The kip maneuver on the horizontal bar is one of the basic skills of apparatus exercise, but it is said to be difficult for beginners to learn and execute. Although knowledge of kinetics is necessary to effectively teach the kip maneuver to beginners, there has been little research on kinetics, especially joint torques, during the kip maneuver. The purpose of this study was to investigate and compare the shoulder and hip joint torques of skilled and unskilled subjects performing the kip maneuver on the horizontal bar. The skilled subjects were made up of ten male varsity club gymnasts, while five male subjects who had no experience performing the kip maneuver comprised the unskilled group. All kip maneuvers performed by the subjects were videotaped and analyzed with two-dimensional videography to calculate trajectories of the center of mass, joint angles, angular velocities, torques, and work at the shoulder and hip joints.
Compared to the skilled group, the center of mass of the unskilled group was raised higher and closer to the bar at the instant of maximal forward swing. In addition, peak shoulder extension velocity of the unskilled group was significantly smaller than that of the skilled group (p < 0.05). Although shoulder extension torque of the skilled group increased during the backward swing phase, that of the unskilled group increased and was larger during the forward and upward swing phases than it was for the skilled subjects. The work done by the shoulder joint torque of the unskilled group was significantly smaller than that of the skilled group (p < 0.05), while there were no differences in work done by the hip joint and total work between the two groups. These results indicate that the difference between the skilled and the unskilled groups was not in the magnitude, but rather in the timing of joint torque exertion.
To improve the kip maneuver for unskilled performers, it is suggested that the shoulder extension and hip flexion torques should be exerted later and that exertion of shoulder extension torque should be emphasized.
