Leg stiffness and stride frequency in human running
Leg stiffness and stride frequency in human running
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DOI：
10.1016/0021-9290(95)00029-1
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发表时间：
1996-02-01
影响因子：
2.4
通讯作者：
Gonzalez, O
中科院分区：
文献类型：
--
作者：
Farley, CT;Gonzalez, O
当人类和其他哺乳动物跑步时，身体复杂的肌肉、肌腱和韧带弹簧系统就像一个单一的线性弹簧（“腿部弹簧”）。一个简单的弹簧-质量模型，由一个单一的线性腿弹簧和一个相当于动物质量的质量组成，已经被证明可以很好地描述跑步的力学。从跑步动物（包括人类）的力平台测量表明，腿弹簧的刚度在所有速度下保持几乎相同，并且通过增加腿弹簧扫过的角度来调节弹簧质量系统以用于更高的速度。本研究的目的是确定当人类在给定的跑步速度下改变他们的步频时，腿部弹簧刚度和腿部弹簧扫过的角度变化的相对重要性。人类受试者以2.5 ms（-1）的速度在安装在跑步机上的测力平台上跑步，同时使用的步频范围从低于首选步频的26%到高于首选步频的36%。测力台测量结果显示，在最低和最高步频之间，腿部弹簧的刚度从7.0 kNm（-1）增加了2.3倍。腿弹簧扫过的角度在更高的步幅频率下减小，部分抵消了腿弹簧刚度增加对弹簧-质量系统的机械行为的影响。我们的结论是，最重要的调整身体的弹簧系统，以适应更高的步频是，腿部弹簧变得更硬。
When humans and other mammals run, the body's complex system of muscle, tendon and ligament springs behaves like a single linear spring ('leg spring'). A simple spring-mass model, consisting of a single linear leg spring and a mass equivalent to the animal's mass, has been shown to describe the mechanics of running remarkably well. Force platform measurements from running animals, including humans, have shown that the stiffness of the leg spring remains nearly the same at all speeds and that the spring-mass system is adjusted for higher speeds by increasing the angle swept by the leg spring. The goal of the present study is to determine the relative importance of changes to the leg spring stiffness and the angle swept by the leg spring when humans alter their stride frequency at a given running speed. Human subjects ran on treadmill-mounted force platform at 2.5 ms(-1) while using a range of stride frequencies from 26% below to 36% above the preferred stride frequency. Force platform measurements revealed that the stiffness of the leg spring increased by 2.3-fold from 7.0 to 16.3 kNm(-1) between the lowest and highest stride frequencies. The angle swept by the leg spring decreased at higher stride frequencies, partially offsetting the effect of the increased leg spring stiffness on the mechanical behavior of the spring-mass system. We conclude that the most important adjustment to the body's spring system to accommodate higher stride frequencies is that leg spring becomes stiffer.