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Rehabilitation Research and Practice
Volume 2011, Article ID 313980, 8 pages
http://dx.doi.org/10.1155/2011/313980
Research Article

Abnormal Leg Muscle Latencies and Relationship to Dyscoordination and Walking Disability after Stroke

1Research Service 151-W, Louis Stokes Cleveland VA Medical Center, 10701 East Boulevard, Cleveland, OH 44106, USA
2Department of Neurology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA

Received 31 August 2010; Revised 10 November 2010; Accepted 19 November 2010

Academic Editor: Arie Rimmerman

Copyright © 2011 Janis J. Daly et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The purpose was to determine timing characteristics of leg muscle latencies for patients following stroke (>12 months) who had persistent coordination and gait deficits, and to determine the relationships among abnormal latencies, dyscoordination, and gait deficits. We compared nine healthy controls and 27 stroke survivors. Surface electromyography measured activation and deactivation latencies of knee flexor and extensor muscles during a ballistic knee flexion task, consistency of latencies across repetitions, and close coupling between agonist and antagonist muscle latencies. We measured Fugl-Meyer (FM) coordination and the functional gait measure, six minute walk test (6MWT). For stroke subjects, there were significant delays of muscle activation and deactivation, abnormal inconsistency, and abnormal decoupled agonist and antagonist activations. There was good correlation between activation latencies and FM and 6MWT. Results suggest abnormal timing characteristics underlie coordination impairment and dysfunctional gait. These abnormal muscle activation and deactivation timing characteristics are important targets for rehabilitation.