Influence of training and match intensity on injuries in rugby league

The aim of this study was to examine the influence of perceived intensity, duration and load of matches and training on the incidence of injury in rugby league players. The incidence of injury was prospectively studied in 79 semi-professional rugby league players during the 2001 season. All injuries sustained during matches and training sessions were recorded. Training sessions were conducted from December to September, with matches played from February to September. The intensity of individual training sessions and matches was estimated using a modified rating of perceived exertion scale. Training load was calculated by multiplying the training intensity by the duration of the training session. The match load was calculated by multiplying the match intensity by the time each player participated in the match. Training load increased from December (278.3 [95% confidence interval, CI 262.2 to 294.5] units) to February (385.5 [95% CI 362.4 to 408.5] units), followed by a decline until September (98.4 [95% CI 76.5 to 120.4] units). Match load increased from February (204.0 [95% CI 186.2 to 221.8] units) to September (356.8 [95% CI 302.5 to 411.1] units). More training injuries were sustained in the first half of the season (first vs second: 69.2% vs 30.8%, P < 0.001), whereas match injuries occurred more frequently in the latter stages of the season (53.6% vs 46.4%, P < 0.001). A significant relationship (P < 0.05) was observed between changes in training injury incidence and changes in training intensity (r = 0.83), training duration (r = 0.79) and training load (r = 0.86). In addition, changes in the incidence of match injuries were significantly correlated (P < 0.05) with changes in match intensity (r = 0.74), match duration (r = 0.86) and match load (r = 0.86). These findings suggest that as the intensity, duration and load of rugby league training sessions and matches is increased, the incidence of injury is also increased.