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Chronic pain alters spatiotemporal activation patterns of forearm muscle synergies during the development of grip force

journal contribution
posted on 2023-05-21, 04:59 authored by Nagarajan ManickarajNagarajan Manickaraj, Bisset, L, Devanaboyina, VSPT, Kavanagh, JJ
It is largely unknown how the CNS regulates multiple muscle systems in the presence of pain. This study used muscle synergy analysis to investigate multiple forearm muscles in individuals with chronic elbow pain during the development of grip force. Eleven individuals with chronic elbow pain and 11 healthy age-matched control subjects developed grip force to 15% and 30% of maximum voluntary contraction (MVC). Surface electromyography was obtained from six forearm muscles during force development before nonnegative matrix factorization was performed. The relationship between muscle synergies and standard clinical tests of elbow pain were examined by linear regression. During grip force development to 15% MVC the pain group had a lower number of forearm muscle synergies, increased similarity in spatial activation patterns, increased cocontraction of forearm flexors, and a greater magnitude of muscle weightings across the forearm when performing the task. During the 30% MVC grip the numbers of muscle synergies were the same for both groups; however, the pain group had lower activation and reduced variability in the timing of peak activation. The timing of peak activation was delayed in the pain group regardless of the task, and performing the grip in different wrist postures did not affect muscle synergy characteristics in either group. Although localized pain causes direct dysfunction of an affected muscle, this study provides evidence that the timing and amplitude of agonist and antagonist muscle activity are also affected with chronic pain.

History

Publication title

Journal of Neurophysiology

Volume

118

Pagination

2132-2141

ISSN

0022-3077

Department/School

School of Health Sciences

Publisher

Amer Physiological Soc

Place of publication

9650 Rockville Pike, Bethesda, USA, Md, 20814

Rights statement

Copyright © 2017 the American Physiological Society

Repository Status

  • Restricted

Socio-economic Objectives

Diagnosis of human diseases and conditions