Kinematic Models For Pitch Location Metrics in Professional Baseball Pitchers

Consistency and accuracy in pitch location is paramount for professional baseball pitchers, however, the contribution of individual kinematic parameters is poorly understood. Professional baseball pitchers (n = 322) were instructed to throw 8-12 fastballs while assessed with motion-capture technology (480 Hz); pitch location was tracked by coaching staff. Elastic net regression with automated parameter optimization was utilized to model the consistency and accuracy of each pitch with a random forest model implemented to assess feature importance. Trunk tilt at foot contact (FC) was the most significant predictor of accuracy indicated by a percent increase of the mean square error (6.6% MSE), followed by lead hip flexion at FC (4.2% MSE), shoulder abduction at FC (4.2% MSE), and trunk tilt at ball release (BR) (3.8% MSE). For pitch consistency, the resulting model explained 57% of the variance. Trunk tilt at FC had the highest predictive value (3.7% MSE), followed by trunk flexion at BR (3.3% MSE), foot rotation at FC (3.2% MSE), and back hip flexion at FC (2.6% MSE). Four of the top six parameters found to be predictive in both models involved variance at the hip and trunk. Pitchers should strive for consistency in hip and upper torso motions, particularly at foot contact.