Factors associated with knee injury occurrence using performance tests in male university rugby players

Abstract

This longitudinal study aimed to determine the performance-related knee injury risk factors in male university rugby union players. Baseline performance measurements were taken in the pre-season and included: (1) strength tests–maximal isometric voluntary contraction (MVC) and single-limb hop test; (2) balance tests–Balance Error Scoring System and Y Balance Test–Lower Quarter; and (3) movement quality–Landing Error Scoring System. The Limb Symmetry Index (LSI) was calculated using strength tests. Knee injury surveillance data, including incidence, severity, and burden, were tracked and analyzed over 1 year. Of the 79 candidate players, 64 completed the test set, and 58 were included in the analysis. We observed 15 knee injuries in 13 players. The injury incidence was 0.4 injuries/1000 player-hours (1000 h) (95% confidence interval [CI], 0.2–0.5); severity was 51 days (95% CI, 0–104); and the burden was 19 days/1000 h (95% CI, 11–31). High LSI of hip internal rotation (odds ratio [OR], 1.09; 95% CI, 1.02–1.16) and MVC of hip extension (OR, 1.10; 95% CI, 1.00–1.20) were identified as significant factors associated with the occurrence of knee injury. In conclusion, the present study suggests that knee injuries are associated with the LSI of hip internal rotation and MVC of hip extension. Players with high performance levels are more exposed to higher injury risks during matches. Given that performance test results may predict knee injury incidence, regular monitoring of such tests may help prevent knee injuries.