THE DEVELOPMENT AND VALIDATION OF A THREE-DIMENSIONAL COMPUTER TECHNIQUE FOR ANALYZING HUMAN MOTION: APPLICATION TO AN OVERHAND FASTBALL PITCH (BIOMECHANICS, MODELING).

摘要

A 14-segment, three-dimensional mathematical model of the human body was developed and validated for analyzing complex, total body human movements. The FORTRAN computer model was incorporated into an existing comprehensive two-dimensional computer analysis technique which was modified to generate three-dimensional results. Upon validation, the computer technique's applicability was demonstrated by an analysis of an overhand fastball pitch. The Direct Linear Transformation cinematographic technique was used to reduce the variables of interest from film records taken of a single pitch thrown by a 19 year old junior college pitcher. The results of the pitching analysis indicated that the computer analysis technique produced results which were very similar to those reported in the literature, thereby, demonstrating its applicability. The conclusions of the pitching analysis for this subject were: (a) the pitching motion was a series of sequentially applied segmental velocities beginning with the lower trunk and transferring segmentally to the hand at release; (b) the legs, though important, were not as critical to producing ball velocity at release as were the trunk and upper arm polar axis rotational velocities, the upper arm horizontal flexion velocity and the lower arm extension velocity; and (c) the extreme positions and accelerations of the upper arm and lower arm around release may explain the high incidence of shoulder and elbow injury reported in the literature.