Sport Specialization and Increased Injury Frequency in Youth Baseball Players: A Prospective Study

Context Sport specialization is thought to be a primary contributor to the throwing-related injury risk in youth baseball players. Objective To (1) establish arm-injury incidence in a cohort of male youth (9–12 years old) baseball players and (2) examine sport specialization and the frequency of arm injuries in the same cohort. Design Cohort study. Setting Greenville, South Carolina, youth baseball programs and tournaments. Patients or Other Participants A total of 159 asymptomatic youth baseball players (age = 11.1 ± 1.1 years) were physically assessed and then were prospectively followed for 6.7 ± 1.5 months. Main Outcome Measure(s) Athlete demographics and playing and injury histories were initially recorded. Athlete-exposures and presence of arm injury were prospectively tracked. All injuries were physically confirmed by a licensed physical therapist. Results Youth players demonstrated an arm-injury incidence rate of 2.22 per 1000 athlete-exposures. Parents and players underestimated sport-specialization status based on the standard research definition (self versus research based: 31% versus 83%, respectively; P = .001). The frequency of arm injuries was higher in specialized players (100%) than in nonspecialized players (80%, P = .03) but did not differ between pitchers and position players (13.2% each, P = 1.00). Conclusions Sport specialization was associated with throwing-related arm injuries in a small cohort of youth baseball players. It is concerning that 57.9% of parents and specialized players were unaware of the athletes' status. Larger studies with longer follow-up periods are needed to further evaluate injury-risk profiles in physically developing youth populations.