著者

阿江 通良 宮下 憲 飯干 明

出版者

バイオメカニズム学会

雑誌

バイオメカニズム

巻号頁・発行日

vol.9, pp.105-113, 1988

被引用文献数

3 2

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The purposes of this study were to analyze energy flows between lower limb segments during a cycle of sprinting and to clarify the characteristics of two different running motions, starting dash and sprinting at a constant speed, by comparing their energy flows. Three male sprinters dashed 20m and ran 100m giving their full effort. They were filmed at the 1-step and 5-step points after the start and at the 80m mark of the 100m sprint with a motion-picture camera. Ground reaction force data were simultaneously sampled at 500Hz. Digitized x and y coordinates of the body marks were smoothed by a digital filter cutting off at 8Hz for the start dash and 10Hz for sprinting. A 14-segment link modelling was used to compute linear and angular kinematics, joint forces, and net muscle moments. Joint force and muscle moment powers (abbreviated JP and MP) were computed as defined by Robertson and Winter (1980). Analysis and comparison of energy flow in a starting dash and sprinting at a constant speed revealed that: 1) Magnitude of energy flow by JP was much greater than that of MP in sprinting, while the difference in power level of JP and MP was less 1 step after the start. 2) In the early recovery period of sprinting, energy in the lower limb flowed from the trunk toward the foot, and it flowed in the reverse direction in the late recovery period. In the support period, the muscles at the ankle and knee joints absorbed most of the energy. Energy flowed from the trunk and thigh to the shank in the first half of the support period, and from the foot to the shank and from the trunk to the shank through the thigh in the second half. 3) In the recovery period of the starting dash energy flowed in the same manner as in sprinting. However, in the support period, the energy flowed from the foot to the thigh and the trunk. Notable was energy flow from the opposite thigh (i.e., the recovery thigh) to the trunk. From the viewpoint of energy flow patterns in the lower limb, a starting dash may be characterized as the running motion that accumulates as much mechanical energy in the trunk as possible through the generation of energy by the knee joint muscles and the transfer of energy to the trunk from the leg, especially the opposite leg at the support stage. Sprinting at constant speed may be characterized as the running motion to redistribute the energy between the body segments and the trunk with the minimum loss of energy.