Is the Selection of Body Segment Inertia Parameters Critical to the Results of Kinematic and Kinetic Analysis of Human Movement?
We studied the effects of body segment inertia parameters (BSPs) on the results of biomechanical analyses of human movement. The vertical jump was taken as an example. A subject was asked to perform 15 vertical jumps. He was measured using an automatic coordinate acquisition system and a force platform. Kinematic and kinetic variables were computed using five BSP sets: 1) Average for three-year-old Japanese children reported by Yokoi and others (1986), 2) Regression equation for young adult Japanese athletes reported by Ae and others (1992), 3) Average for young adult Japanese athletes reported by Ae and others (1992), 4) Average for young Japanese adults reported by Matsui (1956), and 5) Average for aged Caucasian cadavers reported by Chandler and others (1975). Vertical displacement and velocity for body segments and for the whole body exhibit few differences among the five sets. In time-series curves for each joint torque, the variance shown by a single subject was more pronounced than the variance due to differences in BSPs. These results suggest that selection of BSPs apparently has little effect on the results of kinetic analyses of human movement and on conclusions based on these results.