Managing player load in professional rugby union: a review of current knowledge and practices

Macronutrient requirements and intake by professional male rugby players

BACKGROUND

Rugby union is a high-contact team sport where professional rugby players are exposed to considerable training and game loads in pre-season and in-season. Some studies have shown that rugby players' dietary intake remains inadequate for the three macronutrients (carbohydrates [CHO], proteins and fats) required for optimal performance. This study aimed to describe the macronutrient intake of professional male rugby players at Zebre Rugby Club in Parma, Italy, during in-season, and to compare players' macronutrient intake to international recommendations.

METHODS

Thirty-four professional male rugby players participated in the cross-sectional study. A self-developed questionnaire, a food frequency questionnaire and food records (on training and competition days and off day) were used to investigate players' macronutrient intake. Anthropometric measurements were obtained using the International Society for the Advancement of Kinanthropometry (ISAK) standardized techniques. Descriptive statistics were calculated, and associations were investigated using chi-square, Fisher's exact and Wilcoxon rank tests as applicable.

RESULTS

The players' median age was 25.8 years (range 20.6-33.0 years) and 47.5% were Italian. Most players (64.7%) held forward positions and had a median of 5 years (range 2-14 years) of professional experience. More than 75.0% of players lived with a spouse or partner and 30.3% earned between 4 000-4 999 euros per month. The median body weight and height of players were 106.9 kg and 186.3 cm, respectively. The forwards weighed heavier (p < 0.0001) than the backs, which was expected due to positional demands, with no significant difference in height distribution. The median body mass index (p < 0.0001), waist circumference (p < 0.001) and waist-to-height ratio (p < 0.03) of forwards were higher than the backs. Additionally, the median body fat percentage of all players exceeded the international recommendation of 8-17% for rugby union players. The American College of Sports Medicine (ACSM), International Olympic Committee (IOC) and International Society of Sports Nutrition (ISSN) recommend an intake of 5.0-8.0 g/kg body weight (BW)/day CHO, 1.5-2.0 g/kg BW/day proteins and 20-35% total energy (TE) from fats for rugby players. The overall median intake of the three-day food records for all the players was 2.7 g/kg BW CHO, 1.7 g/kg BW protein and 35.1% TE from fat. On each of the three reported days, 90.0% of players' CHO intake fell below the recommended range, with almost all players (>90.0%) consuming less than the recommended amount of carbohydrates and almost 30.0% of players consuming below the recommended amount of protein on competition day. At least 50.0% of players' protein and fat intake was within the recommended range on each of the three reported days.

CONCLUSION

The study's findings can assist various stakeholders at Zebre Rugby Club to align rugby players' dietary requirements to their workload, and encourage players' adherence to dietary guidelines and recommendations. It is advised that attention be focused on accurate dietary education, intake and monitoring to promote individualization and optimal performance and recovery. Future research is needed to adapt standardized macronutrient recommendations for rugby-specific requirements and address obstacles that may impede the optimal intake of macronutrients.

Comparison of Injuries in the First 3 Years of Premier Rugby Sevens Between Male and Female Players

BACKGROUND

Premier Rugby Sevens (PR7S) is a new professional rugby league. Our study aims to examine injury data from PR7S over the last 3 years to clarify the incidence of injury per event and determine any trends within injuries to specific body regions related to both sex and year of competition. Understanding these injury patterns will assure relevant player education campaigns related to injury awareness, inform sex-specific injury prevention strategies, and help medical professionals care for athletes more effectively in future competitions.

HYPOTHESIS

There will be a difference in injury patterns and data between men and women throughout the last 3 years of data.

STUDY DESIGN

Cohort study.

LEVEL OF EVIDENCE

Level 3.

METHODS

This is a cohort study including the whole population of athletes from PR7S from 2021 to 2023. After each of the 9 events, athletes filled out a postevent injury form in Health Insurance Portability and Accountability Act compliant electronic health record with their team athletic trainer which included name, date of birth, event, injury type, and location of injury.

RESULTS

When comparing injury rates year to year, there was a statistically significant increase from 7 to 62 injuries among female athletes (P = 0.004). The number of injuries in male athletes stayed relatively the same. Despite having 432 athletes for both sexes, lower extremity injuries in female athletes have increased each year, whereas male athlete lower extremity injuries have stayed roughly the same throughout the study.

CONCLUSION

There were statistically more injuries in female athletes compared with male athletes.

CLINICAL RELEVANCE

These results are similar to other studies including other sports showing increased lower extremity injuries among female athletes compared with male athletes. More research needs to be done to evaluate the causes of increased injuries into to develop prevention strategies in rugby and in other sports.

Quantifying Trunk Impact Dynamics and Workload with Inertial Sensors in Goalball Players

The aim of this study was to quantify trunk impact dynamics in goalball players using inertial sensors and evaluate the goalball players' workloads, focusing on changes between the first and second halves of a match to enhance understanding of the demands experienced throughout the game. Utilizing inertial technology, trunk impacts during goalball gameplay were analyzed to provide a holistic insight into how these impacts influence athletes' dynamic stress loads, which refers to the physical demands placed on the body during dynamic movements. Six goalball players were recruited to wear an accelerometer during a whole goalball game to quantify trunk impacts. The results showed a higher number of total impacts and a higher number of impacts at higher levels during the first half, compared to a higher percentage of impacts at a low impact level in the second half. These results suggest that the intensity of gameplay is related to the number of impacts sustained, with players experiencing significantly more impacts, particularly at very low, low, and very high impact levels, in the first half compared to the second half. This decline in impacts aligns with the reduction in game intensity as the match progressed, as indicated by a lower heart rate and a trend towards a lower dynamic stress load in the second half. Future research could explore targeted training interventions aimed at optimizing workload and performance in goalball players.

The Incidence and Propensity of Head Acceleration Events in a Season of Men's and Women's English Elite-Level Club Rugby Union Matches

OBJECTIVES

To describe and compare the incidence and propensity of head acceleration events (HAEs) using instrumented mouthguards (iMG) by playing position in a season of English elite-level men's and women's rugby union matches.

METHODS

iMG data were collected for 255 men and 133 women from 1,865 and 807 player-matches, respectively, and synchronised to video-coded match footage. Head peak resultant linear acceleration (PLA) and peak resultant angular acceleration (PAA) were extracted from each HAE. Mean incidence and propensity values were calculated across different recording thresholds for forwards and backs in addition to positional groups (front row, second row, back row, half backs, centres, back three) with 95% confidence intervals (CI) estimated. Significance was determined based on 95% CI not overlapping across recording thresholds.

RESULTS

For both men and women, HAE incidence was twice as high for forwards than backs across the majority of recording thresholds. HAE incidence and propensity were significantly lower in the women's game compared to the men's game. Back-row and front-row players had the highest incidence across all HAE thresholds for men's forwards, while women's forward positional groups and men's and women's back positional groups were similar. Tackles and carries exhibited a greater propensity to result in HAE for forward positional groups and the back three in the men's game, and back row in the women's game.

CONCLUSION

These data offer valuable benchmark and comparative data for future research, HAE mitigation strategies, and management of HAE exposure in elite rugby players. Positional-specific differences in HAE incidence and propensity should be considered in future mitigation strategies.

Quantifying the Training Loads and Corresponding Changes in Physical Qualities among Adolescent, Schoolboy Rugby League Players

OBJECTIVES

The adolescent development period is critical for rugby league athletes, given the physical growth, neuromuscular adaptation, and skill acquisition that occurs. Secondary schools play an important role in the development of adolescent rugby league players; however, players may be selected into rugby league academies and development programs outside of school, as well as participating in additional sports. In turn, the training loads these young athletes accrue and the implications of these loads are currently unknown. Our aim was to quantify the training loads and concomitant changes in physical qualities of schoolboy and adolescent rugby league players during mesocycles within the pre-season and in-season phases.

DESIGN

This is a prospective experimental study.

METHODS

Twenty-one schoolboy rugby league players (16.2 ± 1.3 years) were monitored across separate 4-week mesocycles in the pre-season and in-season. Session frequency, duration, and the session rating of perceived exertion (sRPE) load were reported for all examples of training and match participation in the school rugby league program, as well as club and representative teams for any sport and personal strength and conditioning. Various physical qualities were assessed before and after each 4-week mesocycle.

RESULTS

The sRPE load that accumulated across the 4-week mesocycles was higher in the pre-season than the in-season (8260 ± 2021 arbitrary units [AU] vs. 6148 ± 980 AU, p < 0.001), with non-significant differences in accumulated session frequency and duration between phases. Session frequency, duration, and sRPE load differed (p < 0.05) between some weeks in an inconsistent manner during the pre-season and in-season mesocycles. Regarding physical qualities, improvements (p < 0.05) in the 10 m sprint test, Multistage Fitness Test, medicine ball throw, and 1-repetition maximum back squat and bench press performances were evident across the pre-season mesocycle, with declines (p < 0.05) in the 505-Agility Test, L-run Test, and 1-repetition maximum back squat performances across the in-season mesocycle. Conclusions: These novel training load data show schoolboy rugby league players experience considerable demands that may be suitable in developing several physical qualities during the pre-season but detrimental to maintaining such qualities across the in-season.

Contemporary Themes in Dietary Intake in Rugby Union Players: A Narrative Review

Rugby union is an intermittent team sport with variability in body composition and match-play demands between positions which requires careful consideration for individual dietary requirements. While previous reviews have detailed the macronutrient intake in rugby players, none have discussed the further determinants of dietary intake in this population. Therefore, the purpose of the current review was to summarise the current evidence detailing dietary intake in rugby union players, report on contemporary nutritional research themes, and provide recommendations for athletes, nutritionists, and other stakeholders. In total, eighteen articles report on dietary intake in rugby players, with only one of these detailing dietary intake in female athletes. Recent studies have reported on both protein and carbohydrate periodisation practices in rugby union players; however, there is currently limited evidence as to the influence of these on performance, recovery, and well-being. Factors influencing eating patterns, the impact of sports nutritionists on dietary intake, and food consumption in catered and non-catered environments has been explored in isolated studies. Nutrition knowledge levels in rugby players have been reported in several studies; however, the influence this has on dietary intake in rugby players is unknown. Collectively, despite new contemporary themes emerging in the literature concerning dietary intake in rugby players, the studies are isolated; as such, there is limited scope to the translatability of information due to heterogeneity in sex, level of play, and location of participants. Given this, future research should aim to build upon the themes identified in this review in combination to support practitioners working within their specific environments. This will subsequently build towards the generation of rugby-specific recommendations.

Impact of Weekly Training-Load Structure and Content on the Risk of Injury in Professional Rugby Union Match-Play

ABSTRACT

Chéradame, J, Loursac, R, Piscione, J, Carling, C, Decq, P, and Jacqmin-Gadda, H. Impact of weekly training-load structure and content on the risk of injury in professional Rugby Union match-play. J Strength Cond Res 38(9): 1613-1619, 2024-The aim of this study was to investigate the impact of different components of daily training load during the week preceding the match on the risk of sustaining a match injury in professional rugby union. A cohort of 72 players from a single professional French club participated. Global positioning system-derived data including total distance (TD) and high-speed distance in addition to ratings of perceived effort (RPE) for both on- and off-pitch (gym-based strength conditioning work) training were collected for each training session over 3 seasons (2017-2020). The association between the daily measures of external and internal training load over the week preceding the day of the match (MD) and the subsequent risk of injury in match-play was estimated using a mixed-effects logistic model adjusted for contextual and individual factors. A total of 184 injuries were sustained in 128 matches (incidence: 81.2 injuries per 1,000 player hours). Higher RPE values for the strength conditioning session on MD-5 ( p < 0.001) and for the on-pitch session on MD-1 ( p = 0.04) were associated with an increased risk of injury in matches. On MD-2, a higher TD covered and that run at high speed (>MAS) were, respectively, associated with a higher ( p = 0.03) and lower risk ( p = 0.02) of injury in matches played. This study in professional rugby union shows that different components of external and internal load had varying influences on injury risk and particularly in relation to the day on which these were performed in the week leading up to the next match. At MD-2, training load favoring intensity rather than volume could reduce the risk of match-play injury.

Changes in Physical Fitness, Muscle Damage and Cognitive Function in Elite Rugby Players over a Season

This study proposes to monitor the physical, immune and cognitive responses and adaptations of elite rugby players throughout the season based on the loads performed. Anthropometric measurements, physical fitness tests (e.g., muscle strength and power, linear and change-of-direction speed, cardiorespiratory fitness) and analyses of serum concentrations of markers of muscle damage (creatine kinase [CK] and lactate dehydrogenase [LDH]) and brain-derived neurotrophic factor (BDNF) were carried out over a sporting season (24 weeks) for 17 elite rugby players (10 forwards and 7 backs) aged 18.91 ± 0.76 years. The physical fitness test results show improvements in the performance of both forwards and backs over the season (p < 0.05), with an advantage for backs compared with forwards in most tests (p < 0.05). Muscle damage markers decreased at the end of the season compared with the baseline levels for forwards (p < 0.05). CK levels were unchanged for the backs, but there were increased LDH concentrations at the end of the season compared with baseline (p < 0.05). Serum BDNF levels decreased for the total group between the second and third sampling (p < 0.05). The muscular and physical capacities of rugby players differ according to their playing position. Immune responses and adaptations, as well as BDNF levels, vary throughout the season and depend on the physical load performed.

Workload Risk Factors for Pitching-Related Injuries in High School Baseball Pitchers

BACKGROUND

Pitch counts are only one measure of the true workload of baseball pitchers. Newer research indicates that workload measurement and prevention of injury must include additional factors. Thus, current monitoring systems gauging pitcher workload may be considered inadequate.

PURPOSE/HYPOTHESIS

The purpose of this study was to develop a novel method to determine workload in baseball pitchers and improve processes for prevention of throwing-related injuries. It was hypothesized that our pitching workload model would better predict throwing-related injuries occurring throughout the baseball season than a standard pitch count model.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

This prospective observational study was conducted at an academic medical center and community baseball fields during the 2019 to 2023 seasons. Pitchers aged 13 to 18 years were monitored for pitching-related injuries and workload (which included pitching velocity; intensity, using preseason and in-season velocity as a marker of effort; and pitch counts).

RESULTS

A total of 71 pitchers had 313 recorded pitcher outings, 11 pitching-related injuries, and 24,228 pitches thrown. Gameday pitch counts for all pitchers ranged from 19 to 219 (mean, 77.5 ± 41.0). Velocity ranged from 46.8 to 85.7 mph (mean, 71.3 ± 5.8 mph). Intensity ranged from 0.7 to 1.3 (mean, 1.0 ± 0.08). The mean workload was 74.7 ± 40.1 for all pitchers. Risk factors significant for injury included throwing at a higher velocity in game (P = .001), increased intensity (eg, an increase in mean velocity thrown from preseason to in-season; P < .001), and being an older pitcher (P = .014). No differences were found for workload between injured and noninjured pitchers because the analysis was underpowered.

CONCLUSION

Our workload model indicated that throwing at a higher velocity, throwing at a higher intensity, and older age were risk factors for injury. Thus, this novel workload model should be considered as a means to identify pitchers who may be at greater risk for injury.

Real-World Fatigue Testing in Professional Rugby Union: A Systematic Review and Meta-analysis

BACKGROUND

Professional rugby union is a high-intensity contact sport with position-specific high training and match volumes across a season that may lead to periods of fatigue if above a typically experienced threshold. This study assesses the influence of match play and/or training on fatigue levels in rugby union players.

OBJECTIVE

We aimed to perform a systematic review and meta-analysis of measures used to assess fatigue status in male professional rugby union players.

METHODS

Using electronic databases (PubMed, SPORTDiscus, Web of Science, Cochrane Library, EMBASE, and MEDLINE), a systematic review of fatigue testing in rugby union was conducted on (1) neuromuscular, (2) subjective self-report, (3) biochemical, and (4) heart rate-derived measures.

RESULTS

Thirty-seven articles were included in this systematic review, of which 14 were further included in a meta-analysis. The results of the meta-analysis revealed small, yet not significant, decreases in countermovement jump height immediately after (effect size [ES] =  - 0.29; 95% confidence interval [CI] - 0.64 to 0.06), 24 h (ES =  - 0.43; 95% CI - 3.99 to 3.21), and 48 h (ES =  - 0.22; 95% CI - 0.47 to 0.02) after exposure to rugby union match play or training. Reported wellness (ES =  - 0.33; 95% CI - 1.70 to 1.04) and tiredness (ES =  - 0.14; 95% CI - 1.30 to 1.03) declined over a period of a few weeks (however, the results were not-statistically significant), meanwhile muscle soreness increased (ES = 0.91; 95% CI 0.06 to 1.75) within the 96 h after the exposure to rugby union match play or training. Finally, while cortisol levels (ES = 1.87; 95% CI - 1.54 to 5.29) increased, testosterone declined (ES =  - 1.54; 95% CI - 7.16 to 4.08) within the 24 h after the exposure. However, these results were not statistically significant.

CONCLUSIONS

Subjective measures of muscle soreness can be used to assess fatigue after match play and training in rugby union players. Within-study and between-study variability for countermovement jump height, biochemical markers, and heart rate-derived measures means the utility (practical application) of these measures to assess fatigue in professional rugby union players after matches and training is unclear.

CLINICAL TRIAL REGISTRATION

PROSPERO ID: CRD42020216706.

Position-specific workload of professional rugby union players during tactical periodization training

The positional workload characteristics in rugby union on three acquisition days (i.e. strength, endurance, and speed days) of tactical periodization are still relatively unknown. Therefore, the primary aim of this study was to shed light on the positional external workload variables (10 Hz Global Positioning System and accelerometer microtechnology) and internal workload indicators (the session rating of perceived exertion) of players in a professional rugby union team by utilizing and comparing two tactical periodization models. Twenty-six male players (15 forwards and 11 backs) were recruited from a French second-division rugby club. Data were obtained over 10 weeks of in-season home games: a total of 780 observations were analyzed. Student's t-test observed different external workload profiles between positions among acquisition days. Mean external workload values, except PlayerLoadslow, were significantly higher (p≤0.01; effect size: 0.41-1.93) for backs than forwards for all acquisition days. Moreover, forwards perceived a higher internal workload than backs on the strength day of both models. The findings demonstrate that applying these two tactical periodization models could result in effective rugby union training. Validating external and internal workload characteristics on tactical periodization acquisition days enables extensive analysis of training load monitoring data; these data can be utilized to discover the unique characteristics of each position and design position-specific acquisition days to improve performance.

A Profile of Isometric Cervical Strength in Elite Professional Male Rugby Players

OBJECTIVES: To (1) provide position-specific normative data for isometric cervical muscle strength and endurance in professional, male rugby players and (2) assess the relationship between age, height, weight, and playing position with cervical muscle strength and endurance. DESIGN: Cross-sectional study. METHODS: Professional rugby players completed peak isometric cervical strength testing followed by a test of cervical muscle endurance. Descriptive statistics for continuous variables with strength normalized to body weight were performed. Multiple linear regression was used to estimate associations between strength measurements. RESULTS: In total, 136 players participated including front-row forwards (27%), other forwards (28%), and backs (45%). Front-row forwards had significantly greater peak isometric cervical muscle strength than other position groups, with backs having the lowest strength. Extension produced the highest force for all 3 position groups (429 N ± 104 N), whereas flexion produced the least (275 N ± 65 N). Age was associated with increased isometric cervical muscle strength. There was a statistically significant relationship between peak flexion strength and flexion endurance (P = .003). The average time for the endurance tests were 55.7 (±17.1) seconds and 52.9 (±20.1) seconds for extension and flexion, respectively. Other forwards had lower cervical extension muscle endurance than backs and front-row forwards. CONCLUSIONS: Normative values for peak and endurance isometric strength in professional rugby players illustrate significant differences between playing position. Consider age, body weight, and intraindividual variability when interpreting cervical strength and endurance results. J Orthop Sports Phys Ther 2024;54(3):1-8. Epub 29 January 2024. doi:10.2519/jospt.2024.11830.

The World Rugby and International Rugby Players Contact Load Guidelines: From conception to implementation and the future

Managing training load in rugby union is crucial for optimising performance and injury prevention. Contact training warrants attention because of higher overall injury and head impact risk, yet players must develop physical, technical, and mental skills to withstand the demands of the game. To help coaches manage contact loads in professional rugby, World Rugby and International Rugby Players convened an expert working group. They conducted a global survey with players to develop contact load guidelines. This commentary aims to describe the contact load guidelines and their implementation, and identify areas where future work is needed to support their evolution.

Blood-Based Biomarkers for Managing Workload in Athletes: Considerations and Recommendations for Evidence-Based Use of Established Biomarkers

Blood-based biomarkers can provide an objective individualized measure of training load, recovery, and health status in order to reduce injury risk and maximize performance. Despite enormous potentials, especially owing to currently evolving technology, such as point-of-care testing, and advantages, in terms of objectivity and non-interference with the training process, there are several pitfalls in the use and interpretation of biomarkers. Confounding variables such as preanalytical conditions, inter-individual differences, or an individual chronic workload can lead to variance in resting levels. In addition, statistical considerations such as the detection of meaningful minimal changes are often neglected. The lack of generally applicable and individual reference levels further complicates the interpretation of level changes and thus load management via biomarkers. Here, the potentials and pitfalls of blood-based biomarkers are described, followed by an overview of established biomarkers currently used to support workload management. Creatine kinase is discussed in terms of its evidence for workload management to illustrate the limited applicability of established markers for workload management to date. We conclude with recommendations for best practices in the use and interpretation of biomarkers in a sport-specific context.

The Perception of Volleyball Student-Athletes: Evaluation of Well-Being, Sport Workload, Players' Response, and Academic Demands

Physical activity has been shown to improve the health and well-being of students, athletes and the general population, especially when it is properly monitored and responses are evaluated. However, data are mostly gathered without considering a valuable element, participants' perceptions. Therefore, the objective was to know the perception of volleyball student-athletes when using different monitoring and response tools that assess well-being, workloads, responses to workloads, and academic demands. A qualitative study using semi-structured interviews with female volleyball student-athletes (n = 22) was used to know players' perceptions when using a wellness/well-being questionnaire, session ratings of perceived exertion (sRPE), and countermovement jumps (CMJ), and consider academic demands. Results show that the wellness questionnaire and sRPE increased student-athletes' awareness of well-being and readiness to perform, improved self-evaluation, self-regulation, and self-demand. However, motivation and overcoming challenges were based on the CMJ. Academic demands affected 82% of student-athletes, altering stress, fatigue, and sleep quality. Nonetheless, sport was seen as an activity that helped with academic commitments. Therefore, the wellness questionnaires and the sRPE facilitated self-awareness and positive dispositions toward self-regulation. Simultaneous intensive academic demands and training can produce mutual positive effects if the variables of physical and mental loads are harmonized in the critical academic and sports periods.

The influence of match exposure on injury risk in elite men's rugby union

OBJECTIVES

To investigate the influence of previous season match exposure on injury incidence and burden in elite men's rugby union.

DESIGN

A three-season (2016-17 to 2018-19) retrospective cohort design was used to collect and analyse injury and exposure data across English Premiership rugby union teams.

METHODS

Generalised linear mixed-effects models were used to model the influence of match exposure (all match involvements, match involvements of ≥20 mins, and full-game equivalents) upon match and training injury incidence and burden in the following season.

RESULTS

Involvement in ≥31 matches within a season was associated with substantially increased match and training injury burden in the following season. Match exposure was not clearly associated with injury incidence in the following season. The increased match injury burden associated with higher match involvements appeared to be driven by an increased risk for older (>26 y) Forwards, whilst the increased training injury burden associated with higher match involvements appeared to be driven by an increased risk for older (>26 y) Backs.

CONCLUSIONS

The present study demonstrates that all match involvements, regardless of duration, should be considered when exploring associations between match exposure and injury risk. High match involvements (≥ 31 matches) are associated with elevated injury burden, in both matches and training, in the following season. The physical and psychological load of players with high previous-season match exposure should be carefully managed.

The relative importance of ability, luck and motivation in team sports: a Bayesian model of performance in the English Rugby Premiership

Results in contact sports like Rugby are mainly interpreted in terms of the ability and/or luck of teams. But this neglects the important role of the motivation of players, reflected in the effort exerted in the game. Here we present a Bayesian hierarchical model to infer the main features that explain score differences in rugby matches of the English Premiership Rugby 2020/2021 season. The main result is that, indeed, effort (seen as a ratio between the number of tries and the scoring kick attempts) is highly relevant to explain outcomes in those matches.

Contributors to negative biopsychosocial health or performance outcomes in rugby players (CoNBO): a systematic review and Delphi study protocol

The importance of contributors that can result in negative player outcomes in sport and the feasibility and barriers to modifying these to optimise player health and well-being have yet to be established. Within rugby codes (rugby league, rugby union and rugby sevens), within male and female cohorts across playing levels (full-time senior, part-time senior, age grade), this project aims to develop a consensus on contributors to negative biopsychosocial outcomes in rugby players (known as the CoNBO study) and establish stakeholder perceived importance of the identified contributors and barriers to their management. This project will consist of three parts; part 1: a systematic review, part 2: a three-round expert Delphi study and part 3: stakeholder rating of feasibility and barriers to management. Within part 1, systematic searches of electronic databases (PubMed, Scopus, MEDLINE, SPORTDiscus, CINAHL) will be performed. The systematic review protocol is registered with PROSPERO. Studies will be searched to identify physical, psychological and/or social factors resulting in negative player outcomes in rugby. Part 2 will consist of a three-round expert Delphi consensus study to establish additional physical, psychological and/or social factors that result in negative player outcomes in rugby and their importance. In part 3, stakeholders (eg, coaches, chief executive officers and players) will provide perceptions of the feasibility and barriers to modifying the identified factors within their setting. On completion, several manuscripts will be submitted for publication in peer-reviewed journals. The findings of this project have worldwide relevance for stakeholders in the rugby codes. PROSPERO registration number CRD42022346751.

Tackle Technique and Changes in Playerload™ During a Simulated Tackle: An Exploratory Study

In collision sports, the tackle has the highest injury incidence, and is key to a successful performance. Although the contact load of players has been measured using microtechnology, this has not been related to tackle technique. The aim of this study was to explore how PlayerLoad™ changes between different levels of tackling technique during a simulated tackle. Nineteen rugby union players performed twelve tackles on a tackle contact simulator (n = 228 tackles). Each tackle was recorded with a video-camera and each player wore a Catapult OptimEyeS5. Tackles were analysed using tackler proficiency criteria and split into three categories: Low scoring(≤5 Arbitrary units (AU), medium scoring(6 and 7AU) and high scoring tackles(≥8AU). High scoring tackles recorded a higher PlayerLoad™ at tackle completion. The PlayerLoad™ trace was also less variable in the high scoring tackles. The variability in the PlayerLoad™ trace may be a consequence of players not shortening their steps before contact. This reduced their ability to control their movement during the contact and post-contact phase of the tackle and increased the variability. Using the PlayerLoad™ trace in conjunction with subjective technique assessments offers coaches and practitioners insight into the physical-technical relationship of each tackle to optimise tackle skill training and match preparation.

Injuries to Ice Hockey Referees and Linesmen: A Survey of International Ice Hockey Federation Officials

Background

Ice hockey referees and linesmen are at risk for musculoskeletal injuries because of the lack of protective equipment and contact with players, sticks, pucks, the ice surface and boards.

Purpose

To quantify and analyze injuries reported by officials of the International Ice Hockey Federation (IIHF).

Study Design

Descriptive epidemiology study.

Methods

A 61-question survey tool was designed by an interdisciplinary team to evaluate musculoskeletal injuries experienced by ice hockey officials. This survey was administered to 600 active IIHF referees and linesmen. Only completed survey responses were included in the statistical analysis. Continuous variables were analyzed using unpaired t-tests, while categorical data were assessed utilizing chi-square tests.

Results

Of the 600 surveys administered, 264 surveys were completed by officials from 45 countries (44% response rate). Of the respondents, 72% were male, and 28% were female, with a mean age of 31.1 ± 5.8 years. Officiating experience averaged 11.4 ± 6.0 years (6.3 ± 4.5 years with the IIHF). A total of 295 injuries were reported by 55% of the officials. Injuries occurred more frequently during games compared with training, and officials who worked year-round had more total injuries than those who took time off (P = .03). The most common injuries involved the wrist and hand (n = 64 [22%]), head and face (n = 58 [20%]), and the knee (n = 47 [16%]). Wrist and hand trauma included 23 fractures. Knee and shoulder injuries were most likely to require surgery compared with other body areas (P < .001); 30 officials underwent surgery because of an acute knee injury (10%). Injury prevention activities were effective at reducing injuries (P = .04).

Conclusion

Most ice hockey officials experienced musculoskeletal injuries during their career. The risk of trauma to the wrist and hand can possibly be reduced via equipment modifications including protective gloves. A greater emphasis should be placed on injury prevention programs and time away from officiating competitions.

Identifying the Current State and Improvement Opportunities in the Information Flows Necessary to Manage Professional Athletes: A Case Study in Rugby Union

In sporting environments, the knowledge necessary to manage athletes is built on information flows associated with player management processes. In current literature, there are limited case studies available to illustrate how such information flows are optimized. Hence, as the first step of an optimization project, this study aimed to evaluate the current state and the improvement opportunities in the player management information flow executed within the High-Performance Unit (HPU) at a professional rugby union club in England. Guided by a Business Process Management framework, elicitation of the current process architecture illustrated the existence of 18 process units and two core process value chains relating to player management. From the identified processes, the HPU management team prioritized 7 processes for optimization. In-depth details on the current state (As-Is) of the selected processes were extracted from semi-structured, interview-based process discovery and were modeled using Business Process Model and Notation (BPMN) and Decision Model and Notation (DMN) standards. Results were presented for current issues in the information flow of the daily training load management process, identified through a thematic analysis conducted on the data obtained mainly from focus group discussions with the main stakeholders (physiotherapists, strength and conditioning coaches, and HPU management team) of the process. Specifically, the current state player management information flow in the HPU had issues relating to knowledge creation and process flexibility. Therefore, the results illustrate that requirements for information flow optimization within the considered environment exist in the transition from data to knowledge during the execution of player management decision-making processes.

The Salzburg 10/7 HIIT shock cycle study: the effects of a 7-day high-intensity interval training shock microcycle with or without additional low-intensity training on endurance performance, well-being, stress and recovery in endurance trained athletes-study protocol of a randomized controlled trial

BACKGROUND

Performing multiple high-intensity interval training (HIIT) sessions in a compressed period of time (approximately 7-14 days) is called a HIIT shock microcycle (SM) and promises a rapid increase in endurance performance. However, the efficacy of HIIT-SM, as well as knowledge about optimal training volumes during a SM in the endurance-trained population have not been adequately investigated. This study aims to examine the effects of two different types of HIIT-SM (with or without additional low-intensity training (LIT)) compared to a control group (CG) on key endurance performance variables. Moreover, participants are closely monitored for stress, fatigue, recovery, and sleep before, during and after the intervention using innovative biomarkers, questionnaires, and wearable devices.

METHODS

This is a study protocol of a randomized controlled trial that includes the results of a pilot participant. Thirty-six endurance trained athletes will be recruited and randomly assigned to either a HIIT-SM (HSM) group, HIIT-SM with additional LIT (HSM + LIT) group or a CG. All participants will be monitored before (9 days), during (7 days), and after (14 days) a 7-day intervention, for a total of 30 days. Participants in both intervention groups will complete 10 HIIT sessions over 7 consecutive days, with an additional 30 min of LIT in the HSM + LIT group. HIIT sessions consist of aerobic HIIT, i.e., 5 × 4 min at 90-95% of maximal heart rate interspersed by recovery periods of 2.5 min. To determine the effects of the intervention, physiological exercise testing, and a 5 km time trial will be conducted before and after the intervention.

RESULTS

The feasibility study indicates good adherence and performance improvement of the pilot participant. Load monitoring tools, i.e., biomarkers and questionnaires showed increased values during the intervention period, indicating sensitive variables.

CONCLUSION

This study will be the first to examine the effects of different total training volumes of HIIT-SM, especially the combination of LIT and HIIT in the HSM + LIT group. In addition, different assessments to monitor the athletes' load during such an exhaustive training period will allow the identification of load monitoring tools such as innovative biomarkers, questionnaires, and wearable technology.

TRIAL REGISTRATION

clinicaltrials.gov, NCT05067426. Registered 05 October 2021-Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT05067426 . Protocol Version Issue date: 1 Dec 2021. Original protocol. Authors: TLS, NH.

Ideal Combinations of Acceleration-Based Intensity Metrics and Sensor Positions to Monitor Exercise Intensity under Different Types of Sports

This study quantified the strength of the relationship between the percentage of heart rate reserve (%HRR) and two acceleration-based intensity metrics (AIMs) at three sensor-positions during three sport types (running, basketball, and badminton) under three intensity conditions (locomotion speeds). Fourteen participants (age: 24.9 ± 2.4 years) wore a chest strap HR monitor and placed three accelerometers at the left wrist (non-dominant), trunk, and right shank, respectively. The %HRR and two different AIMs (Player Load per minute [PL/min] and mean amplitude deviation [MAD]) during exercise were calculated. During running, both AIMs at the shank and PL at the wrist had strong correlations (r = 0.777-0.778) with %HRR; while other combinations were negligible to moderate (r = 0.065-0.451). For basketball, both AIMs at the shank had stronger correlations (r = 0.604-0.628) with %HRR than at wrist (r = 0.536-0.603) and trunk (r = 0.403-0.463) with %HRR. During badminton exercise, both AIMs at shank had stronger correlations (r = 0.782-0.793) with %HRR than those at wrist (r = 0.587-0.621) and MAD at trunk (r = 0.608) and trunk (r = 0.314). Wearing the sensor on the shank is an ideal position for both AIMs to monitor external intensity in running, basketball, and badminton, while the wrist and using PL-derived AIM seems to be the second ideal combination.

The Landing Error Scoring System (LESS) and Lower Limb Power Profiles in Elite Rugby Union Players

BACKGROUND

The Landing Error Scoring System (LESS) is a clinical test that assesses landing biomechanics during a drop-jump task. Performance measures such as jump height, power, contact time and reactive strength index are used commonly in athletic populations. Comparing results from the LESS against these performance measures has not been reported in elite rugby union.

PURPOSE

To report i.) normative LESS scores for elite rugby union players ii.) correlations between LESS scores and performance measures and iii.) differences in performance measures between LESS scoring groups. A secondary purpose was to report the intra- and inter-rater reliability of the LESS test when used in elite rugby union players. # Study DesignCross-sectional design.

METHODS

Thirty-six male, elite rugby union players participated. Each participant completed three trials of the LESS and performance measures were recorded concurrently using the OptojumpTM. LESS trials were scored independently by the authors. Statistical analyses were used to confirm reliability, data normality, and between group differences (p<0.05).

RESULTS

The LESS test is a reliable testing tool in elite rugby union players (excellent intra- (ICC=0.96) and inter-rater (ICC=0.94) reliability). One player demonstrated an excellent LESS score, six players had good scores, eight players moderate scores and the majority of the group, 21 players, scored poorly. LESS scores were correlated to contact time (r = -0.461, p = 0.005) only. Participants with moderate to poor LESS scores (a score ≤5) produced greater power (p=0.036, η2 = 0.139), contact time (p=0.002, η2 = 0.268) and reactive strength index (p=0.016, η2 = 0.180). There were no differences in jump height (p=0.842) between players scoring excellent to good and moderate to poor.

CONCLUSION

The results of the current study demonstrate excellent intra- and inter-rater reliability for the LESS, supporting its use as a clinical assessment tool in elite rugby union players. The majority of players presented with moderate to poor LESS scores, indicating an area of concern in this population. Participants scoring moderate to poor in the LESS recorded significantly higher power and reactive strength index, increased contact time but not jump height. This suggests participants with high-risk landing biomechanics may also produce higher performance measures, but these do not necessarily result in an improved jump height.

Pressure. A Qualitative Analysis of the Perception of Concussion and Injury Risk in Retired Professional Rugby Players

This study interviewed retired professional rugby union players (≤10 years since retirement) to discuss their careers in the game of rugby union. The primary aim of the study was to document their understanding of concussion knowledge and the analogies they use to describe concussion. In addition, these interviews were used to determine any explicit and implicit pressures of playing professional rugby as described by ex-professional rugby players. Overall, 23 retired professional rugby players were interviewed. The participants had played the game of rugby union (n = 23) at elite professional standard. A semi-structured individual interview design was conducted with participants between June to August 2020. The research team reviewed the transcripts to identify the major themes from the interviews using a reflexive thematic analysis approach. Four major themes were identified: (1) medical and theoretical understanding of concussion, (2) descriptions of concussion and disassociated language, (3) personal concussion experience, and (4) peer influences on concussion within the sport. These were further divided into categories and subcategories. The interviews highlighted that players did not fully understand the ramifications of concussive injury and other injury risk, as it became normalised as part of their sport. This normalisation was supported by trivialising the seriousness of concussions and using dismissive language amongst themselves as players, or with coaching staff. As many of these ex-professional players are currently coaching rugby (48%), these interviews could assist coaches in treating concussion as a significant injury and not downplaying the seriousness of concussion in contact sports.

Association of mental health help-seeking with mental health-related knowledge and stigma in Japan Rugby Top League players

Background

Globally increasing clinical and research interests are driving a movement to promote understanding and practice of mental health in elite athletes. However, few studies have yet addressed this issue. This study aims to describe the association of the intention to seek help with mental health knowledge and stigma and the severity of depressive symptoms in Japan Rugby Top League players.

Methods

As a target population, we studied 233 Japan Rugby Top League male players (25–29 years = 123 [52.8%]), who were born in Japan, using a cross-sectional design. Surveys were conducted using anonymous, web-based self-administered questionnaires. Structural equation modelling was performed to evaluate the hypothesis of an interrelationship between mental health knowledge, stigma, and severity of depressive symptoms as factors influencing the intention to seek help.

Results

Players with more severe depressive symptoms were more reluctant to seek help from others (β = - 0.20, p = 0.03). Players with greater knowledge about mental health tended to have less stigma toward others with mental health problems (β = 0.13, p = 0.049), but tended not to seek help with their own mental health problems.

Conclusions

Rugby players in need of mental health support, even with greater knowledge, tend not to seek help from others, while having less stigma toward people with mental health problems. Rugby players might require approaches other than a knowledge-based educational approach to encourage them to seek help.

Training Load Monitoring in Amateur Rugby Union: A Survey of Current Practices

ABSTRACT

Griffin, A, Kenny, IC, Comyns, TM, and Lyons, M. Training load monitoring in amateur Rugby Union: A survey of current practices. J Strength Cond Res 35(6): 1568-1575, 2021-Amateur Rugby Union has an inherent risk of injury that is associated with detrimental effects on player welfare and team performance. Training load (TL) is a modifiable risk factor that, when monitored, may provide strength and conditioning (S&C) coaches with opportunities to reduce the risk of injury. The purpose of this study was to explore TL monitoring practices used by S&C coaches working with male and female amateur adult Rugby Union teams and their rationale for using such. Thirty-three (n = 31 male and n = 2 female) S&C coaches representing 62% of the total number of male clubs and 71% of female clubs, playing at the highest national amateur level, participated in the study by completing an online survey. Seventy-three percent of respondents stated that they monitor TL. The most common method of recording TL was the session rating of perceived exertion (sRPE), used in 83% of monitoring systems. Thirty-three percent of the S&C coaches surveyed use the sRPE data to calculate the acute:chronic workload ratio (ACWR) for highlighting when players are at risk of injury. This study is the first of its kind to exclusively examine the TL monitoring practices of S&C coaches working with amateur adult Rugby Union teams. Thirteen S&C coaches responded to the open-ended question and 3 higher order themes were highlighted: (a) communication with players (b) support from other staff and (c) limiting factors.

Prevalence of poor sleep quality in athletes before competition

OBJECTIVES

The purpose of this study was to investigate athletes sleep quality before competition and its relationship with age, gender, sport modality, competitive level, competition result, and practice time.

METHODS

The sample was 1010 Brazilian athletes (656 men and 354 women; 511 young and 499 adults), with an age of 20 ± 7 years old. Participants answered the question 'How would you evaluate the quality of your sleep in the past few days?' Participants rated their sleep quality on a Likert-type scale as follows: 1 = very poor, 2 = poor, 3 = regular, 4 = good, 5 = excellent.

RESULTS

Young athletes were 2.30 times more likely to experience poor sleep than adult athletes (p < 0.01; 95% Confidence Interval [CI] = 1.47-3.61). Individual athletes were 3.45 times more likely to present poor sleep compared to athletes of team sports (p = 0.00; 95% CI = 2.18-5.48). International athletes were 1.71 times more likely to present regular sleep compared to regional athletes (p = 0.01; 95% CI = 1.16-2.51). Conclusions: Thus, our study indicates that young, individual sports, and international athletes may be at higher risk of poor sleep quality before competitions.

Measuring Psychological Load in Sport

Monitoring the physical load undertaken by athletes and examining the subsequent relationship with performance and injury and illness risk is common practice in high performance sport. Less attention has been paid to the psychological factors contributing to the overall load experienced and the impact upon health status and performance. This paper discusses considerations for the conceptualization and measurement of psychological load in sport. First, we outline the importance of ensuring conceptual clarity is adopted in the measurement of psychological load. Next, we discuss the challenges to measuring psychological load in a comparable manner to which physical load is currently evaluated, including use of subjective assessment, adoption of specific and global approaches, and development of measurement instrumentation, techniques, and expertise. We then offer recommendations for practitioners when undertaking assessment of psychological load in sport. We conclude with future research directions to advance the study and measurement of the construct, including the interaction between psychological and physical load, the appraisal of the load faced, and personal and social resources available to successfully cope. We also highlight the need to consider groups of athletes (e. g., transitioning athlete, long-term injured) at greater risk from threats to mental and physical health from increased psychological load.

Is the Acute: Chronic Workload Ratio (ACWR) Associated with Risk of Time-Loss Injury in Professional Team Sports? A Systematic Review of Methodology, Variables and Injury Risk in Practical Situations

BACKGROUND

The acute: chronic workload ratio (ACWR) is an index of the acute workload relative to the cumulative chronic workloads. The monitoring of physical workloads using the ACWR has emerged and been hypothesized as a useful tool for coaches and athletes to optimize performance while aiming to reduce the risk of potentially preventable load-driven injuries.

OBJECTIVES

Our goal was to describe characteristics of the ACWR and investigate the association of the ACWR with the risk of time-loss injuries in adult elite team sport athletes.

DATA SOURCES

PubMed, EMBASE and grey literature databases; inception to May 2019.

ELIGIBILITY CRITERIA

Longitudinal studies that assess the relationship of the ACWR and time-loss injury risk in adult professional or elite team sports.

METHODS

We summarized the population characteristics, workload metrics and ACWR calculation methods. For each workload metric, we plotted the risk estimates for the ACWR in isolation, or when combined with chronic workloads. Methodological quality was assessed using a modified version of the Downs and Black scale.

RESULTS

Twenty studies comprising 2375 injuries from 1234 athletes (all males and mean age of 24 years) from different sports were included. Internal (65%) and external loads (70%) were collected in more than half of the studies and the session-rating of perceived exertion and total distance were the most commonly collected metrics. The ACWR was commonly calculated using the coupled method (95%), 1:4 weekly blocks (95%) and subsequent week injury lag (80%). There were 14 different binning methods with almost none of the studies using the same binning categories.

CONCLUSION

The majority of studies suggest that athletes are at greater risk of sustaining a time-loss injury when the ACWR is higher relative to a lower or moderate ACWR. The heterogenous methodological approaches not only reflect the wide range of sports studied and the differing demands of these activities, but also limit the strength of recommendations.

PROSPERO REGISTRATION NUMBER

CRD42017067585.

Accelerometry-Workload Indices Concerning Different Levels of Participation during Congested Fixture Periods in Professional Soccer: A Pilot Study Conducted over a Full Season

The aim of this study was to analyze the variations of acute load (AL), acute: chronic workload ratio (ACWR), training monotony (TM), and training strain (TS) of accelerometry-based GPS measures in players who started in three matches (S3M), two matches (S2M), and one match (S1M) during congested weeks. Nineteen elite professional male players from a Portuguese team (age: 26.5 ± 4.3 years) were monitored daily using global positioning systems (GPSs) over a full season (45 weeks). Accelerometry-derived measures of high metabolic load distance (HMLD), high accelerations (HA), and high decelerations (HD) were collected during each training session and match. Seven congested weeks were classified throughout the season, and the participation of each player in matches played during these weeks was codified. The workload indices of AL (classified as ACWR, TM, and TS) were calculated weekly for each player. The AL of HMLD was significantly greater for S2M than S1M (difference = 42%; p = 0.002; d = 0.977) and for S3M than S1M (difference = 44%; p = 0.001; d = 1.231). Similarly, the AL of HA was significantly greater for S2M than S1M (difference = 25%; p = 0.023; d = 0.735). The TM of HD was significantly greater for S2M than S3M (difference = 25%; p = 0.002; d = 0.774). Accelerometry-based measures were dependent on congested fixtures. S2M had the greatest TS values, while S3M had the greatest TM.

Effect of an Innovative Mattress and Cryotherapy on Sleep after an Elite Rugby Match

INTRODUCTION

This study aimed to explore the relationship between elite rugby union match and postmatch sleep architecture and to investigate the effects of a high-heat capacity mattress (MAT) and a whole-body cryotherapy (WBC) session on postmatch sleep architecture.

METHODS

Nineteen elite male U23 rugby union players performed in three official matches, followed by three experimental conditions, in a randomized order: MAT, WBC, and no intervention (CONT). Match load was evaluated using GPS trackers and video analyses. Sleep architecture was assessed by polysomnography (PSG). Core body temperature (CBT) and mattress surface temperature were monitored during sleep. Linear mixed-effects models were conducted to assess the effects of each experimental condition on sleep, with match load variables as covariates.

RESULTS

A lower wake after sleep onset (β = -10.5 min, P < 0.01) and higher rapid eye movement sleep proportion (β = +2.8%, P < 0.05) were reported for MAT compared with CONT. Moreover, lower mean CBT (β = -0.135°C, P < 0.001) and mean mattress surface temperature (β = -2.736°C, P < 0.001) during sleep were observed for MAT compared CONT. WBC did not affect nocturnal CBT nor interfere with sleep architecture. For every 100-m increase in high-speed running distance, a higher slow wave sleep (β = +1.1%, P = 0.05) and lower light sleep proportion (β = -1.2%, P < 0.05) proportion were observed. Conversely, for every 10 supplementary collisions, lower slow wave sleep (β = -1.9, P = 0.09) and higher light sleep (β = +2.9%, P < 0.001) proportion were observed.

CONCLUSION

MAT use had a positive effect on sleep architecture after an elite rugby union match, potentially through a more efficient nocturnal heat transfer.

Returning to Play after Prolonged Training Restrictions in Professional Collision Sports

The COVID-19 pandemic in 2020 has resulted in widespread training disruption in many sports. Some athletes have access to facilities and equipment, while others have limited or no access, severely limiting their training practices. A primary concern is that the maintenance of key physical qualities (e. g. strength, power, high-speed running ability, acceleration, deceleration and change of direction), game-specific contact skills (e. g. tackling) and decision-making ability, are challenged, impacting performance and injury risk on resumption of training and competition. In extended periods of reduced training, without targeted intervention, changes in body composition and function can be profound. However, there are strategies that can dramatically mitigate potential losses, including resistance training to failure with lighter loads, plyometric training, exposure to high-speed running to ensure appropriate hamstring conditioning, and nutritional intervention. Athletes may require psychological support given the challenges associated with isolation and a change in regular training routine. While training restrictions may result in a decrease in some physical and psychological qualities, athletes can return in a positive state following an enforced period of rest and recovery. On return to training, the focus should be on progression of all aspects of training, taking into account the status of individual athletes.

Training Load, Injury Burden, and Team Success in Professional Rugby Union: Risk Versus Reward

CONTEXT

Individual and team injury burden and performance are 2 key considerations facing practitioners in the daily prescription of an athlete's training load. Whereas a considerable number of researchers have examined univariate relationships between training load and performance, training load and injury, or injury and performance, few investigators have examined all 3 concurrently.

OBJECTIVE

To assess the association among training load, injury burden, and performance in professional rugby union.

DESIGN

Descriptive epidemiology study.

SETTING

The English Premiership competition.

PATIENTS OR OTHER PARTICIPANTS

Individual injury and training load data, as well as team performance data, were captured during the 2015-2016 (n = 433 players) and 2016-2017 (n = 569 players) seasons.

MAIN OUTCOME MEASURE(S)

Data were aggregated into team average scores for each week, including weekly (acute) load, smoothed chronic load, changes in load, injury burden, and weekly performance. Linear mixed modelling techniques were used to assess the association among measures.

RESULTS

Injury burden was negatively associated with performance, with a high weekly burden associated with a likely harmful (P = .01) decrease in performance. Training load measures displayed only trivial associations with performance. Only the acute:chronic workload ratio measure was clearly associated with injury burden, with a possibly harmful effect (P = .02). Both squad size and player availability were associated with only trivial changes in performance.

CONCLUSIONS

Whereas no association between average training load and performance existed, associations between training load and injury burden and between injury burden and performance were clear. Further investigation using more sensitive and individualized measures of load, performance, and injury may elicit a clearer relationship and should be considered for future work.

Influence of Weekly Workload on Physical, Biochemical and Psychological Characteristics in Professional Rugby Union Players Over a Competitive Season

Dubois, R, Lyons, M, Paillard, T, Maurelli, O, and Prioux, J. Influence of weekly workload on physical, biochemical and psychological characteristics in professional rugby union players over a competitive season. J Strength Cond Res 34(2): 527-545, 2020-This study aimed to (a) quantify the physical workload (P-WL) during training and games throughout the professional rugby season and (b) analyze the influence of the season period and weekly-WL, at short (acute) and moderate (chronic) terms, on physical, biochemical, and psychological responses during the season. Physiological (physical and biochemical) responses to P-WL were analyzed by examining changes in the individual Z score of the Yo-Yo intermittent recovery test (YYIRT), submaximal aerobic tests (5'/5'-test), strength tests, countermovement jump tests, blood sampling, and "recovery-stress" scores (RESTq) in 14 professional players (26.9 ± 1.9 years). Changes throughout the season were analyzed using a linear mixed model to identify changes in P-WL, whereas repeated-measures analysis of variance was used to analyze changes in physiological responses across the season. The relationship between P-WL and physiological responses was analyzed using Pearson's correlation coefficient (r). The results showed that the preseason period comprised the highest level of P-WL compared with all other blocks across the season (p < 0.001). The acute P-WL, acute competitive-WL, and number of impacts seemed to be the WL parameters, which most influenced the physiological responses (changes in testosterone [T], cortisol [C], T/C ratio, IGF-1/C ratio, strength, and RESTq index). The chronic P-WL, particularly conditioning-WL, induced positive changes in fitness characteristics (YYIRT and 5'/5'-test). Finally, this study provides information to players and coaches alike as to the influence of P-WL on as well as adaptations in physiological and psychological indices throughout a playing season. This information can greatly inform the training and preparation of future players in different levels.

Applied Sport Science for Male Age-Grade Rugby Union in England

Rugby union (RU) is a skill-collision team sport played at junior and senior levels worldwide. Within England, age-grade rugby governs the participation and talent development of youth players. The RU player development pathway has recently been questioned, regarding player performance and well-being, which sport science research can address. The purpose of this review was to summarise and critically appraise the literature in relation to the applied sport science of male age-grade RU players in England focussing upon (1) match-play characteristics, (2) training exposures, (3) physical qualities, (4) fatigue and recovery, (5) nutrition, (6) psychological challenges and development, and (7) injury. Current research evidence suggests that age, playing level and position influence the match-play characteristics of age-grade RU. Training exposures of players are described as 'organised chaos' due to the multiple environments and stakeholders involved in coordinating training schedules. Fatigue is apparent up to 72 h post match-play. Well-developed physical qualities are important for player development and injury risk reduction. The nutritional requirements are high due to the energetic costs of collisions. Concerns around the psychological characteristics have also been identified (e.g. perfectionism). Injury risk is an important consideration with prevention strategies available. This review highlights the important multi-disciplinary aspects of sport science for developing age-grade RU players for continued participation and player development. The review describes where some current practices may not be optimal, provides a framework to assist practitioners to effectively prepare age-grade players for the holistic demands of youth RU and considers areas for future research.

Performance indicators during international rugby union matches are influenced by a combination of physiological and contextual variables

OBJECTIVES

Research has linked physiological (e.g., hormonal, affective, fatigue) outcomes to performance indicators in rugby competition, but no work has integrated and contextualised these factors within a test-match environment. We addressed this gap by monitoring 29 athletes from a training squad across eight international rugby matches.

DESIGN

Longitudinal observational study.

METHODS

Pre-match (8-9am) measures of salivary testosterone and cortisol concentrations, sleep duration, pulse rate, muscle soreness, stress, mood, and motivation were taken. Contextual factors were playing time, internal training load (ITL), test-match experience, opponent ranking, and crowd size. Performance was indexed by coach and player ratings of performance (CRP, PRP) and quantitative metrics; offloads, turnovers, runs with ball in hand (RWB), tackles, passes, and defenders beaten (DFB).

RESULTS

Morning cortisol, sleep and mood were positively related to CRP and PRP (standardised coefficient estimates from 0.17 to 0.22). Cortisol, sleep, stress, mood and motivation were associated with one (or more) of turnovers, RWB, tackles, passes and DFB (incidence rate ratio [IRR] from 0.74 to 1.40). Playing time was positively related to all quantitative performance indicators (IRR from 1.01 to 1.04) with ITL, opponent ranking, and crowd size predicting selected outputs (IRR from 0.89 to 1.15). The explanatory models varied (conditional R²=0.15-0.83) but were generally stronger with both physiological and contextual inputs.

CONCLUSIONS

Multiple physiological and contextual factors appear to contribute to player performance in international rugby competition. Measurement of these factors may guide training and management practices, a potential practical consequence but also advancing understanding from marker to causal link.

Sleep quality associated with mood in elite athletes

Objectives: This study aimed to analyze the association between sleep quality and mood in elite athletes of different competitive levels. Methods: Participants were 1041 elite athletes (aged 20.82 ± 6.62 years), with 671 men (64.5%/21.52 ± 6.90 years) and 370 women (35.5%/19.55 ± 5.89 years) from 10 individual sports and 6 team sports. Participants self-reported sleep quality on a Likert-type scale and mood was measured with the Brunel Mood Scale (BRUMS). The data were analyzed using the Kruskal-Wallis test, and binary logistic regression. Results: Results revealed that athletes who compete internationally are 84% more likely to have poor sleep quality than athletes who compete at a regional level. International athletes with good sleep quality showed greater vigor. National athletes with poor sleep quality showed more confusion, depression, and fatigue. Thus, mood and competitive level are factors associated with sleep quality. Confusion, fatigue, and tension impair sleep, and vigor reduces the likelihood of poor sleep. Conclusions: Sleep should be monitored, especially in international level athletes, in order to prevent sleep disorders during competitions. Coaches and athletes should use techniques and strategies for appropriate management of sleep and mood, to maintain the athletes in optimal condition before important competitions.

Changes in performance markers and wellbeing in elite senior professional rugby union players during a pre-season period: Analysis of the differences across training phases

OBJECTIVES

To assess the magnitude of change and association with variation in training load of two performance markers and wellbeing, over three pre-season training blocks, in elite rugby union athletes.

DESIGN

Observational.

METHODS

Twenty-two professional players (age 25±5 years; training age 6±5 years; body mass, 99±13kg; stature 186±6cm) participated in this study, with changes in lower (CMJ height) and upper body (bench press mean speed) neuromuscular function and self-reported wellbeing (WB) assessed during an 11-week period.

RESULTS

There was a small increase in CMJ height (0.27, ±0.17 - likely substantial; standardised effect size, ±95% confidence limits - magnitude-based inference) (p=0.003), bench press speed (0.26, ±0.15 - likely substantial) (p=0.001) and WB (0.26, ±0.12 - possibly substantial) (p<0.0001) across the pre-season period. There was a substantial interaction in the effect of training load on these three variables across the three training phases. A two-standard deviation (2SD) change in training load was associated with: a small decrease in CMJ height during the power phase (-0.32, ±0.19 - likely substantial) (p=0.001); a small reduction in bench press speed during the hypertrophy phase (-0.40, ±0.32 - likely substantial) (p=0.02); and a small reduction in WB during the strength phase (-0.40, ±0.24 - very likely substantial) (p<0.0001). The effects of changes in training load across other phases were either likely trivial, only possibly substantial, or unclear.

CONCLUSIONS

The effect of training load on performance can vary both according to the type of training stimulus being administered and based on whether upper- or lower-body outcomes are being measured.

The Fatigue and Fitness Test for Teams (FFITT): A practical option for monitoring athletes in a team as individuals

We developed the Fatigue and Fitness Test for Teams (FFITT) to address the challenges of monitoring players in a team simultaneously. The test, which takes 8 min for the entire team, incorporates subjective measures of well-being (RTT-Q), and objective measures of the autonomic system (HRR_60s) and neuromuscular function (SLJ). The aim of this study was to present the rationale for the FFITT as a novel athlete monitoring protocol and to measure the reliability of each component of the test. The internal consistency of the RTT-Q questions ranged from α = 0.69-0.92. All questions had an α > 0.83, with one exception of question 'Rate the well-being/stress your school/university/work is causing you to feel' which had an α = 0.69. The reliability of the HRR_60s and SLJ was high (R = 0.92, and 0.91 respectively). The absolute typical error of measurement (TEM) of the SLJ was 8 cm and HRR_60s was 3 beats. When expressed relatively the CV_TEM of HRR_60s was 8.4% and SLJ was 3.0%. Based on the TEM the HRR_60s and SLJ could detect medium and large changes in fatigue and fitness. In absolute terms this equates to more than 5 bpm (HRR_60s) and more than 13 cm (SLJ). The FFITT has the potential to satisfy both scientific principles and the coach's demands of a practical monitoring protocol for frequent use in a team.

Monitoring residual 36 h post-match neuromuscular fatigue in rugby union; a role for postural control?

The present study investigated single-leg balance and landing measures, respectively, at the beginning of a weekly micro-cycle 36 h after a match compared to 48 h rest without any match load. Twenty-seven professional rugby union players performed balance and landing tests on a 1000 Hz force plate across three in-season micro-cycles either with or without match loads in the prior 36 h. Participants were further sub-divided into higher and lower match load groups to investigate changes in balance and landing variables. Differences between rested and 36 h post-match single-leg balance sway velocity were trivial in all cases, except for the higher-load group on the dominant leg, which were possibly impaired 36 h post-match (ES ± 90% CL = 0.68 ± 0.66). Differences between rested and 36 h post-match single-leg landing measures of relative impulse on the non-dominant leg were possibly lower (0.36 ± 0.34), with possible impairment observed on both legs in the higher load group 36 h post-match (0.39 ± 0.33; 0.49 ± 0.42). Differences in landing measures of peak force and time to stabilisation were mainly trivial (ES < 0.20). Postural control measures at 36 h post-match are comparable to a rested state; though impairment of sway velocity on the dominant leg and landing impulse may indicate residual neuromuscular fatigue resulting from increased match exposure.

Validity of a Microsensor-Based Algorithm for Detecting Scrum Events in Rugby Union

PURPOSE

Commercially available microtechnology devices containing accelerometers, gyroscopes, magnetometers, and global positioning technology have been widely used to quantify the demands of rugby union. This study investigated whether data derived from wearable microsensors can be used to develop an algorithm that automatically detects scrum events in rugby union training and match play.

METHODS

Data were collected from 30 elite rugby players wearing a Catapult OptimEye S5 (Catapult Sports, Melbourne, Australia) microtechnology device during a series of competitive matches (n = 46) and training sessions (n = 51). A total of 97 files were required to "train" an algorithm to automatically detect scrum events using random forest machine learning. A further 310 files from training (n = 167) and match-play (n = 143) sessions were used to validate the algorithm's performance.

RESULTS

Across all positions (front row, second row, and back row), the algorithm demonstrated good sensitivity (91%) and specificity (91%) for training and match-play events when the confidence level of the random forest was set to 50%. Generally, the algorithm had better accuracy for match-play events (93.6%) than for training events (87.6%).

CONCLUSIONS

The scrum algorithm was able to accurately detect scrum events for front-row, second-row, and back-row positions. However, for optimal results, practitioners are advised to use the recommended confidence level for each position to limit false positives. Scrum algorithm detection was better with scrums involving ≥5 players and is therefore unlikely to be suitable for scrums involving 3 players (eg, rugby sevens). Additional contact- and collision-detection algorithms are required to fully quantify rugby union demands.

The Relationships Between Internal and External Measures of Training Load and Intensity in Team Sports: A Meta-Analysis

BACKGROUND

The associations between internal and external measures of training load and intensity are important in understanding the training process and the validity of specific internal measures.

OBJECTIVES

We aimed to provide meta-analytic estimates of the relationships, as determined by a correlation coefficient, between internal and external measures of load and intensity during team-sport training and competition. A further aim was to examine the moderating effects of training mode on these relationships.

METHODS

We searched six electronic databases (Scopus, Web of Science, PubMed, MEDLINE, SPORTDiscus, CINAHL) for original research articles published up to September 2017. A Boolean search phrase was created to include search terms relevant to team-sport athletes (population; 37 keywords), internal load (dependent variable; 35 keywords), and external load (independent variable; 81 keywords). Articles were considered for meta-analysis when a correlation coefficient describing the association between at least one internal and one external measure of session load or intensity, measured in the time or frequency domain, was obtained from team-sport athletes during normal training or match-play (i.e., unstructured observational study). The final data sample included 122 estimates from 13 independent studies describing 15 unique relationships between three internal and nine external measures of load and intensity. This sample included 295 athletes and 10,418 individual session observations. Internal measures were session ratings of perceived exertion (sRPE), sRPE training load (sRPE-TL), and heart-rate-derived training impulse (TRIMP). External measures were total distance (TD), the distance covered at high and very high speeds (HSRD ≥ 13.1-15.0 km h^-1 and VHSRD ≥ 16.9-19.8 km h^-1, respectively), accelerometer load (AL), and the number of sustained impacts (Impacts > 2-5 G). Distinct training modes were identified as either mixed (reference condition), skills, metabolic, or neuromuscular. Separate random effects meta-analyses were conducted for each dataset (n = 15) to determine the pooled relationships between internal and external measures of load and intensity. The moderating effects of training mode were examined using random-effects meta-regression for datasets with at least ten estimates (n = 4). Magnitude-based inferences were used to interpret analyses outcomes.

RESULTS

During all training modes combined, the external load relationships for sRPE-TL were possibly very large with TD [r = 0.79; 90% confidence interval (CI) 0.74 to 0.83], possibly large with AL (r = 0.63; 90% CI 0.54 to 0.70) and Impacts (r = 0.57; 90% CI 0.47 to 0.64), and likely moderate with HSRD (r = 0.47; 90% CI 0.32 to 0.59). The relationship between TRIMP and AL was possibly large (r = 0.54; 90% CI 0.40 to 0.66). All other relationships were unclear or not possible to infer (r range 0.17-0.74, n = 10 datasets). Between-estimate heterogeneity [standard deviations (SDs) representing unexplained variation; τ] in the pooled internal-external relationships were trivial to extremely large for sRPE (τ range = 0.00-0.47), small to large for sRPE-TL (τ range = 0.07-0.31), and trivial to moderate for TRIMP (τ range= 0.00-0.17). The internal-external load relationships during mixed training were possibly very large for sRPE-TL with TD (r = 0.82; 90% CI 0.75 to 0.87) and AL (r = 0.81; 90% CI 0.74 to 0.86), and TRIMP with AL (r = 0.72; 90% CI 0.55 to 0.84), and possibly large for sRPE-TL with HSRD (r = 0.65; 90% CI 0.44 to 0.80). A reduction in these correlation magnitudes was evident for all other training modes (range of the change in r when compared with mixed training - 0.08 to - 0.58), with these differences being unclear to possibly large. Training mode explained 24-100% of the between-estimate variance in the internal-external load relationships.

CONCLUSION

Measures of internal load derived from perceived exertion and heart rate show consistently positive associations with running- and accelerometer-derived external loads and intensity during team-sport training and competition, but the magnitude and uncertainty of these relationships are measure and training mode dependent.

A Kinetic Model Describing Injury-Burden in Team Sports

BACKGROUND

Injuries in team sports are normally characterised by the incidence, severity, and location and type of injuries sustained: these measures, however, do not provide an insight into the variable injury-burden experienced during a season. Injury burden varies according to the team's match and training loads, the rate at which injuries are sustained and the time taken for these injuries to resolve. At the present time, this time-based variation of injury burden has not been modelled.

OBJECTIVES

To develop a kinetic model describing the time-based injury burden experienced by teams in elite team sports and to demonstrate the model's utility.

METHODS

Rates of injury were quantified using a large eight-season database of rugby injuries (5253) and exposure (60,085 player-match-hours) in English professional rugby. Rates of recovery from injury were quantified using time-to-recovery analysis of the injuries.

RESULTS

The kinetic model proposed for predicting a team's time-based injury burden is based on a composite rate equation developed from the incidence of injury, a first-order rate of recovery from injury and the team's playing load. The utility of the model was demonstrated by examining common scenarios encountered in elite rugby.

CONCLUSIONS

The kinetic model developed describes and predicts the variable injury-burden arising from match play during a season of rugby union based on the incidence of match injuries, the rate of recovery from injury and the playing load. The model is equally applicable to other team sports and other scenarios.