The Effect of Pitch Type, Pitch Count, and Pitching Mechanics on Risk of Elbow and Shoulder Pain in Youth Baseball Pitchers

September 18, 2014

(Lyman et al.; The American Journal of Sports Medicine; 2002)

The 476 pitchers (from youth leagues in Alabama) made 3789 pitching appearances during the season. Nearly 7% of all pitching appearances (254 of 3789) resulted in elbow pain, with 28% of all subjects (134 of 476) reporting elbow pain at least once during the season (Table 1). More than 9% of all pitching appearances (353 of 3789) resulted in shoulder pain, with 35% of all subjects (165 of 476) reporting shoulder pain at least once during the season. Overall, almost 15% of all pitching appearances resulted in elbow or shoulder pain, with half (50%) of all subjects reporting elbow or shoulder pain during the season.
Only the slider was found to have a statistically significant relationship to elbow pain, with an 86% increase risk of elbow pain among slider users. Meanwhile, use of the curveball accounted for a 52% increase risk of shoulder pain.
Use of the change-up was associated with a 12% reduction in the risk of elbow pain and a 29% reduction in the risk of shoulder pain.
There was a statistically significant relationship between pitches thrown in season up through a given appearance and risk of elbow pain from that appearance (and a similar trend for shoulder pain).
They recommended 75 pitches in a game and 600 pitches in a season for ages 9-14.