Table 2:

Game-related injury outcomes for ice hockey players aged 15–17 years by years of bodychecking experience

VariableAll injuriesInjuries with > 7 d of time lossConcussions
≤ 2 yr bodychecking experience≥ 3 yr bodychecking experience≤ 2 yr bodychecking experience≥ 3 yr bodychecking experience≤ 2 yr bodychecking experience≥ 3 yr bodychecking experience
No. of player-seasons148102014810201481020
No. of outcomes293091920010115
Player participation (game-hours)6010.6225 877.746010.6225 877.746010.6225 877.74
Crude rate, per 1000 player game-hours, (95% CI)*4.82 (1.81–7.84)11.94 (9.65–14.23)3.16 (0.72–5.60)7.73 (5.89–9.57)1.66 (0.89–3.12)4.44 (3.57–5.53)
Incidence rate ratio (95% CI)1 (ref.)2.53 (1.46–4.39)1 (ref.)2.56 (1.70–3.88)1 (ref.)2.66 (1.32–5.38)
Absolute rate increase, per 1000 player game-hours (95% CI)*1 (ref.)7.12 (3.33–10.90)1 (ref.)4.57 (1.51–7.62)1 (ref.)2.78 (1.34–4.22)
  • Note: CI = confidence interval, ref. = reference.

  • * Crude rates and absolute rate increases with a design effect accounting for clustering by team and individual for all injury and injury with > 7 days of time loss, and by team only for concussion, offset for exposure game-hours.

  • Incidence rate ratios based on multilevel Poisson regression, offset by exposure game-hours. For injury outcomes, the analysis was performed with 2 random effects, 1 at a team level and 1 at an individual level. For concussion, the analysis was performed with 1 random effect at the team level.