Research article summary (published 30 Jan 1996):

Leg stiffness and stride frequency in human running.

Full Abstract

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 2.5ms-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.

Author information

Author/s: Farley, C T (CT); González, O (O);

Affiliation: Museum of Comparative Zoology, Harvard University, Bedford, MA 01730, USA.

Grants: AR08189 (Agency:NIAMS NIH HHS) ; AR18140 (Agency:NIAMS NIH HHS)

Journal and publication information

Publication Type: Journal Article; Research Support, U.S. Gov't, P.H.S.

Journal: Journal of biomechanics (J Biomech), published in UNITED STATES. (Language: eng)

Reference: 1996-Feb; vol 29 (issue 2) : pp 181-6

Dates: Created 1996/12/19; Completed 1996/12/19; Revised 2007/11/14;

PMID: 8849811, status: MEDLINE (last retrieval date: 2/18/2009, IMS Date: )

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Adaptation, Physiological Adult Biomechanics Elasticity Gait - physiology Humans Leg - physiology Ligaments - physiology

Ligaments - physiology Male Models, Biological Muscle, Skeletal - physiology Running - physiology Stress, Mechanical Tendons - physiology Weight-Bearing

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