Changes in northern hemisphere male international rugby union players' body mass and height between 1955 and 2015

Classifying Winning Performances in International Women's Rugby Union

PURPOSE

The efficacy of isolated and relative performance indicators (PIs) has been compared in rugby union; the latter more effective at discerning match outcomes. However, this methodology has not been applied in women's rugby. The aim of this study was to identify PIs that maximize prediction accuracy of match outcome, from isolated and relative data sets, in women's rugby union.

METHODS

Twenty-six PIs were selected from 110 women's international rugby matches between 2017 and 2022 to form an isolated data set, with relative data sets determined by subtracting corresponding opposition PIs. Random forest classification was completed on both data sets, and feature selection and importance were used to simplify models and interpret key PIs. Models were used in prediction on the 2021 World Cup to evaluate performance on unseen data.

RESULTS

The isolated full model correctly classified 75% of outcomes (CI, 65%-82%), whereas the relative full model correctly classified 78% (CI, 69%-86%). Reduced respective models correctly classified 74% (CI, 65%-82%) and 76% (CI, 67%-84%). Reduced models correctly predicted 100% and 96% of outcomes for isolated and relative test data sets, respectively. No significant difference in accuracy was found between data sets. In the relative reduced model, meters made, clean breaks, missed tackles, lineouts lost, carries, and kicks from hand were significant.

CONCLUSIONS

Increased relative meters made, clean breaks, carries, and kicks from hand and decreased relative missed tackles and lineouts lost were associated with success. This information can be utilized to inform physical and tactical preparation and direct physiological studies in women's rugby.

Performance indicators associated with match outcome within the United Rugby Championship

OBJECTIVES

The aims of this study were to: i) identify performance indicators associated with match outcomes in the United Rugby Championship; ii) compare the efficacy of isolated and relative datasets to predict match outcome; and iii) investigate whether reduced statistical models can reproduce predictive accuracy.

DESIGN

Retrospective analysis of key performance indicators in the United Rugby Championship.

METHODS

Twenty-seven performance indicators were selected from 96 matches (2020-21 United Rugby Championship). Random forest classification was completed on isolated and relative datasets, using a binary match outcome (win/lose). Maximum relevance and minimum redundancy performance indicator selection was utilised to reduce models. In addition, models were tested on 53 matches from the 2021-22 season to ascertain prediction accuracy.

RESULTS

Within the 2020-21 datasets, the full models correctly classified 83% of match performances for the relative dataset and 64% for isolated data, the equivalent reduced models classified 85% and 66% respectively. The reduced relative model successfully predicted 90% of match performances in the 21-22 season, highlighting that five performance indicators were significant: kicks from hand, metres made, clean breaks, turnovers conceded and scrum penalties.

CONCLUSIONS

Relative performance indicators were more effective in predicting match outcomes than isolated data. Reducing features used in random forest classification did not degrade prediction accuracy, whilst also simplifying interpretation for practitioners. Increased kicks from hand, metres made, and clean breaks compared to the opposition, as well as fewer scrum penalties and turnovers conceded were all indicators of winning match outcomes within the United Rugby Championship.

Protect the Player, Protect the Game: Reflections from Ex-Professional Rugby Union Players on Law Changes, Protective Equipment, and Duty of Care in the Professional Game

The emphasis of this study was to interview ex-professional male rugby union players (n = 23, mean age 35.5 ± 4.7 years) and discuss concussion management during their careers. In this study, two major themes were identified: (1) the duty of care to professional rugby union players by medical personnel, coaching staff, and owners of professional clubs and (2) the use of protective equipment and law changes to enhance player safety. In total, twenty-three ex-professional rugby union players were interviewed, and the majority (61%) had represented their countries at international test-level rugby. These interviews highlighted the belief that medical teams should be objective, independent entities within a professional rugby club. Furthermore, medical teams should not be in a position of being pressurised by head coaches, members of the coaching team, or club owners regarding return-to-play (RTP) protocols specific to concussion. The interviewees believed that they were pressured by coaches or members of the coaching team to play with concussion or concussive symptoms and other physical injuries. The results indicated that they had manipulated concussion testing themselves or with assistance to pass standard concussion testing protocols. The interviewees indicated that club owners have a duty of care to players even in retirement due to the high incidence of physical and mental injuries endured as a professional rugby player. Most participants indicated that a reduction in match playing time and reducing the amount of time engaged in contact training (workload volume) may assist in reducing concussion incidence. The participants suggested that changes to the current laws of the game or the use of protective equipment did not mitigate against concussion risk in the game of rugby union. The main limitation to the study is that participants had retired in the past ten years, and conditions for players may have changed. This study has highlighted that additional efforts are required by professional clubs to ensure the highest duty of care is delivered to current players and recently retired players.

The epidemiology of head injuries at 2019 Rugby Union World Cup

INTRODUCTION

The sequelae of concussion are of growing concern within Rugby. World Rugby has introduced rule changes to improve player welfare and reduce head injury frequency. We aimed to report the incidence of head injuries and head injury assessment (HIA) at the 2019 Rugby World Cup (RWC).

METHODS

We reviewed all 45 tournament matches and recorded the number of head injuries, the injured player's position, and the mechanism of injury; whether the player had an HIA; and if they returned to play following injury. We compared these findings with previous RWCs.

RESULTS

We recorded 68 head injuries (1.33/game). Thirty-six players (52.9%) were removed from the field of play for an HIA. Of these, 23 (63.9%) failed and therefore considered to have concussion. The head injury rate in 2019 was 37.8 per 1000 player hours, which increased from previous tournaments (22.0 in 2015, 14.6 in 2011, and 4.7 in 2007). The concussion rate was 23 per 1000 player hours in 2019, which was lower than 29 in 2015. In 2019, 63.9% of HIAs were failed compared to 48.7% in 2015. We identified 17 cases where medical staff did not attend to a player suffering a head injury on-field. Of these, four players underwent an HIA after the match doctor reviewed the incident.

CONCLUSION

We recorded a higher rate of head injuries, and a player was more likely to fail their HIA than in previous tournaments. These findings may represent a greater awareness from medical staff and the benefits of education. However, 25% of head injuries not receiving an initial on-field assessment provide room for improvement.

A game for all shapes and sizes? Changes in anthropometric and performance measures of elite professional rugby union players 1999–2018

Background

Rugby union player size has increased since the game turned professional in 1995. Changes in physical and performance capability over this period have yet to be fully described.

Hypothesis

Increases in player momentum would result from changes in body mass.

Methods

Within-player rates of change in anthropometric and kinetic variables with season played were sampled in three successively studied professional rugby union club cohorts playing at the highest level of European competition between 1999 and 2019. Data comprised 910 seasons of observation for 291 elite male players. Most players had 2, 3 or 4 seasons of observation. Mixed-effects modelling distinguished changes independent of position played, club and international status.

Results

With each season played, player body mass, fat-free mass and maximum speed increased significantly, while per cent fat decreased. The mean maximal velocity of a rugby player in 1999 was 8.2 (±0.18) m/s, which in 2019 had risen to 9.1 (±0.10) m/s. Player’s momentum in 2019 was 14% more than those playing in 1999. In the Front Five, momentum increased in this period by >25%, mainly driven by greater running speed, disproving our hypothesis.

Conclusions

The momentum of players, particularly forwards, increased markedly over 20 seasons of professional rugby. The resulting forces generated in collisions are thus significantly greater, although these may be mitigated by better player conditioning. Proactive regulation to address player safety may be required to address the changing nature of anthropometric measures and physical performance, minimising injury rates and potential long-term sequelae.

The role of player mass and contact speed on head kinematics and neck dynamics in rugby union tackling

Tackling is the most common cause of general injuries in rugby union, with player speed and mass identified as risk factors. This study aimed to use multibody modeling simulations to examine how tackler and ball carrier mass and contact speed affect inertial head kinematics and neck dynamics. Simulations were run by independently varying the ball carrier and tackler mass (from 60 to 110kg) and speed (from 0 to 10 m/s). Peak resultant inertial neck dynamics (force and moment) and head kinematics (linear acceleration, angular acceleration, and angular velocity) were extracted from each simulation. The greatest inertial head kinematics and neck dynamics sustained by a player was when there was the greatest mass disparity in the tackle, with the lighter player experiencing greatest inertial neck dynamics and head kinematics by up to 24% in comparison with the scenario when both players were the lightest mass (60 kg). As a player's mass increased, the magnitude of their head kinematics and neck dynamics diminished, but increased for their direct opponent, irrespective of whether they were the tackler or ball carrier. For speed, the greatest inertial head kinematics and neck dynamics sustained by the ball carrier and tackler were when they were both traveling at the highest speed. In theory, large discrepancies in mass of players, and high speeds into a tackle should be avoided.

International female rugby union players' anthropometric and physical performance characteristics: A five-year longitudinal analysis by individual positional groups

Longitudinal changes in anthropometric and physical performance characteristics of International female rugby union players were evaluated across 5-seasons, according to field position. Sixty-eight international female rugby union players from a top 2 ranked international team, undertook anthropometric and physical performance measurements across five seasons. Anthropometric and physical performance changes occurred, with skinfolds decreasing between 2015 and 2017 and body mass increasing between 2017 and 2019. Single-leg isometric squat (SL ISO), 0-10 m momentum (0-10 Mom) and 20-30 m momentum (20-30Mom) were higher in 2018 and 2019 than all years. Front-row players were characterised by greater SL ISO and 1-RM bench press than inside and outside backs, with higher skinfolds and lower endurance levels than all positions. Between 2017 and 2019, front-row players had larger decreases and increases in endurance and one repetition maximum (1-RM) bench press, respectively, compared to all other positions. Forwards had the highest 0-10Mom and 20-30Mom, and scrum-half the lowest, while outside backs had faster 0-10, 30-40, and 40 m (TT40 m) times, and greater peak velocity (V_max) compared to forward positions. These longitudinal findings show that physical performance has increased, with anthropometric and performance characteristics becoming more distinctive between positions, among elite female rugby union players.

Body Mass and Body Composition Changes over 7 Years in a Male Professional Rugby Union Team

The purpose of this study was to investigate longitudinal body mass and body composition changes in one professional rugby union team (n=123), (i) according to position [forwards (n=58) versus backs (n=65)], analysis of players with 6 consecutive seasons of DXA scans (n=21) and, (iii) to examine differences by playing status [academy and international], over 7 years. Players [mean age: 26.8 y, body mass index: 28.9+kg.m²] received DXA scans at fourtime points within each year. A modest (but non-significant) increase in mean total mass (0.8 kg) for professional players was reflected by increased lean mass and reduced body fat mass. At all-time points, forwards had a significantly greater total mass, lean mass and body fat percentage compared to backs (p<0.05). Academy players demonstrated increased total and lean mass and decreased body fat percentage over the first 3 years of senior rugby, although this was not significant. Senior and academy international players had greater lean mass and lower body fat percentage (p<0.05) than non-international counterparts. Despite modest increases in total mass; reflected by increased lean mass and reduced fat mass, no significant changes in body mass or body composition, irrespective of playing position were apparent over 7 years.

Elite international female rugby union physical match demands: A five-year longitudinal analysis by position and opposition quality

OBJECTIVES

This study aimed to evaluate changes in rugby union physical match characteristics across five seasons of International female competition, according to position and opposition quality.

DESIGN & METHODS

Global positional systems and performance analysis data from 78 female rugby union players (minimum of five international appearances) were analysed between 2015 and 2019. Mixed-linear-modelling was used to investigate the effects of season, opposition and position during 969 individual match performances from 53 International matches.

RESULTS

Running demands increased between 2015 and 2017 (World Cup year) and plateaued thereafter, except for sprints among the outside backs, which declined between 2017 and 2019, and accelerations and decelerations >3 m s² which increased between 2017 and 2019. Collisions were higher in forwards than backs, and highest against stronger opposition. Running demands were greater against weaker opposition, but the 'most intense periods' of running were greater against stronger opposition in 2017.

CONCLUSIONS

Match demands increased between 2015 and the 2017 World Cup year, which was underpinned by increased sprinting and greater running during maximum intensity periods against top 5 opposition. The increase in accelerations and decelerations in the latter years, alongside the maintenance of average running demands and collision counts, is consistent with the reported continuous playing style of female rugby, thus placing specific demands on players and requiring tailored training methods. Some positions (Forwards and Scrum-halves) appear to be important for this adopted style, demonstrating concomitantly high relative collision and running intensities.

Magnetic Resonance Arthrography in Rugby Players Undergoing Shoulder Stabilization for Glenohumeral Instability: Professionals Have Higher Frequencies of More Pathologies

Purpose

To quantify the magnetic resonance arthrography (MRA) findings in rugby players during preoperative workup for anterior surgical stabilization for glenohumeral instability.

Methods

All patients who underwent glenohumeral instability surgery in our institution between 2008 and 2018 were considered for inclusion. Rugby players were identified using the patient's medical notes, with subsequent identification of all professional players. All rugby player's preoperative MRA findings were recorded and analyzed.

Results

Overall, 267 rugby players were included, 261 of whom were male (97.8%), with a mean age of 22.7 years (range 13-55 years). There were 58 professional rugby players (21.7%). The mean number of pathologies in nonprofessional rugby players was 5.0 pathologies versus 6.2 pathologies in the professional rugby players, with a significant difference in nonprofessional rugby players with up to 3 pathologies versus professional rugby players (26.3% vs 10.3%, P = .01). Professional rugby players had a statistically significant increased incidence of bicipital tendon lesions (25.9% vs 13.9%, P = .009), acromioclavicular joint degeneration (60.3% vs 42.1%, P = .016), glenohumeral bone loss (87.9% vs 69.9%, P = .006), and degenerative changes (67.2% vs 44.0%, P = .002) on their MRAs.

Conclusions

Rugby players undergoing surgical stabilization for glenohumeral instability often have a significant number of pathologies identified on MRA at the time of surgery. Professional rugby players showed concerningly greater frequencies of early degenerative changes when compared with nonprofessional rugby players.

Level of Evidence

III; Retrospective Cohort Study.

Genetic Factors That Could Affect Concussion Risk in Elite Rugby

Elite rugby league and union have some of the highest reported rates of concussion (mild traumatic brain injury) in professional sport due in part to their full-contact high-velocity collision-based nature. Currently, concussions are the most commonly reported match injury during the tackle for both the ball carrier and the tackler (8-28 concussions per 1000 player match hours) and reports exist of reduced cognitive function and long-term health consequences that can end a playing career and produce continued ill health. Concussion is a complex phenotype, influenced by environmental factors and an individual's genetic predisposition. This article reviews concussion incidence within elite rugby and addresses the biomechanics and pathophysiology of concussion and how genetic predisposition may influence incidence, severity and outcome. Associations have been reported between a variety of genetic variants and traumatic brain injury. However, little effort has been devoted to the study of genetic associations with concussion within elite rugby players. Due to a growing understanding of the molecular characteristics underpinning the pathophysiology of concussion, investigating genetic variation within elite rugby is a viable and worthy proposition. Therefore, we propose from this review that several genetic variants within or near candidate genes of interest, namely APOE, MAPT, IL6R, COMT, SLC6A4, 5-HTTLPR, DRD2, DRD4, ANKK1, BDNF and GRIN2A, warrant further study within elite rugby and other sports involving high-velocity collisions.

Trends in player body mass at men's and women's Rugby World Cups: a plateau in body mass and differences in emerging rugby nations

Objectives

This study assessed the mass of international rugby players in the men's and women's Rugby World Cups between 1991 and 2019. The objective was to quantify changes in mass of players by position, and to compare changes between men and women, and between established (Tier 1 (T1)) and emerging (Tier 2 (T2)) rugby nations.

Setting

Rugby World Cups from 1991 to 2019 for men's players and 2010 to 2017 for women's players.

Participants

4447 elite male and 958 elite female players.

Primary and secondary outcome measures

Player body mass, grouped as men and women, T1 and T2 nations, and by playing position, assessed over time.

Results

Men's player mass increased significantly between 1991 and 2019 (T1 overall 9.7% increase), but this increase occurred almost entirely up to 2011. Women's forwards mass increased by 4.8% in T1, with no changes in T2 or backs from either tier. Significant differences in mass were found between T1 and T2 forwards and backs for both men and women.

Conclusions

The body mass of men's players has stabilised after initial increases following professionalisation. Player body mass may be approaching a plateau, beyond which no further performance advantages occur. Changes to laws and tactical approaches by coaches may have contributed to this, by changing match demands on players, necessitating endurance, agility and speed. Trends in the evolution of T2 players suggest a barrier to identifying and developing heavy athletic players, and may require intervention to ensure competitive parity.

Challenges and [Possible] Solutions to Optimizing Talent Identification and Development in Sport

The modern-day landscape of Olympic and Professional sport is arguably more competitive than ever. One consequence of this is the increased focus on identifying and developing early athletic talent. In this paper, we highlight key challenges associated with talent (athlete) identification and development and propose possible solutions that could be considered by research and practice. The first challenge focuses on clarifying the purposes of talent identification initiatives such as defining what talent is and how its meaning might evolve over time. Challenge two centers on ways to best identify, select and develop talent, including issues with different approaches to identification, the need to understand the impact of development and the need to have appropriate resourcing in the system to support continued development of knowledge. Finally, we discuss two challenges in relation to the 'healthiness' of talent identification and development. The first examines whether a talent identification and development system is 'healthy' for athletes while the second focuses on how sport stakeholders could discourage the apparent trend toward early specialization in youth sport settings. Whilst this paper discusses the research in relation to these challenges, we propose multiple possible solutions that researchers and practitioners could consider for optimizing their approach to talent identification and development. In summary, talent is a complex and largely misunderstood phenomenon lacking robust research evidence, and given concerns that it is potentially unhealthy, talent identification and selection at younger ages is not recommended.

Injury surveillance and prevention practices across Rugby schools in Ireland

OBJECTIVES

To ascertain the extent of injury surveillance and prevention practices currently in operation and the availability of qualified personnel across Rugby playing schools in the Republic of Ireland.

DESIGN

Cross-sectional survey design.

SETTING

Rugby playing schools across Ireland.

PARTICIPANTS

The Rugby games master, head Rugby coach or teacher/coach with knowledge of all Rugby activities in the school.

RESULTS

Ninety-three Rugby playing schools responded and reported 356 (97% male, 3% female) school Rugby teams. Rugby injuries were formally monitored in 86% of schools. Injury recorders were primarily coaches (61%). Physiotherapy provision was available in 28% of schools, 14% of schools provided access to a medical doctor and 44% of schools provided access to an S&C coach. Structured warm-ups were undertaken in 66% of schools, weekly gym sessions in 49% of schools and 31% of schools did not implement any formal injury prevention measures.

CONCLUSIONS

Injury monitoring practices, medical personnel accessibility and the frequency of injury prevention practices varies considerably across Rugby playing schools in Ireland. Future injury surveillance and prevention systems should be suitable for use by non-medical personnel and reflect the structural organisation of the school Rugby game so that data are not solely representative of the elite, well-resourced schools.