Changes in perceived stress and recovery in overreached young elite soccer players

Exploring the role of mindfulness on obligatory exercise among young athletes: mediating roles of obsessive passion and cognitive state anxiety

Introduction

In the current trend toward youthfulness and age reduction in competitive sports, the issue of obligatory exercise among young athletes is becoming more severe. This not only affects their physical and mental health but also hampers their future prospects in the sports world. While delving into the impact of mindfulness on the issue of obligatory exercise among young athletes, it reveals the mediating role of obsessive passion and cognitive state anxiety.

Methods

This study is a cross-sectional research that employs convenience and snowball sampling methods. We selected 403 young athletes from several universities and high-level sports teams in the central-southern region of China as valid samples and used AMOS v.23 to construct a structural equation model to validate the hypotheses.

Results

The research findings indicate a significant positive correlation between obsessive passion, cognitive state anxiety, and obligatory exercise. Furthermore, obsessive passion and cognitive state anxiety mediate the relationship between mindfulness and obligatory exercise. This implies that young athletes can better regulate their emotional state during training, manage training loads sensibly, and avoid issues with obligatory exercise through mindfulness training.

Discussion

In conclusion, to enhance the cognitive levels of young athletes and reduce their obligatory exercise behaviors, national sports authorities and coaching teams should develop reasonable mindfulness training programs for athletes and encourage their participation in mindfulness training.

Mass Participation and Tournament Event Management for the Team Physician: A Consensus Statement (2022 Update)

ABSTRACT

Mass participation events include endurance events (e.g., marathon, triathlon) and/or competitive tournaments (e.g., baseball, tennis, football (soccer) tournaments). Event management requires medical administrative and participant care planning. Medical management provides safety advice and care at the event that accounts for large numbers of participants, anticipated injury and illness, variable environment, repeated games or matches, and mixed age groups of varying athletic ability. This document does not pertain to the care of the spectator.

Mass Participation and Tournament Event Management for the Team Physician: A Consensus Statement (2022 Update)

ABSTRACT

Mass participation events include endurance events (e.g., marathon, triathlon) and/or competitive tournaments (e.g., baseball, tennis, football (soccer) tournaments). Event management requires medical administrative and participant care planning. Medical management provides safety advice and care at the event that accounts for large numbers of participants, anticipated injury and illness, variable environment, repeated games or matches, and mixed age groups of varying athletic ability. This document does not pertain to the care of the spectator.

Risk Factors for Running-Related Injury in High School and Collegiate Cross-country Runners: A Systematic Review

OBJECTIVE: To summarize and describe risk factors for running-related injuries (RRIs) among high school and collegiate cross-country runners. DESIGN: Descriptive systematic review. LITERATURE SEARCH: Four databases (Scopus, SPORTDiscus, CINAHL, Cochrane) were searched from inception to August 2023. STUDY SELECTION CRITERIA: Studies assessing RRI risk factors in high school or collegiate runners using a prospective design with at least 1 season of follow-up were included. DATA SYNTHESIS: Results across each study for a given risk factor were summarized and described. The NOS and GRADE frameworks were used to evaluate quality of each study and certainty of evidence for each risk factor. RESULTS: Twenty-four studies were included. Overall, study quality and certainty of evidence were low to moderate. Females or runners with prior RRI or increased RED-S (relative energy deficiency in sport) risk factors were most at risk for RRI, as were runners with a quadriceps angle of >20° and lower step rates. Runners with weaker thigh muscle groups had increased risk of anterior knee pain. Certainty of evidence regarding training, sleep, and specialization was low, but suggests that changes in training volume, poorer sleep, and increased specialization may increase RRI risk. CONCLUSION: The strongest predictors of RRI in high school and collegiate cross-country runners were sex and RRI history, which are nonmodifiable. There was moderate certainty that increased RED-S risk factors increased RRI risk, particularly bone stress injuries. There was limited evidence that changes in training and sleep quality influenced RRI risk, but these are modifiable factors that should be studied further in this population. J Orthop Sports Phys Ther 2024;54(2):1-13. Epub 16 November 2023. doi:10.2519/jospt.2023.11550.

New Perspectives in Resistance Training Periodization: Mixed Session vs. Block Periodized Programs in Trained Men

ABSTRACT

Bartolomei, S, Zaniboni, F, Verzieri, N, and Hoffman, JR. New perspectives in resistance training periodization: mixed session vs. block periodized programs in trained men. J Strength Cond Res 37(3): 537-545, 2023-The purpose of this investigation was to compare the effects of 2 different periodized resistance training programs on maximal strength, power, and muscle architecture, in trained individuals. Twenty-two resistance-trained men were randomly assigned to either a mixed session training group (MSP; n = 11; age = 23.7 ± 2.6 years; body mass = 80.5 ± 9.8 kg; height = 175.5 ± 6.1 cm) or a block periodization group (BP; n = 11; age = 25.7 ± 4.6 years; body mass = 81.1 ± 10.7 kg; height = 176.8 ± 8.4 cm). Both training programs were 10 weeks in duration and were equated in volume. Each training session of the MSP focused on power, maximal strength, and hypertrophy, whereas each mesocycle within the BP focused on one of these components. Subjects were assessed for body composition, muscle architecture, maximal strength, and power. In addition, perceived training load, and training volume were calculated. Subjects in MSP experienced greater improvements in fat free mass ( p = 0.021), muscle thickness of the pectoralis and vastus lateralis ( p < 0.05), and a greater improvement in 1RM bench press ( p < 0.001; +8.6% in MSP and +2% in BP) than in BP. By contrast, BP resulted in greater improvements in vertical jump ( p = 0.022; +7.2%) compared with MSP (+1.2%). No significant differences were noted between the groups for perceived training load ( p = 0.362) nor training volume ( p = 0.169). Results of this study indicated that in a 10-week training study, MSP may enhance muscle hypertrophy and maximal strength to a greater extent than BP, with the same training volume and perceived training load. However, BP may be more effective for vertical jump improvement.

Relationship between physical performance and perception of stress and recovery in daily life post COVID-19-An explorative study

INTRODUCTION

COVID-19 is a multi-systemic disease which can target the lungs and the cardiovascular system and can also affect parts of the brain for prolonged periods of time. Even healthy athletes without comorbidities can be psychologically affected long-term by COVID-19.

OBJECTIVE

This study aimed to investigate athletes' perceived mental stress and recovery levels in daily life, and their maximal aerobic power, at three different time points, post COVID-19.

METHODS

In total, 99 athletes (62.6% male), who had been infected by COVID-19, filled out the Recovery Stress Questionnaire for Athletes (REST-Q-Sport) and completed cardiopulmonary exercise testing (endpoint maximal aerobic power output (Pmax)) at the initial screening (t1: 4 months after infection). Follow-up assessments occurred three (t2, n = 37) and seven months after t1 (t3, n = 19).

RESULTS

Subgroup means from the Recovery category were significantly below the reference value of four at all three time points, except "General Recovery" (3.76 (± 0.96), p = 0.275, d = 0.968) at t3."Overtiredness" (2.34 (± 1.27), p = 0.020, r = 0.224) was significantly above the reference value of two at t1, while all other Stress subgroups were not significantly different from the reference value or were significantly below the maximum threshold of two at t1, t2 and t3. Spearman's ρ revealed a negative association between Pmax and the subcategories of stress (ρ = -0.54 to ρ = -0.11, p < 0.050), and positive correlations between Pmax and "Somatic Recovery" (ρ = 0.43, p < 0.001) and "General Recovery" (ρ = 0.23, p = 0.040) at t1. Pmax (t1: 3.83 (± 0.99), t2: 3.78 (± 1.14), β = 0.06, p < 0.003) increased significantly from t1 to t2. In addition, REST-Q-Sport indicated a decrease in "Sleep" (t2 = 2.35 (± 0.62), t3 = 2.28(± 0.61), β = -0.18, p < 0.023) at t3, when compared to t2.

CONCLUSION

The perceived recovery seems to be negatively affected in post COVID-19 athletes. Physical performance post COVID-19 correlates with both "Emotional and Somatic Stress" and "Somatic and General Recovery", indicating potential mental and physical benefits of exercise. While it is evident that COVID-19, like other viral infections, may have an influence on physical performance, monitoring stress and recovery perceptions of athletes is critical to facilitate their return-to-sports, while minimizing long-term COVID-19 induced negative effects like the athletic objective and subjective perceived recovery and stress levels.

Monitoring Effects of Sleep Extension and Restriction on Endurance Performance Using Heart Rate Indices

ABSTRACT

Roberts, SSH, Aisbett, B, Teo, W-P, and Warmington, S. Monitoring effects of sleep extension and restriction on endurance performance using heart rate indices. J Strength Cond Res 36(12): 3381-3389, 2022-Heart rate (HR) indices are useful for monitoring athlete fatigue or "readiness to perform." This study examined whether HR indices are sensitive to changes in readiness following sleep restriction (SR) and sleep extension (SE). Nine athletes completed a crossover study with 3 conditions: SR, normal sleep (NS), and SE. Each condition required completion of an endurance time trial (TT) on 4 consecutive days (D1-D4). Athletes slept habitually before D1; however, time in bed was reduced by 30% (SR), remained normal (NS), or extended by 30% (SE), on subsequent nights (D1-D3). Daily resting HR and HR variability were recorded. The maximal rate of HR increase and HR recovery was determined from a constant-load test before TTs. Exercise intensity ratios incorporating mean HR, mean power (W), and perceived exertion (RPE) were recorded at steady state during constant-load tests (W:HR SS ) and during TTs (W:HR TT , RPE:HR TT ). Compared with D4 of NS, RPE:HR TT was lower on D4 of SE ( p = 0.008)-when TT performances were faster. Compared with D1 of SR, RPE:HR TT was higher on D3 and D4 of SR ( p < 0.02). Moderate correlations were found between percentage changes in W:HR TT and changes in TT finishing time in SR ( r = -0.67, p = 0.049) and SE ( r = -0.69, p = 0.038) conditions. Intensity ratios incorporating mean HR seem sensitive to effects of sleep duration on athlete readiness to perform. When interpreting intensity ratios, practitioners should consider potential effects of prior sleep duration to determine whether sleep-promoting interventions are required (e.g., SE).

The soccer season: performance variations and evolutionary trends

The physiological demands of soccer challenge the entire spectrum of the response capacity of the biological systems and fitness requirements of the players. In this review we examined variations and evolutionary trends in body composition, neuromuscular and endurance-related parameters, as well as in game-related physical parameters of professional players. Further, we explore aspects relevant for training monitoring and we reference how different training stimulus and situational variables (e.g., competition exposure) affect the physiological and performance parameters of players. Generally, improvements of small magnitude in non- (non-CMJ) and countermovement-based jumps (CMJBased) and in the sprint acceleration (ACCPhase) and maximal velocity phase (MVPhase) are observed from start of preparation phase (PPS) to beginning of competition phase (BCP). A greater magnitude of increases is observed in physiological and endurance performance measures within this period; moderate magnitude in sub-maximal intensity exercise (velocity at fixed blood lactate concentrations; V2-4mmol/l) and large magnitude in VO2max, maximal aerobic speed (MAS) and intense intermittent exercise performance (IE). In the middle of competition phase (MCP), small (CMJBased and ACCPhase), moderate (non-CMJ; MVPhase; VO2max; sub-maximal exercise) and large (MAS and IE) improvements were observed compared to PPS. In the end of competition period (ECP), CMJBased and MVPhase improve to a small extent with non-CMJ, and ACCPhase, VO2max, MAS, sub-maximal intensity exercise and IE revealing moderate increments compared to PPS. Although less investigated, there are generally observed alterations of trivial magnitude in neuromuscular and endurance-related parameters between in-season assessments; only substantial alterations are examined for IE and sub-maximal exercise performance (decrease and increase of small magnitude, respectively) from BCP to MCP and in VO2max and IE (decrements of small magnitude) from MCP to ECP. Match performance may vary during the season. Although, the variability between studies is clear for TD, VHSR and sprint, all the studies observed substantial increments in HSR between MCP and ECP. Finally, studies examining evolutionary trends by means of exercise and competition performance measures suggests of a heightened importance of neuromuscular factors. In conclusion, during the preseason players "recover" body composition profile and neuromuscular and endurance competitive capacity. Within in-season, and more robustly towards ECP, alterations in neuromuscular performance seem to be force-velocity dependent, and in some cases, physiological determinants and endurance performance may be compromised when considering other in-season moments. Importantly, there is a substantial variability in team responses that can be observed during in-season. Consequently, this informs on the need to both provide a regular training stimulus and adequate monitorization throughout the season.

Submaximal Fitness Tests in Team Sports: A Theoretical Framework for Evaluating Physiological State

Team-sports staff often administer non-exhaustive exercise assessments with a view to evaluating physiological state, to inform decision making on athlete management (e.g., future training or recovery). Submaximal fitness tests have become prominent in team-sports settings for observing responses to a standardized physical stimulus, likely because of their time-efficient nature, relative ease of administration, and physiological rationale. It is evident, however, that many variations of submaximal fitness test characteristics, response measures, and monitoring purposes exist. The aim of this scoping review is to provide a theoretical framework of submaximal fitness tests and a detailed summary of their use as proxy indicators of training effects in team sports. Using a review of the literature stemming from a systematic search strategy, we identified five distinct submaximal fitness test protocols characterized in their combinations of exercise regimen (continuous or intermittent) and the progression of exercise intensity (fixed, incremental, or variable). Heart rate-derived indices were the most studied outcome measures in submaximal fitness tests and included exercise (exercise heart rate) and recovery (heart rate recovery and vagal-related heart rate variability) responses. Despite the disparity between studies, these measures appear more relevant to detect positive chronic endurance-oriented training effects, whereas their role in detecting negative transient effects associated with variations in autonomic nervous system function is not yet clear. Subjective outcome measures such as ratings of perceived exertion were less common in team sports, but their potential utility when collected alongside objective measures (e.g., exercise heart rate) has been advocated. Mechanical outcome measures either included global positioning system-derived locomotor outputs such as distance covered, primarily during standardized training drills (e.g., small-sided games) to monitor exercise performance, or responses derived from inertial measurement units to make inferences about lower limb neuromuscular function. Whilst there is an emerging interest regarding the utility of these mechanical measures, their measurement properties and underpinning mechanisms are yet to be fully established. Here, we provide a deeper synthesis of the available literature, culminating with evidence-based practical recommendations and directions for future research.

Nonergodicity in Load and Recovery: Group Results Do Not Generalize to Individuals

PURPOSE

The study of load and recovery gained significant interest in the last decades, given its important value in decreasing the likelihood of injuries and improving performance. So far, findings are typically reported on the group level, whereas practitioners are most often interested in applications at the individual level. Hence, the aim of the present research is to examine to what extent group-level statistics can be generalized to individual athletes, which is referred to as the "ergodicity issue." Nonergodicity may have serious consequences for the way we should analyze, and work with, load and recovery measures in the sports field.

METHODS

The authors collected load, that is, rating of perceived exertion × training duration, and total quality of recovery data among youth male players of a professional football club. This data were collected daily across 2 seasons and analyzed on both the group and the individual level.

RESULTS

Group- and individual-level analysis resulted in different statistical outcomes, particularly with regard to load. Specifically, SDs within individuals were up to 7.63 times larger than SDs between individuals. In addition, at either level, the authors observed different correlations between load and recovery.

CONCLUSIONS

The results suggest that the process of load and recovery in athletes is nonergodic, which has important implications for the sports field. Recommendations for training programs of individual athletes may be suboptimal, or even erroneous, when guided by group-level outcomes. The utilization of individual-level analysis is key to ensure the optimal balance of individual load and recovery.

Exploring the Use of Mobile Athlete Self-report Measures in Elite Gaelic Games: A Qualitative Approach

ABSTRACT

Duignan, CM, Slevin, PJ, Caulfield, BM, and Blake, C. Exploring the use of mobile athlete self-report measures in elite Gaelic games: A qualitative approach. J Strength Cond Res 35(12): 3491-3499, 2021-Athlete self-report measures (ASRMs) are used in research and practice as an accurate, practical, and accessible method of athlete monitoring. Mobile adaptations of constructs from validated ASRM have increasingly been used for athlete monitoring in various sports settings; however, insights on the user experience and perceived value of these systems in the applied team sport setting have been limited. This study aimed to portray the experiences of stakeholders using a pre-existing mobile ASRM (M-ASRM) in elite Gaelic games. Twenty-one stakeholders in elite Gaelic games were recruited for this study (players n = 10, coaches and support staff n = 11). Subjects completed a semistructured interview with the lead researcher regarding their experience of using an M-ASRM in practice. Thematic analysis of the transcripts was conducted using NVivo 12 software. Results were defined under the themes of positive and negative user experience. Positive user experience was portrayed through M-ASRM uses and perceived value: communication and information disclosure, remote player monitoring, decision making and advanced planning, and player education and self-management. Negative user experience was portrayed through M-ASRM challenges: player adherence, player dishonesty, coach time and expertise requirements, and sociotechnical and system factors. Results outline the major uses of M-ASRM in elite Gaelic games and, importantly, highlight the key challenges experienced by stakeholders. These results can be applied by coaches, sports medicine professionals, and sports scientists using or intending to use an M-ASRM, providing key considerations to employ for effective use in team sport.

Developmental Training Model for the Sport Specialized Youth Athlete: A Dynamic Strategy for Individualizing Load-Response During Maturation

CONTEXT

Most available data on athletic development training models focus on adult or professional athletes, where increasing workload capacity and performance is a primary goal. Development pathways in youth athletes generally emphasize multisport participation rather than sport specialization to optimize motor skill acquisition and to minimize injury risk. Other models emphasize the need for accumulation of sport- and skill-specific hours to develop elite-level status. Despite recommendations against sport specialization, many youth athletes still specialize and need guidance on training and competition. Medical and sport professionals also recommend progressive, gradual increases in workloads to enhance resilience to the demands of high-level competition. There is no accepted model of risk stratification and return to play for training a specialized youth athlete through periods of injury and maturation. In this review, we present individualized training models for specialized youth athletes that (1) prioritize performance for healthy, resilient youth athletes and (2) are adaptable through vulnerable maturational periods and injury.

EVIDENCE ACQUISITION

Nonsystematic review with critical appraisal of existing literature.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 4.

RESULTS

A number of factors must be considered when developing training programs for young athletes: (1) the effect of sport specialization on athlete development and injury, (2) biological maturation, (3) motor and coordination deficits in specialized youth athletes, and (4) workload progressions and response to load.

CONCLUSION

Load-sensitive athletes with multiple risk factors may need medical evaluation, frequent monitoring, and a program designed to restore local tissue and sport-specific capacity. Load-naive athletes, who are often skeletally immature, will likely benefit from serial monitoring and should train and compete with caution, while load-tolerant athletes may only need occasional monitoring and progress to optimum loads.

STRENGTH OF RECOMMENDATION TAXONOMY (SORT)

B.

Effects of chronic betaine supplementation on performance in professional young soccer players during a competitive season: a double blind, randomized, placebo-controlled trial

OBJECTIVE

Various nutritional strategies are adopted for athletes to maintain and to improve performance during the competition season. Betaine may enhance performance during a competitive season by increasing the testosterone to cortisol ratio and reducing systemic inflammation. The aim of this study was to investigate the effect of betaine supplementation on the bio-motor abilities in young professional soccer players.

METHODS

Twenty-nine young professional soccer players (age, 15.5±0.3 years) were matched by position and randomly assigned to one of two groups for 14 weeks: betaine (BG, 2 g/day; n=14) or placebo (PG n=15). Diet was standardized by a nutritionist, and measures of muscular power (countermovement jump: CMJ), change of direction: modified 5-0-5), acceleration (10 m sprint), sprint performance (30 m sprint time: SpT), muscular strength (leg press and bench press one repetition maximum: 1-RM), repeated sprint ability (running-based anaerobic sprint test: RAST), and aerobic capacity (30-15 intermittent fitness test) were assessed in the pre (P1), mid (P2) and post (P3) season over the course of 5 days. All subjects participated in one soccer match and five training sessions per week.

RESULTS

Significant (p < 0.05) group x time interactions were found for maximal oxygen uptake (VO2max), anaerobic peak power, and muscular strength favoring BG at P2 and P3 compared to P1. There were meaningful (p < 0.05) group x time interactions for CMJ, SpT, and peak power during the RAST that favored the BG.

CONCLUSIONS

14-week of betaine supplementation increased predicted 1-RM, VO2max, and repeated sprint ability performance in youth professional soccer players. Betaine supplementation seems to be a useful nutritional strategy to improve and to maintain performance during a competitive soccer season.

Quantifying Sub-Elite Youth Football Weekly Training Load and Recovery Variation

Monitoring the training load in football is an important strategy to improve athletic performance and an effective training periodization. The aim of this study was two-fold: (1) to quantify the weekly training load and recovery status variations performed by under-15, under-17 and under-19 sub-elite young football players; and (2) to analyze the influence of age, training day, weekly microcycle, training and playing position on the training load and recovery status. Twenty under-15, twenty under-17 and twenty under-19 players were monitored over a 2-week period during the first month of the 2019–2020 competitive season. Global positioning system technology (GPS) was used to collect external training loads: total distance covered, average speed, maximal running speed, relative high-speed running distance, high metabolic load distance, sprinting distance, dynamic stress load, accelerations and decelerations. Internal training load was monitored using ratings of perceived exertion (RPE) and session rating of perceived exertion (sRPE). Recovery status was obtained using the total quality recovery (TQR) scale. The results show an age-related influence for external training load (p ≤ 0.001; d = 0.29–0.86; moderate to strong effect), internal training load (p ≤ 0.001, d = 0.12–0.69; minimum to strong effect) and recovery status (p ≤ 0.001, d = 0.59; strong effect). The external training load presented differences between training days (p < 0.05, d = 0.26–0.95; moderate to strong effect). The playing position had a minimum effect on the weekly training load (p < 0.05; d = 0.06–0.18). The weekly microcycle had a moderate effect in the TD (p < 0.05, d = 0.39), RPE (p < 0.05; d = 0.35) and sRPE (p < 0.05, d = 0.35). Interaction effects were found between the four factors analyzed for deceleration (F = 2.819, p = 0.017) and between inter-day, inter-week and age for total covered distance (F = 8.342, p = 0.008). This study provided specific insights about sub-elite youth football training load and recovery status to monitor training environments and load variations. Future research should include a longer monitoring period to assess training load and recovery variations across different season phases.

Intra- and Inter-week Variations of Well-Being Across a Season: A Cohort Study in Elite Youth Male Soccer Players

This study describes the weekly variations of well-being ratings relative to fatigue (wFatigue), stress (wStress), delayed-onset muscle soreness (wDOMS), sleep quality (wSleep), and Hooper questionnaire (wHQ) throughout the season. In addition, the well-being variables for the playing position in different moments of the season were discussed. Twenty-one elite young soccer players U17 took part in this study. From the beginning of the pre-season, well-being status was monitored daily by the HQ method throughout 36 weeks, including four periods: (1) pre-season, (2) early-season, (3) mid-season, and (4) end-season. Players trained at least 3 times per week throughout the season. The main outcome was that, in weeks 33 and 28, the highest [wFatigue: 15.85 ± 3.38 arbitrary units (AU); wHQ: 48.86 ± 9.23 AU] and the lowest (wFatigue: 5.38 ± 1.88 AU; wHQ: 20.43 ± 5.49 AU) wFatigue and wHQ occurred, respectively, although the lowest level of wDOMS happened in week 28 (4.86 ± 2.15 AU), while the highest wDOMS was observed in week 5 (14.65 ± 4.16 AU). The highest wSleep (13.00 ± 2.12 AU) and wStress (11.65 ± 2.92 AU) were observed in weeks 8 and 34, respectively, while the lowest wSleep (5.81 ± 2.29 AU) and wStress (3.76 ± 0.94 AU) were marked in week 29 coincidentally. In the HQ between every weekday, except recovery day, and the day of the match (MD), considerable highest HQ was only revealed in 2 days after MD in contrast to overall team comparison. In the present study, we observed that the well-being changes between different phases of the season as well as between weeks and days of the week with the MD are significant. These results provide a great point of view for coaches and practitioners about well-being variations over a season in elite youth soccer level. As a result, coaches will be more aware about non-functional overreaching and taking measures to prevent it.

Insufficient Sleep in Young Athletes? Causes, Consequences, and Potential Treatments

Sleep is essential in the preparation for, and the recovery from, training and competition. Despite being important for all individuals, young athletes are considered an at-risk group for reduced sleep duration and quality. The purpose of this review is to synthesise current literature relating to sleep duration and quality in young (14-25 years) athletes. Specifically, typical sleep and wake patterns, factors affecting sleep and wake patterns, and the consequences of altered sleep and wake patterns in young athletes are discussed. Scheduling training and competition in the afternoon or evening appears to result in reduced sleep duration due to less time in bed. Evidence suggests that young athletes who obtain less than 8 h of sleep per night are at a higher risk of musculoskeletal injury. An increase in sleep duration above habitual nightly sleep may be associated with favourable performance in young athletes; however, the associations between sleep quality and performance- and health-related outcomes remain unclear.

Decreased Sleep Is an Independent Predictor of In-Season Injury in Male Collegiate Basketball Players

Background:

Although decreased sleep has been associated with decreased performance, increased illness risk, and impaired well-being in athletes, the relationship between sleep and injury risk in collegiate athletes is unknown.

Purpose/Hypothesis:

To evaluate the independent effects of sleep duration and subjective well-being on in-season injury in male collegiate basketball athletes. We hypothesized that decreased sleep would be associated with an increased risk of in-season injury.

Study Design:

Cohort study; Level of evidence, 2.

Methods:

During 2 consecutive seasons, 19 male National Collegiate Athletic Association Division I basketball players reported mood, fatigue, stress, soreness, sleep duration (hours), and previous day’s training load every morning. Well-being measures were recorded on a scale from 0 (worst) to 5 (best), and all time-loss injuries were recorded by the team athletic trainer. Separate mixed-effects logistic regression models were used to evaluate the effects of sleep and subjective well-being on in-season injury, with adjustment for same-day training load and individual repeated measures. To determine the independence of sleep and well-being as predictors of injury, each well-being variable was included in a separate mixed-effects logistic regression model, with sleep and training load as covariates.

Results:

During the study period, 32 injuries were recorded. In the initial separate prediction models, in-season injury was significantly predicted by mood (odds ratio [OR], 0.50; 95% CI, 0.37-0.66), fatigue (OR, 0.44; 95% CI, 0.33-0.59), stress (OR, 0.57; 95% CI, 0.42-0.76), soreness (OR, 0.41; 95% CI, 0.32-0.54), and sleep duration (OR, 0.57; 95% CI, 0.49-0.66) (P < .001 for all). In the multivariable models, sleep duration remained a significant, independent predictor in each of the subsequent multivariable models (OR, 0.52-0.69; P < .001 for all) as did soreness (OR, 0.65; 95% CI, 0.44-0.95; P = .024), whereas mood (OR, 1.2; 95% CI, 0.76-1.9; P = .43), fatigue (OR, 1.1; 95% CI, 0.65-1.9; P = .68), and stress (OR, 1.1; 95% CI, 0.75-1.5; P = .69) were no longer significant.

Conclusion:

Increased sleep duration is independently associated with a reduced risk of in-season injury in male collegiate basketball players, even after adjustment for training load and subjective well-being. The effects of mood, fatigue, and stress on injury were no longer evident after adjustment for the effect of sleep duration.

Mental Health in the Young Athlete

PURPOSE OF REVIEW

The goal of the present paper is to provide a comprehensive overview of mental health concerns in young athletes, with a focus on common disorders, as well as population-specific risk factors.

RECENT FINDINGS

Athletes experience similar mental health concerns as non-athlete peers, such as anxiety, depression and suicidal ideation, ADHD, eating disorders, and substance abuse. However, they also experience unique stressors that put them at risk for the development or exacerbation of mental health disorders. Student athletes have to balance academics with rigorous training regimens while focusing on optimal performance and managing high expectations. Physical injuries, overtraining, concussion, sleep disorders, and social identity are some of the factors that also impact the mental health of student athletes. Existing literature highlights the need to develop proactive mental health and wellness education for young athletes, and to develop services that recognize the unique needs of this population.

COVID-19 Surveillance and Competition in Sport: Utilizing Sport Science to Protect Athletes and Staff during and after the Pandemic

The ongoing Coronavirus 2 (COVID-19) pandemic abruptly halted athletic competition and standard training practices, consequently generating great confusion surrounding when and how to safely reintroduce sports. Therefore, tangible solutions disseminated to performance staff, coaches, and athletes are warranted to ensure optimal levels of health and physical performance for all personnel during both the current social distancing standards as well as the impending return of competition despite continued risks. In this commentary, we offer strategies for utilizing technology and data tools as components of longitudinal COVID-19 surveillance based on ongoing research efforts as well as current guidance from governing bodies, while also serving the performance needs of the athletes and staff. Recommended data sources include digital symptom and well-being surveys, standardized and routine physical performance testing, sleep and sleep physiology monitoring, cognitive applications, and temperature. This system is flexible to numerous commercially available products and is designed for easy implementation that permits instant feedback provided directly to the athlete as well as their support staff for early intervention, ultimately mitigating COVID-19 risks. We will discuss multiple options, including examples of data, data visualizations and recommendations for data interpretation and communication.

Effect of Mindfulness on the Stress–Recovery Balance in Professional Soccer Players during the Competitive Season

Professional athletes are subjected to constant stress that often leads them to exceed their capacities and lose their homeostasis, which without a proper recovery program can lead to injury, chronic fatigue, and overtraining. This work examines the effect of six weeks of a psychological intervention called Mindful Sports Performance Enhancement (MSPE), on the stress–recovery balance in professional soccer players during a competitive season. Methods: The RESTQ-76 Sport psychometric questionnaire and heart rate variability (HRV) were used as psychometric and physiological evaluation methods. Under a longitudinal case–control study and having complied with bioethical procedures, 42 professional soccer players (22 control without treatment and 20 experimental), age 17 ± 1 year, weight 63 ± 11 kg, and height 172 ± 7 cm, were analyzed. Results: RESTQ-76 Sport increased the stress–recovery balance and global recovery (p < 0.5), but decreased global stress. The stress–recovery balance values measured by the nonlinear indicators of the HRV: SD1, SD2, SS, and S:PS, were not modified. Conclusions: Six weeks of MSPE improves the stress–recovery balance in third-division professional soccer players during the competitive season, reduces stress, and increases recovery. These positive effects were not observed in the nonlinear indicators of the HRV: SD1, SD2, SS, and S:PS.

Mitigating the Antecedents of Sports-related Injury through Yoga

Context:

Injury risk among athletes is an epidemic. The psychological and physical loads imposed on athletes through psychosocial stressors and training regimens significantly increase athletes' injury risk.

Aims:

This feasibility study assessed whether a 10-week yoga intervention could be implemented successfully and mitigated antecedents of sports injury.

Methods:

Using a prospective, nonexperimental design, 31 male soccer players attending a college in the Pacific Northwest enrolled in the yoga intervention. The Recovery-Stress Questionnaire for Athletes (RESTQ-Sport) was completed at three time-points before and after the yoga intervention. The RESTQ-Sport scales, identified as strongest predictors for injury, were hypothesized to be mitigated through yoga.

Results:

Two stress-related scales were significant in the hypothesized direction: injury and fatigue. The general recovery scale, General Well-Being, was significant at one time-point, but in the opposite direction as hypothesized.

Conclusions:

Positive findings are discussed and explanations for unexpected changes are explored, along with study limitations. Results suggest that yoga can be successfully integrated into the athletic program of soccer players and provisionally support the potential of a yoga intervention to mitigate two significant antecedents of injury, namely, perception of propensity to sustain injury and generalized fatigue.

Circulating, Cell-Free DNA for Monitoring Player Load in Professional Football

Purpose: Player monitoring in elite sport settings is becoming increasingly important. Questionnaire-based methods and biomarkers such as circulating, cell-free DNA (cfDNA) are suggested for load monitoring. cfDNA concentrations were shown to increase depending on total distance covered in football and were associated with overtraining in weight lifters. Thus, the objective of this study was to examine whether cfDNA is feasible as a monitoring tool in elite football players. Methods: Capillary blood samples from 22 male elite football players were collected over 4 mo of a regular season. Sampling was conducted the day before, 1 day after, or several days after regular-season games and/or training. In addition, each player filled in a visual analogue scale (VAS) questionnaire including the items "general perceived exertion," "muscular fatigue," and "mental fatigue." Performance during training and games was tracked by the Catapult system and with the OPTA system, respectively. Results: cfDNA values were significantly elevated in players the day after regular-season games (1.4-fold; P = .0004) in line with the scores of the VAS. Both parameters showed significantly higher values during midweek-game weeks. cfDNA concentrations correlated with training data, and VAS was correlated with the tracking of the season games. However, cfDNA and VAS did not correlate with each other. Conclusions: cfDNA concentrations at rest and VAS scores are influenced by previous load in professional football players. Future studies will reveal whether cfDNA might serve as a practically applicable marker for player load in football players.

Subjective and Objective Responses to Two Rugby Sevens World Series Competitions

Fowler, PM, Murray, A, Farooq, A, Lumley, N, and Taylor, L. Subjective and objective responses to two rugby sevens world series competitions. J Strength Cond Res 33(4): 1043-1055, 2019-The purpose was to examine the utility of subjective and objective measures of player preparedness, interpreted at both group level and individual level, during 2 consecutive competitions of the World Rugby Sevens Series (WRSS). Subjective (sleep, energy, and muscle soreness ratings) and objective (heart rate [HR] at rest [HRREST] and in response to submaximal exercise [HREX]) measures were obtained from 16 male rugby 7s players from 1 team for 3 consecutive days (D1-3) at home (HOME) and on arrival at 4 tournament (T1-4) locations (T1-New Zealand; T2-USA; T3-Hong Kong; and T4-Tokyo) across 2 WRSS competitions (2 tournaments per competition) separated by 1 month. At a group level, energy ratings were significantly lower in T2 and T4 compared with HOME, and on D1 T2 compared with D1 T1 (p ≤ 0.05). Greatest variability in subjective ratings was observed during T1 and T3 at an individual level, particularly for sleep quality. Although at a group level HRREST and HREX significantly decreased in T1-4 compared with HOME (p ≤ 0.05), there was only a ∼50% agreement between the direction of change in HR indices at an individual level. Results from this study suggest that relocation between tournaments within WRSS competitions disrupts player preparedness measures to the largest degree. Hence, this period could be targeted by practitioners with appropriate recovery and/or sleep-promoting interventions or modulation of match-/training-load. Moreover, subjective rather than objective measures seem to be of greater use to inform player preparedness decision making, particularly at an individual level compared with a group level.

Match Fatigue Time-Course Assessment Over Four Days: Usefulness of the Hooper Index and Heart Rate Variability in Professional Soccer Players

The aims of the present study were to (a) examine recovery time-course and (b) analyze the usefulness of the Hooper-Index (wellness index) and resting heart rate variability (HRV) in professional soccer players during an in-season phase. The Hooper-Index and resting HRV were collected on matchday and on the four following days in three consecutive in-season weeks in nine players (25.2 ± 4.3-years). The usefulness of monitoring variables was assessed by (a) comparing noise (typical error, TE) to the smallest worthwhile change (SWC) (TE/SWC) and (b) comparing match-related changes (i.e., signal) to TE (i.e., signal-to-noise ratio). Between-days standardized differences in the changes of Hooper-Index and HRV were compared to the SWC using magnitude-based inferences. The magnitudes of TE were small and moderate for the Hooper-Index and HRV, respectively. The Hooper-Index showed to be more useful than HRV for monitoring match-induced fatigue as having a lower TE/SWC (3.1 versus 4.4) and a higher signal-to-noise ratio (5.5 versus 1.5). Small-to-very large [range of effect sizes, 0.48; 2.43, confidence limits (0.22; 2.91)] and moderate-to-large [-1.71; -0.61 (-2.44; -0.03)] detrimental changes in Hooper-Index and HRV, respectively, were observed on the days following matchday. While group analyses showed a similar pattern for recovery time-course, more individual players responded, similarly when tracked using the Hooper -Index compared to when they were tracked using HRV. An inverse moderate within-individual relationship was observed between changes in the Hooper index and HRV [r = -0.41, (-0.60, 0.18)]. The Hooper index is an easy-to-use, no-cost, and non-invasive monitoring tool and seems promising for tracking match-induced fatigue during in the season in professional soccer.

Submaximal heart rate seems inadequate to prescribe and monitor intensified training

The aim of this study is to investigate whether the change in (sub)maximal heart rate after intensified training is associated with the change in performance. Thirty subjects were recruited who performed cardiopulmonary exercise tests to exhaustion 2 weeks before (pre), 1 week after (post) and 5 weeks after (follow-up) an 8-day non-competitive amateur cycling event (TFL). The exercise volume during the TFL was 7.7 fold the volume during the preparation period. Heart rate and cardiopulmonary parameters were obtained at standardised absolute submaximal workloads (low, medium and high intensity) and at peak level each test. Subjects were classified as functionally overreached (FOR) or acute fatigued (AF) based on the change in performance. No differences between FOR and AF were observed for heart rate (P = .51). On total group level (AF + FOR), post-TFL heart rate decreased significantly at low (-4.4 beats·min^-1, 95% CI [-8.7, -0.1]) and medium (-5.5 beats·min^-1 [-8.5, -2.4]), but not at high intensity. Peak heart rate decreased -3.4 beats·min^-1 [-6.1, -0.7]. O₂pulse was on average 0.49 ml O₂·beat^-1 [0.09, 0.89] higher at all intensities after intensified training. No changes in ⩒O₂ (P = .44) or the ventilatory threshold (P = .21) were observed. Pearson's correlation coefficients revealed negative associations between heart rate and O₂pulse at low (r = -.56, P < .01) and medium intensity (r = -.54, P < .01), but not with ⩒O₂ or any other submaximal parameter. (Sub)maximal heart rate decreased after the TFL. However, this decrease is unrelated to the change in performance. Therefore, heart rate seems inadequate to prescribe and monitor intensified training.

Which parameters to use for sleep quality monitoring in team sport athletes? A systematic review and meta-analysis

Background

Sleep quality is an essential component of athlete's recovery. However, a better understanding of the parameters to adequately quantify sleep quality in team sport athletes is clearly warranted.

Objective

To identify which parameters to use for sleep quality monitoring in team sport athletes.

Methods

Systematic searches for articles reporting the qualitative markers related to sleep in team sport athletes were conducted in PubMed, Scopus, SPORTDiscus and Web of Science online databases. The systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. For the meta-analysis, effect sizes with 95% CI were calculated and heterogeneity was assessed using a random-effects model. The coefficient of variation (CV) with 95% CI was also calculated to assess the level of instability of each parameter.

Results

In general, 30 measuring instruments were used for monitoring sleep quality. A meta-analysis was undertaken on 15 of these parameters. Four objective parameters inferred by actigraphy had significant results (sleep efficiency with small CV and sleep latency, wake episodes and total wake episode duration with large CV). Six subjective parameters obtained from questionnaires and scales also had meaningful results (Pittsburgh Sleep Quality Index (sleep efficiency), Likert scale (Hooper), Likert scale (no reference), Liverpool Jet-Lag Questionnaire, Liverpool Jet-Lag Questionnaire (sleep rating) and RESTQ (sleep quality)).

Conclusions

These data suggest that sleep efficiency using actigraphy, Pittsburgh Sleep Quality Index, Likert scale, Liverpool Jet-Lag Questionnaire and RESTQ are indicated to monitor sleep quality in team sport athletes.

PROSPERO registration number

CRD42018083941.

Association between late-night tweeting and next-day game performance among professional basketball players

OBJECTIVES

In sports, decreased sleep duration is generally associated with poorer performance compared to adequate or enhanced sleep duration. Yet, these findings have primarily been taken from small numbers of athletes performing outside of real games or competitions. It remains unknown how acute decreased sleep duration impacts real-game performance among professional athletes. Here, we merged 2 publicly available datasets to jointly measure late-night social media activity (a proxy for sleep deprivation) and next-day game performance.

SETTING

Professional basketball competition.

PARTICIPANTS

112 players from the National Basketball Association.

MEASUREMENTS

Time-stamped social media activity and in-game individual performance statistics.

RESULTS

Late-night tweeting (compared to not late-night tweeting) is associated with within-person reductions in next-day game performance, including fewer points scored and fewer rebounds. However, we also observe less time played per game following late-night tweets and decreases in the negative outputs of turnovers and personal fouls. The critical measure of shooting accuracy - which is not time dependent - provides the clearest evidence of a performance penalty following late-night tweeting activity (between 11:00 pm and 7:00 am); players successfully make shots at a rate 1.7 percentage points less following late-night tweeting.

CONCLUSIONS

Our findings suggest that acute sleep deprivation, as measured via late-night Twitter activity, is associated with changes in next-day game performance among professional National Basketball Association athletes. More broadly, the use of late-night social media activity may serve as a useful general proxy for sleep deprivation in other social, occupational, and physical performance-based contexts.

Organized Chaos in Late Specialization Team Sports: Weekly Training Loads of Elite Adolescent Rugby Union Players

Phibbs, PJ, Jones, B, Roe, G, Read, DB, Darrall-Jones, J, Weakley, J, Rock, A, and Till, K. Organized chaos in late specialization team sports: weekly training loads of elite adolescent rugby union players. J Strength Cond Res 32(5): 1316-1323, 2018-The aim of this study was to quantify the mean weekly training load (TL) of elite adolescent rugby union players participating in multiple teams and examine the differences between playing positions. Twenty elite male adolescent rugby union players (17.4 ± 0.7 years) were recruited from a regional academy and categorized by playing position: forwards (n = 10) and backs (n = 10). Global positioning system and accelerometer microtechnology was used to quantify external TL, and session rating of perceived exertion (sRPE) was used to quantify internal TL during all sessions throughout a 10-week in-season period. A total of 97 complete observations (5 ± 3 weeks per participant) were analyzed, and differences between positions were assessed using Cohen's d effect sizes (ES) and magnitude-based inferences. Mean weekly sRPE was 1,217 ± 364 arbitrary units (AU) (between-subject coefficient of variation [CV] = 30%), with a total distance (TD) of 11,629 ± 3,445 m (CV = 30%), and PlayerLoad (PL) of 1,124 ± 330 AU (CV = 29%). Within-subject CV ranged between 5 and 78% for sRPE, 24 and 82% for TD, and 19 and 84% for PL. Mean TD (13,063 ± 3,933 vs. 10,195 ± 2,242 m) and PL (1,246 ± 345 vs. 1,002 ± 279 AU) were both likely greater for backs compared with forwards (moderate ES); however, differences in sRPE were unclear (small ES). Although mean internal TLs and volumes were low, external TLs were higher than previously reported during preseason and in-season periods in senior professional players. Additionally, the large between-subject and within-subject variation in weekly TL suggests that players participate in a chaotic training system.

Relation Between Training Load and Recovery-Stress State in High-Performance Swimming

Background: The relation between training load, especially internal load, and the recovery-stress state is of central importance for avoiding negative adaptations in high-performance sports like swimming. The aim of this study was to analyze the individual time-delayed linear effect relationship between training load and recovery-stress state with single case time series methods and to monitor the acute recovery-stress state of high-performance swimmers in an economical and multidimensional manner over a macro cycle. The Acute Recovery and Stress Scale (ARSS) was used for daily monitoring of the recovery-stress state. The methods session-RPE (sRPE) and acute:chronic workload-ratio (ACWR) were used to compare different methods for quantifying the internal training load with regard to their interrelationship with the recovery-stress state. Methods: Internal load and recovery-stress state of five highly trained female swimmers [with a training frequency of 13.6 ± 0.8 sessions per week and specializing in sprint (50 and 100 m), middle-distance (200 and 400 m), or long distance (800 and 1,500 m) events] were daily documented over 17 weeks. Two different types of sRPE were applied: RPE^∗duration (sRPE^h) and RPE^∗volume (sRPE^km). Subsequently, we calculated the ratios ACWR^h and ACWR^km (sRPE last week: 4-week exponentially weighted moving average). The recovery-stress state was measured by using the ARSS, consisting of eight scales, four of which are related to recovery [Physical Performance Capability (PPC), Mental Performance Capability (MPC), Emotional Balance (EB), Overall Recovery (OR)], and four to stress [Muscular Stress (MS), Lack of Activation (LA), Negative Emotional State (NES), Overall Stress (OS)]. To examine the relation between training load and recovery-stress state a cross correlation (CCC) was conducted with sRPE^h, sRPE^km, ACWR^h, and ACWR^km as lead and the eight ARSS-scales as lag variables. Results: A large variation of training load can be observed in the individual week-to-week fluctuations whereby the single fluctuations can significantly differ from the overall mean of the group. The range also shows that the CCC individually reaches values above 0.3, especially with sRPE^km as lead variable. Overall, there is a large range with significant differences between the recovery and stress dimensions of the ARSS and between the training load methods, with sRPE^km having the largest span (Range = 1.16). High inter-individual differences between the athletes lie in strength and direction of the correlation | 0.66|≤ CCC ≥|-0.50|. The time delayed effects (lags 0-7) are highly individual, however, clear patterns can be observed. Conclusion: The ARSS, especially the physical and overall-related scales (PPC, OR, MS, OS), is a suitable tool for monitoring the acute recovery-stress state in swimmers. MPC, EB, LA, and NES are less affected by training induced changes. Comparably high CCC and Ranges result from the four internal load methods, whereby sRPE, especially sRPE^km, shows a stronger relation to recovery-stress state than ACWR. Based on these results and the individual differences in terms of time delay in training response, we recommend for swimming to use sRPE to monitor the internal training load and to use the ARSS, with a focus at the physical and overall-scales, to monitor the recovery-stress state.

Training Load and Fatigue Marker Associations with Injury and Illness: A Systematic Review of Longitudinal Studies

Background

Coaches, sport scientists, clinicians and medical personnel face a constant challenge to prescribe sufficient training load to produce training adaption while minimising fatigue, performance inhibition and risk of injury/illness.

Objective

The aim of this review was to investigate the relationship between injury and illness and longitudinal training load and fatigue markers in sporting populations.

Methods

Systematic searches of the Web of Science and PubMed online databases to August 2015 were conducted for articles reporting relationships between training load/fatigue measures and injury/illness in athlete populations.

Results

From the initial 5943 articles identified, 2863 duplicates were removed, followed by a further 2833 articles from title and abstract selection. Manual searching of the reference lists of the remaining 247 articles, together with use of the Google Scholar ‘cited by’ tool, yielded 205 extra articles deemed worthy of assessment. Sixty-eight studies were subsequently selected for inclusion in this study, of which 45 investigated injury only, 17 investigated illness only, and 6 investigated both injury and illness. This systematic review highlighted a number of key findings, including disparity within the literature regarding the use of various terminologies such as training load, fatigue, injury and illness. Athletes are at an increased risk of injury/illness at key stages in their training and competition, including periods of training load intensification and periods of accumulated training loads.

Conclusions

Further investigation of individual athlete characteristics is required due to their impact on internal training load and, therefore, susceptibility to injury/illness.

Longitudinal motor performance development in early adolescence and its relationship to adult success: An 8-year prospective study of highly talented soccer players

Several talent identification and development (TID) programs in soccer have implemented diagnostics to measure players’ motor performance. Yet, there is a lack of research investigating the relationship between motor development in adolescence and future, adult performance. This longitudinal study analyzed the three-year development of highly talented young soccer players’ speed abilities and technical skills and examined the relevance of this development to their adult success. The current research sample consisted of N = 1,134 players born between 1993 and 1995 who were selected for the German Soccer Association’s TID program and participated in nationwide motor diagnostics (sprinting, agility, dribbling, ball control, shooting) four times between the Under 12 (U12) and Under 15 (U15) age class. Relative age (RA) was assessed for all players, and a total motor score was calculated based on performances in the individual tests. In order to investigate players’ future success, participants were divided into two groups according to their adult performance level (APL) in the 2014/2015 season: Elite (1st-5th German division; N = 145, 12.8%) and non-elite players (lower divisions; N = 989, 87.2%). Using multilevel regression analyses each motor performance was predicted by Time, Time² (level-1 predictors), APL, and RA (level-2 covariates) with simultaneous consideration for interaction effects between the respective variables. Time and Time² were significant predictors for each test performance. A predictive value for RA was confirmed for sprinting and the total motor score. A significant relationship between APL and the motor score as well as between APL and agility, dribbling, ball control, and shooting emerged. Interaction effects distinctly failed to reach significance. The study found a non-linear improvement in players’ performance for all considered motor performance factors over a three-year period from early to middle adolescence. While their predictive value for future success was confirmed by a significant relationship between APL and most of the considered factors, there was no significant interaction between APL and Time. These findings indicate that future elite players had already been better at the beginning of the TID program and maintained this high level throughout their promotion from U12 to U15.

The influence of training load, exposure to match play and sleep duration on daily wellbeing measures in youth athletes

This study assessed the influence of training load, exposure to match play and sleep duration on two daily wellbeing measures in youth athletes. Forty-eight youth athletes (age 17.3 ± 0.5 years) completed a daily wellbeing questionnaire (DWB), the Perceived Recovery Status scale (PRS), and provided details on the previous day's training loads (TL) and self-reported sleep duration (sleep) every day for 13 weeks (n = 2727). Linear mixed models assessed the effect of TL, exposure to match play and sleep on DWB and PRS. An increase in TL had a most likely small effect on muscle soreness (d = -0.43;± 0.10) and PRS (d = -0.37;± 0.09). Match play had a likely small additive effect on muscle soreness (d = -0.26;± 0.09) and PRS (d = -0.25;± 0.08). An increase in sleep had a most likely moderate effect on sleep quality (d = 0.80;± 0.14); a most likely small effect on DWB (d = 0.45;± 0.09) and fatigue (d = 0.42;± 0.11); and a likely small effect on PRS (d = 0.25;± 0.09). All other effects were trivial or did not reach the pre-determined threshold for practical significance. The influence of sleep on multiple DWB subscales and the PRS suggests that practitioners should consider the recovery of an athlete alongside the training stress imposed when considering deviations in wellbeing measures.

Training Load, Physical Performance, Biochemical Markers, and Psychological Stress During a Short Preparatory Period in Brazilian Elite Male Volleyball Players

Horta, TAG, Bara Filho, MG, Coimbra, DR, Miranda, R, and Werneck, FZ. Training load, physical performance, biochemical markers, and psychological stress during a short preparatory period in Brazilian elite male volleyball players. J Strength Cond Res 33(12): 3392-3399, 2019-The aim of this study was to assess the relationship between training load (TL) and physical performance, biochemical markers, and psychological stress during a short preparatory period (SPP) in Brazilian elite male volleyball players. Twelve volleyball players from a team competing in the Brazilian Men's Volleyball Super League were enrolled (26.9 ± 4.6 years). Countermovement jump (CMJ), creatine kinase (CK), testosterone (T), cortisol (Cr), T/Cr ratio, and Recovery and Stress Questionnaire for athletes (RESTQ-Sport) were collected at baseline, after second, fourth, and sixth week. Training load was quantified daily using the rating of perceived exertion. Differences were noted between total weekly training load (TWTL) (F3,33 = 50.907; p = 0.0001), CK (F3,33 = 16.157; p = 0.0001), and T (F3,33 = 3.283; p = 0.03). No differences were seen in CMJ (F3,33 = 1.821; p = 0.16), Cr (F3,33 = 2.409; p = 0.08), or T/Cr ratio (F3,33 = 1.527; p = 0.23). The RESTQ-Sport demonstrated differences between moments in social stress (F3,33 = 2.297; p = 0.04; η = 0.25), success (F3,33 = 4.350; p = 0.01; η = 0.19), general well-being (F3,33 = 4.465; p = 0.01; η = 0.36), and injury (F3,33 = 2.792; p = 0.05; η = 0.62). The results showed a significant correlations of small to moderate magnitude between TWTL and CK (r = 0.32; p = 0.05). In conclusion, a short PP in volleyball leads to increased TL, CK level, and psychological stress. Training load was related with the increase of CK, suggesting muscle damage without increased physical performance.

Comparisons of Perceived Training Doses in Champion Collegiate-Level Male and Female Cross-country Runners and Coaches over the Course of a Competitive Season

Background

Session rating of perceived exertion (sRPE) is a practical tool for coaches to assess internal training load of their athletes. In a sport like cross-country running, that is individual in nature, but has a team training and competition component, information about the association between external and internal load is lacking. Furthermore, there is a need for studies that examine perception of training doses across multiple training cycles including the competitive season as well as between male and female athletes.

Methods

Session RPE, duration, and training load (TL_RPE = sRPE × duration) of 25 highly trained male and female cross-country runners and their coaches were recorded for every training session (110 days) throughout a collegiate cross-country season. Intensity (sRPE), duration, and TL_RPE were compared between coaches and runners by gender separately. Training sessions were also analyzed by those intended by the coaches to be easy, moderate, and hard as well as by training period.

Results

Data from 3024 training sessions were collected, 62% of which were considered “easy,” 18% “moderate,” and 20% “hard.” Men and women rated coach-intended easy sessions significantly harder during each month of the season (effect size (ES) > 2.9, p < 0.0001). Men rated moderate intensity sessions significantly higher than coaches (ES ≥ 1.0, p ≤ 0.002), whereas females rated hard intensity sessions significantly lower than coaches (ES > 0.5, p < 0.008). There was no difference between males and coach’s hard sessions (ES < 0.07, p > 0.05) or females and coach’s moderate sessions (ES < 0.18, p > 0.05). Training intensity and TL_RPE tended to increase throughout the season (p > 0.05), with a significant increase in moderate and hard intensity sessions in the last training period (p < 0.001).

Conclusions

The results indicate the male and female cross-country runners tend to regress to moderate intensity training throughout the cross-country season. Given the success of the athletes in this study, these results show how a simple system for monitoring training such as the sRPE method may improve control of training variables and provide a useful tool for coaches to evaluate training load placed on athletes in a simple, responsive way.

Changes of Swimmers' Emotional States during the Preparation of National Championship: Do Recovery-Stress States Matter?

This study examined the trajectories of emotional states and their within-person synergies with perceived stress and recovery during a 4-month training period preceding the French swimming championships. A Multilevel Growth Curve Analysis approach was used with 16 high level swimmers. Five waves of assessments of emotional states, perceived stress and recovery were completed. Results indicated that emotional states were characterized by distinct trajectories during the training period preceding a major competition. Specifically, significant positive linear effects of time (i.e., linear increase over time) and negative quadratic effects of squared time (i.e., inverted U shape over time) on anxiety, dejection and anger were observed, whereas the opposite pattern of results was found for happiness and excitement. Moreover, level 2 perceived stress and recovery (i.e., inter-individual predictors) were significantly associated with athletes' unpleasant and pleasant emotional states respectively. At level 1, perceived recovery (i.e., intra-individual predictor) was positively associated with happiness and excitement and negatively related to anxiety, dejection and anger. Finally, within-person interactions of general stress and recovery with time and squared time reached significance for excitement, whereas within-person interactions of specific and total stress with time and squared time reached significance for anxiety. Overall, this study provided insights into the central role played by perceived stress and recovery on the emotional states experienced by high level swimmers. Operational strategies were suggested in order to optimize the stress-recovery balance and in turn the athletes' emotional states during a complete training program.

Development of two short measures for recovery and stress in sport

The Acute Recovery and Stress Scale (ARSS) and the Short Recovery and Stress Scale were first established in German for the purposes of monitoring athletes' current recovery-stress states in an economical and multidimensional manner. The aim of this paper is to document the development and initial validation of the English versions of these two psychometric monitoring tools. A total of 267 English-speaking athletes from a variety of team and individual sports participated in the study. The English versions demonstrated satisfactory internal consistency for both instruments (Cronbach α of .74-.89). Furthermore, good model fit was found for the eight scales of the ARSS, matching the structure and results of the German counterparts. Correlations among and between the scales reciprocate the theoretical constructs of stress and recovery, supporting the construct validity of the scales. Correlation coefficients within stress and recovery ranged between r_s = .29 and .68. The correlations between stress and recovery varied between r_s = -.29 and -.64. These constructs were further supported by correlations with the scores of the Recovery-Stress Questionnaire for Athletes, thereby showing convergent validity. The findings demonstrate initial validity and reliability of the two measures and reflect the results of the German versions. However, further research is needed before applying these scales in practical settings.

How much is too much? (Part 2) International Olympic Committee consensus statement on load in sport and risk of illness

The modern-day athlete participating in elite sports is exposed to high training loads and increasingly saturated competition calendar. Emerging evidence indicates that inappropriate load management is a significant risk factor for acute illness and the overtraining syndrome. The IOC convened an expert group to review the scientific evidence for the relationship of load—including rapid changes in training and competition load, competition calendar congestion, psychological load and travel—and health outcomes in sport. This paper summarises the results linking load to risk of illness and overtraining in athletes, and provides athletes, coaches and support staff with practical guidelines for appropriate load management to reduce the risk of illness and overtraining in sport. These include guidelines for prescription of training and competition load, as well as for monitoring of training, competition and psychological load, athlete well-being and illness. In the process, urgent research priorities were identified.

Effect of Post-Exercise Whole Body Vibration with Stretching on Mood State, Fatigue, and Soreness in Collegiate Swimmers

Static stretching (SS) during whole body vibration (WBV) has been suggested for exercise recovery. The purpose was to compare post-exercise self-ratings of fatigue (FAT), mood state (BAM), soreness (SOR), and perceived exertion (RPE) between SS and WBV+SS in swimmers (9 women, mean ± SD: 19.3 ± 1.3 year, 171 ± 5.7 cm, 67.6 ± 7.2 kg, 26.6 ± 4.1 %body fat (%BF); 10 men, mean ± SD: 19.7 ± 1.0 year, 183 ± 5.5 cm, 77.1 ± 4.2 kg, 13.1 ± 2.2 %BF). Athletes were divided by sex, event (sprint, distance), and assigned to SS or WBV+SS. Both conditions consisted of SS performed on the WBV platform with or without WBV (50 Hz, 6 mm). Sessions consisted of: pre and post measures of BAM, FAT, SOR; the condition; and RPE. Mixed factorial ANOVA were run. A significant condition by pre/post interaction was observed (p = 0.035). Post hoc analyses showed WBV+SS elicited lower post-exercise ratings of FAT (p = 0.002) and the BAM affective states, of tension (p = 0.031), and fatigue (p = 0.087). RPE did not differ between conditions. Of interest is the decrease in tension and fatigue noted by the BAM. Mood state can be indicative of how athletes adapt to training volume and intensity.