18 the HAPPY Hybrid Effectiveness-Implementation Cluster-Randomised Trial: Comparison of Two Strategies to Implement an Injury Prevention Exercise Program in Youth Handball

Introduction Injury prevention exercise programs (IPEPs) are insufficiently implemented in practice. We hypothesized that a combination of an online and onsite implementation strategy would be superior to an online-only strategy in enhancing adherence to an injury prevention exercise program (IPEP), and in reducing shoulder, knee and ankle injury risk in youth handball players over a handball season. Materials and Methods In this 30-week hybrid effectiveness-implementation cluster-randomized study, 20 youth handball clubs were assigned to an online and onsite strategy (workshop utilizing the Health Action Process Approach [HAPA] behavior change model and health service provider [HSP] support) or an online-only strategy (control group). The primary implementation outcome was coach-reported adherence, measured as the average IPEP team usage over 30 weeks (weekly exercise usage range 0-33). The primary effectiveness outcome was player-reported handball time to any new handball-related shoulder, knee, and ankle injury, reported weekly using the Oslo Sports Trauma Research Centre Questionnaire on Health Problems. Results We enrolled 945 players (mean age 14.5 years, 55% girls) and 63 coaches (27% woman). Intention-to-treat analyses showed no statistically significant difference between implementation strategies in mean weekly exercise utilization (between-group difference -1.4, 95% CI -3.4 to 0.6) or in cumulative injury risk (between-group difference -5.5, 95% CI -13.1 to 2.2). Conclusion Our findings suggest that in youth handball, a combined online and onsite implementation strategy including a workshop and HSP support was not superior to an online-only strategy in improving adherence to an IPEP or in reducing shoulder, knee and ankle injury risk.