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

Am J Sports Med. 2019 Sep;47(11):2709-2716. doi: 10.1177/0363546519861378. Epub 2019 Jul 23.


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.

Keywords: injury prevention; randomized controlled trial; shoulder and elbow injury; youth baseball players.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Baseball / injuries*
  • Baseball / physiology
  • Child
  • Elbow / physiopathology
  • Elbow Injuries*
  • Humans
  • Incidence
  • Male
  • Muscle Stretching Exercises / methods*
  • Range of Motion, Articular
  • Rotation
  • Shoulder Injuries / epidemiology
  • Shoulder Injuries / physiopathology
  • Shoulder Injuries / prevention & control*
  • Warm-Up Exercise*