Influence of Hip-Shoulder separation on pitch velocity in college baseball pitchers

Abstract

Pitch velocity is a highly valued attribute in baseball pitching, owing to its positive influence on performance outcomes. One variable theorized to contribute to pitch velocity is hip-shoulder separation; however, limited research has examined this relationship. The purpose of this study was to investigate the connection between hip-shoulder separation and pitch velocity. A total of 335 NCAA Division 1 pitchers were analyzed (1.88 ± .06 m; 91.6 ± 10.0 kg; 223 right-handed pitchers, 112 left-handed pitchers). In-game kinematics were collected using a markerless motion capture system. Statistical parametric mapping regression revealed a significant positive relationship between hip-shoulder separation and pitch velocity from 83-90 % between peak knee height and ball release, p = 0.04; peak r = 0.16), which was between foot contact and maximum external rotation. In addition, a multilevel model demonstrated a small, positive relationship between hip-shoulder separation at foot contact and pitch velocity, with high individual variability. These findings suggest a weak, positive relationship between hip-shoulder separation and pitch velocity, though the within-pitcher relationship was not consistent across all pitchers. Consequently, it can be inferred that increased hip-shoulder separation may contribute to higher pitch velocities, but due to significant individual differences, performance assessments should be conducted on a case-by-case basis, with sufficient data collection for each athlete.

Keywords: Baseball; Biomechanics; Kinematics; Pitching; Velocity.