Correlation Among Y-Balance Test-Lower Quarter Composite Scores, Hip Musculoskeletal Characteristics, and Pitching Kinematics in NCAA Division I Baseball Pitchers.

Abstract

Context: Numerous studies have reported kinematic data on baseball pitchers using three-dimensional (3D) motion analysis, but no studies to date have correlated this data with clinical outcome measures. Objective: To examine the relationship among Y-Balance Test-Lower Quarter (YBT-LQ) composite scores, musculoskeletal characteristics of the hip, and pitching kinematics in National Collegiate Athletic Association (NCAA) Division I baseball pitchers. Design: Cross-sectional. Setting: 3D motion analysis laboratory. Participants: Nineteen healthy male college baseball pitchers. Main Outcome Measures: Internal and external hip passive range of motion, hip abduction strength, YBT-LQ composite scores, and kinematic variables of the pitching motion. Results: Stride length demonstrated a moderate positive correlation with dominant limb YBT-LQ composite score (r = .524, P = .02) and nondominant limb YBT-LQ composite score (r = .550, P = .01), and a weak positive correlation with normalized time to maximal humerus velocity (r = .458, P = .04). Stride length had a moderate negative correlation with normalized time to maximal thorax velocity (r = -.522, P = .02) and dominant hip total rotational motion (TRM; r = -.660, P = .002), and had a strong negative correlation with normalized time from stride foot contact to maximal knee flexion (r = -.722, P < .001). Dominant limb YBT-LQ composite score had a weak negative correlation with hip abduction strength difference (r = -.459, P = .04) and normalized time to maximal thorax velocity (r = -.468, P = .04). Nondominant limb YBT-LQ composite score demonstrated a weak negative correlation with normalized time to maximal thorax velocity (r = -.450, P = .05) and had a moderate negative correlation with dominant hip TRM (r = -.668, P = .001). There were no other significant relationships between the remaining variables. Conclusions: YBT-LQ is a clinical measure that can be used to correlate with hip musculoskeletal characteristics and pitching kinematics in NCAA Division I pitchers.