Dynamic analysis of side-step cutting maneuvers during acceleration phase under restricted track-width condition.

Abstract

The purpose of this study was to quantify the mechanism of side-step cutting maneuvers during acceleration phase usually observed in ball games. Four male participants were instructed to perform anticipated 90-degree side-step cutting maneuvers (SS) with the approaching speed of 3.0m/s. In order to reduce the influence of their kinematical differences, they performed SS under restricted track-width condition. Forty-seven reflective markers attached to the body and ground reaction force (GRF) of support legs were measured with a motion-capture system (VICON-MX) and a force platform, respectively. The dynamic contributions of support leg joint torques, during the SS and the next step cutting maneuver (NS), to the generation of GRF and the angular momentum of the HAT (i.e. hat, arms, and trunk) segment through the foot segment of the support leg were quantified by using dynamical force equation regarding 15-segment-linked wholebody system. The results obtained in this study show 1) the extension torque at hip joint play a role in maintaining the upper body posture by controlling forward rotation and side inclination of the HAT segment, 2) individual support leg joint torque maintains the posture of the body on the frontal plane by cancelling the angular momentum of the HAT segment about the axis pointing medial to lateral direction through the foot segment of the support leg, and 3) contribution of the hip joint extension torque to the reduction of body forward rotation in the NS was higher than that in the SS.