Injuries to young professional baseball pitchers cannot be prevented solely by restricting number of innings pitched

J Sports Med Phys Fitness. 2016 May;56(5):554-9. Epub 2015 Mar 18.


Background: The Major League Baseball schedule is longer and more intensive than minor and amateur leagues. As a result, major league pitchers endure a considerably higher cumulative workload throughout the season. Ligament, tendon, muscle, and bone tissues in young pitchers need time to adapt to the workload a major league pitcher must endure. To mitigate the risk of overuse injury, and allow time for tissue adaptation to occur, most teams limit the number of innings a young pitcher may throw. This study examined the relationship between innings pitched and future injury in young professional baseball pitchers.

Methods: All pitchers under 25 years of age that pitched at least one third of an inning in Major League Baseball during the 2002-2007 seasons were included in this study. Total innings pitched were accumulated for each season across three levels of professional baseball (Major League Baseball, and two levels of Minor Leagues). Regression analyses were preformed comparing innings pitched during a single season and difference in innings pitched over consecutive seasons to future injury, as measured by time spent on the disabled list.

Results: No significant correlation was found between innings pitched and future injury or consecutive season innings pitched difference and future injury. No significant differences were found when pitchers were split into groups based upon consecutive season innings pitched difference cutoffs.

Conclusions: Based upon the evidence presented, strength and conditioning coaches, sports medicine specialists, and team trainers cannot rely solely on inning counts to accurately measure the tissue demands of professional baseball pitching. Therefore, inning limits alone cannot be used to protect young professional pitchers against the threat of injury.

MeSH terms

  • Athletic Injuries / epidemiology
  • Athletic Injuries / prevention & control*
  • Athletic Performance / physiology*
  • Baseball / injuries*
  • Baseball / physiology
  • Collateral Ligaments / diagnostic imaging
  • Collateral Ligaments / injuries
  • Collateral Ligaments / physiopathology*
  • Cumulative Trauma Disorders / epidemiology
  • Cumulative Trauma Disorders / prevention & control*
  • Elbow Injuries
  • Elbow Joint / diagnostic imaging
  • Elbow Joint / physiopathology*
  • Humans
  • Male
  • Recovery of Function
  • Shoulder Injuries
  • Shoulder Joint / diagnostic imaging
  • Shoulder Joint / physiopathology*
  • United States / epidemiology
  • Workload
  • Young Adult