Relationship between stride length and maximal ball velocity in collegiate baseball pitchers.

[Purpose] To evaluate the relationship between stride length during a pitch and maximal ball velocity and define the determinants of stride length in collegiate baseball pitchers. [Participants and Methods] Eighteen collegiate baseball pitchers participated in this study. Using a standard tape measure, the distance between each participant's legs was measured after maximal abduction of both hip joints in a standing position. The pitchers threw fastballs on an indoor pitching mound at an official pitching distance. The throwing motion was recorded with four high-speed video cameras (240 Hz), while the ball velocity was measured using a radar gun. The stride length at foot contact was calculated at the maximal ball velocity using a three-dimensional motion analysis system. [Results] The maximal ball velocity (mean 129.8 km/h) had a significant positive correlation with the absolute stride length during a pitch (r=0.55), but no correlation with the relative stride length (% body height, % lower extremity length, and % maximal open legs' width). Stride length during a pitch did not significantly correlate with the pitcher's body height, lower extremity length, and maximal open legs' width. [Conclusion] A longer stride length contributes to a higher ball velocity in collegiate baseball pitchers.