Abstract

Three dimensional (3-D) high speed photography was used to record the fastball actions of four 13 yr old (Group 1) and four 15 yr old male pitchers, (Group 2). The direct linear transformation method of motion analysis for 3-D space reconstruction from 2-D images was used to record the movement of selected anatomical features. Laterally positioned phase-locked cameras operating at 200 fps were used to record the pitching action. Mean pitching velocities of 23.0 m/s and 28.2 m/s were recorded for the 13 yr old and 15 yr old pitchers respectively. A 3-D kinematic analysis of the 2 age groups from the first balance position following the completion of the pump and pivot to the follow through are presented. Major differences between Groups 1 and 2 included the techniques used during the pivot, the excessive rotation at the first balance position, and a longer stride to the plate than required for Group 1, which inhibited an effective transfer of weight during the pitch. Verf.-Referat