Angular momentum of the overhand, three-quarter, sidearm, and underhand delivery styles in the fastball baseball pitch

The aim of the study was to investigate differences in angular momentum values in the global coordinate system and the trunk coordinate system—the latter rotated about the throwing direction by the trunk lateral tilt angle at release for each style—throughout the entire baseball pitching between overhand, three-quarter, sidearm, and underhand styles, using waveform analyses. A total of 91 male Japanese amateur pitchers for the four deliveries of the pitches were videotaped and analyzed. Ball velocity was faster in overhand and three-quarter throws than underhand, and trunk lateral tilt angle at release was greatest for overhand, followed by three-quarter, sidearm, and underhand. System and trunk-and-head angular momentum values around the axis along the throwing direction in the global coordinate system were largely different among the four styles, distinguishing the styles from each other. Although the upper body angular momentum values around the axis perpendicular to the throwing direction in the global coordinate system substantially differ among delivery styles, differences in the area around the corresponding axis in the trunk coordinate system were minimal, and the differences in angular momentum values (overhand, three-quarter > three-quarter > underhand) mainly found around the trunk longitudinal axis, suggesting that the angular momentum around the trunk longitudinal axis is essential for achieving a fast ball.