Incidence of injury in junior rugby league players over four competitive seasons

Summary

While several studies have documented the incidence of injury in senior rugby league players, information on the injury rates of junior rugby league players is limited. In addition, all of the injury surveillance studies performed on junior rugby league players have been performed over a limited time frame (typically one season). The purpose of this study was to document the incidence of injury in junior rugby league players over four competitive seasons. Injury data were collected from 84 matches. An injury was defined as one that occurred in a match and resulted in the player missing a subsequent match. The overall incidence of injury was 56.8 (95% CI, 42.6–70.9) per 1000 playing hours. The majority of injuries were sustained to the shoulder (15.6 [95% CI, 8.2–23.0] per 1000 playing hours). Sprains were the most common type of injury (24.7 [95% CI, 15.4–34.1] per 1000 playing hours). Injuries were most commonly sustained while being tackled (19.2 [95% CI, 11.0–27.5] per 1000 playing hours) and while tackling (10.1 [95% CI, 4.1–16.0] per 1000 playing hours). While there was a tendency towards differing injury rates over the four competitive seasons (χ² = 6.3, d.f. = 3), the differences were not statistically significant (p = 0.10). These findings demonstrate that the incidence of junior rugby league injuries is similar to previously reported for senior competitors. A long-term collaborative effort to reduce the incidence of injury in junior rugby league players is warranted.

Introduction

Rugby league is a collision sport played by junior and senior competitors, at the elite and sub-elite levels.¹ The game is intermittent in nature, requiring players to compete in a challenging contest, comprising intense bouts of sprinting and tackling, separated by short bouts of lower intensity activity (recovery).¹ As a result of the high number of physical collisions and intense nature of the game, musculoskeletal injuries are common.²

Several studies have documented the incidence of injury in senior (amateur, semi-professional and professional) rugby league players.² Studies that have defined injuries in terms of missed matches, have reported an injury incidence of 26.8–60.3 per 1000 playing hours, with the incidence of injury typically increasing with increases in playing level.² Moreover, the incidence of rugby league injury has typically been shown to vary from season to season, with studies of amateur,³ semi-professional⁴ and professional5, 6 rugby league players demonstrating the significant differences in injury rates among playing seasons. In separate studies of professional rugby league players competing in the United Kingdom, Hodgson Phillips et al.⁵ and Gissane et al.⁶ reported progressive increases in the incidence of injury when matches were moved from the autumn and winter months to the spring and summer months. These findings have been supported by Gabbett3, 4 who reported variations in injury rates across playing seasons of up to 25%. It has been suggested that environmental conditions (e.g., low rainfall) and ground conditions (e.g., hard playing surfaces) may contribute to the variability in injury incidence across playing seasons in rugby league players,⁷ although changes in training and playing intensity have also been implicated.⁸

While several studies have documented the incidence of injury in senior rugby league players, information on the injury rates of junior rugby league players is limited.9, 10, 11 In addition, all of the injury surveillance studies performed on junior rugby league players have been performed over a limited time frame (typically one season). Consequently, these short-term studies fail to take into account the inherent inter-seasonal variability in the rugby league injury profile.

Raftery et al.⁹ studied the incidence of injury in sub-elite junior rugby league players over one competitive season. The incidence of injury for Under 17 players was reported to be 15.6 per 1000 playing hours. Estell et al.¹⁰ found an injury incidence of 17.8 and 28.0 per 1000 playing hours in elite Under 17 and Under 19 rugby league players, respectively. However, the findings of Estell et al.¹⁰ and Raftery et al.⁹ are dated, with only one recent study on the incidence of injury in junior rugby league players.¹¹ Using an identical definition of injury (i.e., one resulting in a missed match), King¹¹ reported an unusually high incidence of injury (129.2 per 1000 playing hours) in Under 16 and Under 18 New Zealand junior rugby league players. A limitation of this study was that the competition lasted a total of 7 weeks, providing a total of 340 injury exposure hours. While the short-term nature of the competition may have increased playing intensity and, subsequently, injury rates, the reported incidence of injury is approximately eightfold higher than in other junior competitions, and two times greater than that reported for professional senior players.5, 6 Due to the short-term nature of all of these studies, and the large variations in injury rates, collectively these studies raise questions on the actual incidence of injury in junior rugby league players. To date, there are no published long-term injury surveillance studies of junior rugby league players. With this in mind, the purpose of this study was to document the incidence of injury in junior rugby league players over four competitive seasons.