Contributions of muscles and passive dynamics to swing initiation over a range of walking speeds

JOURNAL OF BIOMECHANICS

卷:43

Article

Fox, Melanie D.¹  Delp, Scott L.^1,2 

[1] Stanford Univ, Dept Mech Engn, Clark Ctr, Stanford, CA 94305 USA

[2] Stanford Univ, Dept Bioengn, Stanford, CA 94305 USA

关键词: Cerebral palsy;    Stiff knee gait;    Forward dynamic simulation;    Muscle function;    Walking speed;    Knee flexion;   

DOI  :  10.1016/j.jbiomech.2010.02.009

来源: Elsevier

【 摘 要 】

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. (C) 2010 Elsevier Ltd. All rights reserved.

【 授权许可】

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