of a single competition, or an entire season of competitions. Soccer is an incredibly demanding sport, involving unpredictable high-intensity movements. Players are required to perform constant low-intensity activity (walking and jogging), paired with high-intensity multidirectional accelerations and decelerations in coordination with teammates and opponents on the field. This makes thorough training and development a massive challenge, especially during periods of multiple matches in a short period of time.

To better understand in-game demands, a method of time motion analysis – known as most demanding passages (MDP) of play – segments the game into time windows (1-, 5-, and 10min) and examines rolling averages of movement (e.g. running, accelerations, decelerations, see ). The analytic method HERE attempts to identify intense periods of movement, which coaches can then use to implement similar situations and intensities in a training setting.

However, there is a lack of understanding as it relates to the differences in movement intensity (e.g. running at various speeds, high-intensity accelerations or decelerations), and any influence a congested competition schedule may have on the MDP With this information, coaches could better prepare athletes for the demanding segments of the season and more appropriately prescribe training. Therefore, the objective of this study was to compare movement characteristics for elite youth soccer players, specifically looking at time windows of the MDP of play during both congested and non-congested match-play

WHAT THE Y DID

Seventeen elite youth male soccer players (outfielders, age 18.2±1.3-yr) from an under-19 Spanish First Division team participated in data collection using Catapult OptimEye S5 units across 30 matches during the 2018-19 competitive season. Twelve of the matches were played in a ‘congested’ schedule (three competitive matches in eight consecutive days), while the other 18 matches were defined as ‘non-congested’ (played with at least five days between matches).

Researchers examined total distance covered, distance at various speeds (running (14-18-km/h), high-speed running (1821-km/h), very high-speed running (21-24-km/h), sprinting (>24km/h)), number of high-intensity accelerations (>3-m/s2), high-intensity decelerations (<-3-m/s2), and player load. These variables were examined as a moving average across each match, identifying the MDP for 1-, 5-, and 10-min windows. Finally, these three MDP time windows of movement were compared between the congested and non-congested matches.

Practical Takeaways

It is critical that coaches recognise the competition schedule and respect athlete readiness heading into match-day This includes adequate exposure to high-intensity activity when time allows between noncongested matches (see ), as well as periods of restoration and recovery when time between matches is HERE sometimes only 48-72 hours.

This may require coaches to be flexible and adaptable to the flow of the season and response of the team, rather than being rigid with a specific practice routine between matches. Specifically, that may mean coaches forgo a traditional on-pitch training session and maximise recovery during non-congested match-play by holding a sit-down tactical session. Alternatively, an active recovery session (e.g. yoga, massage, other treatment modalities with a physiotherapist), or even simply a complete ‘off-day’ to allow players a mental and physical break can potentially boost performance.

A focus on post-match recovery (e.g. treatments, nutrition, sleep, see ) should be consistent across the HERE season, regardless of when the next match is. Any advantage an athlete and team can have in the ability and the amount of time it takes to recover, the better, because that allows for better quality training between matches and performance potential in a subsequent match.

Coaches can also help to manage fatigue and boost quality of play through in-game strategies (e.g. player rotations, modified line-ups based on player readiness, substitutions at critical times in a match). Additionally, tactical advice on how to best defend or attack, so high-intensity movements are effective and efficient.

The preseason period is the pivotal opportunity to introduce high-frequency, high-intensity work that prepares athletes for quick (e.g. potentially 48-hour) turnarounds between matches. Coaches should use that time to include specific exposure to drills that mirror the multi-directional actions and intensity of match-play (see HERE).

WHAT THE Y FO U N D

Total distance covered was significantly less during congested matches when compared with noncongested matches.

No other variable (running at various speeds, highintensity accelerations or decelerations, or player load) was influenced by the congestion or non-congestion of match-play

Therefore, coaches were arguably employing necessary strategies in preparation and during the game to ensure players were capable of performing at a consistent high intensity, regardless of match congestion.

“The results of this study showed there was no reduction in on-field intensity during periods of congested match play, which is excellent feedback for coaches who manage the recovery process between congested matches. Simply put, on-pitch performance remained, suggesting that recovery was allowed. High-intensity performance on the pitch can be the deciding factor between winning and losing (see ) - it cannot be sacrificed or HERE modified as we saw with total distance covered. Players may consciously or unconsciously regulate their low-intensity efforts, but the high-intensity is what enhances the chances of winning and reduces the likelihood of injury due to overload (see HERE).”

“The only way this happens is if training and recovery are properly periodised, programmed, and balanced to ensure players are ready to play at full intensity and duration. Coaches must adapt training to the sport, level of competition, the athlete, as well as the schedule. This starts with understanding ingame demands, as well as the demands of the season as a whole, paying special attention to the MDP (in-game and in-season).”

Validity and re liability of the O U T P U T v e lo city- based dev ice

The opportunity and use of real-time velocity-based feedback is becoming more affordable and practical due to inertial measurement units (see ). These devices can be used to HERE appropriately quantify intensity and help create a more effective training and testing experience, as compared to other methods (e.g. one-repetition maximum (1RM) or ratings of perceived exertion, see HERE).

Given the variability of individuals and various barbell exercises, research has been mixed regarding the reliability and validity of different versions of these devices and their growing technology and ability (see versus ). In order for HERE HERE

coaches to trust the data, make decisions regarding loading prescriptions, or provide feedback to athletes regarding their progress, unbiased research is needed.

The OUTPUT sports wearable inertial unit (see ) is HERE composed of two triaxial accelerometers and a triaxial gyroscope that attach directly to a barbell and claim to measure movement velocity during the concentric portion of an exercise. However, there has been no third-party research or evaluation of the accuracy and repeatability of using this device. Therefore, the objective of this study was to test the validity and reliability of the OUTPUT sensor’s ability to quantify barbell velocity during a squat and bench press.

Eleven athletes (seven men, age 25.6±4.3 yrs, and four women, age 24.5±4.1 yrs) with 6.6+4.3-yr of experience performing the bench press and back squat participated in this study. One specific criteria to improve familiarity with these two exercises, was that participants had to have implemented them in training at least once per week for the year leading into the study

Initially, each participant completed 1RM testing in both the bench press and back squat. A week following testing, three repetitions at six progressive loads (e.g. 35-, 45-, 55-, 65-, 75-, and 85%-1RM) were completed in each exercise while barbell velocity was simultaneously measured using an OUTPUT sensor and four potentiometric cable extension transducers (PCTs) as the criterion comparison. Each repetition was performed with maximal velocity while researchers encouraged and ensured proper technique throughout.

Further, following each repetition, the barbell was returned to the rack to allow a short (5-sec) rest period, in an effort to reduce fatigue and encourage quality repetitions across the set of three. Two minutes of rest was given between each load, and a full 10 minutes was allowed between either back squat or bench press (performed in random order for each participant).

Both mean and peak velocity data were compared between the OUTPUT sensor, for intra-device reliability, and criterion device for validity

Practical Takeaways

The variability in data is potentially due to each individual s technique, not necessarily the device itself (see HERE). Therefore, in order to get consistent data, coaches must encourage consistent execution, so technique (e.g. range of motion and movement sequencing) is the same, no matter the load.

§ Additionally, it is important for coaches to recognise that there is more variability at heavier loads (>~85%1RM, see HERE).

With consistency in technique and use, over time, a coach can gather a general performance potential (average mean or peak velocities, and a high-low (standard deviation)) window for each. Doing this will allow meaningful recognition of differences in performance (e.g. recognising fatigue or improvement) that warrant adjustments to training or provide confidence from favourable improvements.

From a valid and reliable metric standpoint, mean velocity (from start of the concentric to end of movement) is considered the more reliable measure compared to peak velocity or mean propulsive velocity (see HERE).

Therefore, although peak velocity can be encouraging to the athlete in the short-term, mean velocity would be a metric to track from a testing or performance tracking perspective over time (i.e., weeks, months, years).

The greatest opportunity with any velocity device would be the immediate feedback following each repetition, as it provides accountability to the athlete s efforts and promotes focus and intent with maximising each repetition. This promotes a higher quality of training and is likely the reason that velocity-based training has shown to be so effective, with results evident from as early as six weeks (see HERE).

Decisions regarding intensity or volume can be decided based on predetermined velocity thresholds. Coaches can select a minimum bar speed (i.e. target velocity, see , (e.g. 0.4-m.s-1)) based on the goals of training HERE (e.g. force dominant strength or velocity focused power):

§ With opportunity to increase the load used as long as repetitions stay above that target.

§ Likewise, volume (sets and repetitions) can be decided based on that threshold as well. By doing this there is an emphasis on quality outputs and reduces training in an overly fatigued state.

Lastly, given the results of this study, although the OUTPUT is a reliable device, it should not be compared to other technologies or similar devices, as the method of measurement is specific to that software. Find a device that works well for you and your athletes, and simply use it consistently

Overall, the OUTPUT device showed to be reliable across all loads, with one exception: mean velocity of the bench press at 85%-1RM was below standard. Regarding validity as compared with the criterion measure (four PCTs), when using Bland-Altman plot analysis to identify agreement, both the mean and peak velocities were not valid or comparable to the criterion (e.g. overestimating back squat and underestimating bench press at heavier loads).

The OUTPUT device provided measurement for all 198 repetitions performed for the back squat, and only missed two repetitions during the bench press across the 198 potential repetitions.

“From a standpoint of implementing technology within training, reliability in feedback is important. With acceptable reliability, coaches and athletes alike can be more confident in performance, perceptions, and decisions based on the results of an athlete’s efforts.”

“Specifically, given the results of this study, a coach should feel comfortable utilising an OUTPUT device for the back squat or bench press, looking at the mean velocities, and making decisions based on intensity, volume, and progress. It is too early to say whether or not this extends to other exercises, and reliability is questioned as loads increase 85%-1RM. However, when the timing is appropriate (e.g. emphasising power production at roughly 55-75%1RM) a coach may find it beneficial to utilise an inertial measurement unit like the OUTPUT device.”

“From a standpoint of implementing technology as a testing tool, the validity or accuracy of the measure seemed to overestimate (back squat) or underestimate (bench press) the value when compared with a criterion. Therefore, it is critical if implementing a device like this as a testing or assessment tool that results are only compared to results when using this specific device. Despite weak validity when compared to a criterion, this is where the reliability provides confidence in comparing long-term performance progress.”

E ffe ctiv e and e fficie nt Inte rv e ntio n of sle e p hy gie ne

Sleep, of both high quality and adequate quantity, is arguably the greatest weapon in the battle for recovery for athletes (see HERE). Much like physical performance, conducting a sleep assessment of an athlete s sleep hygiene (e.g. their routine, environment, and experience) can help identify areas of improvement and may help an athlete gain an edge with their adaptation to training and overall performance development. Most practically, this assessment process can occur using valid and reliable questionnaires – such as the Pittsburgh Sleep Quality Index (PSQI) (see ) or the Athlete Sleep Behaviour HERE

Questionnaire (ASBQ) (see ) – in an effort to provide an HERE individualised approach to identifying and improving sleep hygiene.

It is well known that sleep can be a challenge for athletes, often disrupting recovery and performance (see ). Yet HERE monitoring and education is still lacking (see ). If HERE practitioners were able to prioritise specific individuals and interventions, efforts to improve the sleep hygiene of those in need may be possible.

Therefore, the purpose of this study was to utilise elite athlete PSQI and ASBQ data to identify general themes regarding sleep habits, in effort to create more effective intervention strategies to improve sleep and support performance.

A total of 412 elite athletes across the world (263 men, 23.2±4.2yrs and 149 women, 23±4.3-yrs) from 27 different sports (e.g. rugby union, rowing, hockey, basketball), participating at the national or international level, provided responses for an electronic version of the PSQI and ASBQ questionnaires. Participation came by social media advertisement, word of mouth, and specific inquiry to governing bodies and clubs.

A specific analytics method (k-means cluster analysis) was performed using an R package (AthSlpBehaviouR) to identify common themes (clusters) related to sleep quality, disturbances due to their training, pre-bed habits, or environmental challenges (e.g. travel).

From the analysis, three clusters (categories) were identified from the PSQI and ASBQ data, and results were presented based on immediacy of need (priority) and a potential effective solution.

Practical Takeaways

For a coach who is beginning to work with a team, or at the start of another training year, the assessment process is important. From a holistic approach, gaining baseline insight via a sleep questionnaire (e.g. SSQI or ASBQ) can help to identify individuals who need immediate support and direction. Likewise, it can provide a generalised understanding of weak points across the entire team that need to be addressed (e.g. sleep duration or disturbances). By doing this, an appreciation for recovery and supporting performance is established.

Following initial assessments, establishing a clear and consistent educational curriculum can be very helpful to build a culture of understanding and action around proper sleep hygiene and its vital role in recovery and performance. Starting with the basics around sleep duration and quality. For example, aiming for a consistent sleep-wake window, looking to be in bed for eight hours each night, and keeping the room dark and cool. As well as establishing a relaxing routine in the hour before bedtime can improve latency and quality. Being consistent with this message helps create a common knowledge to go deeper or more specific with individuals, but ultimately drives conversations in one direction.

Sleep duration and efficiency were the two variables that stood out the most from the PSQI. Therefore, obtaining an objective measure with a reliable wearable device (see ) can help determine the effectiveness of various pre-sleep interventions HERE (e.g. meditation, reducing room temperature, making the room darker). Likewise, even if these devices are limited in recognising sleep efficiency, there is accountability to encouraging an adequate sleep duration window for athletes who may have poor time management skill and struggle getting to bed at a reasonable time.

§ It is important for coaches to identify the typically small percentage of athletes who are truly struggling to obtain sufficient sleep (duration and efficiency). These are the athletes who have the most to gain from a recovery and adaptation to training standpoint, especially since sleep issues tend to get worse as training load increases (see HERE).

Anxiety can negatively impact an individual s sleep, and that lack of sleep can then create even more anxiety. In some instances, cognitive behavioural therapy can be an intervention that has shown promise to improve sleep issues (see HERE). Likewise, coaches should pursue follow-up conversations to identify habits and environmental arrangements that can be detrimental or beneficial. For example:

§ Reducing electronic device use that can be stimulatory

§ Avoid taking naps after 4pm (see HERE).

§ An inconsistent bedtime due to poor time management or distractions.

§ Too much light or distracting noise in the bedroom.

§ Uncomfortable bed, sheets, or pillow

§ Caffeine or alcohol use.

Sleep is a fairly passive recovery tool, but nutrition and hydration are an active method of recovery that requires education as well. Through proper nutrition (e.g. adequate calories and hydration) and education around how to fuel, sleep quality can see improvements due to reduced muscle soreness, thirst, or hunger (see HERE).

Some negative influences on sleep (e.g. travel, late competition or training, unfamiliar hotels) are unavoidable and an athlete must simply do the best they can. Small steps to create some normality or improve an unfavourable environment can help, e.g. bringing a favourite pillow, wearing a sleep mask, ear plugs, or even tape to cover any lights or completely close curtains.

There were three common themes identified from analysing the PSQI and ASBQ data:

§ The first group, although small (14.8%), posed the greatest need, having overall poor sleep duration and efficiency, needing definite behavioural interventions.

§ The second group posed more questions than answers, noting disturbed sleep, but more related to potential routine and environmental factors. Therefore, follow-up conversation was needed to better understand if the disturbance was controllable or not.

§ The final group showed reasonable sleep hygiene, but both education, support, and reassessment are likely valuable.

“When it comes to sleep, coaches need to appreciate that everyone is at risk of having poor sleep hygiene. Therefore, an assessment process to identify these disturbances help highlight those who are at higher risk than others. Followed by specific and consistent interventions that help to support an athlete in improving and changing their sleep hygiene for the better.”

“Ultimately, everyone can benefit from sleep education, gaining an appreciation and understanding for why it’s important and how to improve it. By doing this, it places an emphasis on the recovery process and the accountability necessary for athletes to thrive in a stressful training environment.

“Most notably, prioritising athletes in need through the clustering model used in this research is arguably the most effective strategy. Specifically, the athletes in this study needed to pay attention to behaviours (e.g. time management and bedtime routines) and environmental factors (e.g. room temperature, bedding, reducing potential disturbances). Operating this way ensures the individuals in need get the greatest and most urgent help, as well as using the practitioners time wisely in addressing those in need.”

W hat do e s the re search say abo ut the m e nstrual cy cle’s im pact o n pe rce iv e d re adine ss?

A female athlete experiences considerable psychophysiological variance across their roughly 28-day menstrual cycle and in recent years there has been a concerted effort by practitioners (e.g. researchers, coaches, support staff) to better understand these changes, with the goal of optimising training and performance.

In the past, the menstrual cycle has been oversimplified and divided into three phases: follicular (menstruation), ovulation, and luteal; however, a more appropriate understanding appreciates the differences that occur during both early- and late-follicular and luteal phases (see ). Across these HERE phases, there are gradual fluctuations in various hormone levels (e.g. follicle-stimulating hormone, progesterone, and oestrogen). As it relates to the ability to train, recover, and perform, oestrogen is a significant anabolic hormone that impacts brain function, feelings of affect (e.g. emotions or mood), as well as strength and power adaptations (see HERE).

However, investigation has continued to be ambiguous (see HERE) around the impact the menstrual cycle has on female athletes in training, especially as it relates to their perception of readiness and overall impact on subjective reports (e.g. fatigue, soreness, mood, etc.). Therefore, the objective of this systematic review and meta-analysis was to provide a summary of research around the impact that menstrual cycle phases can have on female athletes.

The authors established specific criteria for studies to be included in this systematic review and meta-analysis: Inclusion of female athletes from all sports, levels, and ages. Assessment of at least two phases of a menstrual cycle.

Evaluation of subjective perception of wellbeing (e.g. effort, fatigue, soreness, mood, motivation, anxiety, sleep)

Change in perception across the menstrual phases.

A search using PubMed, EBSCOhost, and Web of Science was performed in January 2022 using ‘menstrual cycle’, ‘athlete’, and ‘perceptual responses. Articles (n=1,165) were reviewed for inclusion by three reviewers across multiple stages, resulting in 14 meeting the criteria for inclusion.

Study quality was examined, and data was collected from each body of research with focus on the specific menstrual cycle phase (e.g. luteal, follicular, ovulation), athlete perception, and relative change over time.

The athletes’ subjective report of wellbeing and outcome relative to changes across the menstrual cycle were summarised across all studies.

P ractical Takeaways

Most importantly, female athletes would benefit from further education regarding the fluctuations of hormone levels and the impact those changes can have on mood, performance, and the ability to recover (see HERE). An athlete can potentially improve their patience and training efficiency by appreciating the impact this process can have on their ability to train at maximal capacity A female athlete should realise it is acceptable to not feel their best every day

§ For example, oestrogen levels are lowest during the late-luteal and early-follicular phases, which is associated with increased reports of discomfort, reduced vigour, and negative feelings. This psychophysiological interaction reduces performance potential and the ability to train effectively Therefore, coaches must be empathetic with athletes, offering support and information regarding these changes.

§ Coaches either need to take a lead on this education or appoint someone to be involved with their club that serves as a contact person for education around the menstrual cycle as it relates to wellbeing and performance.

§ Coaches can also appreciate these fluctuations when programming volume and intensity This can be done by prescribing ranges (e.g. two to four sets at RPE 7-9) to offer the minimum workload for those who may need a reduction due to menstrual cycle or poor perceived readiness. At the same time, also allow for higher volume and intensity when a session overlaps with an opportune window of trainability (positive subjective reports and hormonal concentrations).

Regardless of the menstrual cycle phase, inquiring about and respecting an athlete s subjective report of readiness can be helpful in adjusting training accordingly This step ensures training is planned appropriately, and athletes are recovering properly. If subjective reports do not meet the expectations of the coach, further conversation should be had to better understand why, and find out what is going on in the athlete’s life outside of sport.

Based on results from this review and meta-analysis, maximising opportunities around ovulation can offer athletes an opportunity to accomplish the highest quality training volume and intensity (see ). From a hormonal standpoint, HERE as testosterone concentration increases (see ), there is also a rise in motivation, energy, and competitiveness HERE (see ). Therefore, identification and appropriate application of training during opportune days can maximise HERE performance potential.

From an educational standpoint, there is research that suggests little-to-no interaction of the menstrual cycle on soreness, stress, fatigue, perceived effort, and sleep quality; to where much of the response is specific to the individual. Ultimately, a coach, support staff, and athletes need to be reminded to appreciate the basics (sleep, nutrition, and stress management), and respect that there are numerous factors that can impact recovery and performance. The menstrual cycle is not necessarily something that can be directly controlled, but efforts should focus on the factors which can be controlled (e.g. proper training prescription, adequate calorie intake, quality sleep, and awareness for mental health).

There were three common themes identified from analysing the PSQI and ASBQ data:

The first group, although small (14.8%), posed the greatest need, having overall poor sleep duration and efficiency, needing definite behavioural interventions.

The second group posed more questions than answers, noting disturbed sleep, but more related to potential routine and environmental factors. Therefore, follow-up conversation was needed to better understand if the disturbance was controllable or not.

The final group showed reasonable sleep hygiene, but both education, support, and reassessment are likely valuable.

“As research continues to explore the interaction of the menstrual cycle on training and performance, avoid getting caught up in the uncontrollable aspects (e.g. hormone fluctuations, mood disturbance) related to readiness. Rather, it is important that coaches focus on the present day and take advantage of opportunities that present themselves for the athlete.”

“The menstrual cycle is one of many factors that can influence a female athlete s readiness and ability to be consistent. However, stress, nutrition, training load, sleep, etc. are other influences at play, all of which impact subjective and objective markers of readiness. Therefore, subjective (e.g. athlete s perception of readiness) and/or objective (e.g. measurable markers of performance such as sprint or jump performance, heart rate variability) monitoring can provide a more holistic and appropriate view of an athlete’s readiness. From this monitoring insight, and hopefully from multiple streams of data (subjective and objective reports), inferences of trainability and adjustments to training can be made.

“In the end, competition dates are set and cannot be adjusted based on athlete readiness. Our goal as coaches is to prepare the athlete to be ready to compete on game day, and this happens through appropriately prescribing and adjusting training throughout the days, weeks, and months prior.”

Fatigue & Re cove ry

This month ’ s top research on fatigue and recovery

T H E E F F E C TS O F D IF F E RE N T T Y

RE S ISTA N C E T RA IN IN G O N E F F

PA IN P E RC E P T IO N

N E U RO M U S C U L A R FAT IG U E A N

E F F E C T O N F U N C T IO N A L M O V

T H E E F F E C TS O F T IM E C O N ST RA IN TS O N P H YS IC A L A N D M E N TA L FAT IG U E

D O E S T H E V E LO C IT Y O F DYN A M IC ST RE T C H IN G A F F E C T J O IN T RA N G E O F M OT IO N , ST RE N GT H O R FAT IG U E ?

H OW D O E S G E N D E R A F F E C T FAT IG U E A N D IS O M E T RIC ST RE N GT H ? W H AT IS T H E A P P RO P RIAT E RE C O V E RY

? H OW D O S H O RT E R RE ST IN T E RVA L S IM PA C T

M U S C L E DA M A G E F O L LOW IN G E C C E N T RIC E XE RC IS E ?

C A N A ST RE N GT H T RA IN IN G P RO G RA M W IT H

RA N D O M IS E D RE ST P E RIO D S BO O ST BA S KE T BA L L P E RF O RM A N C E ?

T H E E F F E C TS O F S L E E P , ST RE S S A N D RE C O V E RY BE T W E E N M A L E A N D F E M A L E E N D U RA N C E AT H L E T E S

H OW D O E S BF R T RA IN IN G IM PA C T O U R

IM M U N E RE S P O N S E C O M PA RE D TO OT H E R ST RE N GT H T RA IN IN G M E T H O D S ?

T he E ffe cts of D iffe re nt Ty pe s of

Re sistance T raining o n E ffo rt and P ain P e rce ptio n

Low load resistance training combined with blood flow restriction (BFR) has been utilised to promote strength gains for clinical populations who cannot tolerate high load resistance exercise programs. Although this has been reported, there are inconsistencies in the research as to whether or not the strength gains with BFR are equal to, less than or greater than high load resistance training. With these training programs, it is also important to consider the effects of perceived effort along with pain levels felt as this will drive motivation to complete them. As such, the current study aimed to investigate the effects of a progressive low load BFR and high load resistance program over eight weeks. Perceptual responses including subjective effort and pain levels were measured while objective measures of muscle strength and size were compared between the two programs.

Sixteen healthy, physically active men ranging from 18-35 years old participated in the study Training sessions were performed twice a week for eight weeks. Perceptual responses, via rating of perceived exertion (RPE), and pain levels, via a Visual Analog Scale of 0-10, were assessed after the end of each session.

The protocol consisted of a unilateral knee extension exercise. At the beginning of each session a warm up consisted of running on the treadmill for five minutes followed by the following resistance training.

High Load Resistance training - performing three sets of eight repetitions at 70% of 1 RM.

Low Load Resistance training - performing three sets of fifteen repetitions at 20% of 1RM with the use of BFR maintained throughout the session. The BFR cuff was inflated to 80% of the subjects AOP (arterial occlusion pressure).

After four weeks of the protocol, 1RM was reassessed and the load was adjusted for training over the final four weeks. Along with this, quadriceps cross-sectional area(QCSA), pain levels and RPE were reassessed at the end of the eight weeks.

Practical Takeaways

When comparing high load resistance training to low load resistance training with the use of BFR, it was found that strength gains were increased through high load resistance to a greater extent. With this, the perceived effort of the program was greater as well. This may be due to a greater sensation of tension on the muscles and tendons with a higher mechanical overload. On the other hand, higher levels of pain perception were found with BFR training, which may be due to metabolic changes induced by the arterial occlusion that occurs with it. Although there were differences in both groups, there were positive strength changes found with each training method which shows value to their use. Moreover, low load BFR training seems to be a safe option to utilise for positive strength gains when high load training is contraindicated. Limitations in this study exist however, with regard to the population utilised as only young men were studied. Changes may occur with a different age group or with a different exercise such as an upper body movement as seen in other studies.

Following eight weeks of training, 1RM increased in both groups but to a greater extent for the high load group. Muscle size measured via MRI increased for both groups but no significant difference was seen between the two. When comparing perceptual responses, there was a greater RPE value with the high load group but a greater pain perception level with the low load BFR group.

Matt’s

“High load resistance training produces greater change in strength along with less perceived pain when compared to BFR training. This was shown in a healthy male population so it may differ when comparing an older population or upper body exercise. Rehabilitation professionals should be mindful of this when prescribing programs.”

“BFR training produces blood occlusion throughout, which can lead to metabolic changes along with higher levels of perceived pain. This is an important consideration for the acutely injured athlete or patient.”

“BFR is a viable strength training program in most cases and although the perception while using may feel more painful, it may be beneficial for those limited with equipment.”

N e uro m uscular Fatigue and its E ffe ct o n F unctio nal M ov e m e nt

Functional movement tests such as the FMS and Fusionetics Movement Efficiency Test (MET) are used to measure various movements and assess dysfunction and injury risk. Accuracy of these tests improve when the scores are combined with a history of previous injury or decreased physical fitness scores. When looking at one s movement, dysfunction can be present and increased when neuromuscular fatigue is occuring. Neuromuscular fatigue is defined as a reduction in the ability to perform a physical activity, generate force or reduce movement efficiency

Performing functional movement screens while in a fatigued state could identify altered movement patterns, which correspond to an increased injury risk, which may have not been seen in a pre-fatigued state for healthy individuals. Therefore, the current study examined the effects of neuromuscular fatigue on a whole-body functional movement test in healthy and physically active adults.

Twenty four physically active adults between ages 18-30 years old participated in the study A whole body functional movement test via the Fusionetics MET was performed in a pre-fatigued state (baseline). Following this, the subjects participated in a graded exercise test to obtain their VO2max followed by an exhaustive run on a treadmill to full exhaustion. This was followed by a repeat of the functional movement test in the post-fatigue state. The scores of the test were determined by clinicians who were trained in the Fusionetics MET

The Fusionetics MET consists of seven subtests which include the following: 2 leg squat, 2 leg squat with heel lift, pushup, 1 leg squat, shoulder movement examination (ROM into flexion, external / internal rotation, horizontal abduction) and trunk / cervical movement examination (ROM into lateral flexion and rotation).

Following testing, the researchers found that test scores for the functional movement examination decreased following the fatiguing protocol for all but one subject. The total mean difference in scoring was 5.2, which is below the defined difference of a real change in movement quality Although this score was not significant, it still showed a change in movement and can therefore negatively impact movement. When looking at specific subtests, the 1 leg squat, shoulder movement and cervical movement showed the greatest decline from pre-fatigue to post-fatigue. The 2 leg squat, 2 leg squat with heel lift and push-up showed decreases in scores which were lower than the aforementioned tests. The trunk movement subtest showed an increase in score from pre-fatigue to post-fatigue.

Practical Takeaways

The Fusionetics MET is a reliable functional movement test that can reveal movement dysfunction, which may lead to subjects being more prone to certain injuries. Practitioners can use this information to make training programs to properly address these dysfunctions along with teaching clients the optimal movement pattern. Through this study, we see that in a healthy population, there is a change in movement patterns following a fatiguing exercise protocol that not only affects the movements associated with running, but also upper body and cervical movements due to possible changes in joint proprioception and neuromuscular activity. From this, we can note that neuromuscular fatigue can cause changes in movement patterns and therefore may increase injury risk even in a healthy population. From the results, we see changes in upper body movement scores, which may have been due to a reduction in postural and dynamic balance along with neuromuscular control. Although this information is valuable, it is not without limitation. The Fusionetics MET does not account for compensatory patterns in upper body movements or loss of balance in squatting motions.

“Fusionetics MET along with other functional movement testing can provide valuable information regarding how clients move through ranges of motion in upper and lower body movements. Practitioners can test their clients with this to determine movement dysfunction and prepare proper treatment programs to address it.”

“This type of functional movement testing is valuable to utilise in pre-season training in order to screen for possible injury risk for athletes of all sports. Utilising this test at midseason or postseason can allow coaches to see player progression and continued weaknesses in movement patterns.”

T he E ffe cts of T im e C o nstraints o n P hysical and M e ntal Fatigue

Tasks that simulate specific competitive situations are vital in order to properly train soccer athletes. Commonly, time constraints are present in matches depending on the score along with the time remaining. This type of time pressure has been known to cause increases in the mental and physical fatigue players may face in both practices and matches. The manipulation of available time as a constraint has been known in soccer training tasks but no previous studies have tested its effects on physical and mental load. The purpose of this study was to determine whether having more or less time to solve soccer tasks had an influence on the physical load and mental fatigue that players experience.

Forty eight semi professional soccer players across three different teams (two male and one female) with an average age of 22.4 ± 2.25 years old participated in the study. Each player had at least ten years of experience without reported injuries.

A Polar Team Pro was used to assess the physical load of the training tasks. Measurements included average and peak heart rate, distance covered, average and maximum speed and the number of sprints.

Fatigue was measured via subjective reporting of the players rating of perceived exertion (RPE) using a 0-10 scale along with the NASA-Task Load Index Questionnaire which quantified feelings of mental load.

Two sessions were carried out with four training tasks: two possession games with the goal of completing a specified number of consecutive passes (five passes equal one goal) and two simulated matches with goalkeepers. In the first session, one team started out trailing 2-0 in the possession game and 1-0 in the traditional game with more available time given. In the second session, the score was 0-0 to begin with and changed to 2-0 in the possession game after two minutes (five minutes total in the task) and 1-0 in the traditional game after seven minutes (twelve minutes total in the task).

Practical Takeaways

When soccer players’ feel more pressure to perform due to time constraints and scoring deficits, they report feeling more physically and mentally fatigued. Despite this, it does not match their objective physical effort which shows a decrease in the output with this constraint. This can be caused by a multitude of factors including mental fatigue increasing perceived effort and consequently decreasing how hard the players’ feel they’re able to work.

Along with this, the mental fatigue reported could have produced an increase in cognitive complexity and further stress which may invoke motivational changes which negatively affect play Another rationale for the increased mental fatigue is the negative match status accompanying a deficit in score. There were limitations in this study including the small sample size utilised along with the amount of sessions used. Future studies should look to add more training sessions to get a better picture of mental fatigue along with adding different constraints within the task to mimic live competition.

There were higher values of mental effort and fatigue noted when the time pressure in the tasks increased. Along with this, RPE and subjective reports of mental load increased with less available time. When it came to physical load however, along with heart rate measures, there was an increase shown with the simulated match and possession game with more available time. This indicates that the player’s subjectively perceived that physical exertion was higher with the time pressure increases although the physical efforts measured via heart rate and speed / distance covered were higher with more available time.

“This review highlights an important concept that mental fatigue can lead to decreases in physical effort and performance. Using time constraint tasks in practice and game simulations can be an effective training tool for coaches to use to allow their players to adapt to mental fatigue and come up with strategies to deal with it in game situations.”

“With this in mind, coaches should also understand that mental fatigue training should be dosed across different situations in order to avoid overtraining and further decrements in physical performance.”

D o e s the V e lo city of D y nam ic Stretching

A ffe ct Jo int Range of M otio n, Stre ngth o r Fatigue?

Dynamic stretching (DS) is utilised in training usually as a warm-up and involves moving the limb through the full range of motion. It differs from static stretching as it involves moving through the position, not just holding it. It has been reported in the past that dynamic stretching increases muscle strength, vertical jump height and joint range of motion (ROM). There exists inconsistencies in the research however, when it comes to the velocity utilised in the dynamic stretch and whether that has an effect on the noted reported benefits. The aim of the current study was to determine the effects of two different velocities of DS on joint ROM and isometric strength at the ankle joint for plantarflexion (PF) and dorsiflexion (DF).

Fifteen healthy male subjects (20.5 ± 1.1 years) with no reported injuries participated in the study A familiarisation session was used to test initial levels of passive DF ROM and isometric strength. The following two visits were experimental sessions.

Passive DF was tested via an isokinetic machine with the foot affixed to a footplate and the knee fully extended. The ankle was dorsiflexed passively until the subject reported discomfort.

Isometric strength was tested prior to DS with subjects placed in the same machine. They performed a five second isometric contraction of the plantarflexors and dorsiflexors twice each.

EMG was used on the gastrocnemius and tibialis anterior to determine muscular activity

The level of subjective fatigue from pre stretching to after the four sets was measured via the Visual Analog Scale which recorded levels of fatigue from 0-10.

For the experimental sessions, the DS was performed consisting of four sets of ten repetitions with thirty seconds of rest in between. The DS was performed standing with the knee fully extended and raising the foot from the floor through PF and DF with as wide a range of motion as possible. The subjects performed DS sets at 100% of their maximal velocity (DS100) followed by DS sets at 50% of their maximal velocity (DS50) dictated via use of a metronome.

Practical Takeaways

Dynamic stretching can be utilised to minimally increase joint ROM at the ankle but does not have a positive effect on isometric strength as noted from this article. Maximal velocity with DS at the ankle can become an injury risk and cause performance decrements including loss of strength and lack of ability to achieve end range dorsiflexion at the ankle. Moderate velocity of DS is suggested in order to improve joint ROM in a safe and effective manner

The noted results of this study have to be taken with caution as it only tested the ankle joint and did not look at other lower extremity joints such as the knee or hip. Therefore, dynamic stretching benefits need to be verified in future studies. Along with this, the sample size was limited and only performed on a male population. This information would be valuable for other populations such as females, older individuals or those with hypermobility

It was found that ankle ROM increased following both trials but no significant difference was found between the DS100 trial and the DS50 trial. The small increase in ankle ROM following the trials was most likely due to increase in stretch tolerance according to the authors. Isometric strength at the plantarflexors and dorsiflexors did not increase to a significant level, which the authors believe was caused the accumulation of fatigue that was noted after the DS. Subjective fatigue was greatest during DS100 compared with DS50. Due to the increases in fatigue noted with a higher velocity, it is suggested that DS be performed at a moderate velocity to avoid performance decrements.

“Moderate velocity dynamic stretching can be a valuable tool for increasing joint ROM at the ankle. Increasing repetitions along with the velocity of it can have a negative effect on strength secondary to fatigue levels. Coaches should be mindful of this when dosing stretching into training programs.”

“It is unclear what the benefits of dynamic stretching would be when combined with other common warm-up tasks such as jogging and static stretching. Future studies should investigate this combination along with the effects of static stretching on joint ROM and isometric strength.”

H ow do e s ge nde r affe ct fatigue and iso m etric stre ngth?

Exercise induced fatigue may be task or muscle specific and can affect males and females differently There is evidence from prior studies showing that females are more fatigue resistant when compared to male counterparts when it comes to resistance training. Along with this, fatigue can affect lower extremity and upper extremity musculature at different rates which is important to understand when designing training programs. Consequently, strength is affected as higher levels of fatigue lead to decrements in performance and endurance. The purpose of this current study was to investigate the changes in isometric strength following a fatiguing strength training protocol for the upper ande lower extremity With this, the authors wanted to examine whether males or females were more fatigue resistant and how the muscles being tested might respond differently

The study consisted of 18 total subjects (13 male and 5 female) who were familiar with resistance exercise. They went through three lab sessions with the first being a familiarisation session to isometric exercises followed by two experimental sessions testing the right elbow flexors and the right knee extensors. With this, the authors wanted to investigate which muscle was stronger along with more resistant to fatigue while comparing gender

In the sessions, the participants performed six, thirty second maximal voluntary isometric contractions with thirty second breaks in between. They performed one session of biceps brachii isometric contractions (elbow flexion) and one session of vastus lateralis isometric contractions (knee extension). A surface level EMG was utilised to show changes in the muscle activation.

Following the sessions, it was found that males had greater isometric strength compared to females although females maintained greater force production throughout the protocol. This was shown as females maintained approximately 57% of their baseline strength compared to 45% for males by the end of the protocol. When comparing musculature, it was found that the isometric strength of the knee extensors were greater than the elbow flexors. With this, decrements in EMG activity were greater at the biceps brachii compared to the vastus lateralis.

Practical Takeaways

This study showed the differences between males and females isometric strength. Although males were stronger at baseline, they showed greater fatigability throughout the protocol leading to a decrease in strength along with activity at the muscles being tested. This may have been due to the skeletal muscle fiber type along with the skeletal muscle metabolism differences in males and females. When comparing the two muscles tested, we see that the biceps brachii is weaker than the vastus lateralis. This may be caused by the differences in size of each muscle along with the blood perfusion levels when comparing the two. From this, we can determine that the biceps brachii has greater levels of electrophysiological fatigue and therefore high intensity movements involving elbow flexion will have a greater rate of fatigue progression. Although this study provided good information regarding the difference between male and females with isometric strength and fatigue, the study may have been limited due to the sample size with inequality between the number of males vs. female participants.

“From this study, we see differences in gender along with strength of muscles performing elbow flexion and knee extension, which are both prime movements in sports and recreational lift programs. Coaches and rehabilitation professionals can use this information in order to format training programs with a better understanding of fatigue so that they can avoid overtraining. They can do so by introducing proper recovery time along with focusing on other prime movers such as the gluteals in the lower body and the latissimus dorsi in the upper body.”

“The use of thirty-second rest intervals that were utilised in this study is a good way to bring on fatigue which is similar to sporting activities where rest is at a minimum. It is a practical way to mimic game action is a safe manner.”

W hat is the appro priate re cov e ry tim e betwe e n po ints in a te nnis m atch?

Tennis matches include both immediate (in between strokes) and short-term (in between points) recovery for each player. Both of these can cause changes in heart rate along with oxygen uptake (Vo2), which can impact players’ performance levels. At the professional level, these measurements – along with speed of play balanced with the appropriate time given for short-term recovery – is of utmost importance to allow for appropriate rest.

For Grand Slam tennis tournaments, a 25-second limit is given between points, a rule enacted in 2018. The purpose of this study was to examine whether the 25second limit is appropriate and what effect it has on physiological performance of elite young players. The hypothesis was that 25 seconds was long enough for sufficient recovery of heart rate and oxygen uptake.

Thirteen elite male tennis players aged between 15-18 were included in this study They were each ranked in the top 30 in their country and were members of their national squad. They were individually tested in three consecutive days at the end of their training cycles. They had no injuries prior to the study

For each session, a 15-minute standardised warm-up was performed followed by 10 minutes of passive rest. The “two-line drill wide mode” test at the lowest ball frequency was used. This test involves players hitting consecutive shots with their left and right hands aiming as close to the baseline as possible. Five two-minute stages of the drill were performed, which included ball throwing speeds of 14-20 balls per minute. Players had a 75-second passive recovery after each stage. Each player performing the drill reached higher than 95% of their maximum heart rate by the end of the five stages.

Before the testing, heart rate at rest was measured for 10 minutes while the players sat in silence, and VO2 measurement was assumed to be 1 MET due to being at rest. Both heart rate and VO2 were measured throughout the drill immediately after each stage.

Practical Takeaways

This study highlights the appropriate time of short-term recovery needed for elite tennis players. There is significant recovery achieved following 25 seconds and up to 35 seconds of rest. Anything shorter than this may have a negative effect on performance.

When players are allotted more than 25 seconds of rest between points, they are being given substantial benefits in their cardiovascular recovery This may give an unfair advantage to a player who is fatiguing faster than their opponent, and can affect the outcome of a match.

This study was performed on elite young tennis players. The conclusions of this study could be different if it was performed on amateur athletes. One can assume that a higher amount of recovery is necessary for untrained participants compared to trained participants. This would be interesting to look at to determine appropriate time limits between points for non-elite junior tennis matches.

Heart rate and oxygen uptake sufficiently recovered following the first 25 seconds of recovery between stages and continued to recover through 65 seconds of rest. The largest magnitude of recovery was achieved between 25 and 35 seconds of rest. Following 35 seconds of rest, the heart rate, along with the oxygen uptake that was recovered every 10 seconds, decreased over time.

From this, the authors determined that in young elite tennis players, 25 seconds is an appropriate time for recovery in between points. Allowing for extra time (up to 10 seconds) following this may allow players to have an unfair advantage in their physiological profile of heart rate and oxygen recovery

“Short-term recovery between points in tennis matches allow for appropriate cardiovascular recoveryn. Going longer than 25 seconds for this measure may produce unfair advantages for elite young athletes. Coaches and umpires need to be enacting this rule consistently to allow for fair competition.

“Training these athletes to recover for a shorter amount of time in between points during drills and practice may be beneficial to improve VO2 and ability to sustain HRmax levels.

“Future studies should look at female athletes to determine whether or not longer or shorter recovery time is appropriate at the professional level.”

H ow do sho rte r re st inte rvals im pact m uscle dam age fo llowing e cce ntric exe rcise?

Eccentric exercise has been shown to increase muscle swelling and delayed onset muscle soreness (DOMS) to a greater extent compared to concentric or isometric contraction.

In order to reduce this risk, redistribution of rest (RR) times in between sets of eccentric exercise has been studied. The theory of RR in between sets is that it allows for more frequent muscle contraction with less rest in between, in order to increase the mechanical pumping of blood flow within the muscle, allow increased circulation and therefore, better recovery

The purpose of this study was to investigate how RR affects indirect markers of muscle damage compared to traditional rest in between eccentric exercise sets.

Eleven male resistance-trained men aged between 24-27 yrs with at least six months of resistance training were studied through a protocol of isokinetic unilateral knee extensions using either traditional (95 seconds) rest in between sets or RR with 15 seconds in between sets.

Each group performed a total of 40 repetitions. The traditional rest group performed four sets of 10 repetitions and the RR group performed two sets of 20 repetitions.

Maximal isometric and fast eccentric strength were measured prior to the protocol along with one minute after completion. They were assessed via three maximal repetitions with the greatest torque used for analysis. Muscle morphology (ultrasound imaging), tensiomyography (speed of muscle contraction), range of motion (ROM; prone knee flexion angle) and muscle soreness were measured. These indirect muscle damage markers were measured at baseline along with immediately after, 24, 48, 72 and 96 hours after the protocol.

Practical Takeaways

The use of redistribution of rest between sets of eccentric contractions does not produce an increase in muscle damage, or a drop in concentric strength, when compared to a more traditional rest break in between sets. Although this was found, the study only measured one exercise and only looked at changes in the quadricep muscle. Future studies should look at how this would change when studying other large lower extremity musculature such as the hamstrings that also are important eccentrically while walking and running.

The use of eccentric exercise may produce muscle damage evidenced via reduced force production, which in this study was noted five days following the exercise program. It would be interesting to see what the results would be if concentric or isometric contractions were utilised in the exercise. From knowledge of muscle physiology, it is noted that isometric contractions produce less muscle inflammation, so may not produce the same results as the eccentric contractions.

Range of motion passively measured decreased following the use of the training protocols. This could have been caused by increased soreness or small changes in muscle swelling as noted on the ultrasound. This could have affected the force production drop that was noted up to five days post-exercise.

This study may have been limited by the participants’ familiarisation period with the eccentric protocols prior to the study. Future studies should look at untrained participants or females to see if results would change or offer different information regarding muscle damage.

The results of this study showed little-to-no difference between protocols for peak torque, total work, isometric strength and fast eccentric strength. Along with this, there were no significant differences between protocols for the measurements of muscle morphology, tensiomyography, or muscle soreness. This suggests there is no increased risk of muscle damage when redistributing rest intervals between eccentric exercises.

It was found that passive ROM was reduced 48 hours after the training, and muscle soreness was increased immediately after and 24 hours after the training (no significant change between protocols). Muscle soreness peaked from 15 minutes to 24 hours after exercise for both protocols.

Although there was a lack of differences between the two protocols, the study still showed changes in muscle following eccentric exercise. It was found there was a decrease in force production noted up to five days postexercise.

“Eccentric training can be advantageous when attempting to increase strength or reduce injury in the quadricep muscle. From this study, there is no additional risk of a redistribution of rest in between sets, which may have been due to the participants having experience with the eccentric exercise. Therefore, it is recommended that rehabilitation professionals and coaches acclimate their athletes to this type of strengthening prior to beginning a training program with them.

“Levels of muscle damage from eccentric strengthening of the quadricep can last up to five days post-exercise. In order to avoid higher levels of this damage, training sessions should be spread out in order to avoid risk of increasing muscle damage leading to overtraining and potentially injury.”

C an a stre ngth training pro gram with rando m ised re st pe rio ds bo o st basketball pe rfo rm ance?

Basketball players need to perform high-intensity actions (HIA) throughout a game. This includes sprints, accelerations, decelerations, turns, changes-of-directions and various jumps. Sustained decrements in the performance of these tasks is common toward the later stages of games and practices, leading to a drop in performance and increased injury risks.

Repeated Power Ability (RPA) is a training method, which uses performance of high-intensity muscle power exercises performed with incomplete recovery in order to improve both isolated and HIA under fatigue.

The purpose of this study was to examine how a 10-week training intervention focused on muscle power output with random recovery times affects the physical performance during a simulated full-court basketball game.

Twenty male basketball players who averaged six hours of basketball training per week, plus at least one year of experience with power and strength training, were split into two groups of 10 (experimental and control). The players ranged from the under-18 age group up to ameteur senior level. They were 15-34 years old.

The training intervention lasted for 10 weeks and included two weekly strength training sessions. This included two blocks of five sets of five repetitions of the free parallel back squat and bench press exercises, with instruction to perform the concentric phase of the repetitions as fast as possible in order to induce changes in power. Both groups participated in the same regular basketball training sessions during this time.

After each set, the players had a rest interval between 15, 20, 25, 30 and 35 seconds that was selected in a random order. No rest interval was repeated more than three times.

The following measurements were taken one and two weeks prior to the end of the 10-week training period and one week after These tests were measured in both groups.

§ Bilateral and Unilateral Countermovement Jump

§ Unilateral Horizontal Jumps

§ Speed: measured via 0-10m and 0-25m sprints.

§ Change of Direction: measured via V-Cut testing

§ Yo-Yo Intermittent Recovery level 1

§ DOMS (Delayed Onset of Muscle Soreness) measured on a 0-100 visual analog scale

At the end of the training period, players participated in a fiveon-five simulated basketball game (the teams were split and had players from both the control and training group), with the following measured:

§ Distance covered

§ High-intensity accelerations

§ Number of body contacts

§ Player load

§ Average peak speed and acceleration

§ Average heart rate

P ractical Takeaways

From this, we can determine that a strength training program with randomised rest periods can improve a basketball player’s physical performance, which can increase the likelihood they can perform more high intensity actions throughout a game.

§ The use of power training with randomised rest intervals changed the capacity for basketball players to be able to perform high-intensity actions throughout a game. This change allowed the players to perform more acceleration and decelerations, which may enable coaches to utilise fast breaks or fast transition situations more effectively in a game setting.

Players in the training group improved their ability to change direction. They showed lower contact times and more efficient breaking ability, which over time can improve neuromuscular control and reduce the risk of injury with those movements.

§ There were limitations in the study, as the control group could have encountered other strength training situations outside of the basketball training. Also, with regard to the training group, informal basketball participation (such as playing with friends away from training) could have influenced their results. Future studies should also look at different exercises being used along with a more robust strength training program, as the current study only used two exercises.

The strength training group showed significant improvements from baseline with the number of highintensity accelerations and decelerations along with horizontal and vertical jumping abilities. The group also showed improvements in speed and change of directions. The control group also made positive changes in these measurements but to a lesser extent than the strength training group.

“The use of power training can improve a basketball player’s speed, change of direction, jumping and capacity for physical contact. Coaches can use this type of training throughout the season in order to improve upon their team’s success.”

“In basketball, high-intensity actions are commonplace and required at various stages throughout the game in order to make winning plays. Including strength training with randomised rest periods between sets can improve physical capabilities and reduce the risk of fatigue at the end of the game. Rehabilitation professionals and coaches can use this type of training throughout the season in order to reduce the risk of lategame fatigue and performance decrement.”

T he e ffe cts of sle e p, stre ss and re cov e ry betwe e n m ale and fe m ale e ndurance athlete s

Sleep is well known to be an important factor in endurance athletes’ ability to perform and recover Cognitive function can play just as much of a role as sleep, as negative emotional states such as anxiety and fear can be detrimental to performance. These two factors can be even more important when it comes to the actual competition and days leading up to it.

The aim of the current study was to measure sleep, and perceptions of stress and recovery prior to an ultra marathon and compare males and females to determine whether sex differences existed. Through this, the authors expected to find that elevated stress levels would disturb sleep, while greater sleep duration would improve the athletes’ perception of personal recovery

Thirty six ultramarathoners running the Two Bays Trail Run (56km) participated in the study. Eighteen females aged 31-45 and 18 males aged 35-49, who were experienced runners and were not diagnosed with sleep issues, were included. Sleep and perceived recovery and stress were monitored over three consecutive days prior to and on the morning of the race.

Sleep: measured via an activity monitor worn 24 hours per day. Bedtimes and get-up times were recorded along with sleep duration and wake after sleep onset (WASO; total duration of wake time in the time from initial sleep onset to final awakening) for each participant.

Perceived recovery and sleep: measured via the Short Recovery and Stress Scale (SRSS) was completed for three days prior to and on race day This is an eight item subjective scale assessing the perceptions of one’s stress and recovery. Recovery items include physical performance capability, mental performance capability, emotional balance and overall recovery. Stress items included muscular stress, lack of activation, negative emotional state and overall stress.

P ractical Takeaways

There exists sex differences when it comes to sleep and the perception of recovery and stress. Males tend to have overall higher levels of stress but this leads to an increase in sleep duration. Females had a higher quality of sleep but suffered from higher levels of negative emotional balance and state, which decreased sleep duration. Females may have been more willing and perceptive to discuss their physical and emotional states, leading to this discrepancy in results.

From sleep monitoring, it was found that both males and females do not get the recommended amount of sleep (>7 hours) and have a higher duration of WASO (<20 minutes) than they should. This may have been affected by thoughts regarding the upcoming race.

Sleep duration was actually increased by reported levels of stress in the male population. This contradicts the authors’ hypothesis.

Strengths of this study included the objective measurement of sleep via an activity monitor The limitations of the study include the sample size from a numbers perspective and recruitment.

Duration of sleep was not statistically different between sexes or on respective nights pre-race. Among both sexes, it was lowest the night before the race. Females had a lower WASO, meaning they had higher quality sleep compared to males. With subjective perceptions, females had a lower score for overall emotional balance meaning they felt less balanced and under control prior to the race. With this however, they experienced a higher physical performance capability on race day compared to all other days measured. For stress levels, overall scores were similar between males and females, although males noted higher levels of stress overall.

When comparing measures, it was found that negative emotional state was associated with sleep duration. Overall stress was positively associated with sleep duration for males.

For each 60 minutes increase in sleep duration, overall recovery scores increased by 0.2. One unit of increase in overall stress led to a WASO increase by eight minutes. For males, each one unit increase in overall stress increased sleep duration by 22 minutes. One unit increase in negative emotional state for females resulted in a 21-minute decrease in sleep. One unit increase in negative emotional balance for females decreased sleep by 31 minutes.

“This study highlights the differences between males and females with regard to how they sleep and how they perceive their stress and recovery. From this, we see that females report greater negative emotional scores, which should prompt coaches to use interventions to decrease stress and improve sleep strategies.

“Both sexes should be educated on sleep quality prior to competition seasons in order to improve sleep duration and quality Interventions like napping may improve subjective and objective measurement of sleep and therefore increase performance.”

H ow do e s B F R training im pact o ur Im m une re spo nse co m pare d to othe r stre ngth training m etho ds?

For strength gains to occur, the American College of Sports Medicine recommends that resistance training be prescribed at 70-85% of 1 repetition maximum (RM), 8-12 repetitions per set and 1-3 sets per exercise.

Blood flow restriction (BFR) training has become popularised as an adjunct to strength training, with use of blood flow occlusion to produce strength gains via higher muscular metabolic stress with less volume. Although it has not been observed chronically, BFR training can produce acute muscle damage including an increase in muscle inflammation. With this, there has been interest in comparing the immune inflammatory responses in BFR strength training to different intensity strength training. This study set out to compare programs with and without use of BFR.

Eighteen male and female participants (20-31 yrs), were divided into three groups (same number of male and female): BFR strength training, low intensity strength training (LI) without BFR and high intensity strength training (HI) without BFR. The BFR group performed the bench press and knee extensions at 30% of their 1RM; 75 total repetitions were completed over four sets (30, 15, 15, 15 repetitions) with a 30-second interval between sets.

The LI group performed the same repetitions, percentage of 1RM and rest intervals without BFR.

The HI group performed exercises at 75% of their 1RM; 30 total repetitions were completed over three sets (10, 10, 10 repetitions). Between sets, there was a rest period of two minutes and 15 seconds.

1RM was calculated through the following measure: Warm-up consisting of 4-10 repetitions, with 50% of the load estimated for the test followed by a five-minute rest. The exercise was then performed with a load of 80-100% perceived load and the maximum number of repetitions was performed. If subjects went above 10 repetitions, the load was adjusted. The load was then calculated via the model proposed by Baechle and Groves (1RM = Load x [(.0375 x reps) + .978]).

Blood Samples were taken and analysed four separate times. This included immediately before, immediately after, 30 minutes after and 24 hours after the training session ended. Measurements included the leukocyte / neutrophil / monocyte count and the lymphocytes and lymphocyte subpopulations of TCD4+ and TCD8+. These are all markers of the immune-inflammatory responses in individuals.

Practical Takeaways

This study shows muscle damage occurs regardless of the intensity of resistance training. BFR accentuates this but that damage is reduced within 30 minutes of recovery When compared to the higher intensity group, the BFR and LI groups’ training variation had a more profound effect on the inflammatory response. This may be due to the higher number of repetitions, longer time of muscle contraction and shorter rest intervals between sets.

BFR training has effects that cause muscle damage which can return to baseline levels with 30 minutes of recovery Although this is the case, muscle adaptation can occur as well which is positive to those utilising it. Future studies should look at these blood markers over a longer period of time or with a greater amount of exercise sessions to deem its safety

Higher intensity training may be better utilised compared to the BFR/LI repetitions in cases where people feel less recovered or are coming off of illness.

There were similar effects found between the BFR group and the LI strength training groups when it came to leukocyte count and lymphocyte counts. With this however, the BFR group showed further increases in these numbers compared with the LI group. Furthermore, the BFR did not promote immunosuppression, as leukocyte modulation returned toward baseline levels within thirty minutes.

The HI group showed differences in the measured markers from pre to post exercise but it did not reach the same level of significance as the other groups. Although this is the case, within 30 minutes, the blood counts returned toward baseline for all training techniques. This suggests that muscle strength recovery occurs regardless of the volume utilised.

“Although changes were seen with BFR when it came to the immune response, this participants used were trained young individuals. How would these results be different if the sample included older or untrained individuals? Along with this, how would these results change with different exercises being utilised?”

“This study’s comparison of BFR with different intensity training programs is eye-opening to the effects that it may have on muscle. Through this study, it was shown that exercise intensity was more influenced by the amount of time a muscle was contracted and the volume of muscle contractions, as opposed to the load that was used. This information is valuable to the rehabilitation professional creating programs for athletes and injured individuals.

Yo uth D eve lo pm e nt

M o nito ring jum p pe rfo rm ance in childre n: C an co ache s e ffe ctiv e ly use dro p- jum ps and augm e nte d fe e dback?

When working with youth, teaching and incorporating jumpbased activities within sessions can be an exciting way for strength and conditioning coaches to be creative, whilst developing many physical qualities (e.g. power) that are useful to all athletes. When teaching athletes to jump, coaches can provide extrinsic feedback (e.g. information that originates from outside of the learner, such as a video example), or intrinsic feedback (e.g. how a movement should feel). Although the use of feedback and its contribution to performance have been well documented in adults, few studies have investigated this in prepuberal youth.

Therefore, the aim of this study was to examine the facilitatory effects experienced from eight weeks of augmented feedback compared to four weeks of no feedback followed by four weeks of regular feedback in prepubertal children.

Twenty-one healthy children (~9 yrs) were recruited from a local primary school. Exclusion criteria for this study required all participants to be free of any neurological disorder, injury and diseases of the neuromuscular system. Following a dynamic warm-up consisting of dynamic stretching and submaximal jumping, pre, during and post measures were collected for 10 countermovement jumps and 10 consecutive drop-jumps from a height of 30cm. In addition, a host of functional motor tasks (rhythmic jumping, standing longjump, and scissor jumps) were also collected at the start, middle and end of the study The addition of drop-jump training was the only addition to a normal physical education lesson.

In total, 24 sessions were observed and 10 students were placed into an intervention group and 11 into a control group. Of these 24 sessions, the intervention group received augmented feedback in all lessons regarding jump height. However, the control group only received feedback from sessions 13-24.

Practical Takeaways

From the results of this study, it may be implied that the transfer of performance gains to functional motor tasks were negligible, suggesting that augmented feedback may not be an effective method when working with young children and adolescence. The authors of this study suggested that a reason for this may be that levels of motivation dropped as the study went on. From personal experience, drop jumps, countermovement jumps and the various functional motor tasks are not the most enjoyable task to be performed over 24 sessions. Children love opportunities to engage in practice which is both fun and progressive (see attached article), so below are some age appropriate introductory plyometrics which although are the same exercises, can be delivered in a varied manner to suit the athlete at hand:

Age 6-9 Yrs – Skipping, pogo jumps and single-leg sticks on flat cones. To make this fun, coaches may incorporate music and play a “musical statues” version where once the music stops, an athlete must “stick” a landing on a flat cone.

Age 9-16 Yrs – At this stage, students will be going through peak height velocity Therefore, coaches/teachers may wish to Increase the amount of attention they pay to cues. For example, with pogo jumps and skipping derivatives, the terms “fast” and “stiff” may be used to communicate ground contact time. To progress, coaches may introduce unilateral variations with assigned set and repetition schemes to monitor and educate around session volume and intensity Assuming that the athlete is now aware of the technical aspects of the movement, the coach can look to play with both extensive (e.g. volume related) and intensive (e.g. intensity driven) variations of these movements. Skipping can be progressed to power skips, whilst pogo s can be performed in a multi-directional nature (e.g. laterally) to work on the holistic lower body

To track improvements in youth, a broad and countermovement jump are a fantastic way to assess both vertical and horizontal ground reaction force (See attached video). The gold standard for measuring this would be to use some form of hardware (e.g. an Optojump). However, healthy competition and results drive buy-in and are great to report to students and parents. Utilising a camera to record some of this can be a great way to gain extrinsic feedback for the athlete, but be mindful to check with your policy holder on this.

The main findings of this study were that drop-jump and countermovement jump heights improved following 24 sessions for both the intervention and control group. Ground contact times for the drop-jumps remained high (>200ms), whilst reactive strength index measures varied between 0.75-1.5 in most children.

When reporting on the impact of feedback type and duration on jump height and functional test, no significant findings were reported at the middle of the intervention. However, when feedback was provided to both groups, jump height significantly enhanced in the post test.

In the functional motor tasks test, only rhythmic jumping increased significantly in both the intervention and control group in the post-test. The authors were quick to report that the transfer between the drop-jump and rhythmic jumping is small from a movement transfer perspective, further suggesting that improvements in rhythmic jumping was more likely due to repeated exposure to the task rather than as a result of the dropjump intervention.

These findings are difficult to infer any meaningful results from, as both groups demonstrated improved results from the mid-post-test, despite the intervention group receiving regular augmented feedback from the start. This highlights that in prepuberal children, feedback type may have less impact than in adults.

The findings of this study offer little insight into how coaches can practically utilise drop jumps and augmented feedback to support learning in young children. This is surprising, as I would have expected a positive transfer in the functional motor task (e.g. rhythmic jumping, standing long-jump and scissor jumps) given their reliance on various stages of the stretch shortening cycle to be developed successfully. In addition, as the functional tests were all jump related, the authors missed out on an exciting opportunity to measure the influence of drop jump training and augmented feedback on agility, strength, speed or imbalances. Such findings could add value to the strength and conditioning industry by providing current practitioners with strategies to include in training to overcome tedium.

As stated in the practical takeaways section, working with children at this age presents numerous challenges. A blend of education and adaptation are only ensured if a child’s interest and attention can be maintained for prolonged periods of time. This is important to mention, as effective changes in an individual s physiology can only occur when an athlete is invested in their programme and buys-in to the process. This has been discussed extensively by Sarah Seekamp in the attached podcast who discusses the contribution of design, rules and autonomy in the learning process. A particularly interesting part of the conversation occurs around 17:32, where Sarah discusses why adults find it hard to let children lead. This is a useful lesson for coaches to carry into their programmes.

N utritio n

This month ’ s top research on nutrition

C arbo hydrate fe ar, skinfo ld targets, and bo dy im age issue s in e lite fe m ale fo otball

Women s football is growing rapidly in participation, opportunity, and professionalism. But the scope of research supporting female players is far from comparable to the men s game. A recent audit showed the need for a ‘strategic and multidisciplinary research agenda to fill the gaps in female football research. A key area of concern was nutrition-related research, which was studied far less than other areas of sport and exercise science.

The lack of research in female football is concerning because female athletes are more susceptible to negative health outcomes associated with chronic low energy availability and relative energy deficiency in sport. Some of these negative health outcomes include disordered eating, low bone mineral density, irregular or total loss of periods, and extreme weight loss. A study by Morehen et al. (2022) showed that 88% of the England Lioness’ (recent European Champions) presented with low energy availability during a four-day training period. Additionally, although mean carbohydrate intake was 3.3g.kg-1, daily carbohydrate intake was not adjusted to daily physical training demands (i.e., an inability to fuel for the work required).

To help prevent under-fuelling in female football, it is important to understand the reasons that underpin it. On one hand, if budget allocations to nutrition and food are low, then actual provision of high-quality carbohydrates would be low and minimise the opportunity to fulfil nutritional strategies. Likewise, if a lack of education provided to the players and supporting staff on the importance of fuelling and current carbohydrate recommendations. Additionally, there may be underlying misconceptions of carbohydrates and sufficient fuelling in an environment where body composition is emphasised as a performance priority

Therefore, the aim of this study was to understand player and stakeholder perceptions of nutrition practices to improve the health and performance of female football players.

The research was gathered using semi-structured interviews with elite English female footballers (n=12), parents/guardians (n=9), technical coaches (n=9), sport scientists (n=7), nutritionists (n=5), and medical staff (n=5).

The interviews were split into three domains: (1) ‘Participant background and demographic’, (2) ‘Perceived impact of nutrition on performance with an emphasis on priorities and challenges’, and (3) ‘Female specific performance nutrition priorities and challenges’

Although the interviews followed this structure, questions were open-ended e.g., “what are your thoughts on…?” to gain the participants' opinion on these domains.

Following the collection of data, four themes were established that present a narrative of the nutrition culture within elite women s football:

1. fuelling is important but under-fuelling is common

2. carbohydrate confusion: do carbohydrates make me fat?

3. skinfold culture, body image issues and social media pressure

4. nutrition support: the current challenge and future solution

Theme 1

Most players (n=9/12) understood it was important to meet fuelling recommendations. One player commented on how energised they felt on the pitch after meeting the recommended carbohydrate intake before game day. Other stakeholders, such as coaches (n=5/9), parents (n=6/9), sport scientists (n=5/7), and medical staff (n=4/5), identified fuelling as the No. 1 performance priority. Despite this, many players and stakeholders were confused about how to fuel before a game (e.g., understanding the carbohydrate recommendations). Additionally, some concerns were raised on player health and wellbeing that is consistent with chronic low energy availability and relative energy deficiency in sport. A sport scientist mentioned “there are players in the club who have never actually had a cycle while I’ve been at the club”. Another medical staff member mentioned that players were “lethargic on the pitch” putting “them at an injury risk”.

Theme 2

As an extension of the previous conversation, many participants perceived that players were under-fuelling due to not consuming enough carbohydrates to meet the recommendations. Some staff members mentioned players had a ‘fear of carbohydrates’ and even used the term ‘carbphobic . One player mentioned “sometimes I just don’t want to eat carbs because I know they will make me fat”. Misunderstandings were also presented by parents, as a sports scientist was “asked by a parent if her daughter, aged 18, should go on a low carbohydrate diet”.

Theme 3

The challenge to simultaneously fuel whilst also meeting body composition targets was reported as a contributing factor to under-fuelling. Players’ body composition was regularly (4-8 weeks) assessed using weighing scales and skinfold, which adds to the perceived pressure to meet body composition targets. One player commented “well if I’m in red now, how am I going to get into green? The only way to get into green is not eating, eating minimally”. This, along with social media influence and pressures from some stakeholders, resulted in players being concerned with body image. A player mentioned they had “seen it (under-fuelling) first-hand affect people to a point where it’s actually ruined their careers because they’ve been more obsessed with what they look like than their football”.

Theme 4

There was a considerable difference in the sport sciences provision, particularly in nutrition-related services, between domestic-level clubs and the international team. This meant players coming to the international set-up had varying levels of nutritional knowledge. Additionally, other stakeholders also showed a lack of nutritional knowledge. This could have added to unhelpful comments from staff members which could have contributed to the previous three themes. For example, a player mentioned “you had a manager, for example, who was telling people they needed to lose weight and, you know, that’s not a good conversation to have, not just with anyone but with a female athlete ‘cause, you know, that can have really, really bad effects on someone’s mental state”. Additionally, players would seek nutrition support online and from other less nutrition-qualified stakeholders, such as sport scientists and parents. A nutritionist mentioned that correcting false nutrition-related information players had read online was “a challenge in itself”.

P ractical Takeaways James’

This study shows it is just as important to educate stakeholders on the importance of nutrition and implemented nutrition practices, as it is to educate the players. A performance nutritionist is one person in a multi-disciplinary team, so it is important the message around nutrition remains consistent between staff members. This can also be used to a nutritionist’s advantage, as other staff members can check on players to ensure nutritional guidelines are being met. For example, ensuring that players had eaten some food before training or consumed their recovery shake posttraining.

Approaching topics around weight, body composition, and body image between men’s and women s sports is very different. This study highlighted the importance of sensitivity around these topics in female sport. In my own applied practice, I prefer to focus on the term functional mass, rather than body fat when talking about body composition changes.

Despite this, body composition and weight still needs to be monitored in female sport; however the approach towards it and how the results are interpreted needs to be altered. An example of this is linking changes in body composition to performance parameters - for example increasing muscle mass (and therefore increasing weight) with improvements in 1 rep max squats. Also blinding the number of the weight scales to ensure players can’t see the figure. When interpreting body composition and weight results, ensure the focus is on performance and making the athletes more functional.

Developing relationships with individual players is probably the most important aspect to ensure honest and open conversations can be had around nutrition and body image. Players need to be able to trust you to open up about these topics and trust is built between two people communicating with each other regularly

C o mme nts

“Outside of the athletic environment, the societal and social media pressures that women face have been thoroughly documented. Therefore, it is not surprising that those pressures translate to a female athletic environment (and are arguably amplified due to the monitoring and emphasis on body composition). This study brings light to those pressures and perceptions and collates them into a tangible report.”

“Additionally, because this study reports on the elite England women’s pathway football squads, I think it adds an additional importance on these topics. These pressures and perceptions are being experienced by some of the top athletes in female sport, who have the most up-to-date support and access to top-quality staff members and provisions. But this just shows that a shift in approach around nutrition, body composition, and body image in female sport needs to change at the top of the sport, to be able to filter down.

“There is a lot to be learned from this study Women s sport is growing rapidly, and therefore the support teams surrounding them are growing too. It is so important that those staff members supporting female athletes understand the unique pressures and perceptions they face and provide the education to their athletes as early as possible (a great podcast and video in this area is below).”

C hange s in bo ne and bo dy co m po sitio n during a seaso n in e lite m ale fo otballe rs

Most people are familiar with many of the benefits of exercise. Perhaps not as well understood is the importance of regular physical activity in building and maintaining healthy bones. Like muscle, bone is a living tissue that responds to exercise by becoming stronger Long-term participation in weight bearing exercise can have a positive effect on bone characteristics.

This physiological benefit has been witnessed in football players, as in 2018 habitual football participation has been associated with a greater whole-body bone mineral density and bone mineral density at specific anatomical locations. Despite this, elite football players can suffer stress-related bone conditions that result in long-term absence from training and match-play

Data on the change in bone characteristics over the course of a season would provide a useful insight for practitioners seeking information on bone adaptation. As a result, the aim of this study was to describe changes in bone and body composition characteristics over the course of a competitive season in elite male football players.

Twenty professional footballers (average stature of 1.82m and body mass of 80.89kg) from an English football team were recruited, and 26 recreationally active (average stature of 1.78m and body mass of 77.91kg) volunteered for the control group. Control participants were age-matched to the football players to ensure there was no significant difference in age between groups.

The football players completed a full-time training schedule, which consisted of 4 x 120 minutes of training per week. This included strength and conditioning, tactical and technical drills, and one or two competitive matches per week. The control group took part in two to three unstructured weight bearing activities per week.

Four dual-energy X-ray absorptiometry (DXA) scans were completed throughout the season to measure bone characteristics and body composition. Visit one was completed at the start of preseason; visit two at the end of pre-season; visit three at the middle of the competitive season; and visit four at the end of competitive season.

A peripheral quantitative computed tomography (pQCT) scan was also taken of the dominant lower leg (defined as the leg that the participant most comfortably kicked a ball with) at the same time points to further measure bone characteristics.

P ractical Takeaways

These findings contribute that regular weight bearing exercise (i.e., team sport) promotes improvements in bone characteristics in one single football season (approx. 42 weeks).

The largest body composition changes occurred during the preseason period. Nutrition strategies during this period should be aligned to the goals of each player but all should have a focus on high calcium intake to support optimal bone health (i.e. an increase in milk and yoghurts).

Observations show that although bone characteristics increased across the season in elite football players, there was between-individual variation, with some players showing a decrease.

Understanding the body composition and bone characteristics of elite football players across a season sets a benchmark for similar populations. Practitioners in other football clubs can use this data to compare their players to this study but also provide a target for young developing players to achieve similar bone mineral health.

Although weight bearing exercise promotes improvements in bone characteristics, stress fractures are still common in high impact sports. This is usually the product of a large increase in exercise intensity or frequency, overtraining, rapid muscle gain, and poor nutrition. Good quality nutrition can support bone health by ensuring an athlete is fuelling to match their energy demands (and therefore avoiding low energy availability).

Increasing calcium and vitamin D intake, either through food or supplements, will also support bone health. Providing a well-rounded supplement strategy is needed to support an athlete’s bone health and avoid stress-related bone injuries.

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Footballers had significantly higher characteristics than controls for 24 out of 29 DXA and pQCT variables. Some of these variables included total lean mass (67kg versus 58kg respectively), legs and total bone mineral density, legs and total bone mineral content, and total area. However, there was also significant random interindividual variation in baseline values for all variables, for both footballers and controls.

Over the course of the season, both the footballers and controls’ body composition significantly improved. Total fat mass decreased and total lean mass increased at a similar rate between groups. For the football players, the largest differences in body composition were witnessed during preseason.

The footballers’ total bone mineral density, total bone mineral content (an increase of 18g), and leg bone mineral content (an increase of 4g) significantly improved between visit one and visit four The footballers’ leg bone mineral density did improve, but not by a significant amount in the time frame.

The control group had improvements in all four bone characteristic measurements, but the differences were not significant and marginal. For example, total bone mineral content only changed by 1g.

Although these findings show a group difference, there was significant inter-individual variation in all variables in both groups (i.e. players within the same group also showed large differences from one another).

James’ C o mme nts

“This study highlights the benefits of exercise, in particular football, for bone health and bone markers. Although it was conducted over a 42-week period, anyone can start playing football or indeed exercising now, which would help bone health. Be mindful that not all players saw a benefit in training and bone turnover however football exercise in general would be beneficial for the young athlete for general health and wellbeing.

“We know bone turnover is high, especially in young and growing athletes. Therefore, good quality nutrition is important to support the development of new bone.”

“Keeping it simple by advising athletes to consume milk, yoghurt, and green leafy vegetables each day would be a good start.”

C an athlete s accurate ly and co nsiste ntly m e

hydratio n status v ia urine co lo ur?

Drinking enough water every day is crucial for many reasons: to deliver nutrients to cells, keep organs functioning properly, regulate body temperature, and improve sleep quality, cognitive function, and overall mood. For an athlete, optimal hydration status can also significantly impact competitive performance. But in practice, how do we measure hydration status?

The best method is to examine urine concentration, either by assessing urine osmolarity or urine specific gravity e.g. But a simpler way to self-assess hydration status may be through urine colour. Individuals can compare their urine colour to a urine colour chart, which systematically ranks urine colour with a number and hydration status i.e., hydrated or dehydrated.

Although little research is available, correlations between urine colour self-assessment and urine concentration by athletes has ranged from moderate to good. However, there are several factors that can influence urine colour scoring, such as light source, the background behind the sample, methodology, nutritional intake, and the individual scoring the sample. Since it’s important for athletes to regularly assess their urine colour to gauge hydration status, it is vital they can perform this assessment accurately and consistently

Therefore, the aim of this research was to investigate the accuracy and reliability of athletes’ assessment of urine colour using artificial samples. The observations demonstrate the athletes capacity to report their own urine colour whilst monitoring their hydration status accurately and reliably

The study included 19 female lacrosse players, 11 female triathletes, and five male collegiate football players – all who competed in the Division 1 National Collegiate Athletic Association in the United States of America.

Four different artificial urine colour samples were developed to match shades 4 to 7 on the eight-colour urine colour chart. Athletes scored two samples twice on two separate days.

The samples were placed in a urine colour scoring box, along with a urine sample taken from the athlete that morning. The urine colour scoring box was created by the first author to standardise urine colour scoring. The front of the box had three windows so the participants could see the three samples. There were two compartments to the box - the first regulated the distance between the sample and participant and was painted black to eliminate reflections from light sources. The second was white and had the samples in.

LED lights were positioned below the samples. This box was placed on a white table in a well-lit room, and athletes were positioned in a chair

The participants looked through the peep holes to focus on the sample and score them based on the eight-colour urine colour chart placed to the side of the box.

P ractical Takeaways

The results show that under controlled conditions, athletes were unable to reliably and accurately assess urine colour to determine hydration status. Therefore, if a hydration status assessment is required, other methods such as measuring urine osmolarity or urine specific gravity should be used to gain an accurate and reliable result.

There are several portable and easy-to-use devices that can measure urine osmolarity or urine specific gravity. Some examples include Osmocheck and Renol Urine Osmolality Controls which both might be better methods for practitioners based on the findings of this study

Situations that require a hydration status assessment before and ideally after performance include: an athlete training or competing in a hot or humid climate, during or post illness (stomach bug or infection), during an intensive training block, to help determine a hydration plan, or when an athlete is exhibiting signs of dehydration.

Urine charts are still a useful tool when providing general advice on hydration to an athlete or group of athletes. For example, it is difficult to measure urine samples from a team of athletes or athletes in the field (cyclists, rowers, skiers etc) but providing them with a urine chart is a simple method for any athlete in the world to self-assess their hydration status.

Combining the urine colour score with differences in athletes’ weight may provide a more complete picture of an athlete’s hydration status. A -2% difference in weight after exercise indicates an athlete is very dehydrated. Using electrolyte tablets may help avoid athletes becoming dehydrated during exercise periods, when an athlete is exercising in hot or humid conditions, or during and after illness.

Practitioners should be aware that some foods can change the colour of urine. For example, I know first-hand how certain multivitamin tablets and hydration powders can discolour habitual urine colour This is important to know for athletes and coaches if using colour charts for hydration assessment.

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Reliability

As a group, there was no significant difference between the average colour ratings for each of the reference colours between day one and day two. Results showed that as a group, participants scored samples similarly between days (4.4±1.2 vs. 4.5 ± 1.2) However, on an individual level, samples were scored inconsistently

Accuracy

Of all 102 individual cases, 21.6% of the scores matched the reference colour exactly The average participant’s score of the artificial sample was lower than their predefined colour The finding suggests the odds are 2.6 to 1 that athletes report urine samples one shade lighter than the actual colour of the sample scored. Similarly, they are 2-3 times more likely to report a lighter urine colour than what it is.

James’ C o mme nts

“Most people know that to stay healthy, you need to drink water The effects of dehydration for anyone can be uncomfortable at best — at worst, they can be dangerous. For athletes there is an added layer of complexity as they push their bodies to compete, sometimes in extreme environments.

“Ensuring an athlete is optimally hydrated is a basic principle of performance nutrition. Although sometimes, staying hydrated during exercise isn't as simple as just drinking water, which is why it's important for any athlete to understand the relationship between hydration and performance.

“As a sports nutritionist, it’s my responsibility to educate athletes on the importance of optimal hydration, and for that, a urine colour chart can be a useful tool. But when an accurate and reliable measurement of hydration status is required, then this research shows other tools should be used ahead of a urine colour chart. For example, previous research shows the beneficial effects of a portable urine refractometer to determine urine osmolality.”

Inv e stigating and analysing the variance of po ly phe no l- rich supple m e nts

Tart cherries (see infographic below), pomegranates, blackcurrants, and blueberries are all examples of fruits that contain high amounts of polyphenols. Polyphenols are a diverse group of plant secondary metabolites, which have antioxidant and anti-inflammatory benefits. Supplementation using polyphenols has been suggested to enhance exercise performance and recovery

A recent review suggested supplementation with >1000mg/day of fruit-derived polyphenols for 3+ days before and after exercise can increase the recovery of exercise induced muscle damage. Additionally, an intake of ~300mg of polyphenols an hour before exercise can enhance endurance and repeated sprint performance.

However, commercially available polyphenol-rich supplements provide little-to-no information about the quantity of polyphenols per serving. This information is important for the athlete to allow the correct dose to be selected to enhance performance and recovery

Therefore, the aim of this study was to produce a catalogue of information on the polyphenolic content of a range of commercially available polyphenol-rich fruit supplements that are commonly used by athletes.

Ten supplements were analysed containing either cherry, pomegranate, blueberry, or blackcurrant. Supplements were purchased directly from manufacturer websites to mirror the process athletes would go through to buy and consume. Authors did not disclose to the manufacturers that they were analysing the products for the study, and supplements were stored at 4°C prior to analysis and analysed before their best before dates.

Tests were conducted to measure the total phenol content and the total anthocyanin content. Further tests, known as ferric reducing/antioxidant power (FRAP) assay and total oxygen radical absorbance capacity (ORAC), measured antioxidant capacity

P ractical Takeaways

Having this information now allows athletes and performance nutritionists to implement a polyphenolfocused strategy (i.e. which food types). Based on the previously stated recommendations, a single serving of POM Wonderful Pomegranate Juice per day for more than three days surrounding exercise would enhance recovery An additional single serving of Active Edge Pomegranate or SIS Rego Cherry Juice one hour before exercise would also improve performance.

There is a cost implication for the athlete or the club when recommending supplements. The most costeffective supplements to achieve the recommended >1000mg/day of polyphenols were the Curra NZ (6 x 45p per serving = £2.70), followed by the POM Wonderful Pomegranate Juice (1 x £4 per serving = £4), then the SIS Rego Cherry Juice (3 x £1.40 per serving = £4.20), and the PAS Cherry Bomb s (2 x £2.50 per serving = £5), and finally the Healthspan Elite Sour Cherry (4 x £1.50 per serving = £6). The remaining supplements cost more than £10 to achieve a total phenol content of >1000mg/day

Although the differences between supplements made from different types of fruit were to be expected, there were also large differences between supplements made of the same fruit. It is important athletes don’t assume that supplements using the same fruit have the same polyphenol content.

The authors commented that the values for total anthocyanins content, stated by the manufacturers, were much higher than the researchers found in the study They put this down to anthocyanins being susceptible to degradation during transportation, storage, and processing. When transporting and storing the supplements, ensure to follow the instructions on the packaging.

It is important to note that consuming polyphenols regularly can blunt training adaptations. It should be applied to situations where an athlete has a need to recover quickly and there are little training adaptations to be gained - for example, surrounding a competition

There was considerable variability across the supplements for all measures. There was an 83-fold difference between the highest and lowest supplement.

In order from highest to lowest, the total phenol content per serving was POM Wonderful Pomegranate Juice (1007mg); PAS Cherry Bomb (591mg); Active Edge Blueberry (432mg); Active Edge Pomegranate (391mg); SIS Rego Cherry Juice (321mg); Healthspan Elite Sour Cherry (247mg); Active Edge Cherry Bottle (239mg); Active Edge Cherry Sachet (208mg); Curra NZ (169mg) and Active Edge Cherry Capsule (12mg).

There was a 385-fold difference between the supplement with the highest content of anthocyanins and the lowest. When comparing total anthocyanin content per serving, in order from highest to lowest, Curra NZ (73.2mg); POM Wonderful Pomegranate Juice (40.5mg); PAS Cherry Bomb (23.7mg); SIS Rego Cherry Juice (14.3mg); Active Edge Blueberry (7.6mg); Active Edge Pomegranate (6.8mg); Healthspan Elite Sour Cherry (5.5mg); Active Edge Cherry Bottle (4mg); Active Edge Cherry Sachet (1.5mg); Active Edge Cherry Capsule (0.2mg). Using the FRAP assay, the POM Wonderful Pomegranate Juice (14,320 µmol) had the highest result, followed by the Active Edge Pomegranate (6464 µmol) and then the PAS Cherry Bomb (4489 µmol). The Active Edge Cherry Capsule (72 µmol) had the lowest recorded value.

The results from the ORAC test showed the SIS Rego Cherry Juice (10,072 µmol) had the highest result, followed by the Healthspan Elite Sour Cherry (8917 µmol) and then the PAS Cherry Bomb (8362 µmol). The Active Edge Cherry Capsule (150 µmol) had the lowest recorded value.

James’

“The key takeaway for me is this paper removes the element of guessing when supplying athletes with polyphenol-rich supplements. Thanks to this study, athletes and sports nutritionists can now make informed decisions about which polyphenol-rich supplement to choose when implementing an accurate and successful polyphenol nutrition strategy.:

“Additionally, the smarter nutritionists will now be working with their chefs to identify which food types (not supplements, but raw food) contain higher concentrations of polyphenols and aim to get these into recipes and postcompetition food stations.:

“Finally, heading down to your local fruit and vegetable stall and buying fresh mixed berries will probably be a cheaper option when compared to buying supplements! (I talk about this in the podcast below).”

Low e ne rgy availability : D o e s it cause o r co - exist with unde rpe rfo rm ing athlete s?

Athletes frequently endure intense training periods to accelerate training adaptations with an aim to improve performance. However, the increase in training load can cause the build-up of training-induced fatigue from insufficient recovery - termed functional and non-functional overreaching. This is different to overtraining which results in recovery taking far longer to achieve, sometimes months.. During these intensive periods, where energy expenditure has increased, there can be an imbalance in energy availability, resulting in low energy availability (LEA).

LEA has been associated with many negative health outcomes as first identified by the Female Athlete Triad. This model linked LEA with poorer bone health and irregular menstrual function in female athletes. But the authors within the International Olympic Committee (IOC) realised this model was too limiting, so created the Relative Energy Deficiency in Sport (RED-S) model. This model also included male athletes and associates LEA with “impaired physiological function including, but not limited to, metabolic rate, menstrual function, bone health, immunity, protein synthesis, cardiovascular health”.

It is accepted that chronic LEA will eventually lead to RED-S. Evidence so far suggests athletes who are underperforming during periods of intense training loads have indicators of LEA. However, although it is possible that LEA is driving underperformance, the authors argue it is also possible that underperformance and LEA are independent factors that coexist.

Therefore, the aim of this review was to gather performance and markers of LEA following endurance training blocks to decipher how overreaching and LEA interact.

The review included studies with men and women over the age of 16 who participated in endurance or team sports. Participants had to have a classification at or above a ‘recreationally active’ level of fitness.

Studies were required to hold an intervention length between two weeks and one year, where training load increased or maintained.

The primary meta-analysis aimed to measure LEA markers in athletes who were underperforming between pre- and posttraining blocks. The secondary analysis measured changes in performance in athletes who had two or more markers of LEA between pre- and post-training blocks.

Markers of LEA included an energy availability of less than 30kcal.kg fat-free mass (FFM).day-1, reduced bone mineral density, a score of 8 or more in the Low Energy Availability in Females Questionnaire, decreases in fat free mass or total body mass, a suppressed resting metabolic rate (RMR) ratio, decreased RMR relative to FFM, decreased resting muscle glycogen content, clinical diagnosis of functional hypothalamic amenorrhea (when a women loses her period due to abnormalities in the release of gonadotropin-releasing hormone), and changes in some biochemical markers that have been demonstrated to be altered in periods of LEA.

In total, 56 studies were included in the review The primary meta-analysis showed that underperforming athletes experienced no changes in body mass, cortisol, insulin, and testosterone markers; however, they did experience reductions in fat mass, relative RMR, and leptin (leptin is a hormone secrete from fat cells which essentially tells the body when you are full and not hungry anymore)

From the three studies that estimated the energy availability in underperforming athletes, all demonstrated an energy availability of less than 30 kcal.kg FFM or an energy deficit throughout the training block. Underperforming athletes with two or more markers of LEA also had a higher VO2max compared to underperforming athletes without markers of LEA. The secondary meta-analysis showed that exercise performance was not affected by athletes with two or more markers of LEA. The length of the training blocks, removing poorer quality studies, separating studies based on exercise capacity tests and exercise performance tests, and increasing the LEA markers to three or more instead of two or more, did not affect this result.

P ractical Takeaways James’ C o mme nts

This research shows underperformance in athletes can occur with and without evidence of LEA stress. Therefore, LEA does not always lead to reduced performance, so it is also possible athletes may be affected by both overreaching and LEA independently

The results show that reductions in fat mass, relative RMR, and leptin can help diagnose LEA. This may be useful when trying to decide if the athlete has LEA or is overreaching. Fat mass decreasing rapidly, or an athlete striving to be as ‘lean’ as possible are good red flags for practitioners to keep an eye on in clubs or working directly with athletes.

Regardless of whether an athlete is presenting with LEA or overreaching, it is important the energy balance is restored. This may result in the combined act of increasing energy intake and reducing exercise load. However, increasing energy intake is a more sustainable way to reduce the gap in the energy balance, as training load may not be able to be reduced for a prolonged period of time to ensure the athlete is still adapting to training.

When athletes approach periods of increased training load, a thorough nutritional plan is needed to compensate for the increase in energy expenditure to ensure that LEA is avoided. This can range from education for athletes and staff, menu preparation, creating strong relationships with hotel head chefs and managers, and food and supplement provision.

Athletes require elements of overreaching and reduced energy intake to become more functional. For example, functional overreaching is necessary to gain training adaptations, and a slight energy deficit may be required to reduce an athlete s fat mass so they become more efficient. However, issues arise when athletes are frequently in a prolonged and/or severe overreaching and LEA states. Therefore, the duration and severity of the LEA must be considered.

Want to learn more?

Then check the se out...

“As a sport nutritionist, LEA is common with people I work with, especially among female and youth athletes. However, it is an issue that can be avoided. Firstly, it’s important to educate the athletes and the surrounding staff on the importance of fuelling and how to fuel correctly to manage the demands of the day. Secondly, a thorough plan needs to be implemented to ensure athletes are receiving the right nutrition at the right times. Sleep should also be reinforced and the importance of recovering and resting enough each day (podcast below).

“An application available to athletes, which is gaining lots of attention is the Hexis App. This allows athletes to plan nutrition around the demands of each day and week and is worth checking out.

“Finally, developing individual relationships with players is important to ensure an open and honest line of conversation can occur and allow individuals to feel comfortable to tell you the truth regarding energy intake.”

E quality , D iv e rsity & Inc lusio n

C all to e nd sexism in sche duling spo rts ev e nts.

Across the world women are under-represented in education, leadership positions and often paid less for doing the same job. This is echoed in sport and although things are changing, with male only sports and events now including women, there is still much to do.

Female athletes continue to fight for equality such as experiencing sexist uniforms, rules around breastfeeding, and sexual harassment and impropriety There is also lower representation of women in sports governance, coaching and journalism.

This editorial sought to focus on the issue of gender equality when it comes to the scheduling of sporting events. This relates to the fact that women s sport continues to receive far less coverage than men s sport with broadcasters favouring male athletes at prime time than women.

P ractical Takeaways

Current practices may impact sports participation for women by reducing visibility of their counterparts and reducing the importance of those sports in the eyes of the public.

The authors of this editorial propose that the International Olympic Committee and all major sports federations around the world who run events in which both men and women compete, such as tennis, to alternate the order of the men’s and women’s finals between tournaments.

They propose that this change is unlikely to negatively impact overall viewership and that it can challenge the gender hierarchy in sport and to explicitly and proudly demonstrate that the achievements of female athletes are as valued as their male counterparts.

In the 2016 Rio de Janeiro Olympic Games, 25 hrs of competition were scheduled for men ’ s events on the last Sunday (prime broadcasting time). For women ’ s events this was a mere 2 hrs. In sports such as tennis and beach volleyball where both men and women compete, the last two events are the women’s and men’s finals – in that order This perpetuates a gender hierarchy in which the women s final is seen as a warmup for the men.

I agree wholeheartedly with the authors of this editorial that improving the visibility of women ’ s sport can help to advance social norms while improving resources and opportunities for girls and women. This will require a long-term commitment though with recent successes of the Lionesses in England winning the European Championships being followed up by record attendances in the domestic game hopefully we are already seeing a change in the tide.