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Experimental Brain Research

, Volume 114, Issue 3, pp 500–506 | Cite as

Anticipatory locomotor adjustments for accommodating versus avoiding level changes in humans

  • B. J. McFadyen
  • H. Carnahan
RESEARCH ARTICLE

Abstract

 The control of locomotion has been studied from various perspectives related to the tasks of pattern generation, equilibrium control or adaptation to the environment. The last of these locomotor components has received comparably less attention, specifically pertaining to anticipatory adjustments. Continuing the work which has been conducted on both humans and cats, the present paper explores the nature of the differences in anticipatory locomotor adjustments for obstacle avoidance versus the accommodation to level changes. Six subjects walked in six different environments including no obstructions, a simple obstacle, two different level changes (a platform and stairs), and a combination of an obstacle with each respective level change. Full dynamic analyses allowed comparison of muscle torques as well as muscle power generated and absorbed at the lower limb joints across conditions. It was found that the previously shown robust lower limb reorganization characterized by a knee flexor generation strategy was upheld in all conditions when the obstacle was present. Pure level changes involved an augmentation of the ongoing hip strategy inherent in normal level walking. In the compound environment of obstructed level changes, subjects chose to combine an augmentation of hip flexor power with a reorganization to active knee flexion. The results are discussed from the point of view of general principles of mechanical coordination and the exploitation of intersegmental dynamics for foot transport.

Key words Locomotion Gait adjustments Kinematics Kinetics 

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Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • B. J. McFadyen
    • 1
  • H. Carnahan
    • 2
  1. 1.Département de Physiothérapie, Faculté de Médicine, Université Laval, Québec, Canada G1K 7P4; Tel.: +1 (418) 656–2874, Fax: +1 (418) 656–2874, e-mail: brad.mcfadyen@pht.ulaval.caCA
  2. 2.Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1CA

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