The influence of mound height on baseball movement and pitching biomechanics

Abstract

Objectives: To determine whether mound height is associated with baseball movement (velocity, spin and break) and baseball pitching biomechanics (kinematics and kinetics).

Design: Controlled laboratory study.

Methods: Twenty collegiate baseball pitchers threw five fastballs and five curveballs from four different mound heights (15cm, 20cm, 25cm, 30cm) in a randomized order. Ball movement was computed by a ball tracking system, while pitching biomechanics were calculated with an 11-camera optical motion capture system. Repeated measures analysis of variance was utilized to detect significant differences among the four different mound heights (p<0.05) for the fastball and curveball pitches.

Results: There were no significant differences observed for ball movement. There were seven significant kinematic differences for fastballs and eight kinematic differences for curveballs. Although these differences were statistically significant, the magnitudes were small, with most joint angles changing by less than 2°. There were no significant kinetic differences for curveballs, but five kinetic parameters (elbow varus torque, elbow flexion torque, elbow proximal force, shoulder internal rotation torque, and shoulder anterior force) varied with mound height for fastballs. In general, fastball kinetics were 1%-2% less from the lowered (15cm, 20cm) mounds than from the standard (25cm) or raised (30cm) mounds.

Conclusions: Lowering the mound may not affect a pitcher's ball movement, but may slightly reduce shoulder and elbow kinetics, possibly reducing the risk of injury.

Keywords: Curveball; Elbow; Fastball; Kinetics; Shoulder.