EFFECT OF JOINT TORQUE ON HORIZONTAL MOTION OF CENTER-OF-MASS DURING SWING ON GYMNASTIC RINGS

Abstract

To perform a good swing on the rings in gymnastics, it is said to be important to keep the center-of-mass (COM) almost along the vertical line through the cable attachment point on the ring frame. However, the theoretical background of this empirical knowledge is not clear. In this study, we address a question whether a gymnast can always affect the horizontal motion of COM by the input of joint torque during swinging. Using a three-segment model in the sagittal plane, composed of a cables-rings segment, an arms segment, and a headneck- torso-legs segment (Sprigings et al., 1998), we analyse the relation between the shoulder torque and the COM motion. The results show that there exist a variety of configurations where the shoulder torque cannot affect the horizontal motion of COM.