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Multijoint reflex responses to constant-velocity volitional movements of the stroke elbow. J Neurophysiol 2009 Sep;102(3):1398-410



Pubmed ID




Scopus ID

2-s2.0-70349299884 (requires institutional sign-in at Scopus site)   10 Citations


Multijoint reflex coupling could impact the voluntary control of functional arm movements in people post stroke. The multijoint responses to active-assist, constant-velocity movements of the elbow joint were measured in 14 individuals post stroke and 9 neurologically intact controls. Resulting responses in the stroke group illustrated a change in the reflex coupling of the elbow and shoulder muscles compared with passive perturbations of the spastic elbow. Voluntary effort during constant-velocity elbow extension resulted in reflex shoulder abduction, differing from the reflex coupling observed between the elbow flexors and shoulder adductors observed during passive elbow extension. These results suggest that post stroke, voluntary drive alters reflex coupling of the elbow and shoulder. Flexion of the elbow during active-assist also resulted in reflex coupling. Shoulder abduction torque decreased with constant-velocity flexion of the elbow; however, no net adduction was observed at the end of the perturbation. Shoulder flexion/extension and internal/external rotation torque responses demonstrated similar modulations to imposed active-assist perturbations of the elbow in subjects post stroke. Responses were absent during passive perturbations of the control elbow; however, shoulder torque modulations were observed during constant-velocity, active-assist tasks. The active-assist response patterns in controls were similar to stroke subjects during the extension task but opposite during flexion of the elbow. This study provides evidence of a neural coupling between elbow and shoulder muscles and a modulation of this coupling during voluntary drive of the spastic arm.

Author List

Sangani SG, Starsky AJ, McGuire JR, Schmit BD


John R. McGuire MD Professor in the Physical Medicine and Rehabilitation department at Medical College of Wisconsin
Brian Schmit PhD Professor in the Biomedical Engineering department at Marquette University
Andrew Starsky BS,PhD,MPT Assistant Professor in the Physical Therapy department at Marquette University

MESH terms used to index this publication - Major topics in bold

Action Potentials
Analysis of Variance
Elbow Joint
Middle Aged
Muscle, Skeletal
Young Adult