Study Details
How to Read Me!
Practical Takeaways from study
Related links to learn more about the topic
Reviewers comments on the study
Research Reviewers
Science of coaching
Will is a Lecturer of Sport Coaching at Deakin University, Australia. Prior to this he has worked with Cricket NSW and Cricket Australia in an array of roles ranging from a sport scientist, development coach and a strength and conditioning coach. He completed his PhD at the University of Newcastle, Australia within the area of practice design.
Strength & Conditioning
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.
The Science of Coaching
Josh is a Performance Manager working for EXOS Tactical. He has previously held roles with English Institute of Sport, Rotherham Titans and Inspire Institute of Sport India.
Youth Development
Tom is the Head of Athletic Development at St Peters RC High School. He holds a Masters in S&C and has previously worked with West Bromwich Albion FC, Gloucester Rugby club, and Great Britain Equine. Tom is our youth research reviewer at Science for Sport.
Strength & Conditioning
James is currently the Head Strength & Conditioning Coach for the Romanian Rugby Union. He has previously worked in America's professional rugby competition Major League Rugby with Austin Elite and the NZ Women’s National Rugby League Team. He is a published author and has completed a MSc in Sport & Exercise Science from AUT, Auckland, NZ.
Technology & Monitoring
Cody is a strength and conditioning coach and adjunct lecturer at the University of Iowa. He has an MSE in Exercise Science from the University of Kansas and also holds a CSCS from the NSCA.
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.
Injury Prevention & Rehab
Jordan is a Physical Therapist and Strength Coach who currently practices in a Sports & Orthopedic clinic in Bergen County, New Jersey. He is passionate about educating athletes on ways to optimize performance while decreasing the risk of injury.
The Science of COACHING
Coaches, parents, or peers: Who has the greatest influence on youths’ life skill d
evelopment?
OBJECTIVE
Participation in sport is regarded as having a positive influence on building a healthy, successful life that positively influences society. This paper aimed to establish who has the greatest influence on life skill development.
WHAT THEY FOUND
This study consisted of 308 English youth sport participants aged 11-21 from 31 different sports. On average they participated in their sport for 2.61 hours per week and were of mixed ability. All participants completed four surveys.
1. Life skills Scale for Sports (see HERE) which was used tomeasure perceived life skills
2. Motivation Climate Scale for Youth Sports (see HERE) which measured the perceptions of the coaching climate
3. Parent Initiated Motivation Climate Questionnaire (see HERE) which assess perceptions of the parent climate.
4 Peer Motivational Climate in Youth Sports Questionnaire(see HERE) which measured perceptions of the peermotivational environment
Multiple regression analysis was conducted to establish which sub groups had the greatest impact on life skill development.
Practical Takeaways
It was clear from this study that creating a mastery climate is conducive to improving life skill development in youth sport participants. Some considerations for the performance practitioner to consider when working youth athletes might include:
A peer-lead ego climate can be facilitated by givingathletes responsibilities to lead aspects of training and thenlimiting feedback from the group to only positive reflections.
A mastery climate can be created by the coach with simple progressive drills, once level one is completed the player can move on, this also promotes autonomy and adds an element of competition.
In summary, this study showed that coaches, parents and peers should aim to create a skill mastery climate to positively influence life skill development.
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WHAT THIS MEANS
The authors found:
Life skill development was positively impacted by mastery climate (see HERE) from coaches, parents and peers.
Coach and parent skill mastery climate was found to positively influence life skill development
Peers had the greatest positive influence on life skill development
Peer-created ego mastery positively promoted life skill development SCIE
75
Josh Fletcher"When trying to impact positive life skill development, performance practitioners can consider:
Running workshops for parents to upskill and educate them on the impact of a process-driven mastery approach on their children’s communication, leadership and teamwork
Create a coaching environment where the athletes are constantly feeding back to each other, so giving a positive and collective experience they feel involved in.
"Focus your coaching on the execution of skills and drills from skill acquisition and skill mastery perspective, as opposed to an outcome."
The Science of COACHING
Coaches, parents, or peers: Who has the greatest influence on youthslife skill development?
OBJECTIVEHow a coach designs and implements a practicesession is something quite personal, often based ona combination of their experience working in theirparticular environment and knowledge they havegained from a variety of sources. A large resourceon which many coaches draw from with regards topractice design is academic research, whichtypically proposes two schools of thought on this.
The first is a more contemporary approach topractice design that follows anon-linear pathway, with akey characteristicof athletes interacting withand using environmental information to determinethe most effective way to complete a task, oftenwith limited input and direction from the coach. Theother is amore traditional approach to practicedesign, which the authors of this study note is characterised by demonstration of ‘optimal’ technique and isolated practice tasks. Despite beingstraightforward and easy to digest amongst coaches,this approach is often criticisedfor its linear ap proach to learning.
Both approaches have advantages anddisadvantages, but the traditional approach topractice design still appears the most popularamong coaches regardless of the level at whichthey are coaching or the sport.
The authors of this study looked to understand the method in which coaches designed their practice sessions as well as why they choose the method.
WHAT THEY FOUND
Ten international tennis coaches (age = 45 ± 11 yr; coaching experience = 22 ± 11 yr) who were employed by a National Governing Body or were working in a Performance Academy took part in a semi- structured interview. The interviews were ba sed around two ma in themes - how the participants designed practice and each participant’s coaching philosophy.
Each interview was transcribed by the authors and inductive thematic analysis was used to code and analyse these transcripts.
SCIENCE FOR SPORT PODCAST EP 84
Practical Takeaways
Using high volume and repetitive drills appears to be one of the key aspects of a tennis coach s practice. Although current research suggests this type of practice can have negative effects on aspects of an athlete’s performance (e.g., limits autonomy and creativity, can lead to boredom and lack of engagement), the coaches of this study clearly see merit in this approach. To avoid (or at least limit) potential negative impacts of high volume and repetitive drills, consider randomising the order of your drills or parts within each drill so players are exposed to different information rather than the same information each time.
Creating a practice environment that recreates not only the movements that would appear during a match but also the context in which these movements occur is what makes it effective. Athletes from all sports are exposed to all types of situations (e.g., a few points behind with only minutes left in the match, injury to a key player, poor’ officiating decisions), so placing them in situations which recreate this will provide them with the opportunity to develop their skills with the confidence they can respond appropriately when faced in a match.
Understanding that athletes can respond differently to the same stimulus is something a coach needs to be aware of. If working in an individual sport like tennis, this can be easier to control since you can more easily adapt the training session to suit the needs and goals of the athlete without impacting on another, particularly since there may not be another athlete. This gets complicated in team sports though. Designing your practice sessions with both individual and team needs in mind is the best approach here. This is where knowing as much about your athletes, such as their strengths, areas for improvement, maturity level, behaviours, etc., comes in handy.
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WHAT THIS MEANS
Two key themes were identified by the authors which formed the basis oftheir results.
Coach Experiences
None of the coaches suggested formal education had a longterm influence on their own coach development and understanding of practice design, rather the biggest influence on this was through experiences (i.e., informal learning) they were involved in.
Playing professionally appeared to be a factor in how many of the coaches approached practice design, which as stated by the authors allowed them to more easily demonstrate technique and on-court behaviour.
The other key influence on how they approached practice design was through ‘on the job’ training. In other words, using trial and error over a number of years allowed them to determine what approach worked best.
Coach Beliefs
The coaches noted their players had to be able to repeat shots and patterns of play in order to be successful, which aligned with the use of repetitive, high volume drills during practice.
Being able to cope with highly pressurised on-court environments was something the coaches identified players needing to be able to manage. This often took the part of outcome-focused tasks during practice.
Individualising the practice to suit the needs of each player was something each coach identified. During practice this included one of three approaches:
Designing tasks based on a player’s skill development goal.
Adjusting their style to help their players reflect on what they are doing and encourage them to find their own solutions to problems they face.
Manipulating practice task constraints based on the game style.
Will Vickery
"As was mentioned by the authors, the findings of this study indicate that despite being aware of contemporary approaches to practice design, coaches still follow a more traditional approach. Considerable research exists nowadays highlighting the benefits of these contemporary approaches, so following a traditional approach somewhat goes against conventional thinking. This, though, might shed some light onto the preference for and practicality of the more recent thinking to practice design that coaches have based on their experience.
“Although an advocate for contemporary approaches to practice design myself, there is clearly some value in different approaches as seen through the eyes of a head coach. When considering what the most effective environment for skill development is, both practitioners and researchers would do well to listen and learn from each other, helping to create a dialogue about what each side suggests is most effective.”
Strength & Conditioning
This month’s top research in strength & conditioning.
HOW MUCH DOES PREVIOUS-DAY ALCOHOL INGESTION IMPACT MUSCLE FUNCTION AND PERFORMANCE?
DOES A HAMSTRING STRAIN WITH TENDON INVOLVEMENT LEAD TO A DELAYED RETURN TO SPORT AND INCREASED RISK OF INJURY?
CAN RUNNING BASED WARM-UPS WITH BLOOD FLOW RESTRICTION ENHANCE SPRINT PERFORMANCE?
HOW DO RESISTANCE BANDS AFFECT MUSCLE ACTIVATION AND BAR VELOCITY WHEN DEADLIFTING
What are the cross-education effects from singleleg decline squats at different execution times?
OBJECTIVE
Blood flow restriction (BFR) training is often used to enhance muscle mass in injured athletes, as minimal loading is needed to maximise metabolic stress. But BFR is not limited to hypertrophy - in running, BFR has been shown to improve 100m sprint times (see Issue # 14 of the Performance Digest and HERE for the abstract).
However, the acute physiological and performance response to running with BFR has not been studied, especially in the context of a warm-up.
Therefore, this study aimed to examine the effects of BFR running as a warm-up on 60m sprint performance and the physiological responses.
WHAT THEY DID
Twelve male sprinters (age = 22.7 ± 4.6 yr) performed two warm-up interventions with two exercise tests. The warm-ups were 5x2 mins of running at 50% heart rate reserve, with 1 min between sets - either with BFR or without BFR. The BFR condition had the cuffs worn on the most proximal part of each thigh at a pressure of 1.3 times resting systolic blood pressure (SBP), which reduced blood flow by 50% in the femoral artery. This equated to 149.8 ± 5.0 mmHg and 14.5 ± 0.5 mins worn for the entire warm-up.
The exercise test was either an is okinetic knee flexion and extension at 60°/s and 180°/s or a 60m sprint. Each warm-up was followed by the strength or sprint exercise on separate days, making four separate exercise trials in a counterbalanced order. Electromyography (EMG) electrodes were placed on the vastus lateralis, biceps femoris, gastrocnemius, and tibialis anterior, where muscle activation was captured for 10 seconds of each running set.
Heart rate, RPE, and blood lactate were taken before and after the warm-ups.
Practical Takeaways
While BFR running as a warm-up may enhance the physiological and neurological response, it doesn’t seem to translate to sprint performance. The authors put this down to the test not being long enough to see the benefits from BFR.
However, that doesn’t make a BFR running warm-up useless and it may have its place within the athletic population. The most useful application I can see for running with BFR is in the return-to-play setting with hamstring injuries and for athletes who are prone to suffering hamstring injuries.
Because BFR running seems to increase H:Q ratio, this may act as an added protective effect for the hamstrings, as when H:Q ratio is below 0.6, hamstring injuries are 17 times more likely to occur (see HERE). Simply adding cuffs to the upper thighs as part of the warm-up may be a way to protect vulnerable players.
The other area I see this working well is in very cold climates. There is nothing worse as a coach than having to perform a speed session with snow around the field in the miserable cold. It takes athletes longer to warm up and some may be reluctant to sprint because of the cold. By applying pressure cuffs, athletes can warm up faster due to the increased physiological response.
Anecdotally, I've found using the Voodoo bands as part of a warm-up routine makes my joints feel brand new and muscles ready to work. Perhaps this feeling can allow athletes to open up when sprinting.
Want to learn more?
Then check these out...
WHAT THEY FOUND
The BFR warm-up significantly enhanced knee flexor strength at both speeds compared to no BFR, with no change seen in knee extensor strength. This significantly increased concentric hamstringquadriceps ratio. Muscle activation was significantly higher during the BFR warm-up for the vastus lateralis and biceps femoris compared to no BFR, with no difference seen in tibialis anterior or gastrocnemius.
Heart rate, RPE, and blood lactate were significantly higher after the BFR warm-up compared to no BFR.
No differences in 60m sprint performance were seen between the warm-up conditions.
SCIENCE FOR SPORT PODCAST EP 78
James’ Comments
“This is an interesting area of research that takes the singular focus of BFR away from hypertrophy and toward sports performance. BFR like this isn’t useable in a team setting but can potentially be used with individual sporting athletes or injured players within a team.
“The main issue with BFR is the equipment needed to accurately measure pressure. Most coaches don’t have the budget or access to this. You can quite simply use knee wraps and Voodoo bands tied to a 6-7/10 pressure - I’ve done this myself and have had no issues doing it and found it to be just as effective.”
How do resistance bands affect muscle activation and bar velocity when deadlifting?
OBJECTIVE
Variable resistance training (also known as accommodating resistance) is a popular method to increase bar velocities due to the reduced initial concentric load resulting in greater bar velocities. The bar can be accelerated to lockout when using variable resistance, as traditional resistance exercise forces the athlete to decelerate at the end of the concentric phase.
To date, no study has investigated the effects of banded variable resistance deadlifts on muscle activation and bar velocity and power. Therefore, this study aimed to compare deadlifts with and without bands, and their effects on power, velocity, and muscle activation.
WHAT THEY DID
Fifteen resistance trained men (age = 28.7 ± 9.3 yr) with a 1RM deadlift of 190 ± 28 kg had surface electromyography (EMG) applied to the gluteus maximus, vastus lateralis, vastus medialis, semitendinosus, and gastrocnemius. Subjects performed maximal voluntary isometric contractions (MVIC) for each muscle group to normalise the EMG signal and provide a baseline measurement.
Following this test, subjects performed six reps of each deadlift condition with three minutes rest between conditions. These conditions were: 100kg barbell (NB), 80kg barbell with 20kg band tension (B20), 75kg barbell with 25kg band tension (B25), 70kg barbell with 30kg band tension (B30). The 100kg load equated to 53.9 ± 7.9 % 1RM.
Bar velocity and power were recorded with a linear position transducer (Gymaware). Muscle activation and rate of muscle activation were measured with EMG.
Practical Takeaways
It seems as band tension is increased, a reduction in muscle activation of the posterior chain muscles is seen in conjunction with greater velocity and power outputs. The reason for the reduction in muscle activation is likely due to the higher average load of the noband condition, as it was 100kg from bottom to top where the other conditions started with lighter loads from the floor. Interestingly, bar velocity started to plateau between B25 and B30, indicating 30% band tension may be the upper limit you want to use when looking to maximise bar velocity. Here is how this study can be used in your practice:
1) If you are using banded deadlifts, you may want to perform glute and hamstring accessory exercises after or on a separate day. For example, Romanian deadlifts or hip thrusts.
2) The approximate 53% 1RM equated to 0.7 m.s-1 mean velocity in the no-band condition and 0.9 m.s-1 mean velocity in the B25 and B30 condition. According to Bryan Mann’s categorisations (picture in links below), this would equate to the lower end of strength/speed. Using 40% 1RM would target speed/strength while approximately 70% 1RM would target accelerative strength. You can alter the loads based on your athletes’ individual needs.
3) If your schedule forces you to train lower body the day of or before speed, then adding bands may be a way to reduce posterior chain load, which is important when needing to sprint.
4) A viable periodisation strategy may be to start pre-season with no resistance bands and progress to the use of resistance bands as a peaking modality to increase velocity and power of the lift.
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WHAT THEY FOUND
Muscle Activation
Peak MVIC% significantly decreased between NB and B25, B30 for the gastrocnemius and NB and B20, B25 for the semitendinosus. There was a trend for a reduction in activation for the gluteus maximus. No other significant differences were found for other muscle groups between conditions.
Rate of Muscle Activation
No differences were found for changes in rate of muscle activation.
Power & Velocity
Concentric peak and mean power and velocity increased significantly between NB and B20, B25, B30 as well as between B20 and B30
Comments
“It would be interesting to see if these reductions in posterior chain muscle activation are magnified at increasing or decreasing percentages of 1RM. This would provide more information to influence programming especially when it comes to needing to add extra glute and hamstring exercises.
“Using banded variable resistance with deadlifts is a viable choice for increasing speed of the lift. However, I would opt for chains if using variable resistance when squatting. The fast eccentric load when performing banded squats could result in more muscle damage than expected and therefore, soreness. Chains don’t have the elastic tension but still unload the bottom of the movement and allow the athlete to accelerate the bar through the full range of motion.”
What are the cross-education effects from singleleg decline squats at different execution times?
OBJECTIVE
Cross-education refers to the neurophysiologic phenomenon where there is strength gain or skill improvement transferred to the contralateral or untrained limb following a unilateral skill. Current research shows strength improvements in the untrained limb can be seen up to 18% after utilising cross-education training (HERE).
The purpose of this study was to compare the effects of execution time of an eccentric single leg decline squat (SLDS) training program on morphological and functional properties of an untrained limb.
WHAT THEY DID
Thirty-six individuals were randomly divided into three groups: a control group, experimental group 1 (eccentric contraction runtime = 6 sec), and experimental group 2 (eccentric contraction runtime = 3 sec).
Each experimental group performed six weeks of single leg decline squat (SLDS) training on their dominant limb (leg they kicked a ball with). Participants performed three sets of eight repetitions (rep) three times a week at 80% 1repetition maximum (RM), with a six second rest between each rep, and a two minute rest between sets.
Thickness and elastographic index of the patella tendon, lean mass and fat percentage of the thigh, contractile properties of the vastus lateralis (VL) as well as triphasic knee extensor peak torques and eccentric SLDS 1-RM were measured after six weeks of training, as well as six weeks of detraining on the untrained limb.
Practical Takeaways
Rehabilitation specialists as well as S&C coaches should consider utilising cross-education to aid in the neuromuscular and rehabilitation process after a unilateral injury or surgical intervention due to the strength gains seen in the untrained limb.
Both three and six-second contraction times used in a SLDS training program are effective in causing hypertrophic and functional adaptations in the untrained contralateral limb.
The gains in strength seen in the untrained limb with cross-education were shown to remain after a six-week detraining process, which can help clinicians speed up the rehabilitation process rather than waiting to load the affected limb.
A SLDS training program consisting of six second contractions is sufficient to increase tendon stiffness although does not occur immediately after training.
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After six weeks of training, there was an increase in lean thigh mass of the untrained limb in both experimental groups.
Both experimental groups yielded increases in 1RM, isometric, concentric and eccentric knee extensor torques in the untrained limb.
No differences were found in the contractile properties of the VL or in the thickness of the patella tendon after eccentric training in either experimental groups.
The SLDS training program induced greater patella tendon stiffness in the six second experimental group compared to the three second experimental group and was noticed at the follow-up after six weeks without training.
SCIENCE FOR SPORT PODCAST EP 81
Jordan August’ s Comments
“Clinically, I use cross-education regularly and see great benefit when working with clients postoperatively, after sustaining an acute injury or when an extremity is immobilised. It allows the untrained leg to benefit from strengthening the contralateral limb when heavier loading is contraindicated.
“In this study, participants were healthy individuals. Future studies should assess the response in pathological tendons undergoing a SLDS training program to determine tendon adaptation to mechanical load.
“Additionally, different types of exercise interventions, loads, and muscle contraction types should be assessed to determine their effect on cross-education.”
Effects of blood flow restriction during and after a short-term training period
OBJECTIVE
Blood Flow Restriction (BFR) training is used to induce hypertrophic and strength responses in skeletal muscle. BFR training involves decreasing blood flow to and from skeletal muscle with the use of a cuff meant to compress underlying muscle.
The effects of BFR have strong evidence for strengthening of both lower and upper extremities but there is a lack of evidence for effects following a detraining period.
This study questioned whether the positive effects of BFR training were present following a period of detraining.
WHAT THEY DID
Ten male subjects who ranged from 19-31 were measured. They were assessed before and after a three-week training protocol, testing quadricep strength using BFR with use of a knee extension machine - 1 Repetition Maximum (RM) and Quadricep Cross-Sectional Area (QCSA) via MRI were assessed in the study.
The subjects completed 12 training sessions over a threeweek period. The training sessions consisted of a standardised warm-up followed by three sets of 15 repetitions at 30% of the subjects 1RM on each leg, with use of the knee extension machine.
A detraining protocol was measured afterwards. This consisted of a 12-day period of time where BFR was used twice a day without exercise on one leg, and no BFR and no treatment on the contralateral leg.
Practical Takeaways
This study shows that BFR training has a positive effect on quadricep strengthening and hypertrophy when used consistently over a short training period. It was shown that three weeks of training caused an average increase of 9.8% for 1 RM and 6.55% for QCSA. Despite this, following a period of detraining, strength and hypertrophy were reversed with BFR application without an exercise stimulus.
Overall, BFR is a great tool to use in order to strengthen when heavy loading is not appropriate - e.g., certain medical conditions or early post -operative care. Its use, followed by continued strengthening in a training or rehabilitation protocol, shows great promise.
Limitations with this study include sample size, along with not controlling nutritional intake prior to the training. Further studies should investigate effects of BFR on post-operative care for the lower extremity in order to decrease effects of immobilisation. Along with this, a study using a larger sample or longer period of training time may produce different results.
SCIENCE FOR SPORT PODCAST EP 88
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WHAT THEY FOUND
The researchers found that BFR training caused a significant increase in quadricep strength as measured via 1RM and QCSA in a three-week training intervention.
However, a two-week period of detraining immediately following the protocol reversed those gains in strength and hypertrophy of the quadricep muscle. It also showed that use of BFR without an exercise stimulus failed to reduce atrophic effects of detraining.
Matt’ s Comments
“
In short-term use, BFR produces positive effects on strength and hypertrophy. Mechanisms for this include an increase in fast-twitch fibre recruitment and increased muscle protein synthesis. BFR effects do not last with detraining however, and may be reversed following a short period of time.
“Secondary to this, BFR can be used in the beginning phases of a rehabilitation protocol with athletes when they have difficulty tolerating higher loads. Following this, a strengthening program focused on isolation of lower extremity musculature along with closed chain strengthening can continue the effects gained by BFR. The use of BFR should always be supervised by a rehabilitation professional who is trained in its use.”
Technology & Monitoring
This month’s top research on technology and monitoring.
HOW DO TRAINING AND COMPETITION DEMANDS VARY ACROSS A BASKETBALL SEASON?
HOW TO APPROACH TRAINING DIFFERENTLY FOR STARTERS AND RESERVES IN-SEASON
How do training and competition demands vary across a basketball season?
OBJECTIVE
A competitive in-season period typically varies anywhere between 15 weeks to upwards of seven months in some sports. During this extended period of time, it is critical coaches manage workloads effectively, potentially even considering the season with a phasic or periodised approach. Via wearable technology (e.g. microsensors or heart rate (HR) monitors), workload management can come in the form of objective internal (e.g. HR) and external (e.g. PlayerLoadTM (PL) or Inertial Movement Analysis (IMA)) measures that help to quantify the demands of training and competition.
These measures can be further understood by combining a subjective measure such as rating of perceived exertion (RPE) to help bolster context and allow for athlete feedback
(see HERE).
Given the extended nature of a competitive season, the changes in game and training demands are not well understood. Therefore, this study examined athlete workloads during training and competitions, both separately and combined, studying average weekly values (e.g. PL, accelerations, jumps, HR zones, RPE), with specific division of the season into phases (e.g. early, middle, and late) to identify variations across a basketball season.
WHAT THEY DID
Seven male semi-professional basketball players (age 23 ± 4) from a team in Australia that consistently played across 15-week season, had on-court, game and practice sessions monitored using microsensors and HR monitors, as well as each athlete’s RPE recorded within 30-min following.
The season was divided into three five-week blocks (early phase: wk 1-5; middle phase: wk 6-10; late phase: wk 11-15) with a total of 18 games (0-3 per wk, played Friday-Sunday ) and 0-3 on-court training sessions per week involving technical and tactical drills and modified games with no influence from researchers. PL is calculated using measures of rate of change in accelerations in three movement planes, IMA actions were also considered based on frequency and intensity, examining total accelerations, decelerations, changes of direction, and jumps. HR was calculated based on a relative intensity (%HRmax) to the highest HR measure recorded during the season, examining the weekly demands of training and competition. RPE was the final variable considered after each game or session as a subjective measure of intensity.
These various metrics were evaluated on a weekly basis, examining competition and practice demands in combination and separately across the various phases (early, middle, late) of the season.
SCIENCE FOR SPORT PODCAST EP 85
WHAT THEY FOUND
Weekly demands were greatest during the late phase (wk 11-15) of the season.
In-game demands remained steady across the season, but RPE and most IMA actions (all except high-intensity events (accelerations, decelerations, or changes of direction >3.5m∙s-2 or jumps >40 cm)) increased by mostly a trivial-small amount in training sessions as the season progressed.
Despite an increase in frequency of games later in the season, volume (total min) reduced in both training and game demands when comparing middle to late phases.
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How do training and competition demands vary across a basketball season?
Practical Takeaways
Intensity and volume are critical variables to manage across a season. An inverse relationship between the two is likely the best strategy - beginning the season with higher volumes of work at lower intensities will properly prepare the body to handle higher intensities later in the season, while being sure to decrease volumes concurrently.
Recognising the intensity demands of competition remain consistent, it is important that coaches progressively build the intensity of training sessions with respect to what measures of intensity (e.g. %HRmax, IMA frequency or intensity, RPE) can impact fatigue or increase injury risk the greatest across a season. Of all the options, coaches should pay special attention to an athlete’s subjective reports (see HERE).
Rating of perceived exertion is the single most simplistic variable of an athlete’s given intensity but combining that measure with additional subjective reports relative to mood, soreness, sleep, or nutrition can be helpful to understanding why RPE may fluctuate. This also encourages accountability towards proper recovery habits (sleep and nutrition). This insight can be gained on a daily basis in the morning prior to training and competitions.
Coaches can mitigate competition load by paying attention to in-game fatigue and playing time, using substitution strategies or calling time-outs during opportune moments - these can help reduce competition demands (e.g. total minutes and RPE). For example, in a high-paced style of play, players need to be able to be aggressive in their tactics and intensity, while maintaining quality, without pacing or degrading their efforts because of extended stints of play. Coaches should encourage and support these efforts with strategic time-outs during competitions.
The various phases of the season (off-, pre-, or in-season) must flow sequentially into one another. The ultimate goal during the non-competitive period is to prepare athletes for competition demands, and training volume and intensities prior must be similar to prevent drastic shifts across the phases of a year. Loads should progress appropriately based on what the athlete has been doing over the previous month (chronic load).
So a season does not appear overly tiresome and mundane, it is important coaches break the season into segments that have recognisable transitions. This can be divided by extended break periods, holidays, or changes in competition (e.g. non-conference to conference play). Ultimately, allow athletes a reduced psycho-physiological load by separating the weeks of a season into manageable portions.
Coaches must be adaptable to the weekly competition demands and vary training accordingly. If fatigue is elevated, maximise periods of time with limited competitions to boost readiness and resolve nagging injuries, possibly shifting training to more instructional and less physically demanding if necessary. Otherwise, continuing to dose athletes with mid-week bouts of competition-specific intensity is necessary and important to maintaining performance.
Cody’ s Comments
“In the end, winning is the goal of competition, and this can take a season’s worth of work which can extend over several months. The best opportunity for winning comes through a collective result of each athlete’s relative performance, where readiness is maximised on the day of competition.
“Readiness really comes down to a measure of an athlete’s psycho-physiological health and is influenced by numerous factors (e.g. training loads, social environment, genetics, stress level, sleep quality, nutrition, etc.), some of which are controllable or uncontrollable by the coaching and performance staff. In an attempt to optimise readiness, it is important to manage the variables that are controllable (e.g. workload volume and intensity) so athletes are prepared not only for the given demands
of a single competition, but the totality of a season.
“Coaches must adjust the volumes and intensities reactively to the fluctuations experienced throughout a season of triumphs or setbacks. If staff can be objective in their measurements and approach, they can improve the precision and accuracy of their adjustments. When this is completely understood and shared with the athlete, it can help them manage some of the seemingly ‘uncontrollable’ factors (e.g. stress and sleep quality) that can interfere with readiness and recovery.
“Coaching and load management is much more than techniques, tactics and monitoring - it extends into strategies that involve planning, educating, and supporting athlete health and well-being. With this approach, the likelihood of athlete readiness is maximised throughout an arduous season.”
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How to approach training differently for starters andreserves in-season
OBJECTIVE
Advancements in wearable technology (e.g. global positioning systems, GPS) have made player tracking more cost effective and beneficial in providing objective measurements of each player’s movement velocity, volume, and intensity on the pitch. This is especially valuable and prevalent for athletes at the university level, where athlete monitoring and load management plays an incredibly important role in preventing injury and optimising performance across the season due to balancing academic and athletic demands.
Further, at the collegiate level, the goal is to not only be competitive, but also to develop younger or reserve players in case of need for the immediate or future seasons. Athletes who play the majority of the match (starters), presumably experience a vastly different training load than reserve players, and considerations should likely be made based on the variance in workloads. Although training- or match- specific workloads (see HERE) for NCAA men’s soccer have been investigated, accumulated season totals and differences between starters and reserves is not well understood.
Therefore, researchers in this study examined variations in workload volumes (e.g. total distance, minutes at various velocities and heart rate intensities) between starters and reserve players accrued over an NCAA soccer season.
WHAT THEY DID
On-field training and match data was collected for five NCAA Division I men’s soccer teams across the 2016 and 2017 seasons using GPS and heart rate (HR) monitors. Eighty-two players had a sufficient amount of data, excluding goalkeepers, anyone who missed more than two weeks due to injury, or anyone with more than 25% of session- or match-data missing from analysis.
Players were classified as a ‘starter’ based on the percentage (>60%) of total matches in which they started, as well as having played more than 60% of the season’s match minutes. Players who did not meet these participation levels were classified as ‘reserves.’
Total distance covered, distance covered in various velocity zones, HR intensity zones (which were calculated into training impulse (TRIMP) values, see HERE), and intensity zones for accelerations were established based on previous research (see HERE). Season totals for these metrics were examined and compared between the ‘starters’ and ‘reserves’ to better understand any potential difference.
WHAT THEY FOUND
Total distance across the season was greater for starters across all running speeds (walking to sprinting).
Total accelerations across the season were greater in volume across all intensity zones (e.g. zone 1.0 - 0.99 m∙s-2, zone 4< :3m∙s-2)Although total distance, TRIMP, and accelerations accrued through the season were higher for reserves in training sessions, the
Significant discrepancy between total distance, TRIMP, and accelerations between starters and reserves, where starters accumulated more volume across all measures across the season.. discrepancy was not enough to overcome the difference in match-workloads between starters and reserves.
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How to approach training differently for starters andreserves in-season
Practical Takeaways
Understanding the workload volumes and intensities that starters will experience in a given match is an important focus when designing off- and preseason training. Especially for those expected to be starters, training volumes should be periodised and progressed in accordance with acute:chronic loads expected during the competitive season (see HERE).
The off-season should be dedicated to improving general capacities in fitness, speed, strength, movement capability, etc. while also implementing soccerspecific tasks progressing and managing loads appropriately at a secondary level.
During the pre-season period, development becomes much more sport-specific to preparing athletes for the demands of a match, prioritising technical and tactical preparation as a means of training and exposing athletes (especially starters) to the recovery demands (2-6 days) between match-specific workloads (e.g. speeds, accelerations, HR intensity, durations, and distance).
By the time a team reaches the in-season period, recovery is the most important strategy to maximising readiness and performance for all players. In order to mitigate fatigue, it is critical coaches devote time to educating athletes on the importance of sleep and nutrition. They should provide them with strategies on improving the quality and quantity of their sleep, as well as teaching them what to eat and how to prepare food that will support healing and calorie needs.
Especially at the NCAA level, competitions are very frequent (every four days, sometimes <48-hr between matches, see HERE), this means much of the preparation for starters between matches will be focused on minimal-level physical demands (low-moderate velocities, minimal accelerations and decelerations, moderate heart rates), but emphasising tactical strategies based on upcoming opponents and film analysis from previous competitions. Coaches should have a long-term approach to starters, minimising the accumulation of fatigue across the season, maximising readiness on match-day, and managing recovery between matches.
Understanding the loads that starters will accumulate across the season, it is important to protect them early on in the season and limit playing time when and where possible. Allowing reserve athletes the opportunity to play when possible can help manage individual fatigue, as well as improve experience across the entire team.
It is not necessary to equate workloads for starters and reserves. Reserve players can be developing in other ways during the season (e.g. understanding the game, ball-specific skills, intellectual maturation). As a coach, it is important to recognise why that individual is in that role and use that time to develop their weaknesses and abilities for the coming years.
Reserve players should continue to maintain the requisite level of fitness and performance ability built through the off- and pre-season periods through soccer-specific conditioning (e.g. on-ball or small sided games), as this is shown to be greater from a physical and skill-specific standpoint (see HERE). This is crucial in the event that a reserve becomes a starter, minimising the increase in workload and mitigating injury risk.
For reserve players that have little to no intention of playing in an evening match, they can maintain the same weekly schedule as starters by performing their supplementary soccer-specific work earlier in the day to provide them the opportunity for direct coaching and high-quality work, as well as mirrored recovery timeline through the week. The goal would be to simulate a match-play with 20-40-min of game-speed intensity and environment (i.e.. as big a field as possible depending on how many athletes are available to participate). Ideally this could occur immediately preceding the team’s pre-game meal, and that feeding opportunity would serve as a post-workout meal for the reserves finishing their training session.
Cody’ s Comments
“The most important aspect of this research highlights the need for an individualised and holistic approach in order for the team to be most successful. There will always be a discrepancy in workload between starters and reserves. Starters can easily become overloaded with stints of condensed competition and poor recovery, and the goal should not be to put reserves in the same high-risk situation. Match-specific workloads are necessary for reserves, and they do need to simulate that exposure on the day of or post-match in order to continue to maintain, if not increase, overall preparedness in their sport.
“The important thing to focus on, starter or reserve, is to maximise their readiness at the time when you’re asking them to perform at a maximal level (i.e. match or match-specific work). By doing this, athletes are given the best opportunity to experience a productive and quality environment because their abilities are ready to shine, and injury risk is at its lowest. This takes a team effort in the athletes maximising their time with recovery habits, as well as coaches managing and monitoring training loads across the days, weeks, and months for both off- and in-season training.
“Ultimately, if coaches are waiting until the competition period to develop starters, it’s too late. Preparation for workloads must happen during the off-season, and the in-season is about recovery and optimising readiness for gameday.”
Fatigue & Recovery
This month’s top research on fatigue and recovery.
HOW MUCH DOES PREVIOUS DAY ALCOHOL INGESTION IMPACT MUSCLE FUNCTION AND PERFORMANCE?
DOES A HAMSTRING STRAIN WITH TENDON INVOLVEMENT LEAD TO A DELAYED RETURN TO SPORT AND INCREASED RISK OF INJURY
How much does previous-day alcohol ingestion impact muscle function and performance?
OBJECTIVE
Intercollegiate athletes have been known to ingest high volumes of alcohol across various college campuses. Although alcohol consumption the day of an athletic event is rare, it has been shown that 58% of athletes consume alcohol the night before a game or practice.
The current study investigated what the effect of alcohol consumption was on morning-after muscular power, strength and fatigue in an exercise session.
WHAT THEY DID
The authors took six female and six male participants with an average age of 25.1 and tested them over five visits to the Applied Physiology Laboratory at the University of North Texas.
Visit one took anthropometric measures. Visit two and four consisted of alcohol consumption, which was equivalent to 4.3 drinks for male participants and 3.14 drinks for female participants. Visits three and five were done the day after each alcohol consumption visit. These visits consisted of measurements of vertical jumps, mid thigh pulls exercise, maximum bicep curls and a constant power cycle ergometer test to exhaustion.
WHAT THEY FOUND
Previous-day alcohol consumption did not have a significant effect on muscular power or strength with the noted exercises when compared to a control group consuming non-alcoholic beverages.
It did however have a negative effect on rapid aerobic and anaerobic activity and thus the cardiovascular system, which was measured via a constant power cycle ergometer test to exhaustion.
Previous-day alcohol consumption led to decreases in VO2max levels when compared to non-alcoholic beverages consumed.
SCIENCE FOR SPORT PODCAST EP 91
Practical Takeaways
Training college athletes can involve many external factors when it comes to improving both cardiovascular and muscular performance.
This study measured the performance of multiple upper and lower extremity exercises as well as full body movements testing the muscular system. It showed that drinking alcohol the day before exercising did not have an effect on the muscular system. It did however have a negative impact on the performance of the cardiovascular system.
As rehabilitation professionals it is important to realise how to get the best out of our athletes and adapt to each training session properly. Although this study lacks evidence for muscular performance changes, it does show negative changes to the cardiovascular system which is important at different stages of all sports.
Coaches and rehabilitation professionals should look to utilise this study to make athletes more aware of the effects that their decisions can have on their performance along with their team s as well.
Matt’ s Comments
“Alcohol consumption has become a normalised activity in most intercollegiate athletic settings. It is important to educate athletes on the risk factors it can have on their athletic performance, especially when training for competition.
“This study shows that previous-day alcohol consumption does not negatively affect muscular performance compared to cardiovascular performance. With that knowledge, rehabilitation and strength and conditioning professionals can better adapt their training sessions with an open conversation with their athletes about their consumption habits. This conversation can be used as a tool to steer athletes away from binge drinking habits especially in times of congested competition periods.”
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Does a hamstring strain with tendon involvement lead to a delayed return to sport and increased risk of injury?
OBJECTIVE
Hamstring strain injuries (HSI) are the most common injury sustained in professional football (soccer) and account for 17% of all injuries with a reoccurrence rate of 12-48% (see HERE). This places a large burden on sporting clubs, with prolonged player time-loss due to injury and questions surrounding adequate rehabilitation and return-to-play processes.
The aim of this study was to determine if HSI involving the intra musculartend on resulted in extended time to return to play, as well as a higher injury risk.
WHAT THEY DID
Twenty-four professional footballers from a single English Premier League (EPL) football club were recorded over four seasons for HSI and underwent an MRI within seven days of initial injury, graded by a radiologist using the British Athletics Muscle Injury Classification (BAMIC a-c, O-4).
Time to return to play (TtRtp) and injury recurrence rates were recorded alongwith whether players were removed from play.
Practical Takeaways
When working with clients post HSI, it is important to know the classification and grade of injury, as well as if they were removed from play, as these are factors that influence TtRtp as well as reinjury risk.
Rehab practitioners can use the British Athletics Muscle Injury Classification (BAMIC) system (see HERE) to grade hamstring injuries, which classifies an injury by grade 0-4, as well as sub classifications of a-c, which determine where the site of injury is - either myofascial (periphery), within the myotendinous junction/muscle, or tendon.
Although respecting healing timeframes based on grade of injury is an important consideration, rehab practitioners and S&C coaches working with athletes post-HSI should focus on progressive strengthening in lengthened ranges of motion to improve overall resiliency, and ability to tolerate the demands of sport.
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WHAT THEY FOUND
A total of 29 HSI were recorded across 24 players.
No difference was observed in TtRtp between hamstring injury without intra muscular tendon involvement and within TtRtp muscular tendon involvement, and no greater risk of injury.
Removal of a player from the pitch and the grade of injury were predictors for TtRtp.
Each step-up in grade of HSI increased a player s TtRtp by an extra three days.
Removal from play following a HSI increased TtRtp by 10 days as opposed to if the player was not removed from play.
SCIENCE FOR SPORT PODCAST EP 83
Jordan’ s Comments
“Hamstring rehab should focus on three major areas - strength, max speed as well as training load. The goal should be to get an athlete back to pre-injury levels of strength with emphasis on eccentric strength.
“Sprinting is a primary mechanism of HSI as well as one that produces the highest hamstring activation so as a result, training speed is important. Prior to returning to sport , athletes should be able to achieve at least 90% of their peak velocity.
Training load should be progressed gradually over time to mirror pre-injury levels as well as energy system development training so athletes are able to handle the demands of sport when they return.
Youth Development
This month’s top research on youth development.
THE RELATIONSHIP BETWEEN RESISTANCE TRAINING AND PHYSICAL ACTIVITY IN YOUTHS
DO ELITE YOUTH SOCCER PLAYERS PERFORM BETTER THAN AMATEURS IN COMMON SPORTS SCIENCE TESTING?
The relationship between resistance training and physical activity in youths
OBJECTIVE
The positive effects of physical activity (PA) are well documented and have been established over years of research. (e.g. cardiovascular disease) and contributes to the development of a healthy mind, musculoskeletal system, and reduced body fat as examples (HERE). A relatively ‘new’ direction for youth research explores the use of resistance training (RT), with previous research showing children as young as five benefitting from appropriately designed and supervised sessions (HERE). However, few studies have investigated the association between strength training and its acute effects on measures of PA. Therefore, the aim of this study is to investigate the correlation between RT and PA.).
WHAT THEY DID
Twelve participants (8.9 yrs) were assigned to either an experimental (EG) or control group (CG). Pre and post intervention assessments for strength (isometric mid-thigh pull), physical self-perception (questionnaire), stretch stature and weight status, fundamental movement skills (FMS), and PA levels were completed.
The EG (n=6) participated in RT sessions consisting of deadlifts, alternating push press/TRX rows, back squats, lunges, various bodyweight core exercises and hanging challenges, which were completed twice a week for 10 weeks. The CG was asked to refrain from any RT and maintain their normal PA for the study period. A feedback session was conducted and recorded with the parents of the EG at the end of the study to report the findings and provide feedback.
WHAT THEY FOUND
This study demonstrated that a 10-week RT intervention has a positive effect on strength development and on FMS measures. FMS scores significantly increased in the EG in comparison to the CG over time (P = 0.036 and P = 0.016 respectively).
The authors of this study found the EG group demonstrated no statistically significant changes in BMI between the EG and CG over time.
There was a large positive effect size found for relative strength (g = 0.825, P = 0.140) and a small, positive effect size for maximum strength (g = 0.329, P = 0.540) although these were not statistically significant.
In the feedback session, children and parents expressed positive changes with regard to “self”, suggesting that feelings of positivity, resilience, confidence and sense of achievement had improved under the RT protocol. Furthermore, one child stated they felt encouraged to try other activities as sport had become easier.
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The relationship between resistance training and physical activity in youths
Practical Takeaways
When looking to integrate RT with youth, coaches/teachers must remember that children are not ‘miniature adults’ and require practice which is suitable for their stage of development and maturity. Coaches/teachers should deliver practice which incorporates a balance of consistency (e.g. basic movement patterns HERE), and opportunities for children to have fun in a developmental manner. Some ways we can ensure this is by providing activities that produce the same outcome (e.g. shoulder strength) in a hidden or ‘fun’ manner. For example, a typical ‘shoulder press’ can be pursued using a chair hand walk (HERE). Such an approach does require some creativity and thinking outside the box. These findings have been echoed recently by Wu and colleagues in the attached article, who suggested that hiding strength training in common movements not only aids fundamental movement skill proficiency, but improves confidence when transitioning between sports.
For teachers looking to implement RT into lessons, the RAMPAGE model (HERE) offers a fantastic guide which has been discussed in the attached video. The RAMPAGE model (Raise, Activate, Mobilise, Prepare, Activity, Games, Evaluate) is designed to allow coaches and teachers to plan and deliver RT across multiple ages and stages of development. The model proposed offers flexibility, variety and complete autonomy over the planning process, which can be delivered and tailored to the specific phase of the session. For example, in the Raise stage, variations of tag can be played to raise heart rate and body temperature. Fast forward in the lesson to the Evaluate stage, and teachers can explore what success looked like in the earlier stages, and prepare students for the next step.
From a practical perspective, designing sessions which incorporate five minutes of mobility, five minutes of strength, and five minutes of continuous conditioning can be a fantastic way to see a shift in movement ability and FMS over time. Within the first five minutes, exercises such as lunges, Spiderman mobility flows (HERE), and basic animal movements such as THESE lend well to movement ability. Following this, building on squat, hinge, pressing, and bracing patterns can be developed over time, with small alterations to keep patterns fresh (e.g. prisoner squat to a pause squat). Finally, ‘conditioning’ is a term used rather loosely with youth. Chase-based games (e.g. bulldog), relay team games (e.g. teams of four relay to complete 2000m), or distance-based trials (e.g. as a team you need to cover 100m within 13 seconds) offers a great way to challenge aerobic and anaerobic performance in a fun manner.
Tom’ s Comments
"This study does a fantastic job for S&C coaches and PE teachers by highlighting the causal relationship between RT and FMS. It is refreshing to hear the students and parents’ interpretations on the benefits of S&C. The most impactful statement for me was from one participant, who stated that RT had given him the confidence to try new sports, as his strength and running had improved and now felt easier. This, in my opinion, is where we can do such a fantastic job of educating students and parents about the benefits of regular RT. In the attached podcast, Ben Pullen supports this message, suggesting S& C coaches play a key role in preventing early specialisation (HERE), supporting holistic development, and securing parent buy-in.
“An important part of this journey, as mentioned above, is ensuring parents become aware of the bigger picture, so regular career professional development and communication between all parties is key. Topics that you may want to include for CPD could be quality movement, maturation and monitoring, nutrition and recovery and the traits of a good athlete. These cover a vast amount of information relevant to youth, but further support the wider applications of S&C to health and wellbeing.
“In terms of future research, the authors should consider the role of maturity, as children can and do mature at different times. Some of the results (e.g. strength development, BMI and FMS) are largely impacted upon by maturation, so ensuring that maturation is monitored and statistically analysed against the findings would add to the validity of this work.”
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The role of bio-banding on participant enjoyment
OBJECTIVE
In soccer, players have to perform several high-intensity tasks during games. As a result of changes in technical, tactical and physical requirements, soccer has become more fast paced in recent years. A consequence of this is that youth athletes are required to be physically astute and robust enough to handle a competitive season. The assessment and development of physical performance can help coaches evaluate and direct players to certain positions, or in certain cases, support talent identification processes for clubs.
In light of the considerations above, this study aims to understand if there is a difference in testing ability between elite and amateur in youth soccer teams.
WHAT THEY DID
Forty-five elite and amateur youth soccer players were recruited from an U17 and U19 squad from two youth training centres. In order to answer the research question (is elite physical performance different to amateur players?), a crossHsectional study was conducted to evaluate the relationship between physical performance and playing level.
Participants were evaluated on their anthropometric (e.g. body mass, body mass index and height) and performance of a squat jump (SJ), 10 and 20m linear sprint, 505 agility test, and Illinois agility test (IAT). Testing was split over two days to avoid the interference effect of fatigue.
The elite players were already familiar with the testing protocol, as this was a routine part of their testing battery. However, the amateur players had to conduct a familiarisation session on two separate days. Results of elite vs. amateur players were then compared.
WHAT THEY FOUND
The main finding of this study is that elite playerswere significantly better in all performance tests than amateur players (p < 0.05). There was a larger effect size on the morecomplex tests (IAT and 10 and 20m sprints) between groups. Moreover, the elite group performed better in these tests as a result. Importantly, the authors stated this may be due to higher training volume/familiarity with the testing procedures.
Anthropometric qualities (height, body mass and body mass index) do not significantly differentiate between the level of play and should therefore not be used for selection.
The authors concluded the SJ, sprint test, 505 and IAT may be useful to use in talent selection bycoaches/organisations. In addition, higher scores may be used to detect ‘elite’ players through ameasure of physical output, but not necessarily skill.
SCIENCE FOR SPORT PODCAST EP 82
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The role of bio-banding on participant enjoyment
Practical Takeaways
As coaches, developing a player’s physical capacity is essential. All of the tests in this study require an individual to be strong and explosive, so developing eccentric strength is a must within a program. In addition, this should support injury prevention due to an increase in muscle and tendon strength (see attached article). To develop muscle and tendon strength, exercises should be tiered based on how much stress they place on an athlete through a mix of coord ination (tier 1), force (tier 2), and velocity (tier 3). In practice, these may look like the following:
Tier 1 – May be typified by exercises which develop control and stabilit y and are introductory by nature. The emphasis here should be on trying to get every repetition looking the same . A typical progression may be a bottom -up lunge, an in-place lunge, and a walking lunge These place the athlete under increasingly difficult constraints which challenges their ability to recruit muscle fibres and maintain stability. Three or four sets of 10-12 repetitions are a fantastic starting point. In as little as four weeks, these should develop jump and speed performance.
Tier 2 – These may be defined as exercises which provide increased or external load to create further stress, and therefore adaptation on the muscle. These may include all of the exercises seen in Tier 1, but with dumbbells/barbells to provide an overload. An exam ple can be seen here with a dumbbell lunge. These develop eccentric strength by overloading the lengthening phase of a muscle action, which is typically stronger than a concentric phase. Another way to load this would be through a forward and reverse lunge. As these exercises are loaded, the s ets/reps should be typically less than Tier 1 4-5 sets of 6-8 repetitions produced at a moderate speed should do the trick.
Tier 3 – Finally, Tier 3 exercises aim to match the movement intent and contraction speed of key movement patterns (e.g. linear speed). For example, acceleration may typically be characterised by longer ground contact times and a requirement to “punch” the knee aggressively in a forward manner. Exercises such as the box step up or repeated medicine ball jump transfer well to sport, as they can be programmed at speed both bilaterally (double-leg) or unilaterally (single-leg). As we are trying to emphasise quality repetitions, 3-4 sets of 3-5 repetitions should be more than adequate, as these could accumulate fatigue to youth athletes.
Tom’ s Comments
"The findings of this study support the idea that physical testing batteries which include SJ, 10 and 20m sprints, 505 agility tests, and IAT may be useful strategies for coaches looking to identify physical qualities that separate elite from amateur athletes. It’s important to state here that whilst I agree with this, I see many examples where the most physically advanced athletes are not also the best in their sport. This view is supported in the attached podcast by Richard Allen (Head of Talent ID for England Football Association), who suggests that talent identification is an incredibly multifaceted and complex phenomenon. Richard states that he worked with individuals who were very able and tested well, but were also lazy and didn’t last long-term. In addition, Richard suggested that coaches were not always the best equipped when dealing with individuals from challenging backgrounds. This may suggest that coaches may need to receive additional training, but also screen/develop psychosocial qualities in youth to bridge this gap.
"In future studies, a simple correlation of the physical testing scores, as collected in this study, coupled with injury and maturation statistics would be extremely useful to support the argument that improved strength leads to improved testing and a reduction in injuries. In addition, this should be conducted with a female cohort to see if these findings are applicable to young females, but also to amateur athletes to bridge the physical gap seen in this study. Finally, for coaches looking to test on a budget, the MySprint and MyJump applications are fantastic and can be downloaded for very cheap on a smart phone or tablet. A video tutorial can be seen in the attached video for the MySprint app."
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Nutrition
This month’s top research on nutrition.
IF YOU CAN'T HANDLE THE HEAT ... CREATE AN INDIVIDUALISED HYDRATATION AND COOLING PLAN
DO ATHLETES KNOW THE IMPORTANCEOF VITAMIN D?
COULD THE KETOGENIC DIET BE BENEFICIAL FOR TEAM SPORT ATHLETES?
If you can’t handle the heat…create an individualised hydration and cooling plan
OBJECTIVE
Dehydration can have a negative impact on performance and this impact is generally seen at dehydration of 2% body mass or more. However, dehydration can also impact performance at losses less than this (see related article). Therefore it s important for athletes to prevent dehydration while competing. There are several factors that affect how much an athlete will sweat, including intensity of exercise, environmental temperature, genetics and the clothing the athletes wear.
American football is a high intensity contact sport and to protect players, pads and helmets are worn. This kit has been shown to increase sweat rate and temperature increase of male athletes, thus contributing to increased body heat and dehydration. Outside of American football, previous studies have shown female athletes can experience a higher core temperature, higher initial heart rate and increases in temperature during intermittent exercise compared to males. Currently, no study has been able to quantify the thermoregulatory andhydration responses of female American football players when in full kit, and therefore this was the aim of this study.
WHAT THEY DID
Using an observational design, 15 adult female American footballplayers were rec ruited from a professional team. The participants hadno history of obstructive gastrointestinal (GI) disease or GI surgery, andplayers completed all practice sessions.
Prior to the study, participants were asked to complete a questionnaireon their medical history along with exercise and football history. Beforethe first day of the study, the athletes were given an ingestible thermistor sensor pill. They were instructed to ingest this five hoursbefore training and to consume food and drink habitually.
Before training, measures of urine colour, urine specific gravity, bodymass, body temperature, and heart rate using a chest strap monitorwere taken. The players also completed an environmental symptoms questionnai re along with a number of perceived scales including thirst, thermal sensation and rate of perceived exertion (RPE).
Training was then carried out in kit, with the fluid intake of each athletebeing measured via amount drunk in standardised bottles. GItemperature, heart rate, and perceived measures of thirst, heat and exertion were taken every 15 minutes across a two-hour practice. Environmental temperature was also taken.
After practice, measures of GI temperature, he art rate, perception, body mass, urine colour and urine specific gravity were taken along with another environmental symptoms questionnaire. After each practice, another thermistor sensor was provided to athletes and they were i nstructed to ingest this five hours before the next practice. Body mass loss was calculated after each practice and urine jugs were used during practice so any fluid lost via urine could be factored in.
A total of four practice sessions were carried out with these measurements being taken during each.
Practical Takeaways
Although we know there are physiological differences between male and female athletes with regards to thermoregulation, this study did not necessarily show that. The current recommendations for hydration practices are to develop an individualised approach. This approach would mean there would be no need for sex-specific hydration guidelines, as any hydration plan would be specific to the athlete themselves considering their sex, the intensity and duration of the exercise they carry out, any specific clothing they wear for their sport.
Practitioners should aim to create these hydration plans based on estimations in sweat loss. Similar to this study, sweat rate tests can be carried out using the difference in an athlete’s body mass pre and post exercise combined with measurements of fluid drunk and urine excreted. When conducting a test like this, practitioners should use situations that are specific to the sport of the individual athlete - multiple sweat tests in different conditions could be used to estimate sweat rates for different environmental settings too. Practitioners should then ensure a hydration plan keeps athletes above a maximum of 2% body mass loss throughout the duration of a competition or training. We saw in this study that perceived thirst was enough to keep fluid intake high enough , however that is often not the case, with athletes either forgetting to drink or focusing nutrition strategies elsewhere (i.e., increasing carbohydrate content for performance)
Hydration and fueling should be treated separately, as the tonicity of beverages has a profound effect on hydration. Hypertonic beverages are useful for fueling, however will not contribute to the hydration status of the athlete. Hypotonic beverages should be used when hydration is the focus.
The composition of an athlete's sweat is also relevant, as losses of electrolytes in sweat have been associated with increased cramping in athletes. It is possible to carry out a sweat composition test with athletes to quantify losses of nutrients such as sodium and potassium, which can then be used to guide replacement of these using products such as hydration tablets. Be wary of how hydration tablets affect the tonicity of the fluid when doing this.
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WHAT THEY FOUND
The GI temperature of the athletes increased during training with a mean GI temperature of 38.0 ± 0.3° C with no significant difference across all days. The maximum GI temperature was measured as 38.4 ± 0.3° C with the baseline temperature being significantly lower at 37.6 ± 0.1oC. A similar trend was seen in heart rate as expected, with a mean practice heart rate of 118 ± 11 beats.min -1, a maximum of 148 ± 13 beats.min-1 and a baseline of 91-106 beats.min-1 which was significantly lower than the maximum for all athletes. Mean heart rate was higher on day one compared with the other three days.
The average amount of fluid consumed across all practices was 0.9 ± 3 L. The authors did not specify what fluid was consumed. There were significant differences in fluid intake across days with more being drunk on day one and day two, 1 ± 0.4 L and 1.2 ± 0.1 L respectively compared to days three and four, 0.7 ± 0.4 L and 0.6 ± 0.1 L. The average sweat rate across all four practices was 0.6 L per hour with a range of 0.2-1.1 L.h-1 across the sessions. Significant differences were found here with rates of 0.7 ± 0.1 L.h-1 and 0.7 ± 0 L.h-1 on days one and two compared with 0.6 ± 0 L.h-1 and 0.5 ± 0.1 L.h-1 on days three and four.
Average percentage body mass loss was found to be -0.3 ± 0.4 % across all sessions with a range of -1.4 to + 1.9 %. No significant differences were found between days for body mass losses.
Both urine colour and urine specific gravity were measured as being higher post practice compared to pre across all days. Urine colour pre practice was measured as 3 ± 1 on a scale up to 7, and post practice found to be an average of 5 ± 0. Urine specific gravity was found to be 1.022 ± 0.007 post practice ranging from 1.006 to 1.037; no pre practice values were stated for urine specific gravity.
Perceived thirst and thermal sensations were stated as moderate across all four days with thirst being similar and thermal sensations being lower on day two compared to days one and three. Mean RPE was 11 ± 1 with a range of 6 to 15 on a scale up to 20. RPE was significantly greater on day one compared to days three and four, day two RPE was also found to be greater than day four. SCIENCE FOR SPORT PODCAST EP 88
“This study is incredibly useful in that it compounds what we previously know and what I currently practice in my work. It would have been incredibly interesting if we saw unexpected physiological responses in either temperature and sweat rate, as we would then have had to adjust current recommendations. However, it’s another feather in the cap for individualised hydration and individualised nutrition as a whole.
“It would be interesting to see future studies look at comparisons between suited and non-suited athletes and male and female populations within the same study but as laid out above, if you ’re working individually with each athlete’s specific needs in mind, then the results are not likely to influence your practice.
“Ultimately, like all aspects of performance nutrition, hydration strategies should be highly individualised for each athlete for optimal performance."
Do athletes know the importance of Vitamin D?
OBJECTIVE
Vitamin D is a nutrient that in its active form plays a role in the activation of certain genes. These genes produce proteins that are involved in many of the body s systems including musculoskeletal, immune, cardiovascular and endocrine systems. Our primary source of vitamin D is through sunlight, whereby ultraviolet B radiation from the sun hits the skin and converts precursors of vitamin D into active vitamin D. We are also able to obtain some vitamin D from our diet, however it s found in very small quantities and tends to be vitamin D2 rather than vitamin D3.
Vitamin D3 deficiency has previously been shown to negatively impact muscle repair, immune function and bone health as outlined in the related article below. Because of this, vitamin D3 deficiency may have a negative impact on health and performance in athletes. Previous studies have shown that up to 56% of athletes around the world may have an inadequate vitamin D status. It is thought poor knowledge and awareness of risks of low vitamin D3 status and of how to obtain vitamin D3 contribute to this low status.
The present study sought to quantify vitamin D awareness and intake in collegiate Division 1 athletes in America and establish any correlations between awareness and intake.
WHAT THEY DID
The authors employed a cross sectional survey that gathered both quantitative and qualitative data around athletes intake and awareness of vitamin D. A survey consisting of questions written specifically for this study along with a diet and lifestyle questionnaire as previously used by Halliday et al (2011) was completed by 29 male and 53 female student athletes who competed in Division 1 of the National Collegiate Athletic Association (NCAA) in various sports at a university in the midwest of the US. The geographical location of the university was above 35 degrees North, which is a risk factor for vitamin D deficiency due to a lack of sun exposure.
The section of the survey on vitamin D consisted of five questions scored on a Likert scale to quantify awareness, followed by three follow-up questions to provide qualitative data. For example, one of the five questions was:
How much have you heard about vitamin D?
Five possible answers ranging from never to a lot could be selected.
An example of a qualitative question is Do you know any factors that affect vitamin D levels (list all)?
Frequency of consumption of vitamin D-containing foods or supplements was self-reported, and product and dose of the supplements were specified to determine the vitamin D content of the supplements. Frequency of time spent outside and using tanning beds was also asked and reported as hours per week.
The authors then used Spearman rank correlation to assess any potential correlations between awareness and intake from either food, supplements or sun exposure.
SCIENCE FOR SPORT PODCAST EP 80
Practical Applications
Collegiate athletes are aware of the impact that vitamin D status can have on health and performance. It appears despite this, they are not concerned about it, which may potentially harm their health and performance due to previously seen prevalence of inadequate vitamin D status within athletic populations. It’s also worth noting the subjects of this study voluntarily responded to the survey and so are more likely to show an interest in these factors. Thus, a larger population group may show even less concern and be at an increased risk of inadequacy.
Because concern of status was correlated with improved intake, education on status and the prevalence of deficiencies could be an effective method of increasing intake. Both the risks of inadequacy and information on the role vitamin D plays should be used to provide athletes with a more complete picture. Education on how to increase status should also be carried out such as interventions around spending more time outside in sunlight, and on appropriate doses within supplements.
As a practitioner, when working with individual athletes, it is always worth quantifying the nutritional status of the athlete before making an intervention. Blood tests to measure serum vitamin D levels (measured as 25-hydroxy vitamin D) can be carried out and concentrations below 50 nmol/L should be avoided.
Doses of 2000-4000 International Units have been shown to be effective and safe, however too much vitamin D can be toxic which is why quantifying status is important. Lower doses of supplements will still help increase intake if needed.
Remember, when using supplements, ensure they are batch tested and where possible registered with a third party testing laboratory like Informed Sport.
It’s worth noting supplementation may not always be needed. The related infographic taken from the related article shows a decision tree on how to decide if supplementation is appropriate.
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It was estimated more than half (62%) of the male athletes met the current recommended daily allowance (RDA) for vitamin D, whereas only 27% of female athletes met the RDA. Mean intake among athletes was estimated to be 693 International Units for males and 263 International Units for females.
Only 42% of athletes (55% of males, 35% of females) supplemented vitamin D. Of these supplements, the most common form was a multivitamin with only around 20% using vitamin D supplements.
In terms of awareness, most athletes (69% of males and 73% of females) believed vitamin D played a role in health and performance, however most also believed they were unlikely or very unlikely to be at risk (59% of males and 62% of females).
Within the male athletes, a positive correlation was found between:
1. belief in vitamin D's influence on health and performance
2. players’ awareness of the benefits of vitamin D and intake
In the female athlete population, an association between familiarity with vitamin D and total intake was found along with a positive association between concern for levels and supplementation. There was modest negative association between sun exposure and concern of risk of inadequate levels in males but not in females.
From the qualitative data, less than half of the athletes (43%) were able to name a benefit of vitamin D, however more than half (54%) were able to list factors that affected vitamin D levels. Of these factors, 81% of them related to sun exposure, their diet and supplements.
James’ Comments
“In the northern hemisphere, we are now in the winter months where hours of sunlight are less and the strength of the sun’s rays are weaker. Over the past few years, especially through COVID-19, I have seen an increase in awareness of vitamin D, which is fantastic, however my experience with athletes and consumption of vitamin D agrees with the findings of this study. During winter it’s very common to see reduced recovery and changes in mood from athletes and often these athletes don’t necessarily link these symptoms with vitamin D status. Only when we quantify it using blood tests do they then show concern and show an interest in improving intakes moving forward.
“Instead of being reactive in this way, I take a proactive approach to educate those I work with on the risk of deficiency at certain times of the year, and on how to prevent this through safe supplementation if needed.”
How can nutrition support recovery following muscle damage?
OBJECTIVE
The ketogenic diet consists of a high fat, adequate protein, and low carbohydrate intake (<5% of total daily energy intake). Very low intakes of carbohydrates (normally <50g) lead to physiological ketosis in the body. In this process, ketone bodies are released from the liver from the breakdown of fats and converted to acetyl-CoA, which enters the Krebs cycle and is oxidised for energy.
The ketogenic diet has been considered a possible alternative to extreme caloric restriction to tackle increases in body fat by athletes in the off-season. However, research on the ketogenic diet is conflicting. Certain studies report negative effects on performance following the ketogenic diet, whilst others suggest a positive effect, or no difference compared to western diets. However, limited research has been conducted on the impact of the ketogenic diet in team sport athletes.
This study investigated the effects of 30 days of a ketogenic diet on body composition, muscle strength, muscle area, metabolism, and performance in semi-professional soccer players.
WHAT THEY DID
Sixteen semi-professional male soccer players participated in this randomised, parallel arm, controlled, prospective study. Participants were randomly assigned to consume a very low carbohydrate ketogenic diet or a western diet for 30 days.
Athletes assigned to the ketogenic diet were provided with nutritional counselling and resources that encouraged the consumption of beef, veal, poultry, fish, raw and cooked vegetables without restriction: protein 1.8g.kg.d-1; carbohydrate: <30g.d-1; fat: 65-70% of total calories. The western diet was composed to ensure constant energy and macronutrient balance: protein: 1.8g.kg.d-1; carbohydrate: 50-55% of total calories fat: 20-25% of total calories.
Training was strictly controlled so that all participants conducted the same level of physical activity (eight hours per week).
Participants were tested on three different days in the week before and after 30 days of dietary intervention. On day one of testing, participants respiratory exchange ratio, resting energy expenditure, body composition using dual-energy X-ray absorptiometry and cross-sectional area of the quadriceps were measured. Following one day of rest, participants performed a counter movement jump test. Following two more days of rest, participants completed a yo-yo intermittent recovery test level 1. Maximal voluntary isometric contraction (strength) of the right quadricep was also assessed.
SCIENCE FOR SPORT PODCAST EP 41
Practical Takeaways
The ketogenic diet could be a feasible strategy to lose body fat in the short-term without impairing power and muscle mass in a team sport like football.
Practitioners should approach making recommendations based on this study with caution since it is the first study to examine the effects of a ketogenic diet in team sport athletes. Furthermore, the results of this study contradict findings from previous studies reporting detrimental effects of the ketogenic diet on sports performance.
Due to its heavily restrictive nature, athletes may require education on adequate supplementation containing sodium and potassium necessary to maintain a healthy electrolytic balance, meal plans, recipes and foods that are prohibited and permitted in the ketogenic diet. This could make it difficult for athletes to adhere to the diet. Practitioners should also consider the psychological risk of athletes developing eating disorders or unhealthy relationships with food due to this restriction.
Practitioners should not make recommendations to female athletes based on the results of this study since participants were all male. Future research should investigate the effects of a ketogenic diet on male and female athletes to determine any potential differences in performance outcomes and related recommendations.
The current study does not consider the health implications of a ketogenic diet. Previous studies adopting similar intervention durations have reported increased total cholesterol levels in athletes following a ketogenic diet. Consequently, long-term adherence to the ketogenic diet could have profound health implications including an increased risk of certain diseases such as increased blood pressure or atherosclerosis, which could indirectly affect exercise performance.
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WHAT THEY FOUND
Total calorie intake was reduced in the ketogenic diet (KD) group (-16%) and western diet (WD) group (-18%), with no significant difference between groups.
Changes in body fat (KD: -1.55kg; WD: -0.92kg), visceral adipose tissue (KD: -63g; WD: -27g), waist circumference (KD: -4.19cm; WD: -1.38cm) and extracellular water (KD: -3.43%; WD: 0.03%) were significantly greater in the ketogenic group than in the western diet group.
Lean tissue mass, quadricep muscle area, maximum strength and resting energy expenditure showed no changes in either group.
Respiratory exchange ratio decreased significantly in the ketogenic group, but no significant changes were observed in the western diet group (KD: -14.18%; WD: -2.85%).
Both groups improved significantly in the Yo-Yo intermittent test (KD: +28.04%; WD: +44.6%2) and countermovement jump (KD: +8.52%; WD: +3.60%), with no significant difference between groups.
Comments
“Adherence plays a central role in the success of athletes following a ketogenic diet. I would question whether eliminating or heavily restricting carbohydrates from the diet is necessary, since safe body composition manipulation can be achieved through a western diet.
“Until more research has been conducted on the ketogenic diet for team sports athletes, practitioners should turn their attention to educating players on strategies to manipulate their current diets to optimise fat loss during the off-season. For example, periodising carbohydrates to fuel for the demands of training, focusing on low-glycaemic foods and increasing protein intake are targets that athletes can adhere to and may be more relevant than a strict ketogenic diet.”
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