Specialization patterns across various youth sports and relationship to injury risk

Objectives: Current trends among young athletes towards earlier specialization age and year-round training on multiple teams has raised concern for increased injury risk. Our previous analyses showed higher risk for injury in highly specialized young athletes. The goal of this research was to determine whether sports specialization and injury patterns vary by sports type. Methods: In this clinical case-control study, injured athletes (aged 7-18 years) were recruited from sports medicine clinics and compared to similarly aged uninjured athletes recruited from primary care clinics. Participants completed a survey reporting age, gender, sport type, specialization patterns, and details regarding sports-related injuries in the previous 6 months. Clinical diagnoses were collected from patients' medical records. Injuries were classified as acute, overuse, or serious overuse. Results: Of 1,190 athletes enrolled, 26% (313) were single-sport specialized (reported participation in one sport and trained >8 months/year). Sports with the highest proportion of single-sport specialized athletes were tennis (46.7%), gymnastics (30.1%), and dance (26.3%). Single-sport specialized athletes in individual sports started specializing at a younger age (11.2 +/- 2.4 vs. 12.0 +/- 2.7, p = 0.05) and reported higher training volumes (11.8 vs. 10.3 h/week, p = 0.04) than those in team sports. Sports with the youngest specialization age were gymnastics (8.9 +/- 1.7), dance (10.8 +/- 3.0), and soccer (10.9 +/- 2.4). Single-sport specialized athletes in individual sports accounted for a higher proportion of overuse injuries (44.3% vs 32.2%, OR = 1.67, p = 0.037) and serious overuse injuries (23.4% vs 11.6%, OR = 2.38, p = 0.011), but a lower proportion of acute injuries (28.8% vs 13.8%, OR = 0.37, p = 0.001) compared to single-sport specialized athletes involved in team sports. Conclusions: Athletes in individual sports may be more likely to specialize in a single sport than team sport athletes. Single- sport specialized athletes in individual sports also reported higher training volumes and greater rates of overuse injuries than single-sport specialized athletes in team sports.