棒高跳におけるボルターとポール間の力学的エネルギーの伝達

抄録

The purpose of this study was to investigate mechanical energy flow between vaulter and pole in pole vaulting. Five pole vaulters and four decathletes performed pole vaulting to clear the cross bar set at the height of 82 to 93% of their personal best record. All trials were videotaped with four video cameras (60 fps), and box reaction forces (500 Hz) were measured with a Kistler force platform on which a specially-designed vaulting box was bolted. Three dimensional coordinates of the points of the vaulting pole and body landmarks of the vaulter were obtained by using a DLT technique. Energy of the vaulter (potential and kinetic energy) and the pole (elastic energy) was calculated using box reaction forces and the kinematics of the vaulter and the pole. Powers at both hands during vaulting phase (from takeoff to pole-straight) were calculated as a scalar product of the force exerted on the pole via both hands and the velocities of the hands. Large mechanical energy flow (about 9.2 J/kg) was observed from the vaulter to the pole through the lower hand in pole-bending phase, and the energy flow from the pole to the vaulter occurred via the upper hand in pole-straightening phase. These results indicate that both hands of the vaulter may play different roles in transferring mechanical energy between the vaulter and the pole.