Running with a load increases leg stiffness

Show simple item record Silder, A en Besier, Thor en Delp, SL en 2015-06-18T02:51:49Z en 2015-04 en
dc.identifier.citation Journal of biomechanics, 2015, 48 (6), pp. 1003 - 1008 en
dc.identifier.issn 0021-9290 en
dc.identifier.uri en
dc.description.abstract Spring-mass models have been used to characterize running mechanics and leg stiffness in a variety of conditions, yet it remains unknown how running while carrying a load affects running mechanics and leg stiffness. The purpose of this study was to test the hypothesis that running with a load increases leg stiffness. Twenty-seven subjects ran at a constant speed on a force-measuring treadmill while carrying no load, and while wearing weight vests loaded with 10%, 20%, and 30% of body weight. We measured lower extremity motion and created a scaled musculoskeletal model of each subject, which we used to estimate lower extremity joint angles and leg length. We estimated dimensionless leg stiffness as the ratio of the peak vertical ground reaction force (normalized to body weight) and the change in stance phase leg length (normalized to leg length at initial foot contact). Leg length was calculated as the distance from the center of the pelvis to the center-of-pressure under the foot. We found that dimensionless leg stiffness increased when running with load (p=0.001); this resulted from an increase in the peak vertical ground reaction force (p<0.001) and a smaller change in stance phase leg length (p=0.025). When running with load, subjects had longer ground contact times (p<0.020), greater hip (p<0.001) and knee flexion (p=0.048) at the time of initial foot contact, and greater peak stance phase hip, knee, and ankle flexion (p<0.05). Our results reveal that subjects run in a more crouched posture and with higher leg stiffness to accommodate an added load. en
dc.format.medium Print-Electronic en
dc.language eng en
dc.relation.ispartofseries Journal of biomechanics en
dc.rights Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. Details obtained from en
dc.rights.uri en
dc.title Running with a load increases leg stiffness en
dc.type Journal Article en
dc.identifier.doi 10.1016/j.jbiomech.2015.01.051 en
pubs.issue 6 en
pubs.begin-page 1003 en
pubs.volume 48 en
dc.identifier.pmid 25728581 en
pubs.end-page 1008 en
dc.rights.accessrights en
pubs.subtype Journal Article en
pubs.subtype Research Support, Non-U.S. Gov't en
pubs.subtype Research Support, N.I.H., Extramural en
pubs.subtype Article en
pubs.elements-id 477126 en Bioengineering Institute en ABI Associates en
dc.identifier.eissn 1873-2380 en
pubs.record-created-at-source-date 2015-06-18 en
pubs.dimensions-id 25728581 en

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