Spin on fastballs thrown by elite baseball pitchers.

Abstract

In this study, we analyzed the direction of the spin axis angles and the spin rate of baseballs pitched by elite collegiate and professional pitchers. The video image of a ball being pitched was taken from the period just before release until 200 ms after release with a high-speed video camera at a rate of 1000 frames per second. A custom-made device was used to analyze the spin axis angle and the spin rate. There were no significant differences in the direction of the spin axis angles or the spin rate between collegiate and professional pitchers. A significant correlation was obtained between spin rate and ball speed; that is, the higher the ball speed, the greater the spin rate. In addition, the spin rate deviated more across subjects than did ball speed. For all subjects, the azimuth and elevation of spin axis were 19° ± 14° and -32° ± 9°, respectively. Some of the pitchers were able to put a characteristic spin on their fastball; the nature of this spin could be related to their pitching success.