High compliance with the injury prevention exercise programme Knee Control is associated with a greater injury preventive effect in male, but not in female, youth floorball players

Purpose Evaluate team and player compliance with the Knee Control injury prevention exercise programme, study the association between player compliance and injury rates, and compare coach demographics, baseline prevention expectancies, and programme utilisation between teams with high and low compliance. Methods Prospective one-season cohort study based on a cluster randomised controlled trial on 301 (107 female) floorball players aged 12-17 years. Floorball exposure and injuries were self-reported weekly by players using the Oslo Sports Trauma Research Center questionnaire. Team and player compliance to Knee Control was reported monthly by coaches. Additionally, coaches answered pre- and post-season surveys. Teams were divided into a high (>= 80%) or low (< 80%) compliance group based on their use of Knee Control during the season. Players were divided into three compliance groups based on their average weekly number of Knee Control sessions; high (>= 2 sessions), intermediate (>= 1 to < 2 sessions), and low dose (< 1 session). Results Mean team compliance for the high and low compliance groups were 95% (range 82-100) and 50% (range 13-66), respectively. Mean +/- SD weekly Knee Control dose in the three player compliance groups were 2.4 +/- 0.3, 1.4 +/- 0.3, and 0.7 +/- 0.3 sessions, respectively. There were no differences in total injury incidence between the player compliance groups, but players in the high-dose group had a 35% lower prevalence of injuries overall [adjusted prevalence rate ratio (PRR) 0.65, 95% CI 0.48-0.89] and 60% lower prevalence of substantial injuries (adjusted PRR 0.40, 95% CI 0.26-0.61) compared with the low-dose group. Male players in the high-dose group had consistently lower injury incidence and prevalence, while no between compliance group differences were seen in female players. There were no differences in sex, years of coaching experience, or baseline prevention expectancies in general between coaches for teams in the high vs. low compliance groups, but teams in the high compliance group had a better utilisation fidelity. Conclusion There was a clear dose-response relationship between more frequent Knee Control use and lower injury rates in male floorball players, but not in female players. Teams with higher compliance also showed a better utilisation fidelity with the programme.