MECHANICS OF RUNNING UNDER SIMULATED LOW GRAVITY
MECHANICS OF RUNNING UNDER SIMULATED LOW GRAVITY
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DOI：
10.1152/jappl.1991.71.3.863
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发表时间：
1991-09-01
影响因子：
3.3
通讯作者：
MCMAHON, TA
中科院分区：
文献类型：
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作者：
HE, JP;KRAM, R;MCMAHON, TA
使用身体和腿部的线性质量弹簧模型(T.A.McMahon和G.C.Cheng。J.Biomech。23：65-78,1990)，我们介绍了模拟低重力条件下人类跑步的实验观测，并对这些实验进行了分析。这项研究的目的是调查腿部的弹簧属性如何调整以适应不同的重力水平。我们假设腿弹簧的刚度在模拟的低重力条件下不会改变。为了模拟低重力，研究人员通过自行车座椅对受试者施加了几乎恒定的垂直力。力是通过手动绞车拉伸长钢弹簧来获得的。受试者在一台机动跑步机上跑步，这台跑步机经过改装，在踏面下安装了一个力量平台。4名受试者在正常重力条件下以一个速度(3.0m/S)跑步，在0.2~0.7G的6个模拟常重条件下跑步。作为对照，受试者也在正常重力条件下以2.0m/S至6.0m/S的5种速度跑步。所有比较得出两个基本原则：腿的刚度(被视为线性弹簧)和飞行阶段重心的垂直偏移都不随前进速度或重力而变化。有了这些结果作为输入，数学模型能够正确地解释确实发生的许多动态参数的变化，包括在正常重力下垂直刚度随着速度的增加以及在模拟低重力条件下观察到的峰值力的下降。
Using a linear mass-spring model of the body and leg (T. A. McMahon and G. C. Cheng. J. Biomech. 23: 65-78, 1990), we present experimental observations of human running under simulated low gravity and an analysis of these experiments. The purpose of the study was to investigate how the spring properties of the leg are adjusted to different levels of gravity. We hypothesized that leg spring stiffness would not change under simulated low-gravity conditions. To simulate low gravity, a nearly constant vertical force was applied to human subjects via a bicycle seat. The force was obtained by stretching long steel springs via a hand-operated winch. Subjects ran on a motorized treadmill that had been modified to include a force platform under the tread. Four subjects ran at one speed (3.0 m/s) under conditions of normal gravity and six simulated fractions of normal gravity from 0.2 to 0.7 G. For comparison, subjects also ran under normal gravity at five speeds from 2.0 to 6.0 m/s. Two basic principles emerged from all comparisons: both the stiffness of the leg, considered as a linear spring, and the vertical excursion of the center of mass during the flight phase did not change with forward speed or gravity. With these results as inputs, the mathematical model is able to account correctly for many of the changes in dynamic parameters that do take place, including the increasing vertical stiffness with speed at normal gravity and the decreasing peak force observed under conditions simulating low gravity.