Abstract
The purpose of this study was to describe the time-course of change in the orientation of the longitudinal axis of the runner's body passing through the center of mass (CM) during the maximum-effort sprinting on a curved runway. Ten male collegiate sprinters were asked to sprint along the 2nd lane on an official 400m track. The performances were recorded with four high speed cameras. The DLT algorithm was used for 3D reconstruction and the longitudinal axis of the whole body passing through the CM was calculated. The results showed that the longitudinal axis of the whole body maintained a forward (5.8±1.9°) and inward (14.1±2.2°) leaning-position during the entire stride cycle. The orientation, however, fluctuated during the stride cycle; the longitudinal axis leaned toward inward direction by 3.6±0.7° during right contact phase and toward outward direction by 2.8±0.6° during left foot contact phase. These results indicate that the ground reaction force exerted on the body during each contact phase generated rotational motion about the antero-posterior axis in the opposite direction in curved sprinting.
