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Prac cal Takeaways from study
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Reviewers comments on the study
Research Reviewers
Strength & Conditioning
James is currently the Head Strength & Conditioning Coach for the Romanian Rugby Union He has previously worked in America s professional rugby competition Major League Rugby with Austin Elite and the NZ Women ’ s National Rugby League Team He is a published author and has completed a MSc in Sport & Exercise Science from AUT Auckland NZ.
Technology & Monitoring
Cody is a strength and conditioning coach and adjunct lecturer at the University of Iowa. He has an MSE in Exercise Science from the University of Kansas and also holds a CSCS from the NSCA
Youth Development
Tom is the Head of Athletic Development at St Peters RC High School. He holds a Masters in S&C and has previously worked with West Bromwich Albion FC, Gloucester Rugby club, and Great Britain Equine Tom is our youth research reviewer at Science for Sport
Psychology
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.
COACHING
Does physical fatigue influence peripheral perception and decision making in young soccer players?
OBJECTIVE
Beyond the physical side of soccer, as with most sports, decision making is a vitally important skill. Decision making can be defined as an individual’s ability to analyse, select and/or perform an appropriate action when facing the multiple response options provided by the environment and those generated by the athlete themselves.
This can be broken down into perceptual-cognitive - the ability an individual has to use existing knowledge to capture, identify and process information to select an appropriate action, and perceptual-motor - what the individual is capable of perceiving, processing, and executing through movement.
Soccer is dynamic and unpredictable with decision making based on well-developed perceptual-cognitive skills such as attention, working memory, and peripheral perception. Within perceptual-cognitive skills peripheral perception has been suggested to be important. This is the process through which players gather and interpret environmental information from the periphery of the visual field.
It has also been suggested that physical fatigue is likely an intervening variable of the game, since players usually experience it in the final periods of matches or after a high-intensity action with short recovery time. Despite some studies investigating players’ decision making under physical exertion, the decision making typically is assessed only from the perspective of the player in possession.
The purpose of the present study was to verify whether the peripheral perception and decision making of young soccer players are influenced by physical fatigue.
WHAT THEY FOUND
A group of 48 male soccer players (17 ± 2 yrs) from two Brazilian clubs visited the lab on two separate days. On the ‘control’ day all participants performed a: (i) peripheral perception test; (ii) TacticUP® video test (response time and decision-making quality) and (iii) peripheral perception test.
During the ‘physical fatigue’ condition (which took place 21 days after the control) all participants performed: (i) peripheral perception test; (ii) T-SAFT90 test (an activity that simulates the physical actions of a 90-minute competitive soccer match)– first part; (iii) peripheral perception test; (iv) T-SAFT90 test – second part; (v) TacticUP® video test and (vi) peripheral perception test. Time between tests was 2 mins and 30 mins after the control and the fatiguing session RPE was collected. The dependent variables of the study were the visual field, tracking deviation, reaction time, response time and decision-making quality The independent variable was the T-SAFT90 test.
WHAT THEY FOUND
Physical exertion
Participants displayed higher perceived exertion in the physical fatigue condition compared to the control condition. This indicated that players experienced the fatigue as being “very hard”.
Peripheral perception
In the “control” condition, a significant difference was found in the tracking deviation measure after the decision-making test (TacticUP®). On the other hand, no differences were found in the comparison of peripheral perception variables in the “physical fatigue” condition.
Decision making
No differences were found regarding players’ decisionmaking quality, in the comparison between the “control” and “physical fatigue” conditions. Under physical fatigue, players improved their response time, i.e., they were quicker in making decisions related to the tactical principles of penetration, width and length with the ball, delay, defensive coverage, and recovery balance.
Practical Takeaways
Findings from this study indicated that peripheral perception was not dependent on physical exertion. On the other hand, results showed an improvement on players’ decision-making response time, yet only for the tactical principles performed inside the centre of play
With respect to decision-making quality, no differences were found between the “control” and “physical fatigue” conditions. Therefore, in contrast to the author’s hypothesis, the peripheral perception and decision making of soccer players was not negatively influenced by the effect of physical fatigue.
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Tom’s Comments
“It’s interesting to see that the findings of this study suggest that participants maintained their peripheral perception and decision-making quality, and that they improved their decision-making response time when fatigued.”
“Although this provides useful information regarding the impact of fatigue on performance, pitch-based studies are important to improve this line of research. Should the addition of considering movement and displacement across the pitch with the player’s ability to perceive information and make decisions provide the same results this would be even more interesting and useful.”
“It would also be interesting to see whether these results would be replicated in younger players to see how it might impact player development as well as senior players to understand how these skills may differ with age and playing level.”
What is the impact of mobile phone use on young athletes?
OBJECTIVE
For better or worse, mobile phones have never played a greater part in our lives than they do now. In fact, the World Health Organization has recognised the potential health effects of problematic mobile phone use and indicated that it might present itself as a new form of behavioural addiction. This has in turn been linked to adverse effects on work productivity, social relationships, and mental health.
Recent research has sought to investigate the potential effect that mobile phone use can have on wellbeing and performance in athletes. The vast majority of previous studies have utilised quantitative methods to investigate this area, with past research suggesting that mobile phone use prior to a sporting activity has adverse effects on ensuing sporting performance. Phone use has also been linked to reduced sleep quality, which would also have negative consequences for athletes.
The current study looked to address the gaps in the current literature by conducting a qualitative investigation into problematic mobile phone use among youth athletes. In particular, the study aimed to address the following: (1) What are the factors which contribute to problematic mobile phone use in youth athletes? (2) What are the effects of problematic mobile phone use in youth athletes? (3) What suggestions can be given to help youth athletes address their problematic mobile phone use?
WHAT THEY DID
21 Singaporean youth athletes (10 males, 11 females) participated in the study The participants were all aged between 12 and 18 years old (M = 15 ± 2 yrs). The participants were split into four focus groups based on their sport, namely shooting (n = 6), netball (n = 5), rugby (n=5), and wushu (n=5). The focus group sessions lasted between 58 and 75 min (M = 65 min).
A semi-structured interview guide containing 13 questions was developed to guide participants freely. For each section, participants were given the freedom to bring up novel points that were not part of the discussion guide, and to elaborate on any answers that they might have given. The guide began with an introduction, delivered by the moderator, who welcomed the participants and established the ground rules for the focus group session.
Various questions pertaining to mobile phone use were explored, including:
1. The use and role of their mobile phone
2. The experience of problematic mobile phone use (e.g., “Was there ever a time that you would have described your mobile phone use as being problematic? Could you please describe that experience?”)
3. The factors contributing to problematic mobile phone use (e.g., “What factors contributed to your problematic mobile phone use?”)
4. The effects of problematic mobile phone use (e.g., “What were the effects of your problematic mobile phone use?”)
5. Suggestions on how to help youth athletes address their problematic mobile phone use (e.g., “How do you suggest we help youth athletes deal with their problematic mobile phone use?”).
The data was subsequently analysed using reflexive thematic analysis.
Practical Takeaways
The current study provided a qualitative investigation to reveal various factors which contributed to problematic use: Personal attributes, needs fulfilment, and external influences.
The effects of such problematic use included areas such as shrinkage of time, performance deficits, and undesirable behaviours. There were various suggestions on how to overcome problematic use, which included strengthening internal resources and tapping into sources of external help.
The authors proposed that future research should seek to use the knowledge derived from this study to create interventions to help youth athletes deal with their problematic mobile phone use.
WHAT THEY FOUND
The findings from this study indicated various factors that contributed to problematic use of mobile phones. These primarily included; Personal attributes, which referred to the various shortcomings within the individual which facilitated the rise and perpetuation of problematic mobile phone use; needs fulfilment, which showcased the various needs that youth athletes sought to fulfil through the use of mobile phones; and external influences, which highlighted the various external pressures and conditions which enabled problematic use to occur
Personal attributes. This theme reflected the underdeveloped skills and personal characteristics within the youth athletes which caused them to engage in problematic mobile phone use. The theme consisted of three sub-themes: Lack of selfcontrol, lack of maturity, and unwillingness to change. Needs fulfilment. This theme underlined several key needs that the youth athletes sought to fulfil through their mobile phone use. While these needs were not necessarily negative in themselves, if taken to the extreme they had the potential to create a maladaptive dependency on mobile phone use, where the youth athletes would cultivate an unhealthy reliance on their phones to fulfil those needs. The theme consisted of three sub-themes: Need for stimulation and alleviation of boredom, need for connection and relationships, and need to be in the know
External influences. This theme covered several external factors that contributed to problematic mobile phone use in youth athletes. The theme consisted of three sub-themes: Peer pressure, parent-related issues, and impact of COVID-19.
“This study is incredibly useful in not only highlighting to us that excessive mobile phone use may be a problem to young athletes, but also in beginning to explain why such use patterns might be in place.“
“We can now understand that the reason for these behaviours stems from personal characteristics, the desire to have certain needs met and external factors such as peerpressure. Crucially, the fact that previous research suggests that excessive mobile phone use also leads to decreased sporting performance should be a cause for concern“.
“As an explorative piece of research, we are currently without strong guidelines as to what to do to combat this situation. It seems important though that coaches and parents are aware of this issue and perhaps look to provide stimulation in other ways to reduce the desire for athletes to default to the phone. This is especially important when it comes to improving sleep quality, which we know can be impacted as a further negative consequence of excessive phone use with a knock on to sports performance”.
Considerations around wellbeing in elite sport
OBJECTIVE
Wellbeing and mental health are currently incredibly important topics in sports. This has led to increased studies being published and significant media attention. During the Tokyo 2020 Olympic Games, Simone Biles, one of the greatest gymnasts of all time, used Twitter to send an important message to the world: Elite athletes are humans sometimes facing crushing pressures. Biles interrupted her participation at the Olympics to protect her mental health and ensure her physical safety
Current research suggests several interrelated riskfactors for athlete mental health within elite sportssystems. These include, organisational stressors, stigma related to mental health problems, normalisation of unhealthy behaviours, injuries, career dissatisfaction, harassment and abuse, and toxic sports leadership or other dysfunctional relationships. Increased commercialisation and professionalisation, together with stakeholders and media, place even greater demands and obligations on athletes. Research suggests that efforts to combat such issues should focus on proactive support increasing athlete wellbeing and resiliency in response to both expected and naturally occurring stressors in the environment. It is also hoped this will support the development of targeted prevention and treatments when mental wellbeing or mental disorders are suspected. This editorial sought to highlight and summarise these proposed solutions.
WHAT THEY DID
This editorial looked at current research with consideration of the issues highlighted above to outline practices focused on.
Conceptual considerations of mental health research
Wellbeing promotion, mental health prevention and treatment
Empirical studies targeting critical processes or career phases for athlete mental health
WHAT THEY FOUND
Conceptual considerations of mental health research
It is unsurprising complex when looking to separate symptoms associated with normal or expected mood variations in relation to sports performance and symptoms that signal mental illness or mental disorders.
The authors highlight a useful overview of theoretical perspectives commonly adopted in mental health research in sports. It considers a number of perspectives as well as presenting strengths and weaknesses of those ideas including wellbeing as a target construct, holistic models, single continuum and stage models, Keyes’ dual-continuum model and the psychiatric/biomedical view
The authors also recommend an integrative framework regarding career termination. It looks at self-reformulation and discusses developmental changes and psychosocial processes essential for elite athletes’ identity reformation during the transition out of elite sports when discovering a new meaningful identity in life after sports.
Wellbeing promotion, mental health prevention and treatment
Within this specific area of the research the authors identified five articles focused on support systems or frameworks for mental health support on approaches from four continents: Asia, Europe, North America, and Oceania.
An evidence-informed framework with a whole system approach in one paper promotes that healthy environments are encouraged together with recommendations on how mental wellbeing among both athletes and staff involved in elite sports environments might be obtained.
Another evaluates practitioners and service-users view of acceptability and appropriateness of a sport-centred and collaborative mental health service delivery model implemented within the Canadian Center for Mental Health and Sports.
Additionally, Japanese athletes' wellbeing and level of knowledge about the topic, together with perceptions of support services is presented in a pilot study The results suggest a need for education programs, guidelines, detection systems and information accessibility related to wellbeing and mental health in the Japanese elite sports system.
A case study the authors highlighted proposes a Mental Fitness Model based on the PERMA model of wellbeing for implementation in Australian youth high performance settings. This is suggested to support wellbeing and promote mental health needs of young high-level athletes.
Finally, another paper raises concerns that evidence on the effectiveness of psychotherapeutic interventions on athletes are lacking, and discusses definitions and procedures used to determine prevalence rates of mental health problems and disorders.
Empirical studies targeting critical processes or career phases for athlete mental health.
In this subsection the authors identify four empirical papers that are of interest.
One interviewed 18 Australian Olympic athletes about their post-Olympic experiences following the Rio 2016 Olympic Games. Factors that positively influenced athlete wellbeing included that performance appraisal met expectations, planning of return to work or studies, and readily available support.
Another investigated links between motivational processes, psychological distress, and burnout in a sample of 685 winter sports athletes. The results of this paper suggested a task-oriented motivational climate to be positively related to basic needs, and autonomous and controlled motivation to show a negative association with symptoms of psychological distress and burnout. Attachment relationships to significant others were investigated in different samples of athletes representing various sports and skill levels in another study The results supported the importance of secure attachment relationships with parents and coaches related to thriving among athletes.
Lastly, an investigation into the prevalence of psychological distress among elite and recreational sambo athletes was reported. Results revealed elite sambo athletes reported significantly lower scores on self-rated depression, anxiety, stress, and general distress than their recreational counterparts.
Mental health is a priority in elite sports. The authors of this editorial concluded that the articles presented within here collectively capture several novel and future-oriented perspectives contributing to the increasing knowledge base of mental health promotion and proactive support efforts within elite sports environments.
Want
“The topic of mental health support to athletes, quite rightly, has a brighter spotlight on it than ever before. We are more aware than ever that consideration for an athlete’s psychological wellbeing should be paramount. As this focus is still relatively new for coaches to specifically consider it can be challenging to understand why support might be needed and how best to build a structure around athletes capable of delivering it”.
“Many sporting organisations now employ psychologists to work directly with athletes. A challenge remains regarding specific understanding around integration of wellbeing support into elite sporting realms. Editorials such as this one can serve as a fantastic starting point for qualified practitioners looking to be more effective and evidence-based when building these optimal, and appropriate, environments”.
Strength & Conditioning
This month’s top research in strength & conditioning.
HOW DOES EXTRA TIME PHYSIOLOG IMPACT SOCCER PLAYERS?
WHAT
PHYSIOLOGICAL PARAMETER INFLUENCE PUNCHING PERFORMAN
How does extra time physiologically impact soccer players?
OBJECTIVE
The physical demands of elite soccer have been increasing over recent years due to the game being played at higher intensities. This is fantastic for a spectator but has obvious repercussions for the players involved regarding how they train and must recover As well as an increase in match demands many top end players also have the addition of European club and international competitions to consider, which also adds to the overall load. Most cup competitions feature the potential for extra time, which again, must be factored in.
At the men’s Union of European Football Associations (UEFA) EURO 2020 tournament, more than half (8 of 15) of the games in the knockout stages went to extra time, and more than 85% of the medallists in the men’s EUROs and World Cups between 1992 and 2020 have participated in games going to extra time.
It is well known that fatigue develops during an elite soccer game and peaks in the last 15 min, which compromises high-intensity performance. Undeniably, repeated sprint ability (RSA), muscle strength, and muscle function are markedly impaired after a normal game. As such, the purpose of this study was to investigate the physiological, biochemical, and performance responses during a 120-min soccer game in well-trained competitive male players with the main emphasis on the impact of extra time in relation to muscle glycogen depletion.
WHAT THEY DID
Twenty competitive players (age, 20 ± 1 yr; VO2max, 59 ± 4 mL·min−1·kg−1) completed an experimental match with their activity pattern (total distance covered, mean speed, high-speed running (distance covered at speeds >21 km·h−1), sprinting (distance covered at speeds >24 km·h−1), number of high accelerations (>2 m·s ), and number of high decelerations (−2 m·s−1)) and heart rate assessed throughout the game.
In addition, countermovement jump and repeated sprint ability (five consecutive 30-m sprints separated by 25 s of active recovery during which they jogged back to the starting line) were tested. Quadriceps muscle biopsies and venous blood samples were taken at baseline and after 90 and 120 min of match play to better understand the underlying physiology
WHAT THEY FOUND
Less high intensity running (12%) was performed in extra time in association with fewer intense accelerations and decelerations per minute compared with during normal time. Peak sprint speed was 11% lower in extra time compared with normal time, and fatigue also manifested in impaired postmatch repeated sprint ability and countermovement jump performance.
Measured via biopsy muscle glycogen declined from 373 ± 59 mmol·kg−1 dry weight (dw) at baseline to 266 ± 64 mmol·kg−1 dw after 90 min, with a further decline to 186 ± 56 mmol·kg−1 dw after extra time and with single-fibre analyses revealing depleted or very low glycogen levels in ~75% of both slow and fast twitch fibres.
Blood glucose did not change during the first 90-min but declined to 81 ± 8 mg·dL−1 after extra time. Plasma glycerol and ammonia peaked at 236 ± 33 mg·dL−1 and 75 ± 21 μmol·L−1 after the extra period.
Practical Takeaways
This study clearly suggests that fatigue after extra time is increased beyond that experienced during normal time alone. The authors suggest this seems to be associated with muscle glycogen depletion, reductions in blood glucose levels, and hyperammonemia.
Taken together this, perhaps unsurprisingly, points to metabolic disturbances being a major part of the integrated and multifaceted fatigue response during extended soccer match play
“It is no surprise that playing a further 30 minutes of soccer leads to greater fatigue than that experienced during a typical 90 minutes. This study proposes that this degree of fatigue may be induced by low glycogen concentrations in a large portion of muscle fibres. This is important to know when thinking about fuelling strategies to try to mitigate against these issues. There is a reasonable amount of research on this subject including studies from Hannon et al and Impey et al proposing how it should be thought about.”
“It is also interesting to note that it is suggested that factors facilitated by lowered blood glucose, hyperammonemia, and/or dehydration may contribute to the deterioration in performance. This shows the likelihood that there is an integrated and multifaceted fatigue scenario at play during extra time. Coaches, both technical and strength and conditioning, should keep this in mind when they are periodising training around potential extra time scenarios and when looking to utilise substitutions to maximise the freshness of those players on the pitch.”
What physiological parameters influence punching performance?
OBJECTIVE
Boxing has many training modalities steeped in tradition. If you’ve watched any Rocky movie, you’ll be familiar with them all. The countless volume of running and calisthenics is to build physical capacities to handle the rigors of boxing as being bigger, stronger, and faster may increase your chances of winning. Therefore, identifying which physiological parameters influence boxing success is important for optimizing a boxers training program. This study collected and identified physiological parameters evident in the Army boxing team.
WHAT THEY DID
Twenty-two male boxers (age = 28 ± 2) of national standard completed two days of testing. The first day consisted of: body composition, punch impact force and velocity measured with a wall mounted force plate called the PowerKube and a linear position transducer, countermovement jump (CMJ) and repeated jump measured on the Chronojump, 1RM back squat and bench press, and the Wingate test. The second day consisted of a treadmill VO2max test. Correlations were calculated between test outcomes.
Practical Takeaways
The lack of correlation between strength and power with punching power is likely due to the level of boxer. More experienced boxers are able to utilize effective mass to a greater extent (see HERE).
Prolific punch researcher Seth Lenetsky (see his thoughts in the video link below) explains how maximizing effective mass has less to do with punch velocity and more to do with being able to transfer momentum through to the target by stiffening at impact. He recommends boxers to perform short high-intensity intervals on the bag to develop this skill. Here’s an example:
§ 5-6 x 6-10 sec w/ 2-3 mins rest.
You could perform intervals until quality of punches declines or cap sets at approximately 6.
All of this doesn’t mean you shouldn’t maximize lower body strength and power to enhance punching power. Here’s a few exercises you can use:
§ Box jump
§ Loaded squat jump
§ Split squat jump
§ Trap bar jump
§ Medicine ball scoop toss and other throws
§ High resistance bike sprints
WHAT THEY FOUND
Body mass significantly correlated with punch impact power but shared variance was only 26% indicating other variables play a greater role. Body fat percentage showed a significant, negative relationship with repeated jumps and VO2max with a shared variance of 18% and 24% respectively. Bench press and back squat 1RM were moderately, significantly correlated with Wingate average power. CMJ was significantly related to back squat and bench press 1RM, and Wingate average and peak power with shared variance ranging between 33-57%.
Repeated jump performance showed a moderately strong relationship with average Wingate power with a shared variance of 20% and a moderately strong and negative relationship with bench press with a 30% shared variance. Rear hand impact power showed a moderately strong significant inverse relationship with CMJ with 21% shared variance. Interestingly, all punch related variables lacked any relationship with strength and power tests other than CMJ
After talking with prolific boxing researchers and S&C coaches, it’s been suggested strength training may not be as important as we deem it to be. That doesn’t mean no strength training is performed. It means limiting it to twice a week and focusing on the conditioning and technical/tactical aspect of boxing. These quotes from the current study support this: “3PARA boxing team may attribute their winning performances on their ability to sustain a fighting workload.” And “3PARA continue to dominate the Inter-Unit Team Boxing competition through technical and tactical superiority and competitiveness through rigorous physiological preparation.” When performing strength training, it should generally be low volume, high intensity to not negatively influence boxing training.
Technology & Monitoring
This month’s top research on technology and monitoring.
IS HIP LOAD A BETTER MEASURE THAN PLAYERLOAD?
HOW CAN COACHES SUPPORT AN ATHLETE’S SLEEP?
RELIABILITY AND VALIDITY OF FORCE-VELOCITY PROFILING USING FREE WEIGHTS
WHAT HAPPENS TO PERFORMANCE FOLLOWING A TWO-WEEK BREAK?
Is Hip Load a better measure than PlayerLoad?
OBJECTIVE
PlayerLoad is a commonly used external load metric that helps coaches quantify the biomechanical loads (e.g. accelerations and decelerations) with the use of an accelerometer in athleteworn devices (e.g. local or global positioning systems, see HERE). However, given the placing of the device (likely affixed to the upper back or torso), the load metric only showcases whole-body actions, and possibly limits more specific joint or lower body stress endured during a sport like soccer that involves running, kicking, and even jumping at times (see HERE).
Specifically, 22% of soft-tissue injuries occur at the hip, thigh or groin in professional soccer players (see ). This has HERE spurred the development of a metric called Hip Load, that uses three inertial measurement units on the pelvis and thighs to quantify movement (e.g. acceleration, angular velocity, see HERE). With this measure, coaches could more appropriately assess high-intensity actions that occur in training and competition. However, the test-retest reliability of the Hip Load measure is yet to be established at different running intensities and during different sport-specific tasks (e.g. running, kicking, and jumping). Therefore, the objective of this study was to assess the reliability and validity of the novel Hip Load measure, and the relationship it has with PlayerLoad while performing shuttle runs, involving kicks and jumps, at various intensities.
WHAT THEY DID
Eleven amateur male soccer players (age 21.3±2.2-yrs) wore local positioning measurement devices affixed between the scapulae, as well as six inertial measurement units on the upper back, lower back, thighs, and lower legs as previously researched (see ). Two testing sessions separated by HERE roughly a week (±1-day) were performed for each participant. The testing included two 16-m runs, followed by three 54-m runs at 9-km.h-1 to synchronise the devices. Testing involved a series of six shuttle run variations. Shuttles were 7-m long, with a 2-m deceleration space, both paced by auditory beeps. There were three different types of shuttles (running only, running with kicks, and running with jumps), each performed thrice at low intensity (9-km.h-1) and thrice at high-intensity (14-km.h-1). Kicks and jumps were completed at the end of each run and instructed to be performed at maximal intensity regardless of running speed.
The first run of each shuttle variation was used as familiarisation, whereas PlayerLoad and Hip Load data from the second and third attempts were analysed for comparison. Testretest reliability was assessed, and the derived external load metrics were normalised relative to performance on the 54-m run for comparison and validation.
Practical Takeaways
The results from this research (acceptable to good reliability) and use of inertial measurement devices affixed throughout the lower body provide support for potential use as a monitoring tool that allows coaches to compare quantified biomechanical loads across the days, weeks, and months of a training and competition period.
§ To support evidence as a tool to mitigate injury, a more long-term study is needed for comparison between Hip Load and injury incidence.
Given the sensitive ability to recognize the intensity of on-field locomotion (which includes speed, acceleration, and deceleration), as well as kicking and jumping. Hip Load provides a more sensitive and appropriate measure than PlayerLoad. This metric has provided a more accurate representation of stress endured in the hips and lower body, which is where the majority of soft tissue injuries occur in soccer (see HERE).
§ It is important for coaches to be able to accurately quantify intensity, given that that is where most acute injuries occur (see HERE).
Coaches need to appreciate that PlayerLoad is limited in the ability to recognise intensity, specifically running speed, especially as a PlayerLoad per meter value. Although it is a load metric to consider, coaches should also inquire about an athlete s soreness as it relates specifically to the hamstrings, adductors, and soft tissues of the lower body (calf, hip, etc.).
§ This can be accomplished through a pre-training questionnaire that asks about overall fatigue, mood, and offers the opportunity to rate soreness, or even note pain to a specific area. This information can help coaches make training decisions or modifications when necessary
WHAT THEY FOUND
‘Acceptable to good’ test-retest reliability for both Hip Load (coefficients of variation (CV) of 13.7-% for Hip Load in kicking leg, 9.11-% in nonkicking leg), and PlayerLoad (CV of 6.4-%) external load metrics.
Hip Load was able to appreciate kicks, jumps, and running speed, especially as it related to the dominant (kicking) leg versus the non-dominant leg.
§ When compared to PlayerLoad, Hip Load provided a more sensitive measure due to the impact from kicking and running speed.
To further the validity of Hip Load, as expected, given the velocity and accelerations experienced directly at the hip, kicking was recognised as a more stressful activity than jumping.
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“Ultimately, this is a great reminder for coaches that have the opportunity to utilise wearable devices that provide running distances, intensities, and even calculated metrics like PlayerLoad; that these values provide a generalised overview of external loads. However, with complex field sports like soccer, coaches need to appreciate the jumping and kicking stresses that athletes endure and are potentially not accurately represented from a device that only measures totalbody movement.”
“There is potential however with the Hip Load measure, providing a more sensitive measure to support quantifying biomechanical load and monitoring stress in effort to enhance readiness and reduce the risk of injury The thought process and research is promising but the practicality of players being able to consistently adhere six devices to their body prior to playing is unrealistic. However, there is a more practical option in the works in the form of inertial measurement units being integrated into clothing (see ). It will HERE be interesting to see if this measure becomes as common and useful as PlayerLoad has in recent years and something to keep an eye on.”
How can coaches support an athlete’s sleep?
OBJECTIVE
Given the numerous psychophysiological benefits of sleep (see HERE), a lack of or disturbance to high-quality and sufficient quantity sleep can be a limiter to performance for an athlete (see ). Sleep is arguably the greatest weapon in the battle HERE of optimising readiness and maintaining balance between training stress-recovery (see ). However, issues with sleep HERE are not completely due to lack of trying and can be negatively impacted by training volume (see ), training schedules HERE (see ), and even competitions (see ) or travel (see HERE HERE HERE).
Although there is evidence of the interaction between training load (TL) and performance in numerous athletes (e.g. ballet dancers (see ), cyclists (see ), swimmers (see ), HERE HERE HERE and even rugby league athletes (see ). There is a lack of HERE research for the impact contextual factors (e.g. training, scheduling, and even age) have on sleep in rugby league athletes.
Therefore, the aim of this study was to identify sleep habits in elite rugby athletes and identify potential interactions with TL. As well as examining schedules, age, and travel on sleep.
WHAT THEY DID
Twenty-six male National Rugby League athletes (age 24.8±3.6yrs) with no sleep concerns participated in this study that examined three different types of training weeks. Subject’s data was classified by age (older or younger than 24-yrs), training start time (before or after 8-AM), distance from training (less or more than 20-km), and travel time to training (less or more than 30-min). Each type of training week (low-, high-, or match-) consisted of 4 consecutive days. Low TL and high TL weeks occurred during the pre-season period and training started before 8-AM to maximise time, whereas the match week (inseason) began training sessions post 8-AM. Notably, players were required to complete ‘recovery activities’ at 10-AM the day prior to a match.
Sleep data (e.g. time in bed, time out of bed, duration in bed, sleep duration, efficiency (sleep duration/time spent in bed (%)), latency (time to fall asleep (min)), wake after sleep onset, number of awakenings, and awakening length) was captured using wrist-worn actigraphy A sleep diary was also used to monitor subjective sleep quality (0-5 point scale), as well as time in- and out-of-bed. To quantify TL and match load, session rating of perceived exertion (sRPE) was taken within 15-min following the completion of activity and was multiplied by session duration.
Training, match, and sleep data was analysed per individual and compared based on classifications, day-to-day variance, and significant differences as it relates to daily and weekly sleep responses, which were reported to infer potential factors that impact sleep behaviour
Practical Takeaways
When collecting objective sleep data, polysomnography is the gold standard for analysing sleep, but an activity monitor is an option to identify sleep routines (see ), and is more reliable than sleep diaries (see ). A HERE HERE wrist-worn device provides quantified insight that removes the burden from the individual, and a comparable reference over time to help identify issues and hold athletes accountable to their behaviours.
However, there are options to reliably assess sleep quality through subjective surveys (see ) and further HERE questions (e.g. fatigue, soreness, wakefulness, mood) that can be related to sleep but provide coaches with useful insight in identifying an athlete s psychological readiness of affective state (see HERE).
§ Just as in this study, responding to these questions on a 0-5 scale provides coaches with a comparable measure to recognise change and potential follow-up to understandthe context to why an athlete s subjective report may be unfavourable.
For the athletes in this study and especially the older (>24-years) athletes, in the evening following a late afternoon or evening match, allow athletes sufficient time to extend their sleep in the morning following.
Requiring athletes to complete recovery activities, although well intended, becomes an unnecessary stressor and time-demand that would arguably better be served to the athlete if it was simply self-guided activity versus a required one.
Time availability is the greatest limiter for athletes being able to achieve sufficient time in bed each night. With this in mind, coaches should schedule training times at reasonable hours (8 AM to 5 PM) when able to allow athletes ample time to take care of themselves and various chores they have outside of training (e.g. shopping, cleaning, relaxing, etc.).
§ Coaches should not be mandating training to monopolise and control an athletes schedule, but rather be efficient with the demands placed on their schedule. Appreciating other responsibilities (work, school, family) that they have to take care of outside of training.
Coaches should provide the athletes they work with with various post-match sleep hygiene strategies (see HERE, e.g. relaxation, meditation, imagery) that ultimately help the athlete to calm themselves mentally and physically following a late-night and intense competition. This can help promote higher quality, restful and restorative sleep that will help support athlete recovery for subsequent training and matches.
WHAT THEY FOUND
Sleep duration was lower during a high TL week, likely due to four (required) early morning training sessions. Sleep duration was most disturbed in the night following a match, likely due to later in-bed time.
§ Therefore, training scheduling appears to be a controllable risk factor that can potentially negatively impact sleep behaviour
When comparing the low-, high-, and match-week sleep data, there were no meaningful differences in sleep quality, but there was a reduction in sleep efficiency following a match.
§ Additionally, older athletes in the study (age 24-33) obtained less sleep and had a poorer subjective report of sleep quality
There were no recognisable differences in sleep behaviour when examining travel time to training (±20km).
Athletes in this study slept between 6-7-hours per night, which is below the recommended 7-9-hours (see HERE).
“As cited in this research (see and ), it appears HERE HERE that consistency in schedule is key to providing athletes with the necessary available time to manage and obtain all too critical sleep. Consistent sleep habits support an athlete s ability to recover and perform, not to mention their psychophysiological health and wellness. Numerous studies (see and have noted that HERE, HERE, HERE) sleep hinges on an athlete’s schedule demands. Further, respecting that even for professional athletes, they have more responsibilities that require time and will influence recovery beyond training and competition.
“Most importantly, ‘recovery’ is not something that should be prescribed or even rushed, but rather something that occurs over time (i.e. an improved state of readiness). Coaches should simply expose athletes to various methods (e.g. hydrotherapy, massage, compression garments, nutrition, meditation), and athletes should experiment with each and every one. However, the one that the athlete believes in and feels the most benefit from is arguably the best method. Regardless of the various potential methods that can support an athlete s recovery, there is perhaps no method that is as beneficial as a full night’s sleep.”
Reliability and validity of force-velocity profiling using free weights
OBJECTIVE
Examining the force, velocity, and power potential (forcevelocity profiling) of a countermovement jump (CMJ) has been simplified in recent years by sport scientists to provide a practical alternative in assessment and monitoring for an athlete. With this insight coaches have the potential to identify performance potential, as well as monitor development before and after a training intervention. The SAM method, first presented by Pierre Samozino (see ) involves computing jump height, HERE system mass, starting height and push-off distance (difference between starting height and take-off position) to produce force and velocity values. From these values, theoretical maximal values for force, power output, and velocity can be generated.
Despite the notable strengths (validity and reliability) of using the SAM method when performing a pausing squat jump (see ) and CMJ on a Smith machine (see HERE HERE), the SAM method has yet to be validated when using free weights (e.g. barbell). Therefore, the objective of this study was to assess the reliability and validity of the SAM method (calculating mean force, velocity, and power) compared to data from a force plate when performing a CMJ using a barbell and hexbar
WHAT THEY DID
Twenty-one active men (age 26±4.1-yrs) participated in one testing session after watching prerecorded instructional videos in the seven days prior for familiarisation. Subjects were consistently instructed to ‘drive their feet through the floor’ and ‘jump toward the ceiling’ when performing each CMJ, aiming to descend to an individualised yet consistent starting height, while jumping up as fast as possible without stopping. Jumps were performed with a weightless dowel and PVC pipe (simulating a barbell and hexbar, respectively) to represent body mass, as well as with a loaded barbell or hexbar at 15-, 30-, and 45-kg. Three jumps were performed for each load with one-minute rest between each jump, three-minutes between loads, and fiveminutes between using the barbell or hex bar
Jumps were performed on a force plate system to provide vertical ground reaction force and velocity data. Additionally, jump height was gained via flight time, and other height measures (starting height and push-off distance) were used to calculate mean-force, -velocity, and -power across all loads used. For each load, the CMJ with the greatest height was used for analysis and given the linear relationship of jump heights at increasing loads (slope), regression analysis allowed for theoretical force and velocity capabilities to be identified. Data directly from the force plate data were compared with those from the SAM method calculations to assess validity and reliability in determining force-velocity variables.
Practical Takeaways
Given the reliability results for the SAM method in this study, coaches can be confident that measures are comparable. Coaches can ensure this through consistent instructions, conditions, and familiarisation with the athletes.
To help coaches make their force-velocity profiling simple and efficient, research supports the use of two separate loads being sufficient to illustrate the linear relationship to determine theoretical maximal force, velocity, and power (see HERE).
Given the poor validity compared with force plate (criterion) results, force-velocity metrics should not be used interchangeably between the criterion and SAM method calculations.
Much of the discrepancy between results could have likely come from a change in jump strategy (i.e. modifying the push-off distance due to change in loading and attempting to jump as high as possible). This subconscious strategy is a physiological response that allows the athlete more time to load and generate force, but could be reduced, possibly eliminated, if the depth of loading was standardized with a soft box or band as a marker of consistent depth.
To best prepare athletes for what an assessment protocol will entail and to ensure they understand specific instructions, coaches may consider providing athletes with a short video that explains the test and their expectations. This can make instruction and the procedures easier to execute and better prepare the athletes psychologically regarding what to expect.
If force plates are not available for measurement, flight time can also be captured via high-speed camera (see ) or a contact grid (see ). HERE HERE
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WHAT THEY FOUND
During both loading conditions (barbell and hexbar), the SAM method was reliable when calculating average force, velocity, and power values.
§ Likewise, the height of push-off was reliable for both loading conditions.
Using anthropometric measures (body mass, height to take-off, squat depth, and height of push off) were reliable avenues when using the SAM method to calculate average-force, -velocity, and -power during loaded and unloaded CMJ
However, contrary to previous research (see HERE), the validity of the SAM method when compared to force plate data for average-force, -velocity, andpower was not supported due to significant differences in data.
§ This notes a limitation in the SAM method to assess force-velocity characteristics using free-weights and is likely due to the variance in height to push-off.
“The use of the SAM method and results of this study are reminders to identify and implement testing that is reliable. When a test provides reliable insight, coaches can gain confidence in the comparability, and hopefully identifying progress, based on results over time. Coaches need to appreciate the steps and strategies that are necessary to ensure this reliability, but from a practical standpoint, the SAM method provides insight into the force, velocity, and power potential of an athlete.”
“By breaking down movement in this fashion, coaches can apply training appropriately and specifically to improve deficiencies on the force or velocity end of things that potentially enhance sport-specific performance. Getting stronger (increasing force output) can help an athlete, but there are no absolutes when it comes to athletic development. Being able to identify a velocity deficiency could be the missing piece from taking an athlete from ‘good’ to ‘great.’ Using the SAM method and assessing force-velocity potential could be where this decision begins.”
What happens to performance following a two-week break?
OBJECTIVE
Given the combination of high-intensity actions (sprints and changes of direction) spread across the long duration of a soccer match, numerous qualities from a power, speed, and endurance standpoint encompass adequate fitness and highlight performance potential. To identify this, coaches can incorporate a range of tests to assess an athlete s preparedness level (e.g. repeat sprint ability (RSA, see ), Yo-Yo Intermittent recovery test level 1 HERE (see ), countermovement vertical jump (CMJ), and HERE sprinting speed (see HERE).
Further, with the use of athlete-worn global positioning devices, coaches can assess distances, speeds, and actions (accelerations and decelerations) during smallsided games (SGG), which has further potential as an assessment and monitoring tool. These measurements also can be implemented to showcase readiness on a daily-weekly basis during the season.
However, there has been no specific research examining the performance changes (improvement, maintenance, or detraining) following a break period in female soccer players. Therefore, the researchers of this study examined the impact that a 2-week break period had on RSA, CMJ, and SSG performance in young female soccer players during their competition season.
WHAT THEY DID
Twelve female national level soccer players (age 17.2±1.5yrs) participated in a total of four assessment protocols. Each testing period involved a CMJ test (three individual jumps with hands on hips, 45-sec rest between each, recording the highest jump (cm)), a RSA test (eight max effort 30-m sprints with 25-sec active recovery between each, examining average, best and the decrement across the repetitions (sec)), and a series (3x5-min) of SSG (5 versus 5, on a 25x25-m pitch) examining various volume and intensity variables (e.g. distance (m), high-intensity distance (>15.5 km.h-1), sprint distance (>20-km.h-1), high intensity accelerations (>3-m.s-)).
The first two assessments were completed on consecutive days, followed by a two-week rest period (‘subjects were asked to refrain from any type of physical activity training or competition (other than daily life physical activity)’). After the two-week break, the same testing protocol was performed on two consecutive days.
An analysis of variance was performed for all the performance metrics collected. Primarily the measures were compared before and after the 2-week break period to identify potential detraining. Secondarily the measures were compared between the consecutive days, which would highlight the ability or inability to recover, suggesting a detraining effect.
Practical Takeaways
This data supports the residual training effect around sprinting performance (best RSA) lasting as long as 28 days following inactivity (see ). However, the ability to sustain repeated high-speed HERE efforts was diminished. Recognising this, should help coaches appreciate either the use of a specific RSA protocol as a conditioning tool (e.g. completing 8-10 maximum sprints for 25-30-m with 15-25sec of active recovery between each) or potentially using SSGs as a sport-specific conditioning tool.
§ Regardless, it appears the maximum potential (sprinting speed) is not as easily lost in females, as is the conditioning aspect (ability to recover between bouts).
With the use of wearable technology, coaches can assess SSG performance during mid-week training and identify readiness for a given session (see ). This helps coaches to recognise an HERE athlete s ability to recover following a match or previous training session and provides direction to the training loads that should be prescribed in subsequent days to support athlete safety in training and recovery before the next match.
§ However, some research suggests that SGG performance is not sensitive or reliable enough to highlight changes in performance (see and ). Therefore, the inclusion of a specific HERE HERE test (RSA or Yo-Yo Intermittent Recovery test) provides a more consistent and constrained measure that is valid and reliable for comparison.
§ Even performing a sub-maximal (6-min) Yo-Yo Intermittent Recovery test following a warm-up has shown to be reliable and sensitive enough (see ) as a measure of fitness potential in- HERE season.
Most notably, the results of this research highlight the importance of maintaining a chronic exposure to workload. Not only did performance potential decrease following a 2-week break period, but also the ability to recover between testing (24-hr) in the two sessions following the break period. Given the consistency in performance and ability to recover in the first two testing sessions, it would suggest that the three training sessions (one focused on recovery, one dedicated to resistance and endurance using plyometrics, strength stations, and SSG, and one focused on sprinting and larger SSG) was enough to maintain performance and support adequate fitness.
Therefore, coaches need to establish a weekly training routine that allows roughly one exposure each week to full speed sprinting and jumping, as well as technical exposure using SSG to support sport-specific conditioning.
WHAT THEY FOUND
Following 2-weeks of inactivity, CMJ and the average RSA were the two variables that showed the most decrement.
The best RSA performance (fastest repetition) did not change following the 2-week break period (~2%) but there was a slower time and greater change in the second day of testing following the 2-week break period.
The RSA decrement across the repetitions did diminish substantially (~4%) following the 2-week break period.
When comparing consecutive training days, there was a decrease in the number of high-intensity accelerations during SSG, but no other changes observed (e.g. total or high-intensity).
“During the competitive season, what matters most is onfield performance. Athletes should be focused on training to compete, not being distracted or anxious about midweek fitness testing between matches. This requires some sort of in-game measure (e.g. speeds or distances on the pitch or a simple subjective report) to showcase readiness and performance for game day potential (i.e. noting that only a seemingly average performance is required for these metrics and an overall team win). Likewise, there can (and arguably should) be mid-week measures that coaches can use to monitor recoverability and mitigate fatigue accumulation across the weeks of the season, appreciating the highs, lows, and fluctuations of data.”
“However, just as I suggested for the athletes, coaches should not get overly distracted by tests mid-week either, but rather find simple and effective measures (e.g. CMJ, heart rate response during a submaximal run) that can be quickly and easily folded into a training session (probably best immediately following a warm-up, prior to any fatiguing activity). From this study we can gain the appreciation for training residuals (the ability to seemingly maintain performance following inactivity) possible for sprint speed, and hopefully recognise that training should be specific to the qualities necessary for optimal performance. For soccer, although this is fairly complex, with the use of SSG and some supplementary jumping, sprinting and strength training a few times a week, an athlete’s fitness potential and ability to recover is maintained.”
Fatigue & Recovery
This month’s top research on fatigue and recovery
DOES FOAM ROLLING IMPROVE LOWER BODY WEIGHT TRAININ
THE EFFECTS OF REST REDISTR ON BARBELL VELOCITY AND PO CLEAN PULLS
IS THERE A CORRELATION BETWEEN MUSCLE ASYMMETRIES AND JUMP PERFORMANCE?
Does Foam Rolling Improve a Lower Body Weight Training Program?
OBJECTIVE
Fascia is a connective tissue that encases and connects our body structures and can transmit mechanical tension across it. This is vital as physiological and biomechanical dysfunctions can cause changes in the fascia, which can increase fibrous adhesions and decrease extensibility This in turn may create negative changes in joint mechanics, reductions in muscle length and decreases in neuromuscular performance.
Foam rolling is a technique used during warm-up for training with the goal to reduce adhesions and tightness in the muscle through an individual's exertion of their own body mass to exert pressure on various soft tissue regions of the body. Several studies previously have looked at performance changes associated following performance of foam rolling with various results found. The purpose of this study was to compare how different periods of foam rolling of the lower extremity musculature affected performance of total repetitions and total volume in a weight lifting training session.
WHAT THEY DID
Fourteen healthy men with two years of resistance training and experience with foam rolling participated. The subjects performed various levels of foam rolling followed by five sets of 4 repetition max (RM) lifts for the deadlift and leg press with two minutes of rest in between sets.
Eight total testing sessions were performed with 48 hours in between sessions. The areas that were foam rolled included the quadriceps, hamstrings and tricep surae (calf musculature). The testing sessions were as follows.
Session 1-3 were for collecting anthropometric measures, familiarisation with the movements and 4RM testing.
Session 4 was the training program performed with no foam rolling.
Session 5 was the training program performed with 1 set of 30 seconds of foam rolling preceding it.
Session 6 was the training program performed with 2 sets of 30 seconds of foam rolling preceding it.
Session 7 was the training program performed with 3 sets of 30 seconds of foam rolling preceding it.
Session 8 was the training program performed with 4 sets of 30 seconds of foam rolling preceding it.
Surface EMG was used in order to assess myoelectric activity while performing the leg press and deadlift motions. Measured areas included the vastus lateralis, vastus medialis oblique, semitendinosus, medial gastrocnemius and bicep femoris. Along with this, subjective levels of rating of perceived effort (RPE) were assessed for each subject
Practical Takeaways
This study suggests that foam rolling did not impact training performance significantly regardless of how it was performed prior to deadlift and leg press movements. For most of the sessions, there were no significant differences found in EMG activity of the muscles measured with the exception of the medial gastrocnemius and VMO This may have been due to neuromuscular inhibition from previous experience with foam rolling or overall accumulating fatigue toward the end of each training session. Although no significant positive correlations were shown with foam rolling, there were no deleterious effects found when using it.
A limitation in this study includes that the level of RM used for the leg press and deadlift are suggested for when performing higher intensity movements. If the goal of training was for hypertrophy, the RM utilised would have been different along with potentially more significant findings with performance. Along with this, the results may have changed if the subjects were instructed on how much pressure to exert on the foam rolling. This study was also performed on those who were injury free; how would this have changed with a population who had a history of injury in the muscles studied.
WHAT THEY FOUND
There were no significant differences between training protocol sessions with regard to total repetitions and volume performed. Along with this, there were similar levels of RPE reported regardless of training session. For the leg press movement, surface EMG did not differ significantly throughout. For the deadlift movement, there were significant differences found for EMG measurement at the VMO for set five vs. set one during the fifth training session (FR for 1 set of 30 seconds) with a reduction in muscular activity found. During this same training session, medial gastrocnemius activity was reduced between set five and set four
“This study provides insight on how foam rolling affects closed kinetic chain lower extremity movements of the deadlift and leg press. Following various periods of foam rolling, there was little to no effect on performance found. Although this was the case, foam rolling may be more beneficial to reduce pain or improve performance when training for hypertrophy with a larger RM. This type of study would be intriguing to look at with other movements like a squat pattern or when looking at subjects who had previous injury.”
“Although there is a lack of changes in performance, foam rolling may be still beneficial in a warm-up setting in order to subjectively reduce pain and tightness in muscles. Rehabilitation professionals can trial various periods of foam rolling in training to find what, if any, benefits it can provide to their athletes whether it can from a training or performance perspective.”
The Effects of Rest Redistribution on Barbell Velocity and Power with Clean Pulls
OBJECTIVE
One of the reasons weight lifting movements are performed is to increase power of the lower limbs. With this, prescription of these movements should look to maximise and maintain movement velocity and power across various loads. Traditionally for power movements, 3 to 5 minutes of rest in between sets is used in order to maximise acute performance. Recently however, fatigue reduction strategies have included added intraset rest periods of shortened duration with the additional goal of better maintenance of barbell velocity and power
The purpose of this study was to use different rest periods between sets of a clean pull exercise to compare changes in barbell velocity, power and performance.
WHAT THEY DID
Fifteen strength trained men (28.8 ± 4.48 years old) with at least one year of resistance training participated in the study They were all able to clean pull at least 90% of their body mass. 1 repetition max (RM) was obtained prior to the training protocols. Mean and peak concentric power and velocity were measured via a GymAware linear position transducer placed on the barbell. Prior to the protocols, a warm up of clean pulls were performed.
Six experimental sessions were performed in a randomised order. During each session, the subjects either performed three sets of six repetitions with 180 seconds rest in between sets or nine sets of two repetitions with 45 seconds of rest in between sets. For each session performed, subjects lifted either 80% of their 1RM, 100% of their 1RM and 120% of their 1RM of the power clean exercise. This was measured prior to the experimental sessions.
Barbell velocity and power output were recorded for all repetitions.
WHAT THEY FOUND
When comparing the two different rest distribution strategies, it was found that the shorter but more frequent rest periods produced greater velocities and power output for repetitions in isolation along with all sets and repetitions together This was most apparent with the sessions using 100% 1RM and 120% 1 RM. Changes in power and velocity were not as apparent with the sessions of 80% 1RM performed.
Overall, velocity and power were better maintained when repetitions were reduced by 66% (six to two) and when rest was reduced by 75% (180 seconds to 45 seconds). These results suggest that only 25% of the rest that is traditionally given for power based exercises is needed and redistributing that rest time may be more valuable to maintain performance.
Practical Takeaways
This study compared different rest periods for the clean pull exercise and found that shorter but more frequent rest periods between sets were more beneficial for maintaining power output and barbell velocity This was most apparent when higher loads were utilised with performance benefits most apparent with subjects using 100-120% of their power clean 1RM. At lower loads, the benefits of rest redistribution is not as advantageous and therefore is not recommended. With this, rest redistribution is viable when loads are high enough to induce significant levels of fatigue.
Rationale for why shorter and more frequent rest periods may be more beneficial include the assumption that there is an increase in the frequency of muscle contractions with shorter rest breaks along with more frequent replenishment of energy stores.
Future studies should look to determine the true optimal rest time in between sets as training can become even more effective if less or more rest time can increase performance to even greater levels than what was found with this study
“Overall, shorter rest intervals were effective at maintaining greater bar velocities and power output within individual sets. This was true with sufficient load to induce fatigue, which for this study was between 100-120% power clean 1 RM. Although this was the case with clean pulls, it may be different when comparing other Olympics lift derivatives such as the power snatch, push jerk or front squat.”
“These results may not be as relevant when looking at movements like the bench press or back squat where fast velocities and high power outputs are not the priority.”
“Future studies need to continue to determine the timing of fatigue with olympic lifts in order to determine the optimal level of repetitions per set performed.”
Is There a Correlation Between Muscle Asymmetries and Jump Performance?
OBJECTIVE
Sport performance involves movements that are performed using both limbs (bilateral) and using a single limb with different force and power outputs produced. The strength and quality of movement performed with both types of jumps can be asymmetrical causing deficits in jumping performance along with muscular contraction.
Determining the cause for this asymmetry is imperative in order to identify potential risk factors for injury along with unilateral strength deficits. One way to look at muscle asymmetry is through tensiomyography (TMG). TMG measures the speed of muscle contractions under isometric conditions and is used to determine functional symmetry of muscles surrounding a joint. The purpose of this study was to assess potential associations between bilateral and unilateral jumping. This was compared with results from TMG of associated lower extremity muscles involved in jumping.
WHAT THEY DID
Subjects were sub-elite male soccer players ranging from 16 to 40 years old with a long soccer history and a training frequency of at least three times a week. There were 23 total subjects after two dropped out following injury
Three double limb jumps, three single limb jumps on the left leg and three single limb jumps on the right leg were performed in a randomised order with one minute of rest in between jumps. The following measurements were obtained.
Inter-limb or lateral asymmetry comparing specific muscles - This was calculated as the difference between the two lower limb jumps. This was then divided by the higher value in the unilateral jump.
Bilateral Deficit (BLD) - The comparison of right and left single limb performance with regard to force. This was then divided by the power measured during bilateral jumps.
Functional symmetry was the symmetry between the muscles surrounding the joints of the knee and ankle.
TMG measurements were performed on all subjects. Assessed muscles included the adductor longus, biceps femoris, lateral and medial gastrocnemius gluteus major, rectus femoris, soleus, tibialis anterior and vastus lateralis and medialis.
Practical Takeaways
§ From this study we see preliminary evidence that there is an association between CMJ performance and results found with TMG looking at muscular contraction properties. Both measurements provide information on muscle asymmetries allowing for identification of injury risk factors in soccer players.
§ Using both unilateral and bilateral CMJ with force plate technology allows for measurement of asymmetries in force production of the muscles utilised. With this information, rehabilitation professionals and coaches can identify muscles to target in training and determine proper cueing for movement patterns in order to decrease injury risk.
§ The bicep femoris and soleus were found to have higher levels of lateral asymmetry This is important to note as these muscles can influence jump performance with the reduction of the effect of the stretch-shortening cycle with early activation of the biceps femoris.
§ Differences in functional asymmetries found with playing position may be due to different load and muscular responses between positions.
§ Future studies should look at other sports involving jumping and landing mechanics in order to expand upon this information. Along with this, looking at a larger sample size will provide further information on muscle asymmetries.
WHAT THEY FOUND
When comparing the TMG analysis of muscle contractile properties, it was found that there was less symmetry between the dominant and non dominant leg for the tibialis anterior, bicep femoris and adductor longus. Low functional symmetry scores were found at both the knees and ankles with the left leg having lower scores compared to the right leg.
CMJ inter limb asymmetry was shown to be correlated with lateral asymmetry of the bicep femoris and soleus. Bilateral deficit, which was found to be an expression of altered muscle coordination, was found to correlate with the CMJ inter limb asymmetry. CMJ variables did not provide significant differences between playing positions but on the other hand, TMG measurements showed differences in muscle contractions. This was seen specifically with players in central roles displaying higher knee functional asymmetry compared to defensive players.
“Measurements of unilateral and bilateral CMJ along with use of TMG are effective ways to determine muscle asymmetries in soccer players. With this information, rehabilitation professionals and coaches can better determine training programs to strengthen weaker musculature and reduce injury risk.”
“Inter-limb asymmetries should be monitored for potential injury risk with rehabilitation professionals and coaches implementing prevention and training strategies to reduce it.”
“Differences in unilateral vs. bilateral jump performance were apparent in this study
Understanding what particular muscles are causing these differences through TMG can provide further information on the different components of the muscle that participate in sport-specific tasks being measured.”
Youth Development
This month’s top research on youth development.
HOW DO DIFFERENT STYLES OF TRAINING AFFECT THE METABO OF YOUNG ATHLETES?
SMALL-SIDED GAMES: THE IMPACT OF POSSESSION VS. SHUTTLE BIASED FORMATS ON PERFORMANCE IN YOUTH SOCCER
How Do Different Styles of Resistance Training Affect the Metabolic Profile of Young Athletes?
OBJECTIVE
Resistance training is used to improve health and sport performance in all age groups as well as a way to decrease fall risk in an older populations. Performed consistently resistance training undertaken between 30100% of an individual s one repetition maximum (RM) has been shown to elicit hypertrophy in muscles along with other positive health outcomes. Traditional resistance training involves performing sets of repetitions of an exercise to achieve momentary muscular fatigue before moving to another exercise. Recently, reciprocal supersets have been researched as an alternative and consist of performing two consecutive exercises for opposing muscle groups with minimal rest time between the two movements. This has recently come into favour due to the time efficiency of a shorter duration of the exercise session. The purpose of this study was to compare the metabolic changes achieved by a traditional resistance (TR) program vs. reciprocal supersets (RSS) in a young, athletic population along with comparing performance of males and females.
WHAT THEY DID
A total of 18 healthy and resistance trained male and female subjects between ages 18 and 27 years participated in the study These participants underwent testing for their VO2max along with their 10 RM prior to performing resistance exercise for the study The RSS session was performed prior to the TR session with matched sets, repetitions and volume for each session. Maximal oxygen uptake was measured via VO2max testing on a treadmill performed at a 3% incline with a self-selected running speed which could be maintained for 30+ minutes.
10 RM testing was performed with the exercises in the sessions being performed at 75% of the subjects 10 RM. Subjects performed all sets to concentric muscle failure while maintaining a repetition range of 12-15.
The RSS session included the following exercises performed with alternating push and pull movements. Each cluster (push and pull exercise) was given a one minute rest period between sets and then two minutes of rest before starting the next cluster. Exercises were performed in the following order: Leg press (Push), hexagonal bar deadlift (Pull); chest press (Push) and seated row (Pull);overhead dumbbell press (Push) and lat dorsi pull-down (Pull).
The TR session included the same exercises and order Subjects were given 90 seconds of rest between sets. All sets of each exercise were completed consecutively prior to starting the next exercise.
HR, blood lactate, RPE (rating of perceived exertion) and EPOC (volume of excess post-exercise oxygen consumed) were measured.
Practical Takeaways
§ -RSS vs. TR allowed the athlete to not only increase metabolic demand, but decrease the amount of time that they were exercising. This was an efficient way for the athlete to train, which is vital within the season with other external demands present including time constraints and the need for skill training.
§ Training via RSS compared to TR showed positive benefits for metabolic demands along with energy expenditure. With this, subjects spent significantly less time exercising in total with a higher benefit compared to a traditional resistance training program. With compliance issues rampant in the population as seen with American Heart Association studies, RSS may be a suitable training program for people with time constraints noted as a barrier and who do not have medical complications.
§ The increase in RPE as well as greater increases in HRmax and VO2max found during RSS is an indicator of greater intensity in the training. This may have been due to the decrease in rest times between sets and exercises. With this, the RSS produced a cardiorespiratory exercise benefit that may not be found with TR. Athletes may find this beneficial within the season in order to improve endurance.
§ Limitations were present in the study including the population studied. How would these results change in an older population or in a population of people who were not experienced with resistance training?
WHAT THEY FOUND
RSS training produced significant increases in the following measures compared to TR: VO2max, HRmax percentage, EPOC, average blood lactate accumulation, aerobic and anaerobic expenditure and RPE levels. Therefore, RSS was found to produce a higher metabolic load compared to TR. Along with this, the RSS session was more time efficient as it was completed within 23-29 minutes compared to the TR session which was performed in 43-47 minutes.
“Overall, RSS training may be a great time saving method for individual athletes along with the general population. It not only can be performed in less time compared to TR, but it produces a bigger metabolic effect. This is vitally important as time of training is noted as a strong barrier to exercise via the ACSM.”
“For the athlete, RSS is a great way to achieve a cardiorespiratory effect with an increase in endurance that they may not achieve via TR. Maximising their training is important as an athlete can have limited training time available in their season and in their schedule. Practitioners can utilise RSS training for their athletes for muscular endurance as well as a secondary training focus.”
“For the general population, the most important benefit of RSS is the time saving effect. This is a huge barrier for the lack of exercise performed and education in this type of training can help to solve this timing constraint issue.”
Small-Sided Games: The impact of possession vs. shuttle biased formats on performance in youth soccer
OBJECTIVE
Soccer is a high-intensity sport, where in order for players to succeed, a host of physiological and technical components must work together to overcome the competition. As the game of soccer has advanced technically, so has the quality and relevance of training to match the physiological requirements of competition. In soccer, small-sided games (SSG) have become a popular training modality for coaches to implement throughout the season. In addition, shuttle running (e.g. covering certain distances in a jog or sprint) can allow players to develop specific fitness (e.g. aerobic or anaerobic) outside of playing the game. SSG requires a small area with modified rules, offering players opportunities to work on the technical, tactical and psychosocial aspects of performance. However, few studies have investigated the impact of SSG with shuttle running in youth soccer players. Therefore, the aim of this study was to investigate the effect of two SSG formats on physiological, metabolic, perceived effort and soccer performance in young elite soccer players.
WHAT THEY DID
In total, ten young male soccer players were recruited from one U19 Italian professional team for a four-week intervention. Only outfield players were selected for this study, including; 2 defenders, 6 midfielders and 2 forwards. In this study, two SSG formats were used on a small pitch (50x30m). Both formats were host to a 5v5 game, with limited touches of the ball when in possession (n=3). In the SSG-P format, players were required to keep possession longer than their opposition. In the SSG-S format, players were required to perform a shuttle run to the nearest cone after touching the ball and return to the game as quickly as possible. In order to minimise interruption when the ball left the SSG dimensions, four members of staff with a number of soccer balls were ready to return the ball when necessary To assess the impact of both interventions, internal workload (i.e. heart rate, blood lactate concentration and rating of perceived exertion), and external workload (via global positioning systems) were collected continuously throughout the study Differences between the SSG modalities were assessed by mean values using a paired t-tests.
Practical Takeaways
SSG’s are a fantastic way for coaches to incorporate tactical and technical factors into training whilst keeping it enjoyable and intense. These skills are not just effective in terms of transfer to competition, but offer the S&C coach a fantastic stimulus to develop aerobic training for soccer players. In addition, SSG offers a versatile approach to training for youth and can be implemented over varying pitch dimensions. In Clemente et al’s (2012) study, a whole host of dimensions and their physiological outcomes can be seen. When combined with skills training, SSG’s make for an effective way to improve conditioning over time. Ensuring that there are a number of coaches to replace footballs that leave the perimeter is essential.
Coaches looking to increase workload capacity may incorporate shuttles into their SSG’s. Higher lactate values in the SSG-S format indicate greater contribution from the anaerobic energy system. In addition, the pitch dimensions (50x30m) and shuttle protocol was highly effective in developing more endurance-specific adaptations (aerobic) as players had to cover greater distances to intercept the ball or regain possession. Such interventions could be useful for coaches who are looking to support players through the later stages of rehabilitation to get “match fit”, or to replace a missed stimulus in players who do not play a game but still need an anaerobic/aerobic stimulus. Shuttle runs can be incorporated into other elements of the session, such as this version of a competitive shuttle rondo (HERE). Armed with this information, coaches are now only limited by their own imagination.
For coaches and sports scientists, SSG’s are a great way to chase adaptations in a fun manner Secondly, a large benefit of SSG’s is that the games can hone in on key positional demands where a team may struggle. For example, part-task SSG training allows players to train subsets of the whole task (e.g. forwards performing shuttles prior to a shot on goal) to work on skills under fatigue. Similarly, defensive orientated players may perform a shuttle followed by a defensive clearance under time or environmental constraints. The possibilities are endless and this fun resource provides over 50 SSG variations that you can use with your players to chase these adaptations.
THEY FOUND
The main finding of this study was that the SSG-S (shuttle) format created significantly higher internal and external workload values than those achieved during the SSG-P (possession) protocol.
More specifically, the SSG-S protocol showed greater distances travelled at moderate speed (14.4-19.8 km.h-1), accelerations ( 2 m·s−2), and decelerations ( 2 m·s−2) when compared to the SSG-P protocol.
In addition, the SSG-S protocol led to higher metabolic responses as measured by blood lactate concentration in soccer players, coupled with increases in self-reported perception of effort in comparison to the SSG-P
From a physiological standpoint, the SSG with shuttle run was more effective than the SSG with possession at developing both internal and external workload in young soccer players.
When designing sessions for soccer players, it is important to ask what outcomes you are trying to pursue for your players. If for example your team is struggling to perform for 90-minutes in a game due to a lack of fitness, the SSGS protocol may be of interest to implement. In the attached podcast, coach Peter Prickett discusses in detail how he changes small variables in training such as the dimensions, team balance or objectives to create the desired physiological outcome. From personal experience, you get a lot more buy-in to tasks that are placed into a game rather than just conditioning work (e.g. shuttle training), so keep this in mind when designing your session.
One limitation of this study which resonated with me immediately was that the authors made no attempt to understand the players perceptions of the task outside of effort. Attaching a simple “enjoyment questionnaire” could have been an easy way for players to communicate what they liked/disliked about both the SSG-S and SSG-P protocols. Secondly, players may have actually improved qualities such as control or movement off the ball in the SSG-P format, which were not picked up on. Player welfare and enjoyment is a big consideration for any S&C coach. Future studies could repeat the same protocol, but investigate the impact that these formats had on players from an enjoyment and skill development perspective.
This month’s top research on nutrition
HOW DOES YOGA HELP US IMPROVE STRESS REGULATION?
How does yoga help us improve stress regulation?
OBJECTIVE
Yoga has been practiced for over 2000 years with the original aim being to bring harmony to the mind, body, and spirit. More recently we may think of yoga as something to aid flexibility though mental focus practices during yoga are thought to produce cognitive benefits beyond the benefits that come from the bodily movements.
Previous review articles have suggested that cognition was improved using yoga when observed in randomised controlled trials. Particularly this was the case for attention and focusing speed, with executive function and memory improved to a lesser extent. Similar results were found following acute bouts of yoga.
As our population ages, and with a desire to identify interventions to improve brain health the spotlight on yoga has intensified as a potential practice that may be beneficial. This review sought to understand the mechanisms underlying the relationship between yoga and cognitive health.
WHAT THEY DID
This review article focused on older individuals, though it is reasonable to think much of the findings may be considered in relation to younger ages also. The authors examined the evidence for underlying mechanisms that might explain the yoga-cognition relationships to better understand how such benefits might be achieved. When reviewing the literature, the authors focused on two main mechanisms: improved stress regulation and improved neurocognitive resource efficiency
Practical Takeaways
§ While long term regular yoga practice seems to be beneficial, it remains challenging to determine the optimal frequency and duration of yoga practice to yield these improvements in brain health. A number of the studies reviewed in this article include cross-sectional work using expert practitioners with 3 or more years experience. Many others are interventional studies typically lasting 12 weeks. This means that time frames between those two relative extremes should be investigated further
These issues focus on overall study design before beginning to consider the more intricate details such as how different postures and breathing/meditation practices might be thought about. These are also interesting avenues for future research to pursue but mean formulating specific guidelines at this stage is quite challenging.
Want
WHAT THEY FOUND
The recurring theme found in the literature relating to yoga was the highlighted benefits of long-term practice leading to improvements in reacting to stress, markers for chronic stress and inflammation, emotional reactivity, grey matter volume, as well as neurocognitive behavioural responses, leading to improved neurocognitive efficiency
Positive findings were also found following short term yoga practice. It was thought this may initially improve stress regulation, which may lead to forming the foundations of more adaptive stress responses, reduced chronic stress, systemic inflammation, and contribution to positive changes in brain structure and function connectivity networks with long term practice.
“This study sought to better understand how the benefits we receive from yoga are achieved. For us as practitioners the findings are still of interest. I expect it is of more use as a reminder that yoga is something that we may want to consider implementing, even if we’re not totally sure how it’s working”.
“Yoga provides a ring-fenced time where our athletes are able to hone their concentration and focus skills in a way that may reduce stress and also provide benefits around sporting tasks. It is something I know that is used quite widely and effectively in professional sport, likely as it provides both psychological and physical positives”.
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