High Sport Specialization Is Associated With More Musculoskeletal Injuries in Canadian High School Students.

Objective: To describe levels of sport specialization in Canadian high school students and investigate whether sport specialization and/or sport participation volume is associated with the history of musculoskeletal injury and/or concussion.

Design: Cross-sectional study.

Setting: High schools, Alberta, Canada.

Participants: High school students (14-19 years) participating in various sports.

Independent Variables: Level of sport specialization (high, moderate, low) and sport participation volume (hours per week and months per year).

Main Outcome Measures: Twelve-month injury history (musculoskeletal and concussion).

Results: Of the 1504 students who completed the survey, 31% were categorized as highly specialized (7.5% before the age of 12 years). Using multivariable, negative, binomial regression (adjusted for sex, age, total yearly training hours, and clustering by school), highly specialized students had a significantly higher musculoskeletal injury rate [incidence rate ratio (IRR) = 1.36, 95% confidence interval (CI), 1.07-1.73] but not lower extremity injury or concussion rate, compared with low specialization students. Participating in one sport for more than 8 months of the year significantly increased the musculoskeletal injury rate (IRR = 1.27, 95% CI, 1.02-1.58). Increased training hours significantly increased the musculoskeletal injury rate (IRR = 1.18, 95% CI, 1.13-1.25), lower extremity injury rate (IRR = 1.16, 95% CI, 1.09-1.24), and concussion rate (IRR = 1.31, 95% CI, 1.24-1.39).

Conclusions: Approximately one-third of Canadian high school students playing sports were categorized as highly specialized. The musculoskeletal injury rate was higher for high sport specialization students compared with low sport specialization students. Musculoskeletal injuries and concussion were also more common in students who train more and spend greater than 8 months per year in one sport.