Why is countermovement jump height greater than squat jump height?
Why is countermovement jump height greater than squat jump height?
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DOI：
10.1097/00005768-199611000-00009
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发表时间：
1996-11-01
期刊：
影响因子：
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通讯作者：
VanSoest, AJ
中科院分区：
文献类型：
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作者：
Bobbert, MF;Gerritsen, KGM;VanSoest, AJ
在文献中，众所周知，受试者能够在反动作跳跃(CMJ)中跳得比深蹲跳跃(SJ)更高。这项研究的目的是估计与SJ相比，CMJ中可用于力量发展的时间以及弹性能量的储存和再利用对提高绩效的相对贡献。六名男子排球运动员表演了CMJ和SJ。对6块肢体肌肉的运动学、动力学和肌电活动(EMG)进行监测。研究发现，即使推举开始时的身体位置与CMJ相同，但CMJ的跳跃高度平均要高出3.4厘米。排除了SJ的非最佳协调性解释跳跃高度差异的可能性：SJ没有运动瓦解的迹象，SJ的脚尖离开位置与CMJ相同。在CMJ中较高的跳跃高度归因于这样一个事实，即反运动允许受试者在开始起跳时获得更大的关节力矩。因此，在CMJ的关节伸展范围的第一部分，关节力矩更大，因此可以产生比SJ更多的功。为了解释这一发现，测量和操纵的运动学和肌电活动被用作肌肉骨骼系统模型的输入。根据模拟结果，可以排除弹性能的储存和再利用作为CMJ比SJ性能提高的原因。反运动的关键贡献似乎是，它使肌肉在开始缩短之前建立了高水平的活跃状态(连接的横桥的一部分)和力，以便它们能够在缩短距离的第一部分产生更多的功。
In the literature, it is well established that subjects are able to jump higher in a countermovement jump (CMJ) than in a squat jump (SJ). The purpose of this study was to estimate the relative contribution of the time available for force development and the storage and reutilization of elastic energy to the enhancement of performance in CMJ compared with SJ. Six male volleyball players performed CMJ and SJ. Kinematics, kinetics, and muscle electrical activity (EMG) from six muscles of the lower extremity were monitored. It was found that even when the body position at the start of push-off was the same in SJ as in CMJ, jump height was on average 3.4 cm greater in CMJ. The possibility that nonoptimal coordination in SJ explained the difference in jump height was ruled out: there were no signs of movement disintegration in SJ, and toe-off position was the same in SJ as in CMJ. The greater jump height in CMJ was attributed to the fact that the countermovement allowed the subjects to attain greater joint moments at the start of push-off. As a consequence, joint moments were greater over the first part of the range of joint extension in CMJ, so that more work could be produced than in SJ. To explain this finding, measured and manipulated kinematics and electromyographic activity were used as input for a model of the musculoskeletal system. According to simulation results, storage and reutilization of elastic energy could be ruled out as explanation for the enhancement of performance in CMJ over that in SJ. The crucial contribution of the countermovement seemed to be that it allowed the muscles to build up a high level of active state (fraction of attached cross-bridges) and force before the start of shortening, so that they were able to produce more work over the first part of their shortening distance.