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

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.

Workload, Fatigue, and Muscle Damage in an Under-20 Rugby Union Team Over an Intensified International Tournament

PURPOSE

To examine the effects of an intensified tournament on workload, perceptual and neuromuscular fatigue, and muscle-damage responses in an international under-20 rugby union team.

METHODS

Players were subdivided into a high-exposure group (HEG, n = 13) and a low-exposure group (LEG, n = 11) according to match-play exposure time. Measures monitored over the 19-d period included training session (n = 10) and match (n = 5) workload determined via global positioning systems and session rating of perceived exertion. Well-being scores, countermovement jump height performance, and blood creatine kinase concentrations were collected at various time points.

RESULTS

Analysis of workload cumulated across the tournament entirety for training and match play combined showed that high-speed running distance was similar between groups, while a very likely larger session rating of perceived exertion load was reported in HEG vs LEG. In HEG, high-speed activity fluctuated across the 5 successive matches, albeit with no clear trend for a progressive decrease. No clear tendency for a progressive decrease in well-being scores prior to or following matches was observed in either group. In HEG, trivial to possibly small reductions in postmatch countermovement jump performance were observed, while unclear to most likely moderate increases in prematch blood creatine kinase concentrations occurred until prior to match 4.

CONCLUSIONS

The magnitude of match-to-match changes in external workload, perceptual and neuromuscular fatigue, and muscle damage was generally unclear or small. These results suggest that irrespective of exposure time to match play players generally maintained performance and readiness to play across the intensified tournament. These findings support the need for holistic systematic player-monitoring programs.

The Quantification of Within-Week Session Intensity, Duration, and Intensity Distribution Across a Season in Australian Football Using the Session Rating of Perceived Exertion Method

CONTEXT

Team-sport training requires the daily manipulation of intensity, duration, and frequency, with preseason training focusing on meeting the demands of in-season competition and training on maintaining fitness.

PURPOSE

To provide information about daily training in Australian football (AF), this study aimed to quantify session intensity, duration, and intensity distribution across different stages of an entire season.

METHODS

Intensity (session ratings of perceived exertion; CR-10 scale) and duration were collected from 45 professional male AF players for every training session and game. Each session's rating of perceived exertion was categorized into a corresponding intensity zone, low (<4.0 arbitrary units), moderate (≥4.0 and <7.0), and high (≥7.0), to categorize session intensity. Linear mixed models were constructed to estimate session duration, intensity, and distribution between the 3 preseason and 4 in-season periods. Effects were assessed using linear mixed models and magnitude-based inferences.

RESULTS

The distribution of the mean session intensity across the season was 29% low intensity, 57% moderate intensity, and 14% high intensity. While 96% of games were high intensity, 44% and 49% of skills training sessions were low intensity and moderate intensity, respectively. Running had the highest proportion of high-intensity training sessions (27%). Preseason displayed higher training-session intensity (effect size [ES] = 0.29-0.91) and duration (ES = 0.33-1.44), while in-season game intensity (ES = 0.31-0.51) and duration (ES = 0.51-0.82) were higher.

CONCLUSIONS

By using a cost-effective monitoring tool, this study provides information about the intensity, duration, and intensity distribution of all training types across different phases of a season, thus allowing a greater understanding of the training and competition demands of Australian footballers.

Macronutrient Intakes of Male Rugby Union Players: A Review

Rugby is a worldwide intermittent team sport. Players tend to be heavier than the majority of similar team sport athletes on whom the dietary guidelines have been developed. Therefore, the aim of the current review was to describe the intakes of rugby union players. Article databases were searched up to February 2017 and were included if they were published in English and reported dietary intakes of male rugby union players. Of the research articles identified, energy intakes were lower than two of three studies that reported intakes and expenditure, which would suggest the players were losing weight that is somewhat supported by the decreases in skinfolds seen during preseason. However, it should also be noted that there are errors in both the measurement of energy intakes and expenditure. Carbohydrate intakes ranged from 2.6 to 6.5 g·kg^-1·day^-1, which is lower than the current relative to body mass recommendations; however, this would not be classed as a low-carbohydrate diet. The consistently low intakes of carbohydrate suggest that these intake levels maybe sufficient for performance, given the players greater body mass or there are errors in the measurements. However, there is currently no evidence for the carbohydrate needs of rugby union players in terms of performance. The lower intakes than expenditure would suggest the players were losing weight. Previous research shows that rugby union players lose body fat during preseason training.

Monitoring Rugby Players for Fitness and Fatigue: What Do Coaches Want?

Purpose: The advantages of monitoring players in a team are well documented. However, barriers associated with lack of resources and time prevent teams from implementing systematic monitoring programs. This study aimed to identify (1) the methods rugby teams use to monitor the training load and associated response to the training load and (2) prerequisites of a monitoring protocol that are scientifically suitable and practically applicable for monitoring fitness and fatigue of rugby players. Methods: Coaches and support staff working with varying levels of rugby union were invited to complete an online questionnaire. Results: Of the 55 respondents, 96% indicated that although they regarded monitoring the training load and training-load response as important, there is no monitoring protocol that is cost-effective, time efficient, and nonaversive to the players. Respondents measured several variables when monitoring and incorporated more subjective than objective measures. Respondents (41%) indicated that they would like a protocol that is time efficient (5–10 min) and provides immediate feedback on players who identify as fatigued (50%). For coaches to have confidence in the information provided by the protocol, it needs to meet basic clinimetric principles of reliability and validity. The technical and biological error in the measurement needs to be known so that meaningful changes in fatigue and fitness can be distinguished from natural variations in the measurements. Conclusions: Prerequisites of an ideal monitoring protocol for rugby players were identified. It follows that a monitoring protocol that fulfills these prerequisites should satisfy both scientific principles and the coach’s demands.

A review advocating caution with Major League Soccer expansion and investment in more rehabilitation professionals

BACKGROUND AND PURPOSE

Major League Soccer (MLS) has aggressively expanded from 10 teams to 23 teams. With the addition of more teams, the league will have to dictate a schedule that maximizes the league's popularity, while also maintaining the health of the players. A longer season and congested game schedule could increase the risk of injury for players. The purpose of this commentary is to make recommendations for the prevention of injuries among MLS players with respect to proposed league expansion.

DESCRIPTION OF TOPIC

MLS has lengthened the regular season with each expansion in teams. An increase in season length was seen in conjunction with the MLS expansion from 14 to 19 teams during the 2008 through 2013 seasons. Data from the inaugural MLS season found injury rates were higher in games compared to practices and more injuries occurred later in the season. With the expansion of MLS, anterior cruciate ligament tears appeared to have increased each year.

DISCUSSION

Current evidence suggests the implementation of a proper preseason in addition to the once-per-week game frequency would best promote player health and well-being. Players may benefit from in-season injury prevention training and weekly load monitoring.

The associations between training load and baseline characteristics on musculoskeletal injury and pain in endurance sport populations: A systematic review

OBJECTIVES

To determine the associations between training load, baseline characteristics (e.g. age or previous injury) and rate of musculoskeletal injury and/or pain specifically within an Endurance Sporting Population (ESP).

DESIGN

Prospectively registered systematic review.

METHODS

Eight electronic databases were searched by two independent reviewers. Studies were required to prospectively monitor both (i) training loads and (ii) musculoskeletal injury and/or pain for >3 months. Methodological quality and risk of bias were determined utilising the Critical Skills Appraisal Program (CASP). Reported effect sizes were categorised as small, medium or large.

RESULTS

Twelve endurance sport studies were eligible (running, triathlon, rowing). Increased injury and/or pain risk was associated with: (i) high total training distances per week/month (medium effect size) (ii) training frequency <2 sessions/week (medium effect size) and (iii) both low weekly (<2hours/week) and high monthly (large effect size) training durations. None of the studies reported internal training load data or acute:chronic workload ratios. Baseline characteristics found to increase the rate of injury and/or pain included: (i) a history of previous injury (medium effect size), (ii) age >45 years (small effect size), (iii) non-musculoskeletal comorbidities (large effect size), (iv) using older running shoes (small effect size) and (v) non-competitive behaviour.

CONCLUSIONS

This review identifies a range of external training load factors and baseline characteristics associated with an increased rate of injury and/or pain within ESPs. There is an absence of research relating to internal training loads and acute:chronic workload ratios in relation to rate of injury and/or pain within ESPs.

Strength and Conditioning Coaches' Application of the Session Rating of Perceived Exertion Method of Monitoring within Professional Rugby Union

Session rating of perceived exertion (session-RPE) is a method of monitoring and managing training loads. The purpose of this study was to research how and for what purpose strength and conditioning (S&C) coaches implement this monitoring method within professional rugby union. The study also aimed to assess if S&C coaches found this monitoring method to be valid and effective. An online survey containing 24 fixed response questions was used to assess how S&C coaches applied the session-RPE method. The survey was piloted with expert researchers and practitioners in the area of session-RPE prior to distribution and alterations were made to the survey based on the experts' feedback. Twenty S&C coaches working with professional rugby union clubs in Ireland, England, Scotland and Wales completed the survey. The coaches' responses indicated that the majority found the session-RPE to be a valid and effective monitoring method. While some good implementation practices were identified, not all of the coaches adhered to these guidelines which may impact on the accuracy of the collected data. For example, 30% of coaches do not collect the RPE for every session that a player does per week limiting the use of the session-RPE variables cumulative training load, training monotony, training strain and acute:chronic load ratio. S&C coaches within rugby should consider using session-RPE as a method of monitoring and implement the method in a manner reflective of research findings to enhance the potential applications of this system in maximising adaptations and minimising the risk of injury.

Exposure time, running and skill-related performance in international u20 rugby union players during an intensified tournament

PURPOSE

This study investigated exposure time, running and skill-related performance in two international u20 rugby union teams during an intensified tournament: the 2015 Junior World Rugby Championship.

METHOD

Both teams played 5 matches in 19 days. Analyses were conducted using global positioning system (GPS) tracking (Viper 2™, Statsports Technologies Ltd) and event coding (Opta Pro®).

RESULTS

Of the 62 players monitored, 36 (57.1%) participated in 4 matches and 23 (36.5%) in all 5 matches while player availability for selection was 88%. Analyses of team running output (all players completing >60-min play) showed that the total and peak 5-minute high metabolic load distances covered were likely-to-very likely moderately higher in the final match compared to matches 1 and 2 in back and forward players. In individual players with the highest match-play exposure (participation in >75% of total competition playing time and >75-min in each of the final 3 matches), comparisons of performance in matches 4 and 5 versus match 3 (three most important matches) reported moderate-to-large decreases in total and high metabolic load distance in backs while similar magnitude reductions occurred in high-speed distance in forwards. In contrast, skill-related performance was unchanged, albeit with trivial and unclear changes, while there were no alterations in either total or high-speed running distance covered at the end of matches.

CONCLUSIONS

These findings suggest that despite high availability for selection, players were not over-exposed to match-play during an intensified u20 international tournament. They also imply that the teams coped with the running and skill-related demands. Similarly, individual players with the highest exposure to match-play were also able to maintain skill-related performance and end-match running output (despite an overall reduction in the latter). These results support the need for player rotation and monitoring of performance, recovery and intervention strategies during intensified tournaments.

How Much Rugby is Too Much? A Seven-Season Prospective Cohort Study of Match Exposure and Injury Risk in Professional Rugby Union Players

INTRODUCTION

Numerous studies have documented the incidence and nature of injuries in professional rugby union, but few have identified specific risk factors for injury in this population using appropriate statistical methods. In particular, little is known about the role of previous short-term or longer-term match exposures in current injury risk in this setting.

OBJECTIVES

Our objective was to investigate the influence that match exposure has upon injury risk in rugby union.

METHOD

We conducted a seven-season (2006/7-2012/13) prospective cohort study of time-loss injuries in 1253 English premiership professional players. Players' 12-month match exposure (number of matches a player was involved in for ≥20 min in the preceding 12 months) and 1-month match exposure (number of full-game equivalent [FGE] matches in preceding 30 days) were assessed as risk factors for injury using a nested frailty model and magnitude-based inferences.

RESULTS

The 12-month match exposure was associated with injury risk in a non-linear fashion; players who had been involved in fewer than ≈15 or more than ≈35 matches over the preceding 12-month period were more susceptible to injury. Monthly match exposure was linearly associated with injury risk (hazard ratio [HR]: 1.14 per 2 standard deviation [3.2 FGE] increase, 90% confidence interval [CI] 1.08-1.20; likely harmful), although this effect was substantially attenuated for players in the upper quartile for 12-month match exposures (>28 matches).

CONCLUSION

A player's accumulated (12-month) and recent (1-month) match exposure substantially influences their current injury risk. Careful attention should be paid to planning the workloads and monitoring the responses of players involved in: (1) a high (>≈35) number of matches in the previous year, (2) a low (<≈15) number of matches in the previous year, and (3) a low-moderate number of matches in previous year but who have played intensively in the recent past. These findings make a major contribution to evidence-based policy decisions regarding match workload limits in professional rugby union.

Modelling injury-burden in rugby sevens

OBJECTIVES

To develop a time-based model of injury-burden for international rugby sevens teams and to demonstrate its utility.

DESIGN

Descriptive, cohort study.

METHODS

Injury data recorded during seven seasons of the Sevens World Series were used to quantify the rate of injury and the rate at which injured players recovered from injury. An equation describing the rate at which injuries were sustained was combined with an equation for the rate at which injured players recovered from injury to produce a time-based equation for the injury-burden of rugby sevens players at any point in time during a season.

RESULTS

The overall rates at which match and training injuries were sustained (incidence of injury) were 108.6 (95% confidence interval: 101.6-116.1) injuries/1000 player-match-hours and 0.91 (95% CI: 0.65-1.27) injuries/1000 player-training-hours, respectively. Injured players recovered from injury according to a first-order rate equation with a rate constant of 0.0257 days^-1 calculated from the median severity of injuries sustained (27 days). The time-based injury-burden values predicted from the proposed kinetic model of injury-burden closely matched the values recorded in the Sevens World Series.

CONCLUSIONS

For governing bodies in rugby, the proposed model provides a way to examine the consequences of changes in the number and timing of international rugby sevens tournaments. For individual teams, the model provides a means to forecast and manage the team's injury-burden as a function of the team's scheduled match and training loads throughout a season.

Evidence in support of the call to ban the tackle and harmful contact in school rugby: a response to World Rugby

In a paper published in BJSM (June 2016), World Rugby employees Ross Tucker and Martin Raftery and a third coauthor Evert Verhagen took issue with the recent call to ban tackling in school rugby in the UK and Ireland. That call (to ban tackling) was supported by a systematic review published in BJSM Tucker et al claim that: (1) the mechanisms and risk factors for injury along with the incidence and severity of injury in youth rugby union have not been thoroughly identified or understood; (2) rugby players are at no greater risk of injury than other sports people, (3) this is particularly the case for children under 15 years and (4) removing the opportunity to learn the tackle from school pupils might increase rates of injuries. They conclude that a ban 'may be unnecessary and may also lead to unintended consequences such as an increase in the risk of injury later in participation.' Here we aim to rebut the case by Tucker et al We share new research that extends the findings of our original systematic review and meta-analysis. A cautionary approach requires the removal of the tackle from school rugby as the quickest and most effective method of reducing high injury rates in youth rugby, a public health priority.

Tensiomyographic Markers Are Not Sensitive for Monitoring Muscle Fatigue in Elite Youth Athletes: A Pilot Study

Objective: Tensiomyography (TMG) is an indirect measure of a muscle's contractile properties and has the potential as a technique for detecting exercise-induced skeletal muscle fatigue. Therefore, the aim of this study was to assess the sensitivity of tensiomyographic markers to identify reduced muscular performance in elite youth athletes. Methods: Fourteen male junior tennis players (age: 14.9 ± 1.2 years) with an international (International Tennis Federation) ranking position participated in this pre-post single group trial. They completed a 4-day high-intensity interval training (HIT) microcycle, which was composed of seven training sessions. TMG markers; countermovement jump (CMJ) performance (criterion measure of fatigue); delayed onset muscle soreness; and perceived recovery and stress were measured 24 h before and after the training program. The TMG measures included maximal radial deformation of the rectus femoris muscle belly (Dm), contraction time between 10 and 90% Dm (Tc) and the rate of deformation until 10% (V10) and 90% Dm (V90), respectively. Diagnostic characteristics were assessed with a receiver-operating curve (ROC) analysis and a contingency table, in which the area under the curve (AUC), Youden's index, sensitivity, specificity, and the diagnostic effectiveness (DE) of TMG measures were reported. A minimum AUC of 0.70 and a lower confidence interval (CI) >0.50 classified "good" diagnostic markers to assess performance changes. Results: Twenty-four hours after the microcycle, CMJ performance was observed to be significantly (p < 0.001) reduced (Effect Size [ES] = -0.68), and DOMS (ES = 3.62) as well as perceived stress were significantly (p < 0.001) increased. In contrast, Dm (ES = -0.35), Tc (ES = 0.04), V10 (ES = -0.32), and V90 (ES = -0.33) remained unchanged (p > 0.05) throughout the study. ROC analysis and the data derived from the contingency table revealed that none of the tensiomyographic markers were effective diagnostic tools for detecting impaired muscular performance in elite youth athletes (AUC, 95% CI, DE%; Dm: 0.46, 0.15-0.77, 35.7%; Tc: 0.29, 0.03-0.59, 35.7%; V10: 0.71, 0.27-1.00, 35.7%; V90: 0.37, 0.10-0.65, 35.7%). Conclusion: The tensiomyographic parameters that were assessed in this study were not sensitive enough to detect muscular performance changes in elite youth athletes.However, due to the preliminary nature of the study, further research is needed to investigate the sensitivity of TMG in this population.