The Performance Digest - January 2023 (Issue 75)

P E R F O R M A N C E

Study Details

How to Read Me!

Praccal Takeaways from study

Related links to learn more about the topic

Reviewers comments on the st udy

Research Reviewers

Strength & Conditioning

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

Youth Development

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

Technology & Monitoring

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

Coaching Science, Strength & Conditioning

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

Fatigue & Recovery

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

Nutrition

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

Tom Green MSc UKAD Advisor

James de Lacey MSc

Cody Roberts MSE

Tom Brownlee PhD

Matt Klayman’s MSE

Dr. James Morehen PhD

C OA C H IN G

H ow do e s what we think abo ut change how we fe e l abo ut diffe re nt running inte nsitie s?

Running is one of the most common types of exercise for those seeking to start, or restart, a healthier lifestyle. Starting a new regime is often done so from a level of low cardiorespiratory fitness, which can lead to becoming disheartened and a lack of long term adherence.

One reason behind this lack of adherence is the fact that people do not feel positively, especially during these initial hard periods. If they are expecting exercise to make them feel good, as is often suggested, these feelings can be especially discouraging. As such, some will link exercise to negative affective experiences and are less likely to repeat it in future. This is especially likely if the intensity of exercise attempted is too high. Feelings like this linked to exercise have been suggested to be connected to context, goal achievement, self-efficacy and personality type.

Specifically considering how these feelings can be linked to exercise intensity we see that below an individual s ventilatory threshold (VT), when exercise might be described as moderate, cognitive processes can have a low-to-moderate effect on acute affective responses. This means it is more likely to remain pleasurable.

At heavy intensities, closer to VT, correlations between cognitive response variables and affect ratings are strongest but are characterised by large interindividual variability. Some will perceive the higher intensity as pleasurable, whereas others won’t. Above VT, in the severe exercise domain, most will experience displeasure.

The aim of the present study was to shed light on the unresolved question of whether an internal focus of attention (IAF) or external focus of attention (EAF) (compared to a control condition) led to differences in affective responses during running in inexperienced runners

Fifty-eight inexperienced runners (30 ± 9 yrs; 38% female) ran 9 × 3 min outdoors around a large pond. This was done while running at three intensities anchored at 11, 13 and 15 on the RPE scale (light, somewhat hard and hard, respectively). The three conditions required them to focus on their breathing, on the environment, or with no specific instruction. Dependent measures were affect, heart rate, and speed.

P ractical Takeaways

These findings shed new light on the interaction of focusing attention and running intensity to improve how inexperienced runners felt about their experiences.

The researchers suggested that the influence of attentional focus should not be overestimated. They stated their study showed that it is primarily the choice of intensity that has an outstanding influence on affective experiences with a large effect size for intensity differences, compared to a small effect size for the interaction of intensity and attentional focus strategy

This means that although there may be some benefit in focusing internally or externally while running but in reality it is how hard it feels that impacts feelings most greatly

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The results revealed a significant interaction between attentional focus and intensity on affect. At a light intensity, participants’ affective outcomes benefited from non-focusing attention, whereas during hard intensity the opposite, to focus on breathing or to the environment, seemed helpful.

In all, 26 % of participants experienced an improvement in affect from “light” to “somewhat hard” intensity, and 69 % had a decline in their affective response. From “somewhat hard” to “hard” intensity, 9 % experienced an improvement in affect, and 86 % of the participants had a decline in affect. No significant differences were found in the attentional focus instructions.

Tom’s C o mme nts

“This is an interesting, though potentially unsurprising, study. I think the practical advice here for those new to fitness or ramping up following an injury is to periodise your training. It is clear that literally running before you can walk is going to impact your adherence.”

“Over time it is important to systematically overreach to tap into the benefits of exercise. However, if this ramp up is too severe then the likelihood of long term adherence is limited. If that is the case then it doesn’t matter how hard you were able to train on the odd run here and there. Consistency is key and staying out there for the long term should be our goal.”

Info rm atio n pro ce ssing is im prov e d fo llowing an acute bo ut of exe rcise.

It is well known that information processing speed is improved following a single bout of exercise. Typically, this is demonstrated through aspects such as improved reaction time (RT) or decreased error when completing cognitive tasks. Despite this, it’s unclear from much of this research which components of RT are affected (central or peripheral location of effect).

Via use of surface electromyography (sEMG), RT can be broken down into premotor time (PMT) (i.e., central processing time) and motor time (MT) (i.e., peripheral processing time). Fractionating RT like this allows more detailed understanding of its components though few studies have used sEMG to assess how acute exercise affects each component.

Therefore, the purpose of this study was to examine the effects of acute exercise on information processing speed using sEMG to fractionate RT. In addition, a second purpose of the study was to examine the effects of two types of high-intensity interval training protocols on information processing speed in healthy adults.

Fifty-eight adults (27 men, 31 women, aged 18 to 40 yrs) participated in two testing sessions. During visit one, subjects performed a simple RT task under regular (i.e., consistent timing – all foreperiods lasted exactly 2500 ms), and irregular (i.e., variable timing) foreperiods.

Subjects were then randomised to an aerobic-only high-intensity interval training (HIIT) group (HIIT-A), an aerobic/resistance HIIT group (HIIT-AR), or a resting control group (CG). Both exercise groups performed a 20-minute, video delivered HIIT exercise protocol while the control group rested for 20 minutes. Following this period all groups rested for an additional 10 minutes before performing the simple RT task that was performed during the baseline visit.

After exercise or rest, when controlling for cardiovascular fitness (measured via VO2max test during baseline testing), no differences were observed for the regular foreperiod conditions. For the irregular foreperiod conditions, the HIIT-A group and the HIIT-AR group had significantly faster mean RTs than the control group.

Additionally, both exercise groups had significantly faster mean PMTs than the control group.

These findings suggest that tasks dependent on central processing may benefit from an acute bout of exercise prior to execution.

In many sport settings, athletes are required to process information quickly and correctly in novel situations where predictability is limited. The ability to make an appropriate response to a stimulus and perform that response is impacted by both central and peripheral processes. The findings from this study suggest tasks or events that are dependent on quick RT and central processing may benefit from an acute bout of exercise to facilitate improved processing speed.

“The findings of this study add to the body of evidence demonstrating the effect of acute exercise on RT and PMT Based on this work, it is clear acute HIIT-A and HIIT-AR elicit similar improvements in information processing during lowpredictability tasks.”

“Therefore, this supports previous statements that there is a complicated relationship between exercise and cognitive functioning and re-emphasises the need for further investigation into how acute exercise influences sensory and cognitive processes. It is useful to know that ending warmups with some high-intensity activities, which is generally the case, may aid performance on the field from a cognitive point of view. It would be advantageous though to understand specifically what these warmups may need to look like and how efficient we could make them to still achieve these advantages.”

Stre ngth & C o nditio ning

This month ’ s top research in strength & conditioning.

H O RIZO N TA L VS . V E RT IC A L F LYW H E

W H IC H IS BE T T E R F O R E N H A N C IN G

S H O U L D YO U VA RY E XE RC IS E S O R K

T H E M C O N S IST E N T F O R O P T IM IZ IN G

G A IN S ?

H OW IM P O RTA N T IS T H E E C C E N T RIC

P H A S E IN RE S ISTA N C E T RA IN IN G TO

C O U N T E RA C T D E T RA IN IN G

H o rizo ntal vs. V e rtical F ly whe e l E xe rcise: W hich Is B ette r Fo r E nhancing P e rfo rm ance?

Change of direction (COD) ability and jump performance are considered critical attributes for sports performance. Because of this, they can often be a focal point during a pre-season training period. Despite the vast research evaluating jump and COD performance, little research has been conducted on the influence of horizontal vs. vertical resistance exercise on these outcomes. In the last few decades, flywheel training has emerged as a useful tool to enhance athletic performance due to the ease of creating eccentric overload. Further, flywheels make multi-planar exercises more accessible than traditional weight training. Therefore, this study aimed to assess the usefulness of different force vectors during flywheel exercise on squat strength, vertical jump, and COD

Thirty-three male recreationally trained athletes (age = 23.4 ± 5.34 yr) from different intermittent sports were stratified based on their relative strength and placed into one of three different flywheel training programs: verticaldirected exercises (VR), horizontal-directed exercises (HR), and a mix of the two (MIX). Participants were training three days per week for their sport but were not strength training at the time of this study They were also unfamiliar with flywheel training. Before embarking on the training program, participants were familiarised with the flywheel exercises: squat, horizontal split squat, vertical split squat, and lunge. On a separate day after familiarisation, a 505 COD test, countermovement jump (CMJ), and 1RM squat were assessed. The training program lasted 4 weeks with 2 sessions per week with equated training volume (two exercises for 3 x 8). After the warm-up, participants performed 8 x 1 505 COD tests with 30 sec rest and 3 x 4 squat jump or CMJ with 30% 1RM. All flywheel exercises were performed with a delayed braking action meaning participants resisted as hard and fast as possible during the last portion of the eccentric phase. Weeks 1 and 2 were loaded with 0.090 kg.m2 and 0.045 kg.m2 for weeks 3 and 4. 505, CMJ, and 1RM squat were reassessed after the intervention.

Practical Takeaways

power, and COD Therefore, if you have flywheel equipment available to you, this is how you can potentially progress loading during a pre-season.

§ Block 1: Slow, heavy loading with bilateral and unilateral vertical exercises (>2 large flywheels).

§ Block 2: Moderate loading with speed (1-2 large flywheels)

§ Block 3: Light loading for speed with delayed braking action (1 small or 1 medium flywheel)

I don’t recommend making the horizontal exercises used in this study as the main exercises. In my opinion, they do not allow heavy enough loading to generate enough force to enhance the performance outcomes in this study such as 1RM strength or jump height. Like traditional strength training, simple exercises tend to work best. I’ve found these lower body exercises to feel best on the flywheel”

§ Squat

§ Split Squat

§ Bulgarian Split Squat

§ Hip Thrust

As technology advances, there are more effective ways to overload the eccentric during flywheel training. Exerfly has an eccentric motor as part of their devices allowing you to eccentrically overload every rep by 10-80% (see ). This means it will give back 10-80% HERE more than the effort you produced concentrically

Significant improvements were found for the 1RM squat in the VR and MIX groups with a trend seen in the HR group (p = 0.093). All groups showed significant improvements in CMJ height. For the 505 with the dominant leg, VR and MIX groups saw a significant decrease in 505 time with the HR group showing a trend for a reduction in time (p = 0.066). All groups significantly reduced 505 time with the non-dominant leg. There was no significant difference between groups for any performance measure.

I believe there are too many confounding variables to this study to make definitive conclusions. For example, the VR group included a bilateral and unilateral exercise whereas the HR group only incorporated unilateral exercises. Bilateral exercises allow greater force production which is likely why we see larger improvements in performance outcomes. Not because of the direction of exercise. However, we could also argue the direction of exercise limits force generating capabilities in this study as the balance factor during the HR group exercises plays a large role. Therefore, if selecting horizontal exercises, choose ones that are stable to allow the greatest pushing or braking action.

S ho uld yo u vary exe rcises o r ke e p the m co nsiste nt fo r o ptim iz ing stre ngth gains?

Training variation, labelled as “novel stimulus” is one of three progression strategies proposed by Issurin in his Block Periodization Vol 2 alongside intensity and volume. However, fixed exercise routines are common and higher frequency of performing the same exercises may lead to better gains in those exercises. Further, it makes it easier to adjust progression through intensity and volume day to day or week to week. However, no research to date has investigated the differences between resistance training routines that used fixed or varied exercises on strength. Therefore, this study aimed to compare strength adaptations between fixed and varied exercise programs.

23 subjects (age = 18-35 yr) with at least 6 months resistance training experience but who weren’t resistance training in the past 4 months participated. The study lasted 15 weeks with weeks 1-3 and 13-15 consisting of testing and the 9 weeks in the middle being the training intervention. Testing consisted of: anthropometry, isometric knee flexion and extension strength, 1RM for the bench press, lat pulldown, biceps curl, triceps extension, leg press, and left and right leg curl. Subjects were randomly split into the exercise variation (VAR) or nonvariation (N-VAR) program for the intervention. Both groups trained 3 times per week with the VAR group performing the same exercises every session. The N-VAR group performed varied exercise throughout the week(e.g., Monday – bench press. Wednesday – incline bench. Friday – decline bench) ensuring the same muscle groups were trained. Training volume was matched between groups performing 3 x 8-12 for each exercise. Load was increased when all 3 sets could be performed with 12 reps. Volume load was calculated as the number of sets x reps x load with total training volume being the sum of all weeks. Food intake was assessed through a 24 hour dietary recall on 3 non-consecutive days before and after the intervention.

Practical Takeaways

While N-VAR produced slightly greater gains in isometric knee extension, strength gain was similar between groups even though N-VAR had greater total volume load. However, they both progressed in volume load similarly over the 9 weeks. What does this mean for you?

In the context of a training week, exercise variation within the same movement category showed similar improvements in strength. Simply varying the exercise is an easy way to potentially increase training motivation and enjoyment.

However, it’s important to note that this study did not look at randomly changing exercises. It was done systematically. Each day was the same program throughout the 9 weeks so subjects could still master the exercise.

In my opinion, this works best within the non-strength sport context where athletes don’t need to always attack the same exercises every training session. What’s important is matching the exercise to the outcome you want. E.g., improving lower body force production can be done using squats, leg press, deadlifts, or isometric exercises.

But for strength sports that have competitive lifts such as powerlifting and weightlifting, exercise variation may only be applicable directly after competition when far away from another competition. As you get closer to a competition, it is justifiable to increase the monotony of exercise selection.

N-VAR had a higher total training volume (TTV) than VAR over the 9 weeks and there was no change in dietary intake throughout the study. Both groups showed significant increases in 1RM for all exercises with no difference between groups. N-VAR showed a significant increase in isometric knee extension from pre-post intervention while VAR saw a non-significant increase. Finally, no significant changes in isometric knee flexion were seen for either group.

In my experience, it’s not often you’ll program the same exercises throughout a training week. Even in strength sports context such as weightlifting, you may back squat one day and front squat the other And the benefits of doing this go further than performance improvements. It can reduce the risk of overuse injury. For example, if you are bench pressing three times per week with the same grip width for long periods, you can potentially run into shoulder, elbow, and wrist issues. But it’s important to take into account volume and intensity. Programs that use the same training session every day of the week have been used successfully for decades. That is the foundation of Bondarchuk s system. But because it is performed daily, the volumes and intensity are low so it relies on the accumulation of volume. For the team sport athlete, I fall into the camp of varying exercises to elicit the stimulus or adaptation I’m after. It leads to less boredom for the athlete and helps increase engagement.

H ow Im po rtant is the E cce ntric P hase in Re sistance T raining to C o unte ract D etraining

The use of resistance training is widespread in sport whether to increase muscle strength or size. Traditionally, this is achieved by performing a full range of motion movement where the key muscles shorten during the concentric phase and then lengthen during the eccentric phase (TRAD). Alternatively, concentric-, or eccentric-only training programmes have also been considered with eccentric-only programmes providing increased mechanical stimuli due to a greater load being able to be used compared to a concentric-only programme.

When volume load is matched, strength gains are equal when measured via 1 repetition max (1RM) across concentric-only, eccentric-only and TRAD strength training methodologies. During eccentric-only hypertrophy is seen to be greater when measured via muscle girth.

Following a period of detraining, eccentric training was also found to lead to greater retention of muscle strength, girth, and muscle endurance. This was true for both concentric and eccentric strength whereas concentric-based training only retained concentric strength gains. This suggests that it is important to test in different modalities to allow for a full picture of adaptation and detraining.

The aim of this study was to investigate the effects of a concentric-based (CONC), eccentric-based (ECC), and TRAD unilateral resistance training on total strength and isokinetic concentric, eccentric, and isometric peak torque, lean mass, muscle architecture, and the postdetraining retentions in women.

Sixty women (22 ± 4 yrs) were randomly assigned to unilateral volume-equated CONC, ECC, or TRAD knee extension training or a control group (15 per group). For each training session, CONC performed 6 sets of 7 repetitions at 85%1RM; ECC performed 5 sets of 6 repetitions at 120%1RM; and TRAD per- formed 4 sets of 5 repetitions at 90%1RM, whereas CTRL did not train. Before training, after an 8-week intervention period, and after an 8-week detraining period, isokinetic concentric, eccentric, and isometric torque were measured. In addition, thigh lean mass was assessed by dual X-ray absorptiometry (DEXA) and vastus lateralis thickness, pennation angle, and fascicle length by ultrasound.

After training, concentric, and isometric torque increased similarly in all groups, whereas eccentric torque increased more in ECC than that in CONC (+13.1%, effect size (ES): 0.71) and TRAD (+12.6%, ES: 0.60). Thigh lean mass increased in ECC (+6.1%, ES: 0.47) and TRAD (+3.1%, ES: 0.33). Vastus lateralis thickness and pennation angle increased similarly in all groups, whereas fascicle elongation was visible in ECC (+9.7%, ES: 0.92) and TRAD (+7.1%, ES: 0.64).

Following detraining, all groups retained similar concentric torque. ECC and TRAD preserved eccentric torque, but ECC more than TRAD (+17.9%, ES: 0.61). All groups preserved isometric torque, but ECC more than CONC (+14.2%, ES: 0.71) and TRAD (+13.8%, ES: 0.65). Thigh lean mass and vastus lateralis fascicle length were retained only in ECC, pennation angle was preserved in all groups, and thickness was retained in CONC and ECC.

Practical Takeaways

Post-training, all groups concentric and isometric peak torque increased, whereas eccentric torque increased in ECC and TRAD more than CONC. Post-detraining, increases in concentric torque were retained similarly in all groups. However, eccentric torque was still greater than baseline in ECC more than that in TRAD, whereas CONC lost the training adaptations.

Isometric torque was retained in all groups, but the retention was greater in ECC than that in TRAD and CONC. Thigh lean mass increased similarly in ECC and TRAD but not in CONC and was retained only in ECC. Vastus lateralis thickness increased similarly in all groups and was retained in CONC and ECC, but not in TRAD. Pennation angle increased and was retained similarly in all groups, whereas fascicle length increased in ECC and TRAD but was retained only in ECC.

These outcomes highlight the importance of the eccentric phase in resistance training to retain the muscle strength and structural adaptations in moderately active women. This is very important, especially when looking to preserve adaptations following a period of detraining.

“These findings could be incredibly important, especially when we think about periods of detraining, which occur both for planned and unplanned reasons. Training eccentrically allows the use of supramaximal loads, which can clearly be beneficial in retention of muscle strength and structural training-induced adaptations. Although traditional resistance training protocol is effective and entrenched in our way of thinking about training, including some sessions with an eccentric-based protocol may be beneficial in increasing and better preserving eccentric strength. This would be of use for performance and day to day activities and is something strength coaches should keep in mind.”

Te c hno lo gy & M o nito ring

A re co ache s adapting training lo ads to change s in m icro cy le le ngth?

For many sports (e.g. basketball, soccer, rugby) and leagues the competition schedule will vary week to week, which has been shown to impact external loads in the training days between matches (see ). Coaches are able to measure external HERE loads (e.g. total distance covered, accelerations, sprinting distance, and even rates of speed and distance relative to the amount of time an athlete participates) using electronic performance and tracking systems (e.g. global positioning systems). This data helps to quantify volume and intensity accomplished in a session or game.

Additionally, coaches can implement an easy and costeffective strategy that captures an athlete s perception of their readiness in the day following a previous day’s session or match, known as a wellness questionnaire. These questionnaires vary with the specificity of questions but are flexible to include a basic report (e.g. 1-7, good-bad rating) of items such as fatigue, sleep quality, stress, or muscle soreness. However, research that examines the interaction of microcycle length, external load, and perceived wellness is limited.

Therefore, the objective of this study was to identify any potential impact that varied microcycle lengths had on daily external load and subjective report of well-being for athletes during a professional soccer season.

Thirty-one soccer player from various positions (forwards, midfielders, full backs and central defenders, age 25.37±3.6-yrs) from a LaLiga Smartbank (Spanish 2nd Division) club had external and wellness data collected during the 2020-21 season. The external variables examined were distance covered (m), total high-intensity accelerations and decelerations (>±3-m.s-1), total sprinting actions and distance (>24-km.h-1, m), and high-metabolic distance (distance covered at >25.5-W.kg-1). This provided volume (distance) and relative intensity profiles (‘rate or distances covered divided by the duration (min)). Additionally, wellness information inquired about fatigue, sleep quality, stress, and muscle soreness. This information was recorded individually based on a 1-7 scale (‘very low or good’ to very high or bad’) and their perceived recovery from the previous day’s activities.

This information was categorised based on the microcycle length, defined as ‘short’ (3-5 days between matches), ‘regular’ (6-7 days between matches, and ‘long’ (8-9 days between matches). In addition, noting the data as a specific day relative to the upcoming match (e.g. 1-5 days prior, or 1-2 days following a match).

The data was analysed to determine the impact that the length of the microcycle had on the external load and subjective wellbeing variables relative to competition (e.g. match day, one day before a match, two days before a match, etc.). Likewise, the microcycle lengths (short, regular, and long) were compared for variance.

P ractical Takeaways

As expected, this research supports the flexibility necessary for coaches to reduce training load when the days between matches are less than normal. Likewise, taking advantage of extended (8-9 days) periods between matches to achieve more volume and intensity than a normal (6-7 days) period between matches.

Most notably, by examining external workloads and collecting subjective reports, coaches can gain insight on both athlete preparation and recovery for matches.

§ If subjective reports of well-being (e.g. soreness or fatigue) are not negatively impacted by a match, coaches can feel confident in the preseason preparation and in-season maintenance of fitness and work capacity. However, if following a match, there is a significant or lingering (across the week) reports of soreness and fatigue, this suggests the athletes endured a load they were not prepared for and are having difficulty recovering.

§ Coaches can observe the external workload variables (e.g. distance, high-intensity accelerations, sprinting distance), examining either total volume or rate (per minute) for comparison between matches. This can suggest if athletes are working to their full capacity (recovered and ready), or pacing themselves (under recovered or fatigued). Supporting or refuting mid-week training loads between matches.

If coaches recognize an increase in soreness and fatigue accumulating mid-season, coaches need to work to maximise recovery, reducing training loads to focus on quality (shorter bouts), allowing for longer rest periods between, and consider working on a smaller sized pitch (e.g. small-sided games).

§ Coaches can provide education and encouragement to improve nutrition habits, sleep environment, and implementing recovery modalities (e.g. massage, cryotherapy, etc.) to maximise recovery time available between training sessions and competition.

Lastly, coaches can take advantage of longer microcycles to increase workload with hopes of increasing fitness and work capacity. By doing this, the physiological impact (endured stress or load) of a match is more easily tolerated and the timecourse of recovery is potentially improved.

§ Therefore, during a long microcycle (8-9 days between matches), coaches should allow two days off. Then gradually increase loads in first 2-3 days back in training, and 5-6 days out from the match have a fitness focused session that occurs after any technical or tactical work. This higher volume day will need a day to recover from and that leaves 3-4 days left to prepare for the upcoming match with renewed focus on quality and execution.

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Microcycle length had significant impact on the volume (distance) and intensity (distance per minute) variables.

§ Likewise, there was recognisable differences in external load for specific days relative to a match as microcycle length fluctuated between short, regular, and long.

§ However, regarding microcycle length, only highintensity decelerations showed a difference related to match day Whereas no other external variable on match day was impacted by microcyle length.

Subjective wellness reports showed no relationship with microcycle length or specific day relative to a match.

“This study highlights the opportunities available when collecting external objective measures, with the ability to cross reference them with subjective reports of well-being. When paired together they can be incredibly impactful and supportive to the path the team is on to perform at the highest level. Coaches can use this information to their advantage at both the team and individual level, getting an overall sense of performance and readiness, as well as identifying individuals that may be struggling to recover.”

“With the subjective reports of well-being coaches can get an initial sense of how the team is feeling and responding to the sessions and matches. Working to identify anyone that may be struggling physically or psychologically. Further pairing this insight with the objective external measures of performance, measuring distances, especially as it relates to high-intensity efforts. This is essentially the accountability or ‘lie detector’ that they simply cannot hide from. Although athletes may not be truthful with their subjective reports at times, they cannot fabricate the outputs and performance on the pitch.”

E valuating the re liability of a lo ad-v e lo city assessme nt

WHAT THE Y DID

WHAT THE Y FO U N D

Assessments play a critical role to guiding and tracking the efficacy of training. One assessment in particular centres around power production and the interaction of force and velocity With the prevalence of force plates in athletic development, coaches are able to assess force-velocity (FV) capabilities while an athlete jumps. Further, when the athlete performs a jump with a range of resistances, a range of higher forces and lower velocities are captured by using various loads. By doing this a linear relationship is recognised that creates a load-velocity (LV) profile specific to the abilities of the athlete. The creation of an individualised FV or LV profile has shown potential to guide training that can enhance specific deficiencies (e.g. it may be considered that they are unable to generate high force), improve jumping ability, and possibly improve on-field performance (see ). However, the HERE reliability of these profiles is uncertain, and further investigation is needed to support their application. Therefore, this study assessed the inter-session reliability of using a free-weight squat jump (SJ) to create both FV and LV profiles.

Eighteen subjects (3 women, 15 men, age 28.1±4.8-yrs) with the ability to squat at least 150% of their body mass (BM) participated in a familiarisation session and two testing sessions separated by 72-hr. Subjects learned to perform a SJ from a noted depth (using an elastic cord) that placed their knee at a 90° angle and established a self-selected stance width that was kept constant. In order to create the FV and LV profiles, subjects used a range of barbell loads across their shoulders (0-, 10-, 20-, 30-, 40-, 50-, 60-, 70-, 80-, 90, 100-% of BM) when performing the SJ, holding their squat depth for at least 2-sec before jumping ‘as high as possible.’

Researchers ensured adequate rest (1-min between repetitions, 2-min between loads), and kept technique (e.g. barbell affixed to upper back and no counter movement prior to jumping) constant for each repetition. At least two jumps were performed at each load.

Force and velocity data (absolute and relative) was collected using a force plate that was placed within a custom-designed squat rack. Researchers looked specifically at peak velocity, peak force, mean velocity, and mean force to develop the FV and LV profiles. The profiles, with specific attention to peak and mean velocity were analysed for inter-session reliability

P ractical Takeaways

When developing an assessment protocol that will guide training, it is critical that the results are reliable and valid. Coaches can help support the reliability of results by standardising the conditions (e.g. time of day, adequate rest prior, following a specific warm-up protocol) and procedures around the test (e.g. instructions, technique, testing order, body position and movement), as well as using tools that provide valid and reliable measures (e.g. force plate, laser timing gates, video analysis). However, given the unfavourable results, it is important to recognise the efficiency and practicality when designing an assessment protocol.

Previous research has shown that five to eight different loads are sufficient to create a FV profile (see HERE HERE ), with some even suggesting that only two loads are necessary (see ). Given that eleven loads proved unreliable in this study, it would appear that too much data was collected and the athletes potentially experienced fatigue across the test. Therefore, coaches should aim to keep efforts minimal, potentially considering using only two if selected appropriately (e.g. one light (BM only) and one heavy (100% of BM) load).

§ Additionally, when working in a team-sport setting, it is necessary that assessments be timeefficient. Therefore, finding the minimal amount of data needed, but enough that provides a valid representation of performance potential is crucial. The data is important for feedback (e.g. monitoring readiness) and appropriate training guidance (e.g. identifying deficiencies).

Specific to developing LV profiles, using loads relative to BM is best practice, providing an appropriate and individualised strategy. Further, suggesting that loads remain lighter than 100% of BM. By doing this, loads are likely conservative enough to accommodate individuals of all strength levels and the test is not overly fatiguing.

§ This is especially true for jumping exercises, where the individual is expected to leave the ground using additional load. Keeping the loads conservative, to where the jump strategy does not change is important to compare the LV relationship. It is likely that the SJ strategy changed with these athletes when using 90-100% of BM and negatively influenced the SJ movement pattern, which would influence velocities as compared to lighter loads.

The use of a force plate can be an expensive option, but there are less expensive velocity measurement devices that have shown to be both valid and reliable (see ). These can be used across a series of HERE loads to develop a LV profile for a given exercise.

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Both LV and FV profiles were unreliable between the two testing sessions.

The FV profile using relative force was the least reliable. When comparing reliability, although all were poor peak force and velocity showed better relative reliability than mean force or velocity

Overall, given the lack of reliability, the FV and LV profiles generated with a SJ in the manner proposed (two repetitions across eleven loads) should not be used to suggest force or velocity deficiencies.

“In order to provide individualised training, an individualised assessment is critical. By doing this, coaches can not only track progress by establishing baseline performance prior to an 812-wk training intervention and retesting at the end, but also can identify specific deficiencies that are limiting performance. This is especially evident as it relates to power production and the relationship between force and velocity”

“Coaches can sometimes get overly focused on the force production end of things, placing a massive emphasis and an athlete s energy into getting stronger through lifting heavier loads in training. However, for most sports, speed is what most directly influences performance. Although being strong (force production potential) can no doubt influence power production and improve resiliency. Strength development can be taken too far, and maximal velocity can be neglected. By performing a LV or FV relationship, coaches can identify, compare, and track the influence that training can have on an athlete’s ability to move, comparing predictive force and velocity potential. This method appreciates two vital qualities that can potentially transfer to on-field sport-specific ability. Likewise, when improvements are noted in force and velocity production during a jumping assessment, coaches can affirm the transfer of training through improvements in sprint time, jump height, or even change of direction ability.”

H ow to e ffe ctiv e ly m o nito r acute to chro nic wo rklo ad

The process of monitoring training involves examining measurements that can help coaches either affirm appropriate loads and an athlete s response or identify an individual at potential high risk of setback or maladaptation. Despite opportunities via technology (e.g. global position systems) to quantify external training loads (e.g. maximum speed or total distance covered), rating of perceived exertion (RPE) is a simple yet valid and reliable measure of an individual’s psychophysiological effort during a match or training session (see ). Further, this RPE score can be multiplied by the HERE session duration to give coaches a session RPE (sRPE) metric. Through consistency in data collection across a season, coaches can mitigate a drastic increase or decrease in training load that could potentially increase the risk of injury (see HERE). This occurs by examining the acute: chronic workload ratio (ACWR), comparing the most recent seven days of training to the three weeks prior (chronic). Although this monitoring method has been challenged (see ), there is also HERE suggestions that research in this area should not be discarded (see ). Further, examining this acute: chronic relationship HERE through exponentially weighted moving averages (EWMA) this alternative calculation method has shown to be a more sensitive measure, as it appreciates the most recent training more and places a decaying emphasis on training that occurred further away from the present acute loads (see HERE).

Currently, there is a lack of research around injuries (contact and noncontact) and the relationship that exists between changes in training load indices. Therefore, the purpose of this study was to identify a potential interaction between weekly training loads and contact and no contact injury, with consideration for the time between a given training load and onset of injury (i.e. lag period), in elite soccer players.

Fifteen soccer players (age 23.4±4.8-yrs) from a team in the Premier League of Ireland participated in this study during the 43-week soccer season in 2018 (Jan-Nov). Participants completed three sessions to understand how to accurately report workloads based on their subjective RPE using a 0-10 modified Borg scale (see ). Session RPE was gathered HERE following every training session or competition (AU). If multiple sessions were performed in a day, the sRPE data was combined for a daily total, and if no training was performed, the day was noted as zero.

Likewise, time-loss injury data was collected when a player was ‘unable to fully participate. Researchers noted the date, location, surface, contact (collision with a player, ball, goal post, or tackle) or noncontact (without any extrinsic contact with a player or object on the field), overuse or sudden, body part, type, duration, and return-to-play for each injury (see HERE).

When examining the EWMA ACWR training load data, lag period was appreciated for each injury This was accomplished by examining training load as a time sensitive rolling measure relative to the days prior and presented as 5-days or 7-days before an injury. Finally, the relationship between changes in workload (sRPE arbitrary units (AU)) and injury risk was presented.

When weekly acute load increased by at least 1000 AU, a player was at higher risk of a noncontact injury 5-days later, which is similar to previous research (see and HERE HERE).

§ However, given the ‘rolling weekly training load analysis,’ injury data was gathered daily until an injury occurred, and researchers were able to identify the specific 5-day lag period from increased load to high-risk for injury

§ Specifically, 62% of noncontact injuries were seen when acute load increased week-to-week by >9%. Another finding that is consistent with previous research (see HERE).

§ Further, monitoring week-to-week changes in training load appeared to be more sensitive to predicting noncontact injuries than ACWR.

Exponentially weighted moving average ACWR showed a relationship with both noncontact and contact injuries in 5-day lag period (when EWMA ACWR >1.2). Offering coaches the chance to monitor and dose training appropriately earlier in the training week (4-5 days prior to a match).

Specific to this research, 57% of contact injuries occurred when cumulative load was >4000 AU for a 2-week period, and 71% of contact injuries occurred when cumulative load >5200 AU in a 3-week period.

Practical Takeaways

Given the relationship that was found between injury (contact and noncontact) and workloads experienced 5-7 days prior, it is important that coaches appreciate the planning and dosing of the microcycle (week of training).

§ This is especially the case during in-season, and is accomplished by:

Ÿ Allowing sufficient recovery following a match (e.g. 1-2 days of rest or low intensity work)

Ÿ A dose of maintenance volume and intensity within training to keep chronic workloads elevated

Ÿ A tapering (reduced volume and intensity) period in the 1-2 days prior to the upcoming match.

Likewise, given the results of this research, it is important to respect the workload accomplished each week (e.g. sRPE load data) and be sure to keep changes in sRPE values within 9% of the previous week to reduce risk of noncontact injuries.

Consistent workloads should not be avoided, but there is a limit to the volume and intensity of work that athletes can recover from across 2-3 weeks.

§ First, coaches should identify minimal needs (e.g. a match and 2-3 practices across a week) and during the preseason period build capacity to handle that AU value.

§ Coaches should also appreciate the thresholds where injury risk can elevate. For example, this group of athletes studied saw 71% of contact injured with 3-week cumulative load when cumulative load exceeded 5200

AU Therefore, loads cannot continue to increase and potentially need to decrease at some point during the season (e.g. every 3-6 weeks).

Gathering sRPE values from athletes is important to appreciate, not just the duration of a session, but the subjective report of intensity Individuals can accumulate fatigue across a week or season and although time may remain constant, the impact may be greater depending on recovery and readiness.

§ However, in order to obtain valid and reliable RPE data, thorough education needs to be implemented for athletes. In this study, researchers took three separate sessions to ensure that participants understood proper application of this method. Coaches should definitely take the time to do the same or similar by explaining the RPE scale (1-10), what each value means, and be certain that understanding is shared across the team.

Most notably, the EWMA method of measuring ACWR is the more sensitive measure to identify individuals at higher risk of injury, as it appreciates the recency of previous training, and the decaying impact that training that occurred at a later date has on an individual. This method, as well as being sure to calculate the acute load (recent 5-7 days) separate from the chronic load (previous 21-28 days), as this provides an uninfluenced comparison between the most recent work in the last week, and workload accomplished in the 2-4 weeks prior Lastly, injuries are complex, and there are numerous influences beyond simply changes in training load from sRPE values (see ). Therefore, monitor multiple HERE variables (e.g. external and internal measures).

As an example, although researchers noted an off day as 0 AU for load, this neglects the potential biopsychosocial influences or stressors (e.g. relationships, societal influences, psychological well-being) that can impact readiness and recovery. Some of these factors can be identified through implementation of a daily wellness questionnaire, inquiring about soreness, sleep, stress, mood etc., that could initiate further conversations or alerts to support an athlete’s psychophysiological health.

“Just like injuries, monitoring athlete readiness and recovery can be a complex endeavour As with any research of one team or season, the results do not directly apply to every and all in the sport, and focus should be on principles versus specifics. However, if coaches are consistent with obtaining valid and reliable information, they do not have to lean on their instincts when making decisions about appropriately dosing training. Session RPE is a simple and zero-cost option that provides coaches with feedback and a starting point to appreciating the relationship of workload across a week and month of a season.”

“It is a coaches’ responsibility to support an athlete’s readiness, because in doing so the risk of injury is mitigated and athletes can perform at their full potential. This is ultimately the goal of any coach during the season, to perform at the highest level on match-day and to sustain, if not improve, that ability across a lengthy season. In doing this, coaches provide their team with the best opportunity for success, competing at the highest level, when it matters most, at the end of a season.”

Fatigue & Re cove ry

The Effect of Fatigue on Hip and Knee Angles in Female Handball Players: How Does this Affect Risk of Injury?

Female athletes have a higher risk of knee injuries especially ACL ruptures in sports involving rapid changes in direction and jumping/landing with pivoting due to anatomical, hormonal and biomechanical factors. Previous studies have shown that higher levels of fatigue during these activities can increase the risk of injury. Using training protocols which elicit fatigue have been sought to investigate this and the link between neuromuscular control and non-contact injuries. One sport in particular which involves risk of injury is handball secondary to the amount of single and double leg landings from jumping as well as sidestepping actions. The purpose of this study was to investigate the effect of a sport specific fatigue training protocol on female handball players. In order to do so, hip and knee kinematics were studied while performing single and double leg dynamic tasks to determine how the fatigue affected the players injury risk.

20 female handball players ranging from 18-25 years old with multiple years of experience and no prior ACL ruptures were studied. Subjects completed a fatiguing training protocol which consisted of a circuit of movements performed during handball practice. This included sidestep cutting, jumping, landing, sprints and lateral / back shifting.

Maximal vertical force via a countermovement jump (CMJ) was measured along with heart rate (HR) and rating of perceived exertion (RPE). These were studied prior to and after the fatiguing training session. The following movements were also measured.

Single leg landing (SLL) via a step down from a 40cm box. Sidestepping cutting (SC) which involved the athletes sprinting four metres as fast as possible followed by a 45 degree cutting motion with their dominant leg.

Drop vertical jump (DVJ) via a jump drop off the 40cm box while landing with feet together and immediately jumping as high as possible.

During these movements, joint angles at the knee and hip were taken via a motion capture system with reflective markers.

Practical Takeaways

The fatigued athlete displays alterations in the angulation of the knee and hip upon landing in different positions and planes of movements. With these changes, injuries may occur more frequently. For example, the reduction in knee and hip flexion during side cutting and depth drops increase ground reaction forces and shear across the anterior knee making it more prone to injury.

Increase in knee valgus, or knock knee was found primarily in the weight acceptance phase of landings whether it be single or double leg. This type of angulation occurring during landing is associated with a risk of anterior displacement of the femur on the tibia making the risk for instability or ACL rupture higher.

Force output was decreased following the fatiguing protocol, which was seen as a decrease in verticality with CMJ. This indicates that the fatiguing protocol not only affected the joint angles but also affected muscular forces. This may have been due to hamstring fatigue which can cause the decrease in knee flexion found in the side cutting and depth drops. With this, the reduced capacity of the hamstrings strength may have negatively affected the knee load and force anteriorly on the knee.

This study was limited based on the population studied. Future studies should look at other types of sports that depend on cutting and landing mechanics such as football, squash or soccer. The results may also change when looking at the male gender which may provide insight on different strategies to address hip and knee kinematics.

Through the movements studied, the authors found that a state of fatigue following training altered lower limb kinematics in female handball players. It was found that there was an increase in knee valgus with single leg tasks along with reduction in knee and hip flexion during sidestepping and depth drops/jumps, which increase the risk of knee injury occurring. Along with this, maximal vertical force was diminished following training with CMJ performance decreasing by about 10%. This force decrement coupled with changes in kinematics and HR / RPE increases lead the authors to conclude that fatigue may lead to a higher risk of knee injuries occurring in handball.

Matt’s

“Sport specific drills performed under fatigue can give an insight into injury risks that are involved during matches and throughout the season. Taking this information can inform coaches and rehabilitation professionals on proper training programs. In this case, female handball players would benefit from education on landing mechanics to reduce knee valgus and improve shock absorption upon landing. Along with this, they would benefit from strength training programs focused on building hamstring, quadricep and hip abductor strength and power.”

“Although this study was performed in a laboratory type setting, it gives insight into the effect that fatigue has while performing sport specific movements. Coaches can utilise information like this to identify athletes that may be at risk for future injury and provide individual programs based on their deficits.”.

H ow D o e s Lo ad A ffe ct P hysio lo gical and P e rce ptual Re spo nses to S le d T raining?

Resisted sled sprinting (RSS) is utilised in many sports to provide a mechanical load above unresisted training in order to improve sprint performance. It accomplishes this via a combination of similar mechanics to unresisted sprinting (URS) with an increase in trunk lean and horizontal ground reaction forces with the addition of a resistive load. It has been suggested in prior studies that using lighter RSS loads leads to increased velocity while higher RSS loads improves acceleration in sprinting. To test this theory, the authors of the study aimed to quantify the physiological and perceptual responses by testing subjects with a session of RSS with light and heavy resistance relative to an individual's maximal RSS load (MRSL).

27 team field sport athletes including 15 male and 12 females participated in the study Testing was performed in a controlled environment in an indoor facility on a 30 metre track surface. Prior to the study, body mass was measured followed by the assessment of maximal resisted sled load (MRSL). This was performed over a series of 20 metre RSS with progressively higher sled loads based on the subjects % body mass. The heaviest load was determined by the load that allowed the subject to continue to accelerate over the final 5 metre of the 20 metre sprint. The subjects were split into two training groups; 30% of MRSL and 80% of MRSL.

The training session consisted of a standardised warm up followed by measurement of a countermovement jump (CMJ) and a 20 metre unresisted sprint. The subjects then completed 12 RSS repetitions at their respective load (30% or 80% MRSL) with each repetition separated by three minutes. CMJ and URS were repeated, five minutes and 24 hours following the session.

Blood lactate, rating of perceived exertion (RPE) between repetitions and within the entire task, heart rate and muscle soreness were assessed as well.

P ractical Takeaways

Increases in perceptual changes via RPE along with physiological changes via blood lactate and HR show that the external and internal demands imposed by heavy RSS was greater than the distance matched session for light RSS.

Overall, heavy RSS imposes a greater metabolic demand on the individual athlete compared to light RSS whether male or female. With this however, measurement of lower limb power via CMJ and unresisted sprint performance return toward baseline levels within 24 hours. This may have been due to rest times provided in the study (three minutes) between RSS bouts. Future studies should look at the effect of decreasing rest times for RSS on the power and performance as this may give better insight on the benefits of a particular type of load used.

No significant differences were found between men and women when looking at velocity decrement between heavy and light RSS repetitions. From this, one can suggest that using the prescription of resistance load based on MRSL percentage matches between sexes.

Due to the extra demand placed on the athlete with heavy RSS, practitioners need to take into consideration whether or not it is appropriate for use based on the demands that the sport places on the athlete.. During the season, opting for a light RSS may be more beneficial due to similar benefits along with less risk of overtraining their athlete with a load above what they can handle. This may be most important for the fatigued or injured athlete.

The study found that RSS at higher loads produced greater increases in velocity decrement from URS compared with lower loads. With this, overall sprint times were slower with high RSS as well but did not differ between groups from sprint 1 to sprint 12 within the session.

When it comes to physiological and perceptual responses, heart rate, blood lactate levels and RPE within session and whole session levels were higher for higher load RSS compared with lower load RSS. CMJ height, which was a measure of power output, was lower following the session compared to before but returned close to baseline within 24 hours; it did not differ significantly between groups. Muscle soreness was present in both groups but did not reach a significant difference; it was higher in men compared to women that were tested.

“RSS is a great way to improve power and sprint performance for athletes. Using varied loads and decreased rest times between sprint bouts may be beneficial for athletes requiring power along with velocity / acceleration such as track and field athletes.”

“Performance decrements in power which was measured via CMJ height as well as sprint times and muscle soreness all reduced within 24 hours of completing the RSS performed in the study. Practitioners can use this information when planning training programs. Sled training can be used within the season, although the specific loads utilised may differ based on the individual athlete. Avoiding back to back days of sled training may be appropriate.”

Yo uth D eve lo pm e nt

Movement mastery and self-esteem: Can one influence the other?

The relationship between motor competence (MC) and health, behaviour and physical attributes have been well researched. MC is considered a critical element in promoting physical activity in youth, so ensuring that children understand and can replicate the core demands of sport in both practice and competition is important. In addition to the physical benefits of good motor competence, MC has a host of psychosocial benefits, including self-esteem, which can promote wellbeing. In the context of MC and self-esteem, few studies have investigated the longitudinal relationship between these factors. Therefore, the main purpose of this study was to assess if MC and self-esteem are impacted upon by one another.

WHAT THEY DID

This study recruited 144 Portuguese students over a five-year period (2009-2013) with both sexes included (69 girls). Six groups were followed and MC was assessed on five annual occasions. Self-esteem was evaluated in the last two years of this study. To assess MC, the authors utilised the Korperkoordination Test für Kinder (KTK) protocol, which consist of four tests: (1) walking backwards, (2) jumping sideways, (3) hopping for height and (4) shifting platforms. An example of this can be seen . To assess self-esteem, the HERE Portuguese version of Physical Self-Perception Profile for Children and Youth (PSPP-CY) was used. This questionnaire explored six categories ranging across sport competence, physical condition, attractive body, physical strength, physical self-worth, and global selfesteem. When necessary, especially for younger children, a research assistant helped with the interpretation and responses to the questionnaire.

Practical Takeaways

Motor skill is a global term used to describe gross movements that involve large muscle groups working together (e.g. running). It is important that teachers and coaches continue to train motor skills through regular exposure to programmes such as the SKIP programme (). Coaches HERE can utilise a host of movements such as ball bouncing, kicking, catching, throwing, running, galloping, skipping and jumping. As S&C coaches, we can think of creative ways to implement these into warm-ups or rest periods (e.g. side planks into tennis ball catches against a wall). Programmes that have incorporated these movements do make a difference and have previously shown impressive results ( & HEREHERE).

A large part of the long-term athletic development project is “future proofing” our athletes for the challenges that accompany life. In this study, self-esteem was found to decrease. Those who had higher levels of MC also had higher levels of self-esteem. When working on these qualities, I have had a lot of personal success by simplifying my “confidence” work under the four following titles with examples:

1.Control the controllables – I spend a lot of time reinforcing this concept with young students. Control what you choose to allocate your mental resources too. Can you change it by thinking about it? If not, move on and make a new plan.

2.Engage in mental preparation – There are a host of methods available for coaches to use, but I’ve had personal success when using the following methods; mindfulness, imagery, reflective thinking, positive self-talk, goal setting and meditation. The hardest thing when implementing these is getting children to understand why you are doing it. I would use THIS video as an introduction to mindfulness meditation for children and use supplementary videos of professionals involved in their sport ( ) to drive engagement. See attached video

3.Recall previous success – In the moment, youth can be quickly overwhelmed with negative feelings or emotions. Teaching young athletes to become mindful of “how” they are feeling is an important bookmark that the coach can place into an athlete’s mindset, as they can then quickly resort back to this when an athlete is feeling this way again. Conversations such as “you felt this was before and still played really well” are practical examples of how to reinforce this during training. Designing sessions that expose an athlete to this are a good way to dampen the effect of negative psychological energy.

In order to reverse the impact of low MC, coaching organisations or schools may look to screen children as early as possible to top up movement skills. Additional time spent working with children when they are young may foster an increased MC, as well as the cognitive and psychological benefits (e.g. self-esteem), which can lead to increased participation. Practically, coaches could identify young individuals (e.g. 5-7 year olds) and place some skipping ropes out during a break to encourage children to develop the rhythm, coordination and fitness to skip.

WHAT THEY FOUND

MC was found to positively influence self-esteem in youth. However, MC was found to decrease in children between 7-13 years of age.

Despite MC having a positive effect on self-esteem, MC was found to have no correlation on sports competence, physical condition, feelings of attractiveness and physical strength.

The results of the present research show that there are no differences between males and females when investigating the impact of MC on selfesteem.

Promoting MC during childhood and adolescence may have a positive effect on a child’s physical and mental wellbeing.

The promotion of MC throughout childhood and adolescence should be a central focus of S&C coaches, due to the relationship with self-esteem. Other benefits, although seemingly obvious, include; an active lifestyle, reduced risk of obesity, cardiovascular disease and various forms of cancers as examples (HERE). It is also important for future studies to understand the challenges that youth are facing, considering that MC decreases between 7-13 years of age in both males and females.

Visually, low MC can be hard to hide from your peers, so encouraging a group to be “problem solvers” instead of critics would be useful here. For example, youth who struggle to catch or digest technical/tactical information may struggle to shine in front of their peers. Some of the advice that I have used with children can be found in this attached article, which represents the wider influence that one child can have on another. For example, teaching children that the score doesn’t always matter and that everyone can and should contribute to a team is vital. Such interventions could prove beneficial to those who struggle to participate in sports due to low confidence. To help these individuals, parents and coaches may wish to set individual challenges (e.g. “make 10 good passes with both feet”) to support motivation. When working with youth with higher MC, individuals must pay attention to changes in mood, behaviour, attitude and recognise that a child-adult relationship is reciprocal. More examples like those above can be listened to in the attached podcast.

Talking G rowth and M aturatio n: H ow do co ache s wo rk with athlete s during this pe rio d?

Academy football is a competitive environment, placing large physical and psychological demands on young athletes. Academy players have the challenging task of navigating the complexities of adolescence, whilst simultaneously trying to make it as a professional player To add to this challenge, players grow at different rates, making the process of talent identification difficult and sometimes unfair due to individual differences in maturity tempo and timing. This can make the role of coaches, especially if they are responsible for developing players through an academy system, particularly challenging. Therefore, the aim of this study was to understand coaches’ perceptions, experiences and the challenges of working with male adolescent football players on their development through an academy pathway

This study adopted a mixed-methods approach, utilising the benefits that both a quantitative and qualitative approach bring to research. This approach allows for a rich collaboration between the opinions and perceptions of coaches working with children going through maturation and the use of numerical data to support/refute this research aim. Participants included a total of nine coaches, who ranged between 20-60 years old, with a minimum of the UEFA-B licence. In total, ninety-eight football players from one academy system were recruited (U12-16). Data such as; maturation status, growth velocities and match performance were measured, with interviews conducted in parallel with the coaches. Semi-structured interviews allowed the researcher to maintain structure within the study, whilst allowing the coaches to elaborate on their experiences of working with maturing youths over five group and eight individual interviews.

P ractical Takeaways

Whilst conversations surrounding growth and maturation should not be challenging, it can be difficult to discuss this in the absence of a quality coach-athlete relationship. This really matters, not only because this drives better performance (attached article), but because this creates the social environment where these types of conversations are more likely to be had. To achieve this, the COMPASS model (Conflict management, openness, motivational, preventative, assurance, support and social networks) has a long-standing history of being an effective guide for coaches to manage and direct their professional practice. On the job, coaches may wish to avoid conflict by having clear expectations with the squad by explicitly stating what is and is not acceptable. To support motivation, questionnaires or conversations are a rich source of information surrounding what really drives an athlete s participation. This is a reflective process which I believe develops continually over time, but must be practiced objectively I have found the support of other coaches particularly useful when doing this.

When working in an academy system, coaches have the challenging decision of selecting and releasing players. From the offset, I believe that parental engagement is one of the key pillars to keep an athlete on track. Coaches should focus on hosting a variety of workshops, utilising the knowledge provided in videos, such as the one attached, to improve transparency surrounding the growth and maturation process. Whilst growth and maturation can alter performance, players must still be accountable for their effort and actions as parents may look to use this period (i.e. growth and maturation) to excuse their child’s poor effort. Being very clear on what you wish to see in their training, attitude and in competition is vital. If this can be tracked and placed into a report, it’s an even better way to provide adequate information to overcome any claims or bias or favouritism as a coach and makes challenging conversations less personal.

Adolescence or maturation can present some diverse challenges for youth. Representing an academy system is not without its challenges. For example, players can miss movement opportunities (e.g. practice which encourages throwing, catching or balance) that prevent total athletic development through solely playing football. A simple and effective solution is for coaches to include multisport activities to develop an athlete s movement toolbox. These factors may make a player more visually appealing, and therefore, increase their likelihood of progressing through an academy system. These additions may be simple introductions such as balance drills ( ), throwing and catching training ( ), or utilising a host of tennis ball drills to develop HERE HERE hand-eye coordination ( ). These can be placed into warm-ups, rest periods or regular training and should HERE not be avoided by coaches working with youth.

Coaches described the adolescent growth spurt as a “condition”, closely mimicking the same terminology that someone would use to describe a medical condition (e.g. “affected by” or “suffering from”).

Players who were categorised as having “growth” were often described as performing poorly in training games and testing. Coaches noted that many visual signs accompanied this, including; long legs, big feet, broadening and filling out and becoming lean and gangly

Growth was also found to impact the coach’s perceptions on players and did have implications for selecting players to remain in the squad or to be released.

The authors concluded that maturation is a complex phenomenon which is a challenge to manage within an academy system.

The results of this study are specific to one club, which may limit the transfer to other institutions. In addition, these results are from an academy system with male athletes. Therefore, these findings may not apply to lower level clubs (e.g. grassroots) or to females. However, those working with youth must consider the challenges that accompany growth such as a decrease in movement quality, technical ability, decreased mood, challenges with instruction and clashes with their peers or family

A worrying finding from this study is that coaches described growth related issues as a “condition”. I would hope that the modern coach can communicate with youth in a way that is both direct and empathetic in consideration that their choice of words can have a lasting impact on a youth athlete.

The challenges that accompany growth and maturation are complex, so ensuring that coaches are empowered to have these conversations from an informed and educated stance is important. For any coach who is or is not aware of the challenges facing children, Dr Sean Cumming of Bath University discusses growth, which is a natural process, in the attached podcast. Dr Cumming introduces the topic brilliantly by stating that “it took me 17 years and 114 days to become an overnight success” with reference to Lionel Messi. This reinforces the notion that athletic development is a long process that requires quality time and focus to allow successful athletes to emerge.

M e n vs. B oys: W hat do e s G P S te ll us abo ut senio r and yo uth diffe re nce s in exte rnal lo ad?

Soccer is a physically demanding sport played by athletes of all different ages, sizes, genders and ethnicities. Authors such as Bradley et al., (2016) suggests that football is becoming increasingly dominated by physical interactions between players over the last two decades. The evolution of the game (e.g. greater anaerobic contributions) aligned with improved technology (e.g. tracking devices) has yet to produce research that supports coaches in their understanding of playing load. To date, no study has examined the peak physical characteristics present in the match play of a youth and senior soccer team from one club. Therefore, the aim of this study was to analyse a selection of physical performance indicators to allow coaches to prepare players for the senior game.

Twenty-two first team (25.9 yrs ± 4.5 years) and sixteen youth players (16.8 ± 0.9 years) were examined over the 2021-2022 season from one Scottish Club. A selection of match performance variables were collected using a global positioning system (GPS). These included: total distance covered (m), high-intensity distance (m; 5.57m/s), sprint distance (m; total distance covered >7m/s), the number of explosive distances (1.12/m/s2), number of very high-intensity accelerations (>+3m/s2) and the number of very high-intensity deceleration distances (<3 m/s2). This data was collected across all playing positions except the goalkeeper and all extracted data was monitored using exact time points to ensure that all measures were collected during playing time only (e.g. excluding half-time).

P ractical Takeaways

In line with previous studies, the incidence of injury increases as a game of football progresses, with most injuries occurring in the last 15 minutes of each half, with a game typically lasting 90 minutes (HERE). By utilising GPS technology, coaches could practically use this information to support players and manage injury load. For example, players who show a higher amount of accelerations and decelerations in a game may benefit from being substituted 15 minutes before half time or full time, as players who perform at a higher intensity are at greater risk of injury during these cut off periods With this information, coaches may look to bring on fresh players to reduce injury (HERE). risk. In the short-term, this may reduce the rate of injuries within a team. However, in the long-term, sports scientists should study the intensities utilising their GPS software around minutes 30-45, and 75-90 in order to recreate these scenarios in training with the overarching goal to expose players to these intensities in a safe and closed environment.

According to Le Gall and colleagues strains, sprains and contusions are the most common (HERE), injury types in youth. These occur mostly in the upper leg, followed by the ankle, knee and groin. These types of injury may be heightened during intense training. Given that wingers, midfielders and strikers typically perform higher levels of sprints than defenders, coaches need to ensure that training considers these factors. To reduce the risk of injury, coaches should ensure that an adequate warm-up is performed such as the one in this video. In addition, strengthening the posterior chain (e.g. bilateral/unilateral Romanian Deadlifts and Nordic Hamstring Exercise) coupled with quadricep (e.g. Goblet squats) and calf work (e.g. isometric calf holds, raises and plyometrics) should all be performed at least 48 hours before a fixture.

In the attached podcast, Dr Mishra suggests that in youth, early specialisation or highly voluminous training are the primary causes of injury. If we relate these findings back to this study, it would appear that the intensity of an U18 game is very similar to that of a senior team. A key difference between these teams is that the U18 team are still in education, and therefore, have high levels of academic stress and are typically more reliant on their parents for travel and finance. When considered as a whole, these factors most likely lend to overuse injuries or high playing loads and should be reduced by ensuring adequate rest, recovery and nutrition.

The main finding of this study was that no significant differences were found between the senior and U18 team across all variables.

On position, centre backs covered 295m more than wing backs in the lower high-intensity distance and performed on average 36 fewer decelerations than wing backs.

Compared to midfielders and strikers, centre backs performed less sprints, deceleration and sprint distances in both the senior and U18 squads. These findings indicate that elite Scottish players show a similar external load value compared to the U18 squad at the same club.

In this study, GPS provided coaches with an invaluable source of information that can immediately be utilised within sessions. An example of how Brighton FC use their GPS to influence practice can be seen in the attached article and highlights how coaches may use this information to rest/rotate players. For example, if wingbacks, as found in this study, are completing more sprints at greater distances, then these players may need to recover more between games. Similarly, the coach may design sessions that do not expose players to greater distances. To do this, a coach may alter the dimensions of a pitch (i.e. make the pitch narrower) to encourage passing through the lines of attack and limit opportunities to sprint for distances greater than 5-10m.

In summary, there are many variables that exist in a game of football and whilst GPS data provides information on distances and speeds, this only explores a small segment of football’s physical nature. Future research may wish to uncover the physical determinants of the game by looking into other measures (e.g. number of tackles or times dispossessed) to build a more thorough understanding of the differences between youth and senior teams.

N utritio n

This month ’ s top research on nutrition

H OW A C C U RAT E A RE RE ST IN G

M E TA BO L IC RAT E P RE D IC T IO N E Q UAT IO

F U E L L IN G T H E F E M A L E AT H L E T E :

D O T H E C U RRE N T C A RBO H YD RAT E

IN TA KE G U ID E L IN E S A P P LY TO T H E

F E M A L E P O P U L AT IO N ?

How accurate are resting metabolic rate prediction equations?

OBJECTIVE

Energy intake is frequently measured and modified by sports nutritionists to optimise performance and work towards body composition goals. Adequate energy intake, helps athletes maintain/grow lean body mass, fuel for the energy required, support recovery, and maximise training adaptations.

If the athlete could benefit from changes to body composition, energy balance can be altered to achieve this. For example, when energy expenditure exceeds energy intake (i.e. a negative energy balance) weight loss or body fat reduction can be achieved. Conversely, when energy intake surpasses expenditure, an individual is in a positive energy balance, which can support weight gain.

To provide individualised energy recommendations, practitioners must first know an athlete’s total daily energy expenditure (TDEE). TDEE is made up of 60-75% of resting metabolic rate (RMR) (energy costs of the processes essential for life), 10% of the thermic effect of food (energy expended to digest, absorb and covert food to energy around the body), and 20% of physical activity. As RMR accounts for the majority of TDEE, accurate assessment of RMR is required to support an athlete’s nutrient needs.

Indirect calorimetry is currently accepted as a non-invasive, valid, and reliable measure of RMR. However, its application limits its feasibility as it requires strict conditions for an accurate measurement (e.g period of fasting and resting before testing, and a quiet, dark, undisturbed room) combined with high equipment cost, long measurement times, and need for trained technicians. Therefore, many practitioners use equations to estimate RMR.

Although there are a myriad of equations predicting RMR, few of them apply to athletes as they are validated in other population groups (e.g older adults, obese adults, minimally active adults, general population adults). Additionally, there are distinct differences in body composition across different sports and at different competitive levels, which also affects the suitability of certain prediction equations.

Therefore, the purpose of this study was to examine the accuracy of ten commonly used RMR prediction equations in men and women collegiate athletes.

WHAT THEY DID

The observation study included 187 athletes (97 men and 90 women) from the National Collegiate Athletic Association (NCAA) Division III. This included athletes participating in baseball, cross country, diving, football, soccer, swimming, track and field, volleyball, wrestling and tennis.

On the morning of testing, participants arrived at the laboratory having fasted for at least 12 hours. Upon arrival, participants were assessed for height and body mass. Participants then completed the RMR assessment via indirect calorimetry. This test required the participants to remain in a supine position on an examination table for 20 minutes, whilst a clear, hard plastic drape was placed over the participant’s neck, head, and shoulders to determine resting oxygen uptake and energy expenditure. Following this assessment, body composition was measured using the BODPOD.

RMR values for each participant were then estimated from ten prediction equations: Cunningham, De Lorenzo, Freire, Harris-Benedict, Mifflin, Nelson, Owen, Tinsley, Watson (women, only), and Schofield.

Practical Takeaways

Practitioners should interpret predicted RMR with caution, and assume the equations underestimate the measured values. Therefore, the prediction equations can still be used to estimate RMR, as long as practitioners account for this in their overall prediction for TDEE.

De Lorenzo’s equation has shown to accurately predict RMR in female athletes, therefore it can be a suitable tool for practitioners to use when working with female athletes. This is despite the variation in sports played, and therefore the potential differences in body composition, weight, and stature, by the female athletes participating in this study.

Tinsley’s equation estimated RMR closest to measured RMR in male athletes, although this prediction was significantly (p=0.001) underestimated (-301 kcals). Practitioners can still use this equation to estimate RMR in male athletes but should account for the large underestimation. There is potential to develop a more accurate RMR equation in male athletes.

To accurately measure RMR, indirect calorimetry is still preferred to the prediction equations.

WHAT THEY FOUND

All prediction equations significantly underestimated RMR in male athletes. Tinsley’s equation estimated RMR closest to measured RMR but was still lower by 301 kcals. Schofield’s equation resulted in the largest mean difference at −726 kcals. In female athletes, Watson’s, De Lorenzo’s, and Freire’s equations all estimated RMR above measured RMR (5 kcals, 47 kcals, and 273 kcals, respectively). Whilst all other equations underestimated RMR. The closest estimated RMR was De Lorenzo’s equation at +5 kcals. Nelson’s equation resulted in the largest mean difference at −355 kcals.

Accurately calculating RMR is important an tool to ensure an athlete isn’t under or over fuelling. Underestimations in RMR could subsequently lead to inappropriate nutrition plans for athletes, which could lead to insufficient fueling, loss of fat free mass, and increased risk in low energy availability and injuries. Overestimations in RMR could lead to increased unwanted body fat, potentially hindering sport performance.

When working as a Sports Nutritionist, it is always good to assess the validity, reliability, and accuracy of the tools you are using. Previous research argues both for and against the accuracy of these equations in athletic populations, and this study hopes to provide some clarity on this topic.

The takeaway message is that these equations provide an estimate, and therefore should always be used with caution. Different research over or under estimates the accuracy of these equations in different population groups.

Therefore, these equations can provide a practitioner with a ballpark figure, but accurate RMR assessment should always be measured using indirect calorimetry.

Further research like Dr Marcus Hannon’s has started to publish more sport specific RMR equations unique to football players which is great, and more research should be done like this for sport specific athletic groups.

Fuelling the Female Athlete: Do the current carbohydrate intake guidelines apply to the female population?

OBJECTIVE

The rapid growth of women’s sport has exposed some cracks in sport science research when it is looking to be applied to female athletes. A fair conclusion in the nutrition sphere is that most of the seemingly robust nutritional guidelines practiced with female athletes are based on research completed with male athletes. This questions whether these guidelines are suitable and specific to female athletes and recent data suggests this is open for scrutiny.

Acute recommendations focusing on the type, timing, and amount of CHO are critical to ensure athletes can fuel for the performance demands. Due to the finite nature of body CHO stores relative to the fuel demands of common training sessions and competitive events, most nutrition strategies promote the high consumption of CHO to enhance performance.

As with all guidelines where sex-based differences could exist, it is important to investigate the population from which these guidelines were derived. This is important to ensure that outcomes from male populations are not being generalised to female populations. Current recommendations already account for body size differences in men and women, by prescribing CHO intake relative to body mass. However, other possible sexbased differences including muscle fibre composition and hormonal differences that contribute to changes in substrate utilisation, may need to be considered to support sex-based CHO guidelines.

The aim of this paper was to audit the research that has led to the current CHO guidelines in the acute period before, during and after exercise to determine if the evidence supports the use of CHO strategies in female athletes. The second aim was to examine if these recommendations should change during different menstrual cycle phases or with hormonal contraceptive use.

WHAT THEY DID

The search strategy started with an electronic search on PubMed to find studies where the primary aim was to investigate the effects of an acute CHO fuelling strategy on a performance and/or health outcome.

The acute CHO fuelling strategies were then categorised into CHO loading protocols, CHO mouth rinsing without ingestion, and studies examining the type, amount, or timing of CHO intake either before, during, or after exercise.

The researchers removed any duplicate papers, and studies including participants outside of 18-50 years of age, untrained, with medical conditions or lifestyle diseases, or involved an occupational task (military, and police and fire services). Researchers also removed papers where the CHObased intervention was used as a control condition only, the study outcome was irrelevant to the area of interest, and/or failure to explicitly state the sex of participants.

Data was extracted from the papers that met the inclusion criteria. This data included study population (females only, males only, mixed-sec etc), athletic calibre (sedentary, recreationally active, trained, highly trained/national, elite/international, world class), sample size, research theme (performance outcome, health focused etc), study quality, and menstrual cycle status.

WHAT THEY FOUND

A total of 937 studies were identified including 11,202 participants. Of these participants, ~11% were female and ~89% were male. Of the 937 studies, ~96% (n = 899) of studies included at least one male participant whereas only ~21% (n = 197) of studies included at least one female participant. While 740 studies (~79%) involved an exclusively male cohort, only 38 studies (~4%) involved a female only cohort.

Most research (~54%, n = 506 studies) measured CHO intake with a performance outcome, with the expectation of studies focusing on post-exercise CHO intake which mostly (~65%, n = 93 studies) measured mechanisms that underpin performance (e.g rates of glycogen synthesis or effects on exercise myokines).

Of the 937 studies, 496 studies (~53%) failed to provide sufficient information to identify the athletic calibre of participants. Of the remaining 441 studies, most participants (~83%) were determined to be sedentary, recreationally active, or trained. No study included world class participants.

Of the 197 studies that included women (mentioned above), 61 studies (~31%) provided sufficient information to define menstrual status. These 61 studies included cohorts of naturally menstruating women (n = 44), a mixture of naturally menstruating and hormonal contraceptive users (n = 11), hormone contraceptive users (n = 5), and women with menstrual irregularities (n = 1). No studies were awarded gold standard for their methodological control of ovarian hormones. There was also confusion in 22 studies over the definition of eumenorrheic (regular menstruation), meaning some female participants were wrongly categorised.

Of the studies that included cohorts of naturally menstruating women (n = 55), 32 described their intent to investigate outcomes in a standardised phase of the menstrual cycle. The majority of these studies targeted the follicular phase (n = 31) while one study examined the luteal phase. The five remaining studies involving naturally menstruating women compared the effects of an acute CHO fuelling strategy at different phases of the menstrual cycle, with the strategy of interest being CHO during exercise (n = 4) and CHO loading (n = 1). Although these studies provided interesting results, none provided information about the athletic calibre of participants.

Among studies of hormonal contraceptive users (n = 16), two studies indicated outcomes were investigated during the active phase of the oral contraceptive pill cycle. Of the remaining 14 studies, eight did not provide information on the oral contraceptive pill cycle phase.

P ractical Takeaways James’ C o mme nts

It is evident that most of the research establishing the current CHO recommendations have been based on male population. However, with little quality research suggesting that the recommendations should be different, practitioners should continue to implement these with female athletes combined with anecdotal information from the players lived experiences. This will help to individualise recommendations to best support the female athlete.

Practitioners need to develop a positive and open relationship with female athletes to ensure she feels comfortable talking about their menstrual cycle function.

It is evident that a collective effort to clearly define the criteria for terms such as eumenorrhea (regular menstruation), oligomenorrhea (infrequent menstrual periods), and amenorrhea (absence of menstruation) is needed.

The low energy availability in females questionnaire (LEAF-Q) is a great resource to measure symptoms of low energy availability including menstrual cycle and contraceptive use. This can help practitioners screen if any female athletes are at risk of low energy availability and implement how best to support them on a case by case basis.

When working with female athletes, it is not always possible to standardise her phase of the menstrual cycle when collecting performance data or body composition measurements. However, it is still important to make note of this, and how it affects her. For example, asking a female athlete which stage of the menstrual cycle she is in and any associated symptoms before doing skinfold or body weight measurements.

Although the quantity of research in sports nutrition involving female athletes needs to increase, the quality of the research should not be compromised to achieve this. A more fully formed, high quality study will provide practitioners with more robust recommendations.

The marked difference between male and female athletes is that there are many different ‘types’ of women. Although the basic physiology between male and female athletes is similar, females experience vast differences in hormonal levels based on their age, hormonal contraception use and menstrual cycle function. For example, women who menstruate normally and naturally, women using hormonal contraception (and the vast differences between each type of hormonal contraception), women with menstrual irregularities, pregnant women, lactating women, and menopausal women (just to name a few categories!). So, when applying nutrition guidelines mainly established through the male population, the first question should be which type of woman are you applying them to?

Now at this stage we can’t definitively answer that different nutrition recommendations should be a) different to males b) different for different types of women, but sex-based and hormone differences infer that this needs more exploration. For now, it is important for practitioners to have an open and honest conversation with female athletes about their menstrual cycle and how it affects them - an athlete’s lived experience is just as important as the current supporting scientific research.

This audit provides a needed critique of research focusing on CHO recommendations before, during, and after exercise. From here, new, high-quality research focusing on the CHO recommendations in female athletes can be developed to fill in the literature gaps. It’s an exciting time to be supporting female athletes!