Center of Mass, Ball Velocity, and Elbow Valgus in Baseball Pitching Stride Strategies

Two distinct baseball pitching stride styles, tall-and-fall and drop-and-drive, are characterized by center-of-mass movement. Our purpose was to determine whether forward center-of-mass and vertical center-of-mass velocities are related to fastball velocity and peak elbow valgus torque for each technique. In-game motion capture data were recorded for 251 Division I pitchers. Multiple backward linear regressions and statistical parametric mapping regressions were performed. No significant findings were found in drop-and-drive pitchers between forward center-of-mass or vertical center-of-mass and fastball velocity or peak elbow valgus torque, nor in tall-and-fall pitchers between forward center-of-mass and fastball velocity or peak elbow valgus torque. However, in tall-and-fall pitchers, backward multiple linear regression showed that the maximum downward vertical center-of-mass velocity was associated with increased fastball velocity, and Statistical Parametric Mapping regressions showed that the association between vertical center-of-mass and fastball velocity occurred between 39.4 and 69.1% of the stride phase. Specifically, greater peak downward vertical center-of-mass velocity was associated with higher fastball velocity, suggesting that tall-and-fall pitchers seeking to improve fastball velocity could benefit from increasing downward vertical center-of-mass velocity during the middle of the stride. No significant findings were found between vertical center-of-mass velocity and peak elbow valgus torque in tall-and-fall pitchers; therefore, modifying vertical center-of-mass velocity in tall-and-fall pitchers may enhance performance without increasing peak elbow valgus torque, yet further work is needed to elucidate the effects on other kinematics or kinetics.