Throwing Injuries in Youth Baseball Players: Can a Prevention Program Help? A Randomized Controlled Trial

Jun Sakata, Emi Nakamura, Tatsuhiro Suzuki, Makoto Suzukawa, Masaki Akeda, Tetsuya Yamazaki, Todd S. Ellenbecker, Norikazu Hirose

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Background: Throwing injuries of the shoulder and elbow are common among youth baseball players. Hypothesis: A prevention program will reduce the incidence of throwing injuries of the shoulder and elbow by 50% among youth baseball players. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: The authors block randomized 16 youth baseball teams consisting of 237 players aged 9 to 11 years into an intervention group (8 teams, 117 players) and a control group (8 teams, 120 players). The intervention program consisted of 5 stretching, 2 dynamic mobility, and 2 balance training exercises performed during warm-up. Both groups were followed up for 12 months, during which the incidence of shoulder and elbow injuries was recorded. In addition, ball speed during pitching as a performance-related factor and variables of physical function (passive range of motion of the elbow, shoulder and hip, dynamic balance, and thoracic kyphosis angle) were assessed during the pre- and postintervention periods. Results: The incidence of shoulder and elbow injuries in the intervention group (1.7 per 1000 athlete-exposures) was significantly lower than that in the control group (3.1 per 1000 athlete-exposures) (hazard ratio, 1.940; 95% CI, 1.175-3.205; P =.010). The factors related to pitching performance, as assessed by ball speed, tended to increase in the intervention group as compared with the control group (P =.010). The program also improved shoulder horizontal adduction deficits on the dominant side, hip internal rotation on the nondominant side, and the thoracic kyphosis angle. Conclusion: A prevention program decreases throwing injuries of the shoulder and elbow and enhances the parameter of pitching performance in youth baseball players.

Original languageEnglish
JournalAmerican Journal of Sports Medicine
Publication statusPublished - 2019 Jan 1



  • injury prevention
  • randomized controlled trial
  • shoulder and elbow injury
  • youth baseball players

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation

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