Shoulder Stretching Intervention Reduces the Incidence of Shoulder and Elbow Injuries in High School Baseball Players: a Time-to-Event Analysis

We prospectively evaluated the effects of a prevention program on the incidence of shoulder and elbow injuries in high school baseball pitchers. Ninety-two pitchers participated in this study and were taught to perform stretching and strength exercises aimed at improving shoulder external rotation strength in the preseason. The pitchers freely chose to participate in one of four groups [SM-group: performed both exercises, S-group: performed stretching exercise only, M-group: performed strength training only, and N-group: performed neither intervention]. Injury was defined as inability to play for ≥8 days because of shoulder/elbow symptoms. Kaplan-Meier survival curves were generated and hazard ratios (HRs) for injury occurrence were calculated using multivariate Cox regression. Log-rank test was used for between-group comparisons of survival distributions. The injuries occurred in 25, 35, and 57% of participants and median times to injury were 89, 92, and 29.5 days in the S- (n = 32), SM- (n = 46), and N- (n = 14) group, respectively. Nobody chose M-group. HRs were 0.36 and 0.47 for the S- and SM-group, respectively, based on the N-group. The incidence of injury was significantly lower in the S-group than in the N-group (p = 0.04). Daily posterior shoulder stretching may reduce the incidence of the injuries in high school baseball pitchers.