Changes in angular momentum during curved sprinting in Track and Field

Abstract

The purpose of this study was to describe the angular momentum of the runner's body about the center of mass (CM) during the maximum-effort sprinting along 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 angular momentum of the whole body about the CM was calculated. The results showed that the runner’s body possessed throughout the stride cycle an inward-directed component (33.5×10^–3±2.8×10^–3s^–1) of angular momentum and that the head and torso possessed a cranially-directed component (0.4×10^–3±0.2×10^–3s^–1). The antero-posterior component of angular momentum changed its sense from forward- to backward-direction during the right ground contact phase. These results indicate (a) that the runner's head and torso changed its orientation continuously throughout the support- and the airborne-phases to face forward along the curved runway and (b) that the angular impulse exerted on the body during the right ground contact phase changed the direction of the forward somersaulting angular momentum of the whole body possessed primarily by the limbs, so that the runners could maintain the plane of the limbs' rotary motion in the tangential direction to the curved runway.