其他标题：Take-off motion for jumping with an increase in the number of steps in the approach run for the long jump: focusing on the rate of change of take-off action from a short to a long approach jump
出版社：Japan Society of Physical Education, Health and Sport Sciences
摘要：The aim of this study was to clarify the take-off motion required to perform a longer leap when an athlete increases the number of steps in the approach run for the long jump. Seven senior jumpers performed the long jump using different numbers of approach-run steps. The number was increased from 6 strides to 16 strides every 2 strides. The following results were obtained. (1) When athletes increased the number of approach-run steps, the change in the approach velocity did not correspond to that of the jump distance. (2) To heighten the increased jump distance when athletes increased the number of approach-run steps, it was necessary to shorten the contact time and gain vertical velocity with less deceleration of horizontal velocity during the take-off phase. (3) To decrease the contact time when athletes increased the number of approach-run steps, it was effective to lower the angular deviation of the radius from the center of gravity (c.g.) to the grounding point of the take-off leg and increase the angular velocity during the take-off phase. In order to gain vertical velocity with less deceleration of horizontal velocity, it was necessary to increase the maximal lengthening velocity of the radius during the second half of the take-off phase. These results suggest that when deciding the number of approach-run steps it is necessary to evaluate not only sprint ability, as has been done in the past, but also contact time and take-off index, which is defined as the value of the vertical velocity at take-off divided by the deceleration of the horizontal velocity during take-off. At the same time, we should also evaluate c.g. behavior because of its relationship to contact time and take-off index.
其他摘要：The aim of this study was to clarify the take-off motion required to perform a longer leap when an athlete increases the number of steps in the approach run for the long jump. Seven senior jumpers performed the long jump using different numbers of approach-run steps. The number was increased from 6 strides to 16 strides every 2 strides. The following results were obtained. (1) When athletes increased the number of approach-run steps, the change in the approach velocity did not correspond to that of the jump distance. (2) To heighten the increased jump distance when athletes increased the number of approach-run steps, it was necessary to shorten the contact time and gain vertical velocity with less deceleration of horizontal velocity during the take-off phase. (3) To decrease the contact time when athletes increased the number of approach-run steps, it was effective to lower the angular deviation of the radius from the center of gravity (c.g.) to the grounding point of the take-off leg and increase the angular velocity during the take-off phase. In order to gain vertical velocity with less deceleration of horizontal velocity, it was necessary to increase the maximal lengthening velocity of the radius during the second half of the take-off phase. These results suggest that when deciding the number of approach-run steps it is necessary to evaluate not only sprint ability, as has been done in the past, but also contact time and take-off index, which is defined as the value of the vertical velocity at take-off divided by the deceleration of the horizontal velocity during take-off. At the same time, we should also evaluate c.g. behavior because of its relationship to contact time and take-off index.
关键词：-;短助走跳躍;-;長助走跳躍;身体重心の挙動;-;助走距離;-;踏切動作
其他关键词：jump with a short approach-run ; jump with a long approach-run ; behavior of center of gravity ; approach-run distance ; take-off motion
