Superior compliance with a neuromuscular training programme is associated with fewer ACL injuries and fewer acute knee injuries in female adolescent football players: secondary analysis of an RCT

BACKGROUND: Little is known about the influence of compliance with neuromuscular training (NMT) on the knee injury rate in football. AIM: To evaluate team and player compliance with an NMT programme in adolescent female football and to study the association between compliance and acute knee injury rates. METHODS: Prospective cohort study based on a cluster randomised controlled trial on players aged 12-17 years with 184 intervention teams (2471 players) and 157 control teams (2085 players). Exposure and acute time loss knee injuries were recorded. Team and player compliance was recorded by the coaches on a player attendance form. The intervention group was divided into tertiles of compliance. Injury rates were compared by calculating rate ratios (RRs) and 95% CIs using exact Poisson tests with the low-compliance tertile as reference. Seasonal compliance trends were analysed using linear regression. RESULTS: Players in the high-compliance tertile had an 88% reduction in the anterior cruciate ligament (ACL) injury rate (RR 0.12, 95% CI 0.01 to 0.85), whereas the rate in the control group players was not significantly different from those in the low-compliance tertile (RR 0.77, 95% CI 0.27 to 2.21). A significant deterioration occurred in team (b=-3.0% per month, 95% CI -5.2 to -0.8) and player (b=-5.0% per month, 95% CI -7.1 to -2.9) compliance over the season. CONCLUSIONS: Players with high compliance with the NMT programme had significantly reduced ACL injury rate compared with players with low compliance. Significant deterioration in team and player compliance occurred over the season.