| Contributions of muscles and passive dynamics to swing initiation over a range of walking speeds. | |
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MedLine Citation:
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PMID: 20236644 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Stiff-knee gait is a common walking problem in cerebral palsy characterized by insufficient knee flexion during swing. To identify factors that may limit knee flexion in swing, it is necessary to understand how unimpaired subjects successfully coordinate muscles and passive dynamics (gravity and velocity-related forces) to accelerate the knee into flexion during double support, a critical phase just prior to swing that establishes the conditions for achieving sufficient knee flexion during swing. It is also necessary to understand how contributions to swing initiation change with walking speed, since patients with stiff-knee gait often walk slowly. We analyzed muscle-driven dynamic simulations of eight unimpaired subjects walking at four speeds to quantify the contributions of muscles, gravity, and velocity-related forces (i.e. Coriolis and centrifugal forces) to preswing knee flexion acceleration during double support at each speed. Analysis of the simulations revealed contributions from muscles and passive dynamics varied systematically with walking speed. Preswing knee flexion acceleration was achieved primarily by hip flexor muscles on the preswing leg with assistance from biceps femoris short head. Hip flexors on the preswing leg were primarily responsible for the increase in preswing knee flexion acceleration during double support with faster walking speed. The hip extensors and abductors on the contralateral leg and velocity-related forces opposed preswing knee flexion acceleration during double support. |
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Authors:
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Melanie D Fox; Scott L Delp |
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Publication Detail:
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Type: Journal Article; Research Support, N.I.H., Extramural; Research Support, U.S. Gov't, Non-P.H.S. Date: 2010-03-16 |
Journal Detail:
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Title: Journal of biomechanics Volume: 43 ISSN: 1873-2380 ISO Abbreviation: J Biomech Publication Date: 2010 May |
Date Detail:
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Created Date: 2010-05-10 Completed Date: 2010-08-20 Revised Date: 2012-10-09 |
Medline Journal Info:
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Nlm Unique ID: 0157375 Medline TA: J Biomech Country: United States |
Other Details:
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Languages: eng Pagination: 1450-5 Citation Subset: IM |
Copyright Information:
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Copyright 2010 Elsevier Ltd. All rights reserved. |
Affiliation:
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Department of Mechanical Engineering, Clark Center, Room S-324, Stanford University, Mail Code 5450, 318 Campus Drive, Stanford, CA 94305-5450, USA. melanief@stanford.edu |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Adolescent Child Computer Simulation Female Gait / physiology* Humans Leg / physiology Male Models, Biological* Muscle Contraction / physiology* Muscle, Skeletal / physiology* Physical Exertion / physiology* Postural Balance / physiology* Walking / physiology* |
| Grant Support | |
ID/Acronym/Agency:
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R01 HD046814/HD/NICHD NIH HHS; R01 HD046814-04/HD/NICHD NIH HHS; R01HD046814/HD/NICHD NIH HHS; T32 GM063495-01/GM/NIGMS NIH HHS; T32GM063495/GM/NIGMS NIH HHS; U54 GM072970/GM/NIGMS NIH HHS; U54 GM072970-01/GM/NIGMS NIH HHS |
| Comments/Corrections | |
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