Stride Length: A reactive response to prolonged exertion potentially effecting ball velocity among baseball pitchers

This study assessed pitching performance by examining variability in ball velocities among skilled pitchers over two simulated games, where stride lengths were altered while monitoring the effect of fatigue on performance. Nineteen competitive pitchers were randomly assigned to pitch two simulated, 80-pitch games, at ±25% of their desired stride lengths while throwing a ratio of 3 fastballs for every change-up, or off-speed pitch. Conventional motion capture tracked 3D throwing biomechanics while the velocity of every pitch was simultaneously monitored using a professional radar gun. Seventy-two hours rest was allocated between games. A two-way repeated measures ANOVA tested the effect of stride length and the number of innings pitched on ball velocity, while pairwise t-tests were used to compare between conditions variables. Ball velocities for the fastball (mean and peak) and change-up (mean and min) were significantly different (p<0.001). Despite over/under-stride lengths were statistically different from the desired stride, within and between subjects ball velocity variability (BVV) and ball velocity differentials (BVD) were no different within the same pitch type. Compensatory throwing mechanics owing to altered stride lengths had no influence on ball velocity, meaning fastball and change-up velocities could be maintained while fatigued.