DOES HIP-SHOULDER SEPARATION, ELBOW VARUS TORQUE, AND FUNCTIONAL MOVEMENT RELATE TO PITCH PERFORMANCE IN COLLEGIATE BASEBALL PITCHERS?

Elbow injuries in youth baseball players have led to increased study of pitching biomechanics. This study evaluated the concurrent validity of PULSE inertial measurement units (IMUs) against marker-less motion capture (KinaTrax) in measuring elbow varus torque, a key metric linked to injury. It also examined relationships between functional movement, hip-shoulder separation, and torque, as well as whether changes in torque predicted pitch velocity. Seven participants each threw 15 fastballs while elbow varus torque was recorded using both systems. Results showed PULSE significantly underestimated torque (63.07 ± 1.07 Nm) compared to KinaTrax (99.22 ± 10.42 Nm), indicating PULSE IMUs are not suitable for precise torque measurement. However, changes in torque measured by both systems were positively associated with increases in pitch velocity (PULSE: R = 0.54; KinaTrax: R = 0.80). Functional movement scores negatively correlated with hip-shoulder separation (R = -0.35), and hip-shoulder separation was negatively correlated with elbow varus torque (R = -0.91). These findings suggest that while functional movement does not improve hip-shoulder separation, greater hip-shoulder separation may reduce elbow torque and potentially lower injury risk. Overall, IMUs alone are insufficient for monitoring torque or predicting injury, but biomechanics insights may help inform safer pitching mechanics.<p></p>