A 10-year prospective cohort study of 481 youth pitchers aged 9-14, following them annually from 1999-2008. The study quantifies cumulative incidence of serious arm injury and tests whether pitching volume, early curveball use, and dual pitcher-catcher roles are independent risk factors. Injury was defined as elbow surgery, shoulder surgery, or retirement due to throwing injury.
Youth pitching guidelines before this paper were based on associations between pitch counts and pain — no prospective data existed linking volume or pitch type to serious injury (surgery or career-ending retirement).
This paper provides the evidence base for the 100-inning annual limit. When a family asks how much their 13-year-old should pitch, the answer is grounded here: exceeding 100 innings per year in any calendar year triples the risk of a serious arm injury requiring surgery or ending the career.
The curveball finding is worth knowing for boards and clinic. Despite longstanding expert warnings, this study could not confirm that early curveball use increases serious injury risk. And the biomechanical literature it cites actually shows curveballs produce less elbow varus torque than fastballs in youth pitchers.
The pitcher-catcher data (OR 2.7, P = .088) should inform how you counsel families even though it missed significance. The point estimate is large enough to matter clinically, and it is the direct basis for Little League's 2009 rule prohibiting pitching and catching in the same game.
A 10-year prospective cohort study of 481 youth pitchers aged 9-14, following them annually from 1999-2008. The study quantifies cumulative incidence of serious arm injury and tests whether pitching volume, early curveball use, and dual pitcher-catcher roles are independent risk factors. Injury was defined as elbow surgery, shoulder surgery, or retirement due to throwing injury.
Youth pitching guidelines before this paper were based on associations between pitch counts and pain — no prospective data existed linking volume or pitch type to serious injury (surgery or career-ending retirement).
This paper provides the evidence base for the 100-inning annual limit. When a family asks how much their 13-year-old should pitch, the answer is grounded here: exceeding 100 innings per year in any calendar year triples the risk of a serious arm injury requiring surgery or ending the career.
The curveball finding is worth knowing for boards and clinic. Despite longstanding expert warnings, this study could not confirm that early curveball use increases serious injury risk. And the biomechanical literature it cites actually shows curveballs produce less elbow varus torque than fastballs in youth pitchers.
The pitcher-catcher data (OR 2.7, P = .088) should inform how you counsel families even though it missed significance. The point estimate is large enough to matter clinically, and it is the direct basis for Little League's 2009 rule prohibiting pitching and catching in the same game.