Original research
Physical collisions and injury in professional rugby league match-play

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Abstract

Objective: To document the frequency of physical collisions and incidence of contact injury in professional rugby league match-play. Design: Prospective cohort study. Methods: Video recordings of 77 National Rugby League (NRL) matches were coded for the number and type of physical collisions in which players were involved. Each match was analysed and coded for defensive (i.e. tackles, missed tackles, and ineffective tackles) and attacking collisions (i.e. tackled in possession, broken tackles, offloads, support runs, and decoy runs). Injuries that occurred as a result of a physical collision were also recorded. Results: The total number of physical collisions performed per game was greatest in the wide running forwards (47 [95% CI, 42–52]), and was significantly greater (P < 0.05) than the hit-up forwards (36 [95% CI, 32–40]), adjustables (29 [95% CI, 26–32]), and outside backs (24 [95% CI, 22–27]) positional groups. A total of 48 collision injuries were sustained, resulting in an overall injury incidence of 10.6 (95% CI, 7.6–13.6) per 10,000 collisions. Injuries resulting from attacking collisions were consistently higher than injuries sustained in defensive collisions. Wide running forwards had the lowest incidence of injury, and the adjustables and outside backs had the highest incidence of injury. Conclusions: These results highlight the physical demands associated with collisions and tackles in professional rugby league. Furthermore, the results of this study suggest that playing position and the type of collision sustained have a greater influence over contact injury risk in rugby league than the number of physical collisions performed.

Introduction

Rugby league is a collision sport played in several countries worldwide.1 The sport has similar rules and movement patterns to rugby union, however, unlike rugby union, rugby league does not have a line-out, involves 13 players per team (rather than 15), and involves an immediate play-the-ball after each tackle.2, 3 A typical senior rugby league match is 80 min in duration, requiring players to compete in a challenging contest, comprising intense bouts of sprinting and tackling, separated by short bouts of lower intensity activity. During the course of a rugby league match, players are exposed to multiple physical collisions and tackles.4 As a result, musculoskeletal injuries are extremely common.5, 6

To date, few studies have documented the frequency of collisions in professional rugby league. Early research suggested that rugby league players are involved in 20–40 tackles each match, depending on position played.7 However, more recently it has been shown that these values may underestimate the actual physical cost of collisions in some positions (e.g. prop, hooker, second row), and overestimate the actual number of collisions in others (e.g. fullback, wing).4 In a series of studies, Gissane et al.4, 6 coded the number of collisions sustained by a professional rugby league club over one competitive season. The authors coded collisions that occurred both in attack and defence, including tackles and incomplete tackles, and whether the attacking player broke the tackle, offloaded out of the tackle, or was caught in possession of the football. On average, forwards were involved in 55 collisions (39 defensive collisions and 16 attacking collisions), while backs were involved in 29 collisions (16 defensive collisions and 13 attacking collisions). Interestingly, the incidence of injury was higher in backs, despite their involvement in significantly fewer collisions.6 While this study provided important information on the contact demands of professional rugby league, and the injury risk associated with these events, the findings of Gissane et al.4, 6 are dated. Indeed, significant rule changes, including the introduction of the limited interchange rule, makes generalizations of these findings to the modern game problematic. Furthermore, no information was provided on the incidental contacts (e.g. support and decoy runs) that occur throughout a game.

It has recently been shown that the number and intensity of collisions performed in rugby league skills training differ significantly among playing positions.8 Hit-up forwards (i.e. props) and wide running forwards (i.e. second row and lock) reportedly perform more collisions than the adjustables (i.e. hooker, halfback, five-eighth, and fullback) and outside backs (centre and wing) positional groups. However, the incidence of contact injury in the training environment is greatest in the adjustables positional group.8 This finding may reflect the different physiological and anthropometric characteristics (e.g. strength, body composition), the specific nature of tackles affected, and/or different levels of tackling proficiency among the different playing positions.9 Indeed, the adjustables are typically required to defend greater spaces, and are often required to tackle larger players (e.g. wide running forwards).

Given the importance of tackling in rugby league,3, 9 the high frequency of tackles and collisions,4 and that the highest incidence of injury occurs as a result of these physical collisions,5 information on the contact demands of the game are critical from both an injury prevention, recovery, and performance enhancement perspective. With this in mind, the purpose of this study was threefold. Firstly, we documented the demands associated with high-intensity physical collisions in professional rugby league match-play. Secondly, the incidence of contact injury was investigated. Finally, we investigated the effect of short, medium, and long recovery periods between matches on contact injury rates in these athletes.

Section snippets

Methods

Fifty-one professional rugby league players (mean ± SD age, 23.6 ± 3.8 yr) participated in this study. All participants were highly motivated players from the same professional rugby league club and were competing in the elite National Rugby League (NRL) competition. All players were free from injury at the commencement of the study. All participants received a clear explanation of the study, and written consent was obtained. The University of Queensland Ethics Committee for Human Investigation

Results

Players competed in a mean of 15 (95% CI, 13–17) matches per season. Players were involved in significantly more (P < 0.05) defensive collisions per game (19 [95% CI, 17–21]) than attacking collisions (13 [95% CI, 12–14]). Forwards were involved in significantly more (P < 0.05) collisions per game than backs (38 [95% CI, 35–41] vs. 25 [95% CI, 24–27]), with the total number of defensive collisions per game significantly greater (P < 0.05) in forwards (25 [95% CI, 24–27]) than backs (12 [95% CI,

Discussion

This study documented the frequency of physical collisions and incidence of contact injury in professional rugby league match-play. The results of this study demonstrate that during professional rugby league match-play, the number of collisions performed by wide running forwards, hit-up forwards, adjustables, and outside backs is 47, 36, 29, and 24, respectively. However, despite their high number of collisions, the wide running forwards had significantly lower contact injury rates. In

Conclusion

In conclusion, we documented the frequency of physical collisions and incidence of contact injury in professional rugby league match-play and investigated the effect of short, medium, and long recovery periods between matches on contact injury rates in these athletes. The results of this study demonstrate that during professional rugby league match-play, wide running forwards perform the greatest number of collisions, followed by hit-up forwards, adjustables, and outside backs. However, despite

Practical implications

  • Collisions and tackles increase the physiological demands of rugby league match-play, with the majority of injuries also sustained in physical collisions.

  • Wide running forwards experience the greatest number of collisions, while the adjustables and outside backs positional groups experience the least number of collisions.

  • Despite being involved in fewer collisions, the contact injury rates of the adjustables and outside backs is approximately 3.5 times higher than that of the wide running

Conflict of interest

No sources of funding were used to conduct this study. The authors have no conflict of interests that are directly relevant to the content of this study.

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