Injuries/Violence
Determining the effect of changing training duration on injury risk in adolescent ice-hockey players: target trial emulation Chinchin Wang* Chinchin Wang Sabrina Yusuf Russell J. Steele Jay S. Kaufman Paul Eliason Jean-Michel Galarneau Carolyn A. Emery Ian Shrier
Objective: Few studies have estimated causal relationships between training load and injury risk. Here, we emulate a target trial to estimate the intent-to-treat effect of changing training duration on injury risk among adolescent ice-hockey players without recent injuries.
Methods: We performed a secondary analysis of data from a 5-year cohort study (2013-2018) in Alberta and British Columbia. We identified eligible player-weeks where players had been training and were not injured in the previous 4 weeks. The intervention was a change in training duration (practice and game minutes), defined as the ratio of the planned average daily training duration in the current week to the average daily training duration over the previous 4 weeks. The outcome was any medical-attention or time-loss injury occurring in the current week. We modelled the relationship between changes in training duration and injury using a generalized additive model with generalized estimating equations to account for repeated measures. We included age group and body-checking league (yes/no) as covariates. We estimated potential outcomes for each player-week under hypothetical interventions, and calculated injury risks and risk ratios relative to no change in training duration. We estimated 95% CIs with cluster bootstrapping.
Results: There were 3,226 eligible participants contributing 162,675 player-weeks and 837 injuries. Figure 1 shows the intent-to-treat effects of changing training duration. Injury risk is expected to be 2.5% for no change in training duration. The largest increases in injury risk occurred for changes in training duration up to 2-fold. Injury risk increased slightly for changes in training duration between 2- and 3-fold, and further for changes over 3-fold. Injury risk decreased with decreased training duration in the current week.
Conclusions: Injury risk increases slightly with increasing training duration among adolescent ice-hockey players without recent injuries.
