The Performance Digest - August 2022 (Issue 70)

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

Fatigue

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.

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

Strength & Conditioning

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.

Nutrition

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

Dr. Jordan August DPT, CSFC, SFMA, FM S

Injury Prevention &

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

Tom Green MSc UKAD Advisor

Dr. James Morehen PhD

Cody Roberts MSE

Reha b

Matt Klayman’s MSE

& Recovery

James de Lacey MSc

James is

Strength & Conditioning

This month ’ s top research in strength & conditioning.

HOW STRENGTH LEVEL IMPACTS RATE OF DEVELOPMENT ADAPTATIONS

IS COMPLEX OR COMPOUND TRAINING SUPERIOR FOR ATHLETIC PERFORMANCE?

CAN OVERLOADING THE ECCENTRIC PHA POTENTIATE CONCENTRIC PERFORMANCE?

How strength level impacts rate of force development adaptations

OBJECTIVE

Rate of force development (RFD) and impulse under a range of loads is a vital component of athletic performance. Olympic Weightlifting derivatives are considered an effective approach for developing these qualities. This is likely due to their ability to generate high force and velocity simultaneously

However, it is unclear how physical characteristics (such as strength) impact training adaptations to RFD and impulse under heavy loads. Thus, this study aimed to see if changes to RFD and impulse differed between higher and lower level weightlifting performance and to compare jump strategies and force-velocity relationships between groups.

WHAT THEY DID

Twenty recreationally trained men were ordered by their power clean 1RM. The middle four subjects were removed, leaving 16 subjects in two groups: a stronger (age = 24.1 ± 5.1 yr; bodyweight = 78.1 ± 4.0 kg; 1RM power clean = 1.08 ± 0.09 kg; 1RM squat = 2.0 ± 0.2 kg) and weaker (25.9 ± 2.6 yr; bodyweight = 82.6 ± 14.0 kg; 1RM power clean = 0.78 ± 0.1 kg; 1RM squat = 1.38 ± 0.32 kg) group.

After being grouped, subjects undertook a 10-week training intervention involving three sessions per week, split into two five-week mesocycles. Days 1 and 3 in the first mesocycle consisted of the power clean at 70% 1RM and jump squat at 4050% 1RM for 5 x 5. Day 2 consisted of hang power clean and snatch grip pull at 55-70% power clean 1RM for 4 x 5.

The second mesocycle increased the power clean to 85% 1RM for four reps per set, with the jump squat reducing to 0-30% 1RM. The hang power clean and snatch grip pull increased to 70-85% 1RM for four reps per set. A depth jump was added to day 1 and 3 while a plyometric split squat was added to day 2. 1RM power clean and squat were reassessed between mesocycles and training maxes were adjusted. Pre and post testing consisted of the jump squat at loads of 0, 20, 40, 60, and 80% squat 1RM with a standardised countermovement depth of internal 85° knee angle.

A force plate collected measures of RFD at 200ms, impulse, and peak force. Data was further analysed by plotting forcevelocity relationships.

Finally, jump strategy was analysed by force-time waveform data on the force plate measured from the initiation of countermovement until the subject left the force plate.

Practical Takeaways

The combination of Weightlifting derivatives and loaded jumping is very effective for enhancing RFD within stronger and weaker athletes. However, stronger athletes adapt faster but may need a maximal strength stimulus if the goal is to continue improving peak force. Lesser trained individuals produce more general adaptations across multiple qualities, albeit over a longer time course.

What can you take from this study to apply to your own training or to your athletes?

§ ‘Surfing the curve is a great way to program for lesser trained athletes. That is providing a balanced training program targeting force and velocity capabilities over a loading spectrum.

§ Stronger athletes may have been velocity deficient, as with the removal of traditional strength training, they didn’t show improvements in peak force but did see large improvements in RFD. So, targeting RFD ability in stronger athletes may still need traditional strength training if your goal is to continue getting stronger

§ This was a very minimal training program, showing how a simple approach can yield great results. If you are short on time, two ballistic exercises three times per week is enough to spur gains.

If you’re wondering how to categorise loading of exercises to ‘surf the curve,’ you can use the guidelines from this paper:

§ Strength: 80-95% 1RM (Squat, Deadlift, Leg Press)

Strength-Power: 80% 1RM (Clean Pull, Deadlift). 70-80% BW (SJ, CMJ)

§ Power: 10-45% BW (SJ, CMJ, SLCMJ, SLSJ). 65% 1RM (Clean Pull Jump)

§ Power-Speed: BW-10% BW (Depth Jump, SJ, CMJ, Box Jump)

§ Speed: <BW (Band Assisted CMJ, CMJ with arms)

Want to learn more? Then

WHAT THEY FOUND

Jump Squat

Mid-Test

Stronger subjects produced significant and very large improvements for RFD at 20% 1RM (ES = 2.1). Weaker subjects showed significant moderate improvements in RFD at 60% 1RM (ES = 0.27). Further, weaker subjects significantly improved peak force at 20% and 60% 1RM (ES = 0.71), and impulse at 20% 1RM all to a small magnitude.

Jump Squat

Post-Test

Stronger subjects showed significantly very large to large improvements for RFD at 20% and 40% 1RM. Only trivial to small nonsignificant changes were found for RFD, impulse, and peak force at 60% and 80% 1RM for mid- and post-test. RFD at 40% 1RM in the weaker subjects significantly improved at post-test relative to baseline and post-test relative to mid-test. No changes differed between groups.

Force-Velocity Relationship

Stronger subjects showed significant shifts of the force-velocity relationship upward and to the right increasing force and velocity Weaker subjects showed a rightward movement at higher force with an upward shift under higher velocity conditions. No significant differences were seen between groups.

Jump Strategy

Stronger subjects produced significant changes in force-time waveform from baseline to post-test during the propulsive phase of squat jump leading to greater force generated earlier in propulsion. No changes were seen baseline to mid-test or mid-test to post-test. Weaker subjects showed significant changes in force-time waveform from: baseline to mid-test during the unloading phase where athletes could more efficiently unload, mid-test to post-test during propulsion generating more force earlier, and baseline to post-test during the unloading and propulsion phases leading to better unweighting and generating more force quickly

James’

Comme nts

“What may have added another layer of practical application would’ve been to categorise subjects into force deficient, velocity deficient, or wellbalanced individual force-velocity profiles. This way, we could see individual responses to the training.

“Also, it’s challenging to extrapolate these results to an athletic population. These significant results could be due to the fact the subjects were recreationally trained, and loaded jumps and Weightlifting derivatives were a novel stimulus leading to fast gains. Whereas an athlete may be used to this training stimulus and therefore may not see the same gains, especially if their force velocity profile is force deficient.”

Is complex or compound training superior for athletic performance?

OBJECTIVE

There is little scientific data regarding specific preparation routines and their effect on performance for track & field throwers. Two popular training methods have been proposed: complex and compound training. The complex method involves performing a high-load strength exercise followed by a high-velocity power exercise in a superset to take advantage of the post activation potentiation (PAP) phenomenon. The compound method involves performing strength and power exercises on separate days. For example, a strength-focused day of heavy squats and bench press then 2-3 days later a power-focused day of jump squats and bench throws. Currently, these two methods have not been compared regarding their influence on athletic performance. Therefore, this study examined the effects of complex and compound training on competitive throwing performance, strength, power, rate of force development (RFD), and lean mass.

WHAT THEY DID

Ten well-trained track & field throwers (age = 18-27 yr; 8.2 ± 1.7 yr of training and competition experience) participated in a counterbalanced study design where all athletes performed the complex and compound training programs during the winter and spring pre-competition period.

Before each intervention, athletes followed an eight-week training program targeted towards strength, hypertrophy, and throwing performance. They were then randomly assigned to the complex or compound training groups for four weeks prior to competition. Subjects performed the following tests before and after the intervention:

§ Maximum competition throws.

§ Underhand and overhand shot put throws for distance (7.26kg for males, 4kg for females).

§ 1RM snatch, back squat, and bench press.

§ Countermovement jump (CMJ) with and without arm swing performed on a force plate to calculate jump height and power

§ Overcoming isometric leg press collecting maximum isometric force, and rate of force development up to 250 ms.

§ Body composition using DXA.

I’ve provided a visual of the study design in the attachments at the bottom of this review

WHAT THEY FOUND

Competition throwing performance significantly increased in the complex (5.46 ± 2.9%) and compound (1.96 ± 1.7%) groups, with a significant difference between groups.

Both shot put throws significantly increased after both programs, with no differences between groups.

Complex training led to significantly greater snatch and back squat 1RM increases than compound training, with no significant change seen in the bench press.

CMJ height and power with and without arm swing were significantly higher after complex compared to compound training.

Leg press maximum isometric force and RFD only increased significantly after complex but not compound training. However, compound training did significantly increase RFD at 30 ms.

Body mass remained unchanged in both groups. However, total lean mass and leg lean mass were significantly greater only in the complex group. Body fat percentage decreased significantly in the complex group with significant difference between groups.

When combining all athletes into one group, competitive throwing performance could be explained by the percentage increase in 1RM snatch, back squat, and bench press. Further, a combination of percentage changes in leg press RFD at 150 ms, back squat, snatch, and total lean mass explained 80% of the percentage increase in throwing performance.

Practical Takeaways

Based on the findings of this study, it suggests complex training is a far superior performance-enhancing strategy for improving throwing and athletic performance in well-trained athletes. The key here is to be well-trained.

In my post activation potentiation mini-course in the Coach Academy, I lay out how well-trained athletes greatly benefit from complex training compared to untrained or lesser-trained individuals. Because of that, I often view compound to complex training as a continuum. Lesser-trained athletes can use a compound approach, then leading into a complex approach.

However, there are ways to make complex training work for lesser-trained athletes, which may be important when short on training time. Here are some guidelines:

§ > 8 minutes recovery between pre-conditioning and PAP exercise.

§ Use multiple sets.

§ Sub-maximal loads instead of maximal loads.

§ Reduce range of motion (e.g., quarter/half squats).

§ Further, for competitive track & field throwers, focusing on lower body RFD, strength and power with the back squat and snatch, and becoming a lean muscled athlete should be priorities in training outside of technical throwing.

James’

Comme nts

“I did not expect such a vast difference between training methods. And it’s difficult to speculate why other than assuming the PAP exercise within the complex was enhanced.

“It would have been interesting to see kinetic data between the compound and complex training sessions to see if higher outputs were maintained during training that could explain the significant differences between training protocols.

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“One other explanation was the novel stimulus. Subjects undertook an eight-week strength/hypertrophy training program that did not use the complex method. As the compound method is a straight sets approach like the eightweek program likely was, the complex method was a novel stimulus leading to greater gains. A podcast I did with Martin Bingisser (linked below) fleshes this concept out well where periodisation may not need to be phasic. Rather, it’s the change that really drives new adaptation.”

Can overloading the eccentric phase potentiate concentric performance?

OBJECTIVE

Accentuated eccentric loading (AEL) is using a load greater than concentric 1RM during the eccentric phase of an exercise. Typically, AEL is paired with a lighter concentric phase as an intra-set primer

However, research is inconsistent in this area, with literature showing improvement and no improvement in concentric performance. Therefore, this study compared kinetic factors of AEL and traditional set loading with and without using cluster set configurations in the bench press exercise.

WHAT THEY DID

Thirteen male subjects with at least a 1x bodyweight bench press (age = 23.7 ± 4 yr) first performed a 1RM bench press test to base the experimental training percentages from.

Following this, subjects performed four loading conditions in a randomised order on four separate days:

§ Traditional loading (TRAD) used 80% 1RM with no rest between reps.

§ Traditional cluster set loading (TRDC) used the same 80% 1RM but with 30 seconds rest between each rep.

§ AEL loading used weight releasers, with the AEL cluster protocol (AELC) using eccentric overload for all five reps with 30 seconds between reps.

§ AEL1 used eccentric overload for the first rep only with subsequent reps performed in a traditional manner. Both AEL loading protocols used 105% 1RM during the eccentric phase with 80% 1RM during the concentric.

All loading protocols used 3 x 5 reps.

A linear position transducer (Gymaware) measured concentric mean velocity (CONMV), concentric mean force (CONMF), concentric mean power (CONMP), rate of force development (RFD), eccentric peak force (ECCPF), and eccentric peak power (ECCPP).

WHAT THEY FOUND

Greater CONMP & CONMV was seen in TRDC than TRAD

AEL1 led to the greatest increase in CONMF compared with all other loading protocols. Further, AEL1 provided greater concentric RFD compared to AELC and TRDC, but wasn’t significantly different to TRAD

AELC showed similar performance to traditional loading. Overall, AEL loading conditions did not have greater influence on concentric exercise performance compared to traditional loading except when looking at CONMF For the eccentric phase, AEL1 elicited the greatest ECCPP and ECCPF

Practical Takeaways

When looking to use AEL to enhance concentric performance, we must first define what concentric performance is. Is it force, velocity, power, or RFD? If the goal is maximising force production, using AEL during the first rep may be beneficial for priming force production during the concentric phase. However, avoid using AEL for an entire cluster set due to the high levels of fatigue.

In my opinion, AEL loading should solely be prescribed to elicit eccentric specific adaptations. For example, enhancing the passive elastic structures and stretch-shortening cycle performance. Based on this study, here is how you could use AEL within your own or your athletes’ training:

Bench Press or Back Squat

3 x 5 @105/80% 1RM for first rep only

However, what do you do after a cycle of AEL to continue to spur further eccentric adaptations? You can progress to fast AEL which uses heavier loads during the eccentric and lighter loads during the concentric. For example, 120/50% 1RM. Following a slow AEL protocol similar to the present study, reduced ground contact times, increased RFD and leg stiffness have been found (see or PD #24). HERE

James’

Comme nts

“Importantly, eccentric-specific adaptations require loading greater than concentric 1RM. Otherwise, it is just tempo training. To do AEL, you need special equipment like weight releasers or flywheel devices. But all is not lost if you don’t have these in your arsenal. While you can’t quantify loads easily using these methods, they are practical for everyday use. For example, 2 up 1 down leg press or having a partner push a kettlebell during the eccentric phase of a kettlebell swing.”

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Technology & Monitoring

This month ’ s top research on technology and monitoring.

MONITORING AND MANAGING TRAINING LOAD TO REDUCE INJURY RISK ACROSS A

DEFINING VELOCITY ZONES IN FEMALE RUGB LEAGUE PLAYERS

OPTIMISING INTENSITY WITH RESISTANCE TRAINING

PSYCHOPHYSIOLOGICAL MONITORING STRATEGIES ATHLETES ACROSS A SEASON

USING INSTANTANEOUS PLAYERLOAD FOR SINGLE-LEG ASSESSMENTS

Monitoring and managing training load to reduce injury risk across a season

OBJECTIVE

Monitoring and managing competition and training load (TL) is suggested to be the best strategy for injury mitigation in soccer players (see ). Due to the HERE demands of the game, more than 30% of injuries are skeletal-muscle related, predominantly affecting the hamstrings, adductors, quadriceps, and calf muscles (see HERE). Sadly, despite our best efforts, this issue continues to increase (see HERE).

Generally speaking, a muscle strain occurs when the load experienced (chronic or acute) exceeds the tissue s capacity, and numerous findings suggest that running distance, accelerations, sprinting volume, and even competition itself increase the risk of skeletal-muscle injuries. All of which are external loads, however, if exposure is appropriately managed and monitored over time, non-contact injuries could potentially be mitigated due to a better load: capacity relationship.

Likewise, session rating of perceived exertion (sRPE) is a subjective internal load measure that has also shown to be related to injury risk (see ), and a useful proxy for HERE an athlete’s psychophysiological response to the external loads mentioned. Lastly, monotony and strain are two variables that can be calculated from TL that have also shown a relationship with increased injury incidence (see HERE).

Although research has shown relationships with various TL variables and injury incidence (see ), due to the HERE complexity surrounding the root cause of an injury, the direct influence of a given TL variable and the specific actions occurring on the pitch prior to injury remain uncertain. Therefore, this research wanted to understand the risk factors associated with a non-contact muscle injury that occurred while playing soccer, specifically examining weekly internal and external TL, and the characteristics of movement (e.g. high-speed running, acceleration, deceleration) in the minutes prior to sustaining an injury

WHAT THEY DID

Forty professional soccer players (age 28.5 ± 2.8-yr) from two First-Division Spanish league teams participated in this study during the 2013-14 season. Of the 40 selected, 19 sustained a total of 31 non-contact lower limb muscle injuries during competition.

These injuries were assessed by the team physician using video analysis to identify the movement characteristic occurring prior to injury. Injury ‘severity’ was classified by time-loss (‘slight’ 0 days, ‘minimal’ 1-3 days, ‘mild’ 4-7 days, ‘moderate 8-28 days, and ‘severe >28 days), and injury ‘burden was defined as the number of training and competition days missed per team, per season.

Player movement during competition was monitored using a multicamera tracking system. Total distance covered, high-speed running distance (21-24-km/h), and sprinting distance (>24-km/h) were the external load variables examined as movement performance data. When an injury occurred, movement data was assessed at 15-min and 5-min before the injury occurred and compared this time-point in a competition to the average of the previous 10 matches prior

Rating of perceived exertion (RPE) and duration were recorded for each training session and match to create a sRPE value, which served as a weekly internal TL measure, calculating monotony and strain. When an injury occurred, this data (e.g. sRPE, monotony, and strain) was compared to the average of the previous 10 weeks prior to injury

The comparison of these variables, when an injury occurred versus the previous average, was conducted to identify potential relationship or influence.

WHAT THEY FOUND

A week of elevated training volume (+21.5%) and sRPE values (+16.2%), as well as an increased 5-min window of high-speed running or sprinting was associated with lower body muscle injury during competition. Training load monotony and strain were indistinguishable between a week where injury occurred or did not.

A short acceleration paired with reports of fatigue prior led to 75% of injuries noted during competition. More than half (66%) of injuries were noted in the final 15-min of competition.

The majority (~40%) of non-contact muscle injuries occurred in the final nine matches of the season.

Practical Takeaways

Coaches must expose athletes to competition-style demands in order to adequately prepare them for the duration and intensity of competition. Most notably, extended 45-min blocks of training that mimic a competition, involving and encouraging full-speed running and accelerations, especially in the final 15-min of the block suggested.

§ Coaches should gradually build the duration of a simulated match in the off- to pre-season, beginning with 10-20min at first, and adding 10-20% every week or few sessions of exposure.

§ In order to minimise risk during a preparation period, while also appropriately developing athletes for the chaotic and unpredictable high-intensity actions under fatigue in the final minutes of competition, coaches can prescribe repeat sprints (with incomplete or active rest periods) or individual drills with the ball, at the end of a pre-season practice session. Small-sided games or complex multi-player drills that encourage technical or tactical development can be implemented earlier in the session during the off- or pre-season period, incorporating intermittent rest to promote quality and technical improvement.

§ One way to encourage higher-intensity efforts is to make the simulated match competitive, keeping score between teams.

As coaches monitor training load across the week, when an elevation in TL greater than 20% occurs for a given athlete –due to increased volume, intensity, or sRPE – a close watch to performance, body language, and reducing on-field minutes should be pursued to reduce injury risk.

§ Most importantly, any advantage a coach can take from moments in competition to rest this athlete from being on the field (substituting) will be helpful to long-term (overall season) success.

§ Likewise, hopefully an increase in TL is identified in the 72-48-hr prior to competition (following the hardest training session for the week), and efforts can be made to reduce volume and intensity of work on the field to allow them to play the full match.

§ Appreciation for TL and RPE reports is especially important as the season progresses. Coaches should not look at weeks independently across a season, as loads accumulate over time. Therefore, a slight and gradual reduction in TL across a season could be advantageous to improving readiness and reducing injury risk on match-day Incorporating a proper warm-up prior to training and competition, as well as adequate warm-up following halftime are critical in reducing injury risk and decreased performance (see HERE).

For appropriate monitoring of each individual, measuring the intensity of running by using individualised speedthresholds can be helpful and most accurate to understanding a player’s TL and identifying changes in performance (see HERE).

Coaches should look to use an objective measure of readiness in addition to a subjective report of RPE postpractice/competition or fatigue report pre-practice. Coaches can use the data from their movement tracking devices if possible, or have athletes perform a short (10-20-m) acceleration or broad jump prior to a high-intensity session.

§ Avoid asking questions regarding fatigue on the day of matches, with the expectation of maximised readiness and using observation or live movement data as the measure for readiness.

Cody’s Comme nts

“This research does an excellent job of noting the complexity of non-contact softtissue injuries. The results note it is not one specific thing that led to the injuries noted across the season, but rather a combination of both acute (within 5-min) and chronic (weekly) load that influences the resultant injury. Likewise, this increased load is not the root cause, but an influence, when combined with other factors, ultimately limiting the athlete’s capacity and creating an imbalance that results in an injury Therefore, it’s the combination of factors (controllable and uncontrollable) that influence the risk of injury during competition.

“To reduce these risks, coaches must be both reactive and proactive to controlling and encouraging what they can. This begins with understanding the demands of competition, in order to adequately prepare athletes through the off- and preseason period, prescribing training that offers progressive exposure to in-season volumes and intensities expected. To do this, coaches need to have a plan in place that builds by 10-20% each week. Additionally, being reactive and proactive to managing TL variables during the season, being flexible to the training sessions that are planned. Coaches should go beyond just monitoring but managing (adjusting) volume and intensity of training sessions, especially since those are controllable, whereas the volume and intensity of competition is not a modifiable load. Coaches should aim to have their best players on the field in the final minutes, and that starts with optimising readiness on match-day.”

Defining velocity zones in female rugby league players

OBJECTIVE

The prevalence and equity between both male and female sports implementing microtechnology devices to monitor movement demands has increased in the past several years. Previously, much of the research centred around male sports, and adjustments to velocity zones for female sports were made based on educated guesses from scarce research.

This lack of research is especially evident in female rugby league, but with a plethora of data available as the sport becomes more popular and competitive, there is an influx of various data-mining techniques (e.g. k-means, Gaussian Mixture Models, or spectral clustering) to analyse and better understand the specific movement demands of female rugby league. Specifically, there is lack of consistent research regarding classifications of velocity zones that would better help coaches monitor and adequately prepare players for the demands of the sport.

Therefore, the researchers of this study used the most applicable data-mining technique (spectral clustering) to analyse elite female rugby league movement data, in an effort to classify velocity thresholds (e.g. low to very-high) and provide specific understanding of player demands during competition.

WHAT THEY DID

A full season of match-data using OptimEye S7, microtechnology devices, from all National Rugby League Women s (NRLW) teams (n=4, 85 players) in Australia was analysed using a spectral clustering algorithm (data-mining technique).

Data files were used if signal quality allowed for >95% of data to be evaluated, and duration exceeded 15-min of play. Data was divided into four zones, ‘low’ (e.g. walking, slow jogging), ‘moderate (e.g. jogging), ‘high (e.g. running), and very-high (e.g. sprinting) velocities, creating three thresholds or cut-offs for general analysis.

These four zones were also applied to three specific position groups (backs, adjustables, and forwards), excluding any ‘interchange’ players who played multiple positions, to provide generalised understanding of position specific movement demands during competition.

WHAT THEY FOUND

Four velocity zones were identified:

§ ‘Low’ velocity – 0-11.49-km∙h-1 (walking, slow jogging)

§ ‘Moderate velocity – 11.50-17.49-km∙h-1 (jogging)

§ ‘High’ velocity – 17.5-20.99-km∙h-1 (running)

§ ‘Very-High velocity – >21-km∙h-1 (sprinting)

Based on position, adjustables (halfback, fiveeighth, and hooker) and backs (fullback, wing, and centres) had greater movement demands than forwards, spending more time on the field and covering more total distance and distance per minute than forwards.

Further, backs accumulated the greatest distance at very-high velocity when compared to other positions.

Practical Takeaways

Results from this research, as well as others that are specific to women’s rugby league (see ), help HERE coaches understand the position-specific demands and can guide workloads in training for suitable preparation.

§ From a volume of work standpoint, athletes in this study covered roughly 30-130m of ground (depending on position) at speeds >21-km∙h-1 (the ‘very-high velocity’ distance’). Therefore, coaches should look to prepare athletes with that upper amount of volume (especially for backs) in a given session during the pre-season period in order to prepare them for that potential load and stimulus. That way, when it is experienced during the season, it is not as stressful or difficult to recover from.

§ Adjustables spend more time playing with the ball directly, requiring short bouts of accelerations, decelerations, and change of direction. These qualities should be a priority for them in training through strength and power work, as well as maximal intensity movements within a 10-20-m range.

§ Backs on the other hand, need to cover large areas of open space with the ball, so their ability to achieve higher velocities will be important to their overall performance. Exposure in training that allows for maximal effort sprints >40-m is important to develop this quality

§ Although playing time and distances for forwards are lower, this comes with good reason as they still have an extremely fatiguing workload that involves not only high intensity accelerations, but they take on the brunt of most collisions due to tackling demands. Strength and hypertrophy are a great goal with ancillary training for these players, improving fortitude and durability

Further, based on speed capabilities, using these zones (especially sprinting speed) as performance standards can help with placing players in specific positions. Based on the position-specific demands, the fastest players should be backs, because their need to sprint is greatest. The faster these players are (greater speed reserve), the less stressful sprinting >21-km∙h-1 will be.

By monitoring workloads in these various velocity zones, coaches can identify efficiency in actions, as well as performance maintenance across the season. Ultimately, the strategy of when to sprint needs to be managed so a player can be successful in their decision, as well as being able to maintain that output throughout the match. Coaches should expect efficiency to improve across the season but monitoring the volume of sprinting can be a way to make sure that fatigue is not inhibiting performance.

§ For example, if distance covered at sprinting (>21-km∙h-1) is considerably reduced, it may be due to fatigue limiting their performance potential. Suggesting more rest and recovery in the days following should be considered.

The ability to analyse data across the league creates a better generalisation and further research. The league can look after players’ health by having consistent and defined velocity zones. Especially as NRLW games are extended from 30-min to 35-min halves this 2022 season, the aim should see players continuing to play at maximum velocity, when needed, in the latter portion of a competition. This makes games more entertaining, and ensures players are not overly fatigued (at higher risk of injury).

Spectral clustering, looking at player velocity throughout the entire match, was the best data-mining method because it provided ‘logically valid’ zones, with the ability to recognise the distances covered at higher velocities, whereas k-means and Gaussian Mixture Models did not provide an accurate representation of the range of velocities that players produced during play

Although this research provides a broad and general understanding of four speed-zones for elite women s rugby, a player’s maximum speed is very individual. For example, the >21km*h-1sprinting threshold in this study may be 95% of one athlete’s capacity, but only 80% of another’s, which would greatly impact the relative intensity of that effort. For monitoring a team, it is best practice to also use individualised thresholds (see ), and dividing distance covered into a more relative (percentage of maximum) to HERE understand the intensity and volume of their efforts.

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Cody’s Comme nts

“The two things that stand out to me about this research are the fact it is specific to a rapidly growing female sport (women’s rugby), highlighting opportunities at the elite level, as well as the large amount of data that was analysed (an entire season of four teams). This is a great effort by researchers and an impressive step by the NRLW to share this data so research can continue with a set of consistent speed thresholds that classify the workload demands of players in competition and different positions.

“With this insight, further research can continue, especially as the league manages the health and wellbeing of the players. Game length increased from 60- to 70-min this season in Australian NWRL but is still going to be 20-min shy of the length of a Women’s Super League (WSL) game in England. I would be interested to know how speed thresholds compare when analysing an equivalent amount of data for WSL using the same spectral clustering method used in this study

“Understanding data-mining techniques like this one will only be more important as technology continues to provide a massive amount of data that can be compared and explored for greater understanding and direction in training. Supporting the ultimate goal of improving performance and reducing injury risk.”

Optimising intensity with resistance training

OBJECTIVE

Resistance training (RT) is a necessary means of ancillary training for an athlete looking to increase strength and improve body composition, providing functional and morphological adaptations that enhance performance and reduce injury risk.

As with any training, it is not merely ‘what’ you do, but ‘how’ you do it that makes a difference in the effectiveness of an athlete s efforts. Coaches can manipulate volume, intensity, and frequency of RT and exercises to promote progress, but there appears to be a lot of variation in the number of repetitions an individual (male or female, trained or untrained) can perform with a given percentage of one-repetition maximum, and this is exercise specific (see HERE).

When prescribing RT, coaches often dictate a specific number of repetitions to execute for a given set, but the intensity at which the set is performed is uncertain and potentially inappropriate for the intended adaptations. Coaches need to understand their athletes’ capacity to self-select loads based on the repetitions prescribed and the intended goals of training. Therefore, this research examined an individual s ability, based on sex, experience, and exercise, to estimate appropriate loads for a given rep range with RT

WHAT THEY DID

A total of 53 men (n=28, age 24.4 ± 4.3 yr) and women (n=25, age 26.6 ± 5.9 yr) who had been RT at least twice per week for the last six months participated in a study that involved achieving concentric failure in the bench press, bicep curl, and 45° leg press. The load that was used was chosen from referencing previous training logs and through discussion with the participant based on ‘how much weight they use to complete 10 repetitions.

A warm-up set of 10 repetitions at 20% of the testing load was performed for the bench press, leg press, and bicep curl (in that order). Following a two-minute rest period, participants were verbally encouraged to perform as many repetitions as possible until failure or reaching technical compensation. Unbeknownst to the participant, the goal was to complete 8-12 repetitions with the given load.

Analysis was performed comparing the number of repetitions per exercises between sex and training experience (12-months versus >12-months).

Practical Takeaways

The biggest encouragement from this study should be for coaches to go beyond merely prescribing exercises, sets, and repetitions, but also suggesting an associated relative intensity to support the objectives of the training and promote progress over time with RT. If trainees are allowed to self-select loads, they run a high-risk for using loads that are not substantial or progressive.

For a given set to be most productive, pushing for near maximal repetitions (within two repetitions of concentric or volitional failure) should be encouraged for enhanced sport performance, increased hypertrophy, and greater strength when RT

While continuing to promote near maximal intensity with RT, the most effective repetition range is 3-11 repetitions per set, as this helps to limit unnecessary fatigue but also provides sufficient volume to experience positive benefits of RT

The best way to teach an athlete how to understand what their maximal intensity is, is by allowing them to experience it (concentric failure). As an athlete learns their limits, their training can be more effective, because the stimulus will be sufficient. One of the safer ways to go about this is by using a machine-based exercise that constrains technique, stabilisation, and multiple joints. For example, a leg extension exercise can help an athlete overcome apprehension associated with pushing efforts to failure.

Familiarisation with an exercise is important for an athlete to have an idea of their limitations and abilities. This is likely why the males in this study experienced the best gauge of loading with the bench press, because it is likely that exercise is one they’ve had the most experience with and have experienced failure in training.

Testing an athlete’s one-repetition maximum is arguably unsafe and impractical. Not to mention since the number of repetitions for a given percentage of one-repetition maximum is highly variable and exercise specific (see HERE), prescribing intensity based on a percentage of one-repetition maximum should not be the only way a coach guides intensity

An effective way to help athletes learn training intensity is to teach the ‘repetitions in reserve’ (RIR) method, which can be accomplished while an athlete is pushing to complete concentric or volitional failure (0 RIR). As the athlete nears failure, the athlete will experience what a 1,2,3, or 4 RIR feels like. Also, teammates can learn what those intensities should look like, visually seeing the speed of movement slow, as the athlete strains to push/pull concentrically, training to an effective intensity level.

An important piece for coaches to remind athletes as they encourage near-maximal efforts, is to never sacrifice the technique of the movement (e.g. range of motion or safe posture and positions) for consistency in progress and safety of the athlete.

When planning and programming RT, coaches should consider periodising the progression of intensity across the weeks to manage fatigue and promote progress. The first week of training should only work in the 3-4-RIR range, learning exercises, technique, and getting a feel for optimal loads for desired repetitions. Week-two can progress in load and intensity (2-RIR), which can be a productive zone that an athlete can still see improvement for several weeks, but at some point, allowing the opportunity (as discussed above) to push to failure (0 RIR) has benefits.

§ This highest-intensity week can fit best immediately prior to an unloading period (where athletes reduce volume (number of sets) and intensity of work (4-RIR).

§ Likewise, fluctuating intensity allows for frequent assessments that are built into training and allow for feedback for coaches and athletes based on performance and the program’s effectiveness, potentially suggesting changes to, or supporting continued, training.

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WHAT THEY FOUND

The majority of subjects were loading substantially below their maximum potential when RT, which was most pronounced in females across all exercises, and males performing leg press.

Males performing bench press had the best prediction of appropriate intensity; 46.5% fell within the 8-12 repetition goal.

Females had no differences in ability to estimate intensity for a given exercise in the 8-12 repetition range.

Training experience did not appear to influence the results of this study

Cody’s Comme nts

“For both monitoring and prescription of training, intensity is a critical variable to appreciate for effective RT. Given the recreational nature of these participants, it is difficult to know what their training objectives were, but a great reminder for coaches working with athletes and providing them return on their efforts. In my mind, this is the difference between ‘training’ and simply ‘working out,’ where someone who is ‘training’ has a purpose and wants to see results or support performance in their sport; going beyond ‘working out,’ where someone is merely exercising for the general benefits of health and longevity Encouraging a mindset of ‘training with a purpose’ plays well into the mindset and encouragement of working to a sufficient intensity

“Lastly, intensity is a performance measure that can be used to monitor training productivity and identify fatigue. For many athletes, effort is something to be controlled and managed because they can quickly overdo it if not guided. Training to failure is a necessary stimulus, but also a notable stress. Athletes who are committed and want to work hard can be their own worst enemy, and a coach needs to ensure that the execution of RT matches the intended prescription for training to be effective.”

Psychophysiological monitoring strategies athletes across a season

OBJECTIVE

It is well understood that the physical and psychological stresses that athletes experience can gradually accumulate if training loads and recovery time are not properly balanced. This is especially important during an in-season period that can stretch across several months of constant competition, training, and travel (see HERE).

Given these demands and the uncertainty of how an athlete will respond, monitoring fatigue during the inseason period is a vital piece to maximising performance and mitigating injury throughout the season.

Advancements in technology (e.g. GPS, accelerometery, heart rate (HR) monitors, blood draws, oxygen uptake, and validated questionnaires) have allowed coaches access to accurate and readily available data for informed decision-making. Despite continued research, there is not one generalisable monitoring strategy for coaches to follow (see ); however the primary goal HERE of monitoring is to quantify the workload an athlete performs (e.g. external or internal, objectively or subjectively) and identify the psychophysiological response that the athlete has following the given load. By gauging this readiness and response, coaches can better adjust and prescribe training in an effort to maintain performance potential and safeguard athlete availability later in the season.

However, research is lacking around comprehensive monitoring strategies that examine a combination of physiological and psychological variables, especially for competitive female soccer players. Therefore, this study aimed to identify fluctuations in various psychophysiological variables in a collegiate female soccer team across a season.

WHAT THEY DID

Twenty-five NCAA D1 female soccer players (age 19 ± 1yr) were monitored across a season for a combination of psychophysiological biomarkers, wellness, sleep, and performance variables. Training load, exercise energy expenditure, time spent at HR-maximum, total distance covered, and distance covered at high-speed were measured using GPS, HR, and accelerometery devices for all practices and competitions.

Testing was performed four times across the seasoninitially prior to the start of the two-week preseason and then three more times, every four weeks through the season, to provide feedback on the impact that training and competition loads had on athlete performance.

Blood draws were part of this incremental testing battery, analysing stress (cortisol), muscle damage (creatine kinase), inflammation (interleukin-6), anabolism (growth hormone, insulin-like growth factor, testosterone), markers of reproductive health (oestrogen, prolactin, and sex hormone-binding globulin), metabolism (triiodothyronine and thyroxine), and nutritional makers (iron, tryptophan, glutamine, phenylalanine, and taurine).

Additionally, questionnaires (Multi-component Training Distress Scale and the Pittsburgh Sleep Quality Index) examined psychological wellbeing (e.g. depressed moods, vigour, stress, fatigue), as well as sleep quality and duration. A maximal countermovement vertical jump was also performed prior to the season and every four weeks, with the last testing period occurring 25 days before the final match.

Analysis of the data was performed to identify changes and potential relationships between the different variables being monitored.

WHAT THEY FOUND

Examining a combination of objective physiological data and subjective psychological wellbeing information provides a more comprehensive understanding of training loads and athlete response.

Training demands were highest during the initial four weeks of the pre- and in-season period (two weeks each).

Following the initial four weeks (condensed twoweek preseason and two weeks of in-season competition), blood biomarkers showed the most drastic changes, as well as decreased countermovement vertical jump height and vigour, despite improved perception of stress and total training distress from the Multi-component Training Distress Scale. Which is consistent with changes in free cortisol, a stress hormone, that saw increased levels across the first three tests, but returned to baseline value by the final testing.

Variables that were never able to rebound across the season:

§ Growth hormone, an anabolic hormone, steadily decreased.

§ Reports of vigour continued to be reduced.

In the final half of the season, there was unfavourable changes in:

§ Interleukin-6, a marker of inflammation, was elevated

§ Total training distress increased via increased fatigue and depressed moods.

§ Countermovement vertical jump height and tryptophan levels also decreased across the final two testing periods.

Of note, the training workloads remained stable during the final half of the season despite blood biomarkers and performance showing a negative trend, suggesting a build-up of fatigue that negatively impacted recoverability

Sleep (disturbances, quality, or duration) was seemingly consistent across the season, but that may have been a lack of sensitivity from the questionnaire used.

Practical Takeaways

Collecting subjective reports (e.g. rating of perceived exertion 15-30 minutes post training or a standardised questionnaire (Multi-component Training Distress Scale)) from athletes regarding their perception of fatigue and overall mood is likely the most realistic and consistent monitoring variable available. However, it is important to cross-reference that information with objective measures of training load (e.g. total distance covered, training duration, high-speed running) and an athlete s physiological response (e.g. blood biomarkers, jump performance, heart rate variability) to provide confidence and better understanding of the dosage of work and an athlete s ability to adapt and recover across the days and weeks of a season.

Subjective reports are conversation starters for deeper understanding - coaches must follow up with reports, both positive and negative as it relates to stress, mood, and energy to build a relationship and provide a sympathetic environment that cares about the individual and their stressors (sport and non-sport related) in order to truly support an athlete’s performance and wellbeing.

Perceptions of fatigue, depression, and vigour are important qualities for coaches to inquire about. Based on the results of this study, these are not necessarily related to high workloads, but do suggest an inability to adapt to the imposed demands. Winning games can help this, but maintaining a supportive, inclusive, and transparent environment can also make athletes enjoy the demanding schedule of in-season competition and training.

Most importantly, coaches must encourage honesty in subjective reports for reliable and actionable insight to health status and performance potential. An athlete should never feel weak or punished for being vulnerable and candid in their subjective report.

Performing a countermovement vertical jump consistently (e.g. weekly) as a marker of performance is simple and easy to do at the end of a dynamic warm-up prior to training, not to mention the results from this study suggest it is receptive to changes in athlete readiness. This can encourage competition and increase excitement and focus prior to a training session.

Sleep is the most effective strategy to managing fatigue and improving recovery (see and That said, it HERE HERE). must be promoted, allowed (e.g. avoiding early morning practices following matches and travel), and assessed in a way that provides reliable and responsive insight that aids coaches in actionable insight to not only hold athletes accountable but also give them every opportunity to succeed if there is a potential limitation to sleep quality and duration. Given the sleep questionnaire (the Pittsburgh Sleep Quality Index) seemingly went unchanged across this soccer season despite other warning signs suggesting lack of recovery and fatigue, coaches may explore a more athlete specific surveys (e.g. the Athlete Sleep Behaviour Questionnaire or the Athlete Sleep Screening Questionnaire for better insight to potential sleep disturbances.

Coaches need to appreciate the high volume and intensity demands of speed-endurance sports (e.g. soccer, rugby, football, field hockey) - the stresses of these competition and training environments can impact physiological function, reducing energy and mood if training loads and recovery practices (e.g. sleep, nutrition, and stress management) are not explained and encouraged.

The ability to analyse blood biomarkers can be valuable objective insight to what an athlete may not recognise or be willing to share subjectively as it relates to warning signs and symptoms that are associated with unfavourable physiology Athletes often do not recognize the severity at which they are struggling to recover, developing a normalised state of fatigue, lack of vigour, or chronic soreness. Examining blood provides answers to questions about health, nutrition, and the ability to adapt to workloads and stresses of the individual s environment, offering the most holistic physiological and objective assessment of the overall health status of an athlete.

§ For example, elevated resting cortisol levels can indicate a lack of recovery and signify an athlete who is overly stressed, struggling to adapt to their demands (see HERE).

§ Creatine kinase is a marker of muscle damage, that when elevated, suggests physical stress that needs time and attention to overcome, recover, and rebuild to mitigate injury risk. This would be expected to be elevated following a game but could be cross-referenced with subjective reports of soreness to help athletes recognise the physiological need to recover following a match.

§ Interluekin-6 is a proinflammatory protein that increases an immune response to muscle contraction, damage and reduced muscle glycogen associated with activity or exercise (all things that occur following training and competition) and is shown to negatively impact mood, sleep and fatigue (see HERE).

§ Anabolic hormones (insulin-like growth factor and growth hormone) help to support muscle protein synthesis, a process that helps to maintain and rebuild skeletal muscle tissue during training. Lower levels indicate limited adaptive ability, specifically muscular adaptations and suggest a calorie deficit in general. Coaches must encourage and educate around maintaining energy balance through adequate calorie intake, with special attention to protein and carbohydrate intake.

§ Examining iron levels can help identify adequate nutrition during intense and important training periods. Deficiencies in this area impact performance but can be elevated through diet (e.g. chicken liver, spinach, beef, almonds) and potentially exploring supplementation if a rapid and drastic increase is needed (see HERE).

§ Glycine is another amino acid that can indicate immune system status in response to training and is possibly associated with infection and illness during the high volume and intensity in-season period. Glycine is found in meat, forms of collagen (gelatine, bone broth, poultry skin), legumes, spinach, see HERE).

§ Tryptophan levels can be associated with attitude, and influence sleep and eating behaviours (see ) - HERE reduced levels can be a sign of overtraining. Milk, tuna, chicken, turkey, oats, cheese, nuts and seeds are all great sources to help increase protein intake and tryptophan levels (see HERE).

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Cody’s Comme nts

“In-season training and competition is guaranteed to be demanding. Therefore, finding simple and effective ways to monitor is important. Subjective variables are a good starting point, but often lead to more questions than specific answers. Objective markers are helpful because they remove the emotion, desire, or simply ignorance of what healthy is and feels like. Many athletes do not even recognise or understand what feeling ‘good’ is (e.g. limited soreness, no fatigue, elevated mood and energy).

“Pairing subjective and objective measurements allows coaches to truly optimise readiness and maximise performance potential by strengthening their understanding through multiple variables. Limiting your monitoring strategies limits execution, and coaches must respect the relationship that monitoring numerous variables allows.

“Not to mention, these objective and subjective monitoring strategies carry more than just data. They can offer actionable insight to better understanding, a stronger coach-athlete relationship, and an overall enhancement to the experience of an athlete.

Assessments early and monitoring throughout are efforts to maintain performance and be ready for the most important phase of the season - the end of the season where tournaments, playoffs, and championships are held, and teams strive to be their very best. By the time you get there, coaches and athletes do not want fatigue or injury due to lack of recovery to interfere.”

Using instantaneous PlayerLoad for single-leg assessments

OBJECTIVE

Assessment and monitoring strategies hinge on the ability to identify an athlete s level of readiness and reduce the risk of injury. Implementing strategies that are sensitive to change, but also practical to the multi-directional nature of sport-specific performance are important. For example, examining single-leg multi-directional movements (e.g. hops, both forward and lateral) helps to eliminate potential modified movement strategies that can occur with bilateral tasks, such as a countermovement jump.

However, the opportunity to implement research level testing protocols using video analysis, force plates, or electromyography is often limited and impractical for coaches and athletes in a team-based setting. Especially as it relates to immediate and actionable information during or immediately prior to a training session.

Recently, the use of triaxial accelerometers, have shown potential as an assessment tool for on-field tasks (e.g. vertical acceleration or instantaneous PlayerLoad) by affixing the unit to the lower leg (see ). Therefore, this study explored the HERE acceptability of measuring multi-directional single-leg hops using an accelerometer as an option for screening movement strategy, monitoring performance, and reducing injury risk in elite soccer players.

WHAT THEY DID

Twenty-five male soccer players (age 23.6 ± 5.2-yr) from an English Championship league club participated in a series of tests examining single-leg hops forward, lateral, and medial in direction. Participants identified their dominant limb based on primary kicking leg, were divided based on previous injury (n=13) or no injury (n=12), as well as noting which specific limb (dominant or non-dominant) was affected.

The best of three jumps was recorded for each, encouraging maximum distance but requiring a balanced and stable landing. Participants had a triaxial accelerometer (Optimeye X4) taped to a consistent location on each of their Achilles tendons to provide measure of planar acceleration.

Hop distance, peak instantaneous PlayerLoad (a calculation of change in acceleration) after landing, the time to peak PlayerLoad following landing, limb dominance, and previous injury (injured or not, and affected or unaffected limb) were noted for the best jump in each direction (forward, lateral, medial).

Analysis of this data was compared with the specific jump, limb dominance, and previous injury to identify the effectiveness of implementing any of these assessments as a screening protocol for monitoring readiness and managing reconditioning from injury

Practical Takeaways

The greatest opportunity this research supports is the implementation of triaxial accelerometers as an assessment and monitoring tool for landing mechanics. Coaches could use this as an assessment tool prior to off-season training, providing baseline values or individualised direction in training. Likewise, this could be used for an athlete reconditioning from injury, providing objective feedback for progress and encouragement for both coach and athlete regarding the readiness to return to play

Coaches can use triaxial accelerometers to quantify ankle inversion (see and knee kinematics (see ) HERE) HERE providing an option for assessment that goes deeper than simply jump distance, and beyond a subjective report of balanced or not. Coaches can use this information to challenge and guide athletes in their pursuit to improve performance and reduce injury risk.

A dominant limb is a greater risk of injury (see ) potentially because of the greater load tolerance and HERE performance capacity it holds. This is why it is important for coaches to train the non-dominant limb to operate with the same potential and capacity, aiming to reduce injury risk through an athlete who does not overly favour one side versus the other in ability to accelerate, decelerate, or change direction.

Especially for a previously injured athlete, the results of this study (as well as others, see suggest an injury to HERE) one limb impacts the athlete systemically in their apprehension or movement strategy The data gained from single leg jump performance, with frequent testing (weekly) can help to reduce any associated risk or avoidance of performing at their maximal capacity

Continuing to monitor and assess athletes with a previous injury is critical, as a previously injured athlete is at greater risk of injury (see and a more severe one at that (see For a previously injured athlete, build training HERE) HERE). specifically to support the athlete mentally and physically, providing supportive feedback for performance improvements due to consistent training.

Using a single-leg hop test versus a double leg jump helps to constrain the task and limit the amount of unidentifiable compensation that can occur (see This can help to tease out potential asymmetry and identify a HERE). limb, joint, or movement that needs to be strengthened to support performance and reduce injury risk.

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WHAT THEY FOUND

The forward hop was associated with the greatest distance covered, as well as peak instantaneous PlayerLoad in the vertical and antero-posterior planes when compared to the medial and lateral hops. This suggested that peak instantaneous PlayerLoad is representative of the performance of a jump and associated demands based on direction.

Time to peak instantaneous PlayerLoad was not sensitive to the direction of jump performed, but average magnitude for all jump directions at ~30-msec was consistent with other research regarding peak ACL strain and ankle inversion.

Jump distance was not sensitive to limb dominance or peak instantaneous PlayerLoad in the vertical or anteroposterior planes, but the dominant limb did have higher peak instantaneous PlayerLoad values in the mediolateral plane when data was combined for all jump directions.

The greatest medio-lateral loads were seen with the dominant limb forward hop.

Previous injury influenced asymmetry with medio-lateral loading with a medial hop.

Participants without a previous injury were able to jump further than players who were previously injured in both the affected and unaffected limbs.

Previous injury did not have a recognisable influence on peak instantaneous PlayerLoad in the antero-posterior or medio-lateral planes but was lower in the vertical plane, with a longer time to peak in the medio-lateral loading phase, suggesting reduced potential for performance and load with a higher risk of injury

Cody’s Comme nts

“PlayerLoad is commonly a cumulative measure of load that occurs across a match, representing a summation of the demands in each plane of motion. However, this research is encouraging use in an immediate fashion to monitor performance and identify variance between limbs using instantaneous PlayerLoad. This method, especially implementing it in a single-leg fashion, allows for greater potential in identifying injury risk and tracking progress for an athlete training or reconditioning from injury

“Valid and reliable objective feedback is the hallmark of any assessment or monitoring strategy and this research supports the use of the PlayerLoad calculation as an indicator that is sensitive to previous injury and the movements performed. Further, identifying tests that are repeatable from a simplistic and practical standpoint is important. The single-leg jumps forward, lateral, and medial that were performed in this study are great examples of a task that is familiar for an athlete and low-level enough for a previously injured athlete to incorporate into their reconditioning plan.”

Fatigue & Recovery

This month ’ s top research on fatigue and recovery

THE EFFECTS

OF PRE-MATCH

NAPPING IN PROFESSIONAL RUGB

THE IMPACT OF MENTAL FATIGUE ON YOUNG ATHLETES PRIOR TO COMPETITION

The effects of pre-match napping in professional rugby

OBJECTIVE

Sleep is viewed as an important factor in the performance and recovery in athletes. Throughout research, it has been found that professional athletes often do not get the recommended amount of sleep that is suggested for the general population due to a variety of factors including pre-competition environments.

Napping has been used in order to curb sleep decrements and improve alertness and mental/physical performance. In professional rugby, napping is commonly used by athletes prior to matches for the above reasons.

This study was performed to identify the use of napping along with assessing the effect on subjective performance ratings in home and away match environments.

WHAT THEY DID

Thirty professional rugby union athletes in the Super Rugby competition participated in the study over a 19-week season consisting of 17 matches.

On the day of the match, the athletes were asked to prepare as they normally do. They were given two time periods for preparation/napping; one following breakfast (9am-2pm) or one following a pre-match meal (4-5.15pm). The shorter duration of the second time period was due to match schedules.

If the athlete chose to nap during either time period, they were asked to keep track of the duration of the nap and their level of alertness following the nap on a 1-5 scale (Likert scale; 1=poor, 3=normal, 5=excellent).

Within 36 hours post-match, participants were asked a questionnaire consisting of the following: Did you nap on match day?

How long did you nap if you did?

How alert did you feel upon waking (Likert scale)?

How do you rate your match performance?

Along with this, the head coach and position-specific coach rated each player’s match performance. The result of the match, the time of the match and time zone in which the match took place were noted.

After the season, additional questionnaires were given to the players for their perspective on their individual napping habits.

Practical Takeaways

Sleep education and monitoring should become a part of preseason training in these professional athletes in order to optimise performance during a competitive season.

Prematch naps in professional rugby are utilised for a multitude of reasons including improving energy and mood. There is a strong correlation between players napping and their self-reported performance rating being good or above; this was similar to what their coaches rated them as well. Athletes should be educated on the benefits of napping especially when their sleep habits the night prior to matches are flawed.

Athletes prefer to take naps closer to the start of their match compared to earlier in the day Along with this, they take a higher number during away games compared to home matches.

Napping preferences are individualised but clearly important with professional rugby players. Coaches should be questioning their athletes on this in order to optimise performance. Allotted scheduled times for naps especially during away matches would be beneficial.

The study had limitations including data collection being 36 hours following a match compared to being immediately reported. This may have changed performance ratings either positively or negatively

WHAT THEY FOUND

Twenty-six out of 30 athletes reported taking a nap on match day, with a higher number occurring before away games compared to home matches. Along with this, napping occurred significantly more frequently in the second afternoon block (45.15pm) compared to the morning block of time given. Nap duration during this study was at 32 +/- 19 minutes with no significant difference between home and away matches. For players who took naps, 68% reported feeling better than normal upon waking up.

The post-season questionnaire revealed preferred nap duration was between 15-120 minutes with 83% reporting their preference between 20-45 minutes. With this, 87% reported that napping was beneficial to performance. On the other hand, 14% of the sample did not nap, citing feeling groggy after naps and choosing to sleep in on match days as their preference over naps.

Performance ratings were measured in this study as well. Of the players who napped prior to away matches, 81% rated their performance as good compared to 58% for non-napping players. When comparing these two for home matches, the results of rating their performance as good was similar When comparing the coaches ratings, there was no significant differences between napping and not napping.

Reasons cited to nap included the following starting with the highest reported:

§ Increased energy

§ Increased performance

§ Increased alertness

§ Alleviating sleep debt or jet lag

§ Boredom

§ Attenuate nerves

“Napping has been shown to positively affect selfreported energy, mood and performance. In professional athletes, varied sleeping habits throughout the night and day need to be monitored throughout the competitive season. Sleep journals and questioning athletes regarding their preferences are ways to help athletes in this space.

“Napping should be utilised as part of a recovery strategy in not only rugby but other sports. Encouraging napping along with allotting scheduled times for them throughout the pre- and in-season time periods are an excellent method to improve self reported performance, mood and energy.”

The impact of mental fatigue on young athletes prior to competition

OBJECTIVE

Mental fatigue among athletes has been the focus of more recent studies due to the possible effects it may have on performance. It can emerge from intense periods of cognitive effort and can increase the perception of effort. This can lead to a decrease in motivation as well as tolerance to exertion.

Earlier studies looking at amateur athletes found mental fatigue that was induced prior to competition led to worsening performance in resistance testing, along with worsening efficiency of tactical behaviour in sport. This study investigated the effects of fatigue prior to competition (pre-induced fatigue) on performance and tactical behaviour among young male Brazilian elite football players.

WHAT THEY DID

Eighteen male Brazilian athletes between the ages of 16 and 17 competing in the first division were studied. They were all at the same club and were self-selected by the technical staff to account for possible withdrawals. The players had to be injury free for three months or longer

The study assessed tactical behaviour and performance along with physical fitness in the conditions of no mental fatigue or pre-induced mental fatigue.

The pre-induced mental fatigue was done via the Incongruent Stroop test, which is a cognition test performed to measure executive control and concentration. The test consists of naming colours written in different colours. The players performed 30 series of 60 seconds of the Stroop test, with 10 second intervals for each answer

The protocol for this study is below:

1. Groups of players were placed into teams of three, based on positions. All teams had similar talent levels based on the coaches assessment.

2. Players were tested for tactical evaluation via the FUT-SAT which is a four-minute drill on a small sided field. The tactical actions of the players were filmed and then analysed based on 10 core tactical principles of football, offensively and defensively

3. Players were tested for physical fitness via the Yoyo Recovery 2 which is a running-based test using an audio signal to control running velocity

4. In the first week, the players did the recovery test followed by the FUT-SAT the next day

5. The next week, they completed the two tests on separate days but performed the Incongruent Stroop test prior to.

6. Following the protocol with induced mental fatigue, the players were asked to rate their level of mental fatigue on the VAS (0 for absence of mental fatigue and 10 for mental exhaustion).

Practical Takeaways

§ Pre-induced mental fatigue limited physical performance quantitatively but improved it from a quality perspective. This may have partly been due to the players being elite athletes compared to amateurs - elite athletes have more experience and exposure to mental fatigue through decisive games, pressure from fans and other high stress situations. This led to more intelligent actions on the pitch, with less effort.

§ Players became more selective in their actions following mental fatigue. They were able to adapt to cognitive stress and perform quality movements that produced better efficiency

§ There were limitations throughout this study which questions its practical applications to different settings. Although the Incongruent Stroop test has been found to induce mental fatigue, it is not related to situations encountered during sport. Along with this, the FUT-SAT test consisted of four-minute drills, which is a small percentage of the total match time for football. Future studies should look at extended drills which can mimic match conditions. Lastly, the subject pool was self-selected by the training staff which could affect the overall results of the study

§ This type of study could be performed in other sports such as basketball and rugby to measure the effect of pre-induced mental fatigue. It would be interesting to see whether the players could adapt the same way as footballers do or if it is more sport specific.

WHAT THEY FOUND

Following pre-induced mental fatigue via the Stroop test, the players reported a higher level of mental fatigue compared to baseline levels in both the physical fitness test (Yoyo Recovery 2) and the tactical performance test (FUT-SAT). They also showed a decrease in physical performance, with the physical fitness test covering less distance compared to baseline levels without pre-induced fatigue.

During the FUT-SAT analysis, it was found there was a decrease in the total number of offensive and defensive tactical actions following the pre-induced mental fatigue. These offensive actions included offensive penetration, offensive coverage and offensive unity The defensive unity measure was also limited under mental fatigue. Although this was the case, the players increased the efficiency of total offensive and defensive tactical actions in the pre-induced mental fatigue situation.

In general, the players decreased the overall quantity of their offensive and defensive actions but improved the quality and efficiency of the actions that they did perform. This was shown to contribute to an overall improvement of the tactical performance of the players following the pre-induced mental fatigue. This was found despite the fact the players scored lower in physical fitness and reported higher levels of fatigue following the tested intervention

“Pre-induced mental fatigue is something that all athletes will deal with at one time or another, whether it be planned or not. Strategies such as relaxation and napping prior to match play have been found to improve performance.

“Amateur athletes, compared with elite athletes, would likely not handle pre-induced mental fatigue as efficiently. Repeated exposure to intensive physical and cognitive tasks are ways that lower level teams can improve their athletes’ performance.”

Youth Development

This month ’ s top research on youth development.

FINDING THE BALANCE: IS THERE LINK BETWEEN PROPRIOCEPTIVE AND TECHNICAL SKILLS IN FEMALE SOCCER PLAYERS?

Finding the balance: Is there a link between proprioceptive ability and technical skills in female soccer players?

Soccer is a competitive sport, with ever-changing demands placed on an individual throughout a game. As a majority of these actions are open skills and require a multitude of perceptual-cognitive motor skills to be carried out, coaches must be constant in their search for new ways to train such skills in practice. Coupled with prioritising training to develop an athlete s skillset, coaches must also ensure they are robust enough to handle numerous fixtures throughout a season.

Therefore, the aim of this study is to examine the effects of neuromuscular coordination, proprioceptive, and balance exercises on a host of physiological and technical abilities in female soccer players.

In this study, 48 female soccer players from a Greek A division team were assigned to either an intervention group (N = 24) or control group (N = 24).

The intervention group was to undergo proprioceptive training which lasted for 20 minutes and were implemented over 16 weeks. This training consisted of agility ladder drills, drills with hoops, and balance exercises with coaching on proper foot positioning, coordination and balance received every session.

The control group resumed their regular training.

Pre- and-post testing were collected for both groups which consisted of a soccer-specific juggling test, a heading, shooting, passing, and dribbling test, alongside an Illinois agility test.

The main findings of this study were:

§ On physiological attributes, participants of the intervention group had significantly higher VO2 Max and agility scores when comparing their levels to the control group. Furthermore, improvements in agility and speed were observed despite limited experiences in the intervention protocol focussing on these qualities.

§ On technical ability, the individual skills test revealed some interesting findings. Firstly, all qualities (i.e. heading, shooting, passing and dribbling) significantly improved following the intervention. Secondly, this study was the first –to the authors’ knowledge – to combine specific performance exercises with sportspecific examples to highlight the novelty of this study

§ In summary, the results suggest that a 16-week intervention for improving agility, speed and accuracy in female soccer players can be achieved by implementing basic neuromuscular training. Moreover, the improvements seen in technical skills, such as juggling, could be attributed to improved proprioceptive and balance ability in female soccer players.

Practical Takeaways

Proprioceptive signals from mechanoreceptors in the joints, muscles, tendons and skins are essential for muscle tone, balance and control. Therefore, any loss in proprioceptive afferents will impair reflexes and motor control. In accordance to this, coaches should allocate 10-15 minutes per week to develop proprioceptive qualities ( ). With proprioceptive HERE training in mind, I like to train one stable and proprioceptive exercise in succession. This is similar to complex training ( where the proprioceptive exercise replaces the plyometric/ballistic portion: HERE)

1. Bilateral Romanian Deadlift > Single-leg Romanian Deadlift with chest pass (HERE)

These pairings are very complimentary The Romanian deadlift (RDL) allows for greater loading, which in turn should develop rate of force development qualities. The single-leg RDL supports greater tension on this biarticular movement, with an increased demand on the balance and stabilisation at the ankle, knee and hip. The chest pass to the floor may mimic the deceleration qualities needed in many sports. I would also recommend athletes do these with no shoes on for greater training.

2. Dumbbell chest press > Medicine ball front support (HERE)

The dumbbell chest press is a fantastic way to challenge trunk stability To make this exercise more complex, a singlearm variation can be useful, but should be lighter than the combined weight of two dumbbells. The pairing with the medicine ball front support is a fantastic way to stabilise the shoulder through contributions from the rotator cuff, latissimus dorsi and pectoral muscles. Again, this can be made harder with single-arm variations once the individual can control their scapula. Further additions can be seen in the attached video.

Typically, proprioceptive training accompanies many injury rehabilitation programmes and do not feature enough in regular training. However, recent research by Al Attar et al., (2022) found that programmes which regularly incorporated proprioception exercises in injury prevention sessions reduced ankle injury risk by 36%. Therefore, coaches should look to implement proprioceptive training in the warm-up or into programmes, such as the exercises seen above, that are both regular and consistent annually

“In this study, 16 weeks of proprioception training was highly effective at improving technical and physiological attributes in female soccer players. This research is important, as few studies are published for female soccer players and such training interventions are incredibly useful.

“The practical applications of these findings are that current warm-up routines used by coaches could be replaced by exercises that challenge balance, singleleg stability and proper foot positioning. These findings were supported in the attached podcast by Matt Cooper, who discusses some of the benefits of proprioception training which include greater time to stabilisation, improved intrinsic foot strength and increased force production. Over a similar timeframe, these methods may be better than the traditional methods of warming up.

“On technical qualities, all of the activities undertaken (i.e. heading, shooting, passing and dribbling) significantly improved from pre- to post-test. However, all of these tests were measures of accuracy in the absence of a goalkeeper and defender As every reader should attest to, it is far easier to score a goal with no time or space pressure, which leaves questions surrounding the reliability and validity of these tests. In the future, the author may wish to oppose these efforts to add validity.”

Nutrition

This month ’ s top research on nutrition

CAN MITOQ SUPPLEMENTATION BE A POTENTIAL ERGOGENIC AID FOR CYCLIS

SHOULD RECOVERY DRINK OPTIONS CHANGE WITH DIFFERENT PHASES OF A MENSTRUAL CYCLE?

HOW IMPORTANT IS THE CONCEPT OF INADEQUATE ENERGY INTAKE FOR BOTH HEALTH AND PERFORMANCE?

Can MitoQ supplementation be a potential ergogenic aid for cyclists?

OBJECTIVE

High intensity or long-duration exercise results in an increased production of reactive oxygen species (ROS) in skeletal muscle. Increased levels of ROS contribute to oxidative stress, which has been proposed to increase muscle fatigue, modulate muscle force function, and suppress immune function. Oxidative stress occurs when there is an imbalance between free radicals and antioxidants. Antioxidant supplementation has been proposed to reduce oxidative stress by neutralising ROS as a potential strategy to delay the onset of muscular fatigue and improve athletic performance. Antioxidant supplementation has been shown to improve performance during very high intensity, short-duration cycling. However, results from studies have been inconsistent, with some studies reporting performance-enhancing effects of antioxidant supplementation whilst others show impaired training adaptations.

Mitochondria-targeted coenzyme Q10 (MitoQ) is a novel antioxidant that has been shown to protect against exerciseinduced increases in mitochondrial DNA damage. However, the effects of MitoQ on exercise performance are currently unknown.

The following study investigated the effects of MitoQ on 8km cycling time trial performance.

WHAT THEY DID

Nineteen recreationally trained male cyclists participated in this double-blind, placebo-controlled crossover study. Before supplementation, participants completed an incremental ramped cycling test, starting at 125 watts and increasing at 25 watts.min-1 until voluntary exhaustion, to determine VO2peak.

Cyclists were then randomised to determine whether they would receive the MitoQ (20mg.day-1) or appearance matched placebo tablet. Participants were instructed to consume one tablet per day for 28 days before completing a performance trial. In the performance trial, cycling intensity was increased incrementally every minute at 50, 60, 70, 80 and 90% of peak power output, determined from the initial VO2peak test. Cycling intensity was then reduced to 100 watts for five minutes. Participants then cycled at 70% VO2peak for 45 minutes.

Rating of perceived exertion (RPE) and respiratory gases (VO2, resting expiratory exchange ratio (RER) and carbohydrate and fat oxidation rates) were collected at 15- and 30-minutes for three minutes. Participants then immediately completed an 8km time trial. Blood samples were collected immediately after the 45minute cycling period and the 8km time trial. Plasma F2isoprostanes, lactate, glucose, non-esterified fatty acid (NEFA) and triglyceride concentration were measured prior to and preceding the 70% VO2peak and 8km time trial.

After a six-week washout period, participants crossed over to the other treatment group for 28 days before completing a second identical performance trial.

Practical Takeaways

Supplementation of the mitochondria-targeted antioxidant MitoQ could improve cycling time trial performance in recreationally trained male cyclists.

However, practitioners should avoid making recommendations based on the results of this study since this is the first study to assess the effects of MitoQ on exercise performance.

This is particularly pertinent since researchers of this study did not control for potential deficiencies or elevated basal mitochondrial oxidative stress levels in participants, which previous studies have shown can skew observed ergogenic outcomes of antioxidant supplementation.

Practitioners may instead adopt a food-first approach, recommending foods high in coenzyme Q10, such as meat, fish or nuts. Inclusion of these foods may correct any deficiencies or account for elevated basal rates of oxidative stress whilst avoiding the danger of blunting training adaptations through supplementation. Indeed, greater adaptations may be made since these foods are high in protein, an essential aspect of nutrition for recovery in athletes.

However, practitioners should be mindful that this study only observed recreationally trained male cyclists. Therefore, results cannot be extrapolated to other cohorts such as elite athletes and females.

WHAT THEY FOUND

§ 70% VO2peak performance measures

There were no significant differences in VO2, resting expiratory exchange ratio (RER), carbohydrate and fat oxidation and RPE between the MitoQ and placebo groups.

§ 8km time trial performance measures

Time to complete the 8km time trial was significantly faster (1.3%) following MitoQ supplementation (12.91 minutes) than placebo (13.09 minutes).

No significant difference in RPE was observed between groups, despite a significant increase in average power output (4.4%) following MitoQ supplementation (280 watts), than placebo (270 watts).

§ Blood measures

Blood glucose, NEFA and triglyceride concentration increased throughout the trial. However, no significant differences between the MitoQ and placebo groups were observed.

Plasma lactate concentration increased throughout the trial and was significantly greater post-exercise following MitoQ supplementation (12.09 mmol.L-1) than placebo (10.27 mmol.L-1).

Plasma F2-isoprostanes increased throughout the trial in both groups but was 18.3% lower on completion of the time trial following MitoQ supplementation (35.89 pg.ml-1) than placebo (44.68 pg.ml-1).

“Mitochondrial DNA damage from exercise is an exciting area of emerging research. As well as confirming the results of this study, future research will help determine whether mitochondrial oxidative damage triggers exercise-related cell adaptations and whether subsequent supplementation could blunt these adaptations.

“Previous studies have shown relatively small adaptations from high dose acute supplementation of antioxidants on skeletal muscle but have not directly assessed mitochondrial function. Thus, acute supplementation methods may be useful in future research to determine any potential differences between different types of antioxidant supplementation.

“It is worth reminding athletes about the dangers of supplements with limited research such as MitoQ on health and potential bans from sport due to lack of product testing. Adopting a food-first strategy and advocating athletes to intake foods high in coenzyme Q10 such as meat, fish or nuts eliminates these risks and could improve recovery by providing additional sources of protein intake, particularly for those with a deficiency or in clinical populations with elevated basal mitochondrial oxidative stress levels.”

Should recovery drink options change with different phases of a menstrual cycle?

OBJECTIVE

The consumption of carbohydrates in the acute window post-exercise is important for the resynthesis of skeletal muscle glycogen, and therefore supports short-term recovery. Previous research demonstrates this is largely influenced by the type, total and timing (3T’s of nutrition) of carbohydrate intake. The addition of protein or fat to carbohydrates has been shown to positively affect glycogen resynthesis and subsequent same-day endurance performance. However, little information exists on the effects of post-exercise milk consumption on performance and substrate responses in females.

To understand the effect of milk intake with short-term recovery in females, it is necessary to consider the menstrual cycle. The menstrual cycle can be divided in two key stages: the early follicular phase and the late follicular phase. These phases are characterised by differences in ovarian hormone levels. Oestrogen, in particular, is lower during the early follicular phase and higher during the late follicular phase. High serum concentration of oestrogen promotes increased fat oxidation, sparing muscle and hepatic glycogen, and increasing exercise time until exhaustion.

This study examined the effect of a carbohydrate drink or a carbohydrate+milk drink on performance and substrate utilisation during four-hour post-exercise recovery throughout different menstrual cycle phases.

WHAT THEY DID

Twelve recreationally active women who experienced a regular menstrual cycle (26-35 days) were recruited for this study. Each woman’s phase of the menstrual cycle was determined using a menstrual cycle diary, ovarian predictor kits, and serum estradiol (oestrogen) and progesterone.

The study followed a randomised crossover design, so each participant completed each condition, i.e. early follicular phase + carbohydrate drink, late follicular phase + carbohydrate drink, early follicular phase + carbohydrate+milk drink, and late follicular phase + carbohydrate+milk drink.

The carbohydrate drink contained dissolved carbohydrate with 200ml of water (carbohydrate: 6.2g, protein: 0g, fat: 0g per 100ml), and the carbohydrate+milk drink contained dissolved carbohydrate with 200ml of milk (carbohydrate: 5.4g, protein: 3.7g, fat: 1.9g per 100ml). The rate of carbohydrate intake in the carbohydrate drink was 1.3 g.kg BM.hour-1, whereas the carbohydrate+milk drink provided 1.0 g.kg BM.hour-1 of carbohydrate.

Prior to testing, participants completed an incremental exercise test on the cycle ergometer to determine VO2 max and watt max. On the day of testing, the participants arrived at the laboratory at 9am after fasting for 12 hours. An exercise protocol using the cycle ergometer was used to deplete muscle and liver glycogen. This protocol included two-minute blocks alternating between 90% and 50% of Watt Max to exhaustion. The blocks then decreased in intensity to 80/70/60% of Watt Max.

Following exercise, participants consumed one of the recovery drinks every 30 minutes, for 210 minutes (seven drinks). At 240 minutes, the participants then completed an exercise capacity test. Blood and gas samples were taken to determine carbohydrate and fat oxidation at four stages: before, immediately after, 120 minutes after, and 240 minutes after the glycogen depleting protocol.

WHAT THEY FOUND

The serum estradiol (oestrogen) concentrations were significantly higher in the late follicular phase compared to the early follicular phase in both the carbohydrates (41.5 versus 101.5 pg/mL) and carbohydrate+milk (38.5 versus 139.5 pg/mL). However, there were no significant differences in progesterone between the menstrual cycle phases.

There was no significant difference in the total exercise time until exhaustion in the glycogen depleting protocol or the exercise capacity test, between the menstrual cycle phases and recovery drinks.

On average, carbohydrate, and fat oxidation at all stages of recovery were not significantly different between each menstrual cycle phase and recovery drink.

Practical Takeaways

The recovery drinks both included a similar amount of carbohydrate (1-1.3 g.kg.hour-1). These values are in line with the recommended amount of carbohydrate for short-term recovery (1-1.2 g.kg.hour1), which has been previously demonstrated to be essential for glycogen resynthesis.

It is possible there isn’t any difference in the effectiveness between recovery drinks because the participants were receiving the nutrient (carbohydrate) recovery that was needed, and therefore the addition of milk to the recovery drink was obsolete. Regardless of adding milk to the post-exercise drink, it is still important to follow a protocol of 1-1.2 g.kg.hour-1 of carbohydrates to optimise shortterm recovery and in practice this can be something as simple as a chocolate flavoured milk.

Using milk or water with dissolved carbohydrates has the same effect on substrate utilisation and timed performance. Therefore, both drinks can be used interchangeably. Irrespective of the menstrual cycle, practitioners might want to consider that athletes may prefer using one recovery drink than another or have options to change it up! Individualised strategies always result in better uptake from the athlete.

Adding milk to a carbohydrate recovery drink (rather than water) will increase the overall calorie intake, protein intake, fat intake, and calcium intake. This may be beneficial for athletes wanting to gain weight, or to support an athlete with a calcium deficit. In contrast, athletes looking to improve body composition may want to choose water

There was also no difference on substrate utilisation and timed performance between menstrual phases, potentially supporting that short-term recovery is not affected by the menstrual cycle. Therefore, this allows practitioners to focus on the athlete's recovery as a matter of importance.

It is key to note that the study reports on the results as an average from 12 women. Different phases of the menstrual cycle affect every woman differently, therefore there may be some women who would benefit from either recovery drink. As a practitioner, it may be beneficial to trial a different recovery drink if short-term recovery or performance changes during different phases of the menstrual cycle.

James’ Comme nts

“The menstrual cycle affects every woman and is a subject area that is starting to be openly spoken about in female sport. There are significant amounts of research on the impact of the menstrual cycle on sports performance, but there is less research on how nutrition strategies can support different stages of the cycle.

“The key to understanding women s menstrual cycles is individualism. Different stages of the menstrual cycle affect each woman's mood, sleep, pain, physical discomfort, energy levels, physiology, body composition, and performance (just to name a few) completely differently

“As a performance nutritionist, to gain insight into the impacts of the menstrual cycle on an active woman, open and honest communication is key. It is possible to track the menstrual cycle using a menstrual diary and correlate this with performance efforts and their self-reported changes in mood, sleep, pain etc. Beyond this, there is some research to suggest some nutritional strategies that could benefit performance and wellbeing at different stages of their cycle (linked below), so this can be employed through some trial and error

“The findings in this study don’t demonstrate much, but it does contribute to an important conversation and a growing body of research about the effect of the menstrual cycle on nutritional strategies in active women.”

How important is the concept of inadequate energy intake for both health and performance?

OBJECTIVE

I have worked in professional sport for nine years now and have certainly seen elements of disordered eating and eating disorders with the athletes I have supported in rugby, football and boxing. I’m not convinced many of the athletes knew they had various traits of disordered eating patterns, nonetheless, let's dive into this area a little deeper

Since 1992, the term Female Athlete Triad has been used to describe the combination of amenorrhea, osteoporosis, and disordered eating. However, developments have been made and as of 2007, the Triad is now described as a disorder that features menstrual dysfunction, altered bone health and low energy availability (LEA) with or without an eating disorder

In 2014, the International Olympic committee produced a consensus statement which encompasses the full scope of this symptomology and was given a new term, the Relative Energy Deficiency in Sport (RED-S). Importantly it was highlighted that this new framework includes males and recreational athletes. The video link below is an outstanding listen on this.

The purpose of this review was to synthesise available evidence and provide coaches with the scientific basis underlying the concepts of LEA disorders. An overview of RED-S is provided and importantly nutritional guidelines to help prevent LEA.

WHAT THEY DID

The authors synthesised evidence from peer-reviewed studies published between 1986 and 2021 that they believe are essential for coaches to know so they can better guide their athletes and prevent LEA. The review is split into the following sections:

1. The female athlete triad and relative energy deficiency in sport: diagnosis, mechanism, and prevalence

2. Performance and health impairments of LEA and RED-S which is then further broken down to:

A) Hormonal and metabolic function

B) Bone health

C) Cognitive ability and mental health

3. Nutritional practices to help prevent LEA and RED-S

4. Monitoring athletes for risk of LEA

5. Supporting athletes at risk of LEA

WHAT THEY FOUND

The signs of the female athlete triad exist on a continuum from healthy to pathological. Optimal energy availability will result in normal menstruation and optimal bone health. Low energy availability will result in hypothalamic amenorrhea and unfortunately can lead to Osteoporosis. Males show signs and symptoms of the Triad with the exception of irregular menstrual patterns. Hence the adoption of RED-S defined as “impaired physiological functioning caused by relative energy deficiency and includes but is not limited to, impairments of metabolic rate, menstrual function, bone health, immunity, protein synthesis and cardiovascular health.”

Commonly reported performance impairments of RED-S are broken into two areas – physiological and psychological. The physiological components include decreased training response, glycogen stores, endurance performance and muscle strength. The psychological effects include decreased coordination, concentration, impaired judgement, depression and irritability. RED-S impairs the physiological functions that support athlete growth, development, health and performance. The main effects can impact the endocrine system including menstrual function, bone health and metabolism.

The most effective approach to mitigate the adverse performance and health consequences of RED-S is through proper nutrition and the need to obtain sufficient total energy from food. Energy requirements will depend on sex, body mass, biological age and energy expenditure from training and competing.

In addition to carbohydrate, protein and fat, micronutrient intake is important. Calcium, Iron and Vitamin D should be consumed in line with recommendations to ensure adverse health effects are not present.

Monitoring early signs of LEA include injury, illness, prolonged under performance compared to normal (one of the most obvious), feeding and diet behaviours outside of what you would expect, athlete self-criticism, social withdrawal and depression.

They found the first step in supporting your athlete through LEA is to document the signs and symptoms that you observe. The next step is to speak with the athlete (and parents if a youth) stating your observations are consistent with those of RED-S. The final step is to encourage the athlete to consult with a sports medicine physician who is a specialist in managing these disorders.

Practical Takeaways

Several challenges hinder the diagnosis of RED-S. The first is the spectrum of dysfunction that can present between individuals. The second challenge is the accurate assessment of energy intake. The third challenge is that RED-S specific questionnaires are still being developed and validated almost every month. The podcast below discusses this in more detail.

LEA is the underlying mechanism that causes RED-S. Energy availability is calculated as energy intake minus exercise energy expenditure, with each term in the equation expressed in units of kilocalories per kilogram of fat-free mass.

The accepted daily energy expenditure for female athletes ages 11 to 18 is approximately 2200 kcal, while that for males of the same age range is 2500-3000 kcal.

Athletes are advised to consume 5-12g of carbohydrate per kg of body mass per day, however in practice I would never have an athlete reaching 12g per kg of body mass! (Maybe in endurance cycling but certainly not football or rugby). My advice would be to periodise carbohydrate intake aligned to the specific body composition, training, and competition goals – i.e., fuel for the work required. Protein intake between 1.2-1.7g per kilogram of body mass per day is suggested and this should increase 1.2-1.5 times the athlete's body weight if they are injured. Fat intake should equate 15-30% of total intake.

When supporting athletes at risk of LEA, the earlier the plan of action is implemented, the sooner the athlete may be able to return to form and the lower the risk of long-term impacts on physical and mental health. The coach should always communicate with the athlete and ensure conversations remain private whilst respecting the athlete’s autonomy (it is their choice to seek medical support).

Finally, and a very important point, coaches must respect their scope of practice; they are not medical professionals, and they cannot diagnose illnesses, injuries or disorders.

Want to learn more?

James’ Comme nts

“All athletes are at risk of LEA but is it a problem for everyone? Some of the boxers I work with experience elements of under-fueling, but this is strategically planned into their overall nutritional strategy to help them make weight. Personally, I think acute bouts of LEA are ok, but if this transitions into chronic periods of time, then that’s when the health and performance problems will arise.

“As nutritionists, we are uniquely positioned to be able to spot the early signs of eating disorders or disordered eating before these manifest into LEA and RED-S. I would encourage other practitioners to quickly get to know their athletes’ habitual eating behaviours at meal times and observe if these change from the norm.”

Injury Prevention & Rehab

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

EARLY VS. DELAYED LENGTHENING EXERCISES FOR AN ACUTE HAMSTRING INJURY: WHICH ALLOWS FOR A QUICKER RETURN-TO-SPORT?

Early vs. delayed lengthening exercises for an acute hamstring injury: Which allows for a quicker return-to-sport?

OBJECTIVE

Hamstring injuries are one of the most common injuries suffered by athletes who engage in high-speed movements that combine extensive muscle lengthening into hip flexion and knee extension. Not only is the incidence high, but the risk of re-injury is as well, which places strain on team performance due to player missed time.

Incorporating eccentric training in a rehabilitation programme has been shown to be effective in reducing the risk of re-injury and preparing the hamstring musculature for rapid lengthening that occurs during sprinting activities. However, early vs. late introduction of eccentric training in the rehab process has been questioned as it relates to time to return-to-sport.

The purpose of this study was to evaluate early vs. delayed introduction of eccentric training for acute hamstring injuries, and its impact on return-to-sport timeframe.

Practical Takeaways

WHAT THEY DID

In Doha, Qatar from March 2014 through December 2018 , 90 male athletes ages 18-36 with an acute hamstring injury were divided into two groups: early lengthening vs. delayed lengthening.

Both groups received a similar, standard, six-stage criteria-based rehabilitation programme; however the only difference was the introduction of lengthening exercises at different time points.

In the early lengthening group, exercises were introduced on day one and in the delayed lengthening group, exercises were introduced when the subjects were able to run at more than 70% of max speed.

Time to return-to-sport and the rate of re-injury within 12 months was assessed for each group.

WHAT THEY FOUND

The median time to return to sport for the early lengthening group was 23 days; it was 33 days in the delayed lengthening group

Within six months, there were six re-injuries (three from each group).

From 2-6 months, there were three reinjuries (one from the early lengthening group and two from the delayed lengthening group).

From 6-12 months, there were three re-injuries (two from the early lengthening group, and one from the delayed lengthening group).

Differences were found between groups in eccentric strength of the injured leg. (198 nm in the early lengthening group vs. 182 nm in the delayed lengthening group via isokinetic dynamometry).

Early introduction of lengthening exercises like the extender, diver and slider seen in the Askling LProtocol does not decrease return-to-sport times or lower re-injury rates compared with a delayed introduction; however early introduction of lengthening exercises is safe.

Introduction of early lengthening exercises does not seem to play a significant role in return-to-sport time, however implementation of lengthening exercises in a rehabilitation programme is important to challenge the hamstring musculature through a full range of motion and help reduce the risk of reinjury

Lengthening exercises like the Nordic Hamstring (three sets of 4-6 reps), and well as eccentric sliders (three of 6-8 reps) and the 45° hip extension (three sets of 6-8 reps, progressing from double-leg to single-leg) are additional exercises that should be implemented into a hamstring rehab programme to help reduce the risk of re-injury

“Although there wasn’t a significant difference in return-to-sport times for early vs delayed lengthening implementation of exercises, eccentric strength did improve in the early lengthening group. Although injuries can’t be prevented, strength is more protective over injury than mobility, and improving strength is an integral part of a safe return-to-sport.

“One limitation of the study was that the time to return-to -sport varies depending on the sport. Clinicians often adopt different interventions in this stage of rehab to match the biomechanical demands of each sport, which may impact athletes’ time to return. Future studies should include specifics as it pertains to injury classification to get a better idea of location and severity for reinjuries.”