Task dependency of motor adaptations to an acute noxious stimulation

Hug, Francois, Hodges, Paul W. and Tucker, Kylie (2014) Task dependency of motor adaptations to an acute noxious stimulation. Journal of Neurophysiology, 111 11: 2298-2306. doi:10.1152/jn.00911.2013

Author Hug, Francois
Hodges, Paul W.
Tucker, Kylie
Title Task dependency of motor adaptations to an acute noxious stimulation
Journal name Journal of Neurophysiology   Check publisher's open access policy
ISSN 1522-1598
Publication date 2014-06-01
Year available 2014
Sub-type Article (original research)
DOI 10.1152/jn.00911.2013
Open Access Status DOI
Volume 111
Issue 11
Start page 2298
End page 2306
Total pages 9
Place of publication Bethesda MD, United States
Publisher American Physiological Society
Language eng
Abstract This study explored motor adaptations in response to an acute noxious stimulation during three tasks that differed in the number of available degrees of freedom. Fifteen participants performed three isometric force-matched tasks (single leg knee extension, single leg squat, and bilateral leg squat) in three conditions (Control, Pain, and Washout). Pain was induced by injection of hypertonic saline into the vastus medialis muscle (VM; left leg). Supersonic shear imaging was used to measure muscle shear elastic modulus as this is considered to be an index of muscle stress. Surface electromyography (EMG) was recorded bilaterally from six muscles to assess changes in neural strategies. During tasks with fewer degrees of freedom (knee extension and single leg squat task), there was no change in VM EMG amplitude or VM shear elastic modulus. In contrast, during the bilateral leg squat, VM (-32.9 ± 15.8%; P < 0.001) and vastus lateralis (-28.7 ± 14.8%; P < 0.001) EMG amplitude decreased during Pain. This decrease in activation was associated with reduced VM shear elastic modulus (-17.6 ± 23.3%; P = 0.029) and reduced force produced by the painful leg (-10.0 ± 10.2%; P = 0.046). This work provides evidence that when an obvious solution is available to decrease stress on painful tissue, this option is selected. It confirms the fundamental assumption that motor adaptations to pain aim to alter load on painful tissue to protect for further pain and/or injury. The lack of adaptation observed during force-matched tasks with fewer degrees of freedom might be explained by the limited potential to redistribute stress or a high cost induced by such a compensation.
Keyword Pain
Supersonic shear imaging
Shear elastic modulus
Muscle coordination
Q-Index Code C1
Q-Index Status Confirmed Code
Grant ID APP1002190
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2015 Collection
School of Biomedical Sciences Publications
School of Health and Rehabilitation Sciences Publications
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