TY - JOUR
T1 - The effects of selective muscle weakness on muscle coordination in the human arm
AU - Roh, Jinsook
AU - Beer, Randall F.
AU - Lai, Andrew
AU - Rho, Monica
AU - Karvelas, Kristopher R.
AU - Nader, Antoun M.
AU - Kendall, Mark C.
AU - Rymer, William Z.
N1 - Funding Information:
The work was supported by NIH R24 (5R24HD050821-10; PI: William Z. Rymer; Project PI: Jinsook Roh) and the American Heart Association Scientist Development Grant (17SDG33670561; PI: Jinsook Roh).
Publisher Copyright:
Copyright © 2018 Jinsook Roh et al. This is an open access article distributed under the Creative Commons Attribution License
PY - 2018
Y1 - 2018
N2 - Despite the fundamental importance of muscle coordination in daily life, it is currently unclear how muscle coordination adapts when the musculoskeletal system is perturbed. In this study, we quantified the impact of selective muscle weakness on several metrics of muscle coordination. Seven healthy subjects performed 2D and 3D isometric force target matches, while electromyographic (EMG) signals were recorded from 13 elbow and shoulder muscles. Subsequently, muscle weakness was induced by a motor point block of brachialis muscle. Postblock subjects repeated the force generation tasks. We quantified muscle coordination pre- and postblock using three metrics: tuning curve preferred direction, tuning curve area, and motor modules analysis via nonnegative matrix factorization. For most muscles, the tuning direction for the 2D protocol was not substantially altered postblock, while tuning areas changed more drastically. Typically, five motor modules were identified from the 3D task, and four motor modules were identified in the 2D task; this result held across both pre- and postblock conditions. The composition of one or two motor modules, ones that involved mainly the activation of shoulder muscles, was altered postblock. Our results demonstrate that selective muscle weakness can induce nonintuitive alternations in muscle coordination in the mechanically redundant human arm.
AB - Despite the fundamental importance of muscle coordination in daily life, it is currently unclear how muscle coordination adapts when the musculoskeletal system is perturbed. In this study, we quantified the impact of selective muscle weakness on several metrics of muscle coordination. Seven healthy subjects performed 2D and 3D isometric force target matches, while electromyographic (EMG) signals were recorded from 13 elbow and shoulder muscles. Subsequently, muscle weakness was induced by a motor point block of brachialis muscle. Postblock subjects repeated the force generation tasks. We quantified muscle coordination pre- and postblock using three metrics: tuning curve preferred direction, tuning curve area, and motor modules analysis via nonnegative matrix factorization. For most muscles, the tuning direction for the 2D protocol was not substantially altered postblock, while tuning areas changed more drastically. Typically, five motor modules were identified from the 3D task, and four motor modules were identified in the 2D task; this result held across both pre- and postblock conditions. The composition of one or two motor modules, ones that involved mainly the activation of shoulder muscles, was altered postblock. Our results demonstrate that selective muscle weakness can induce nonintuitive alternations in muscle coordination in the mechanically redundant human arm.
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U2 - 10.1155/2018/5637568
DO - 10.1155/2018/5637568
M3 - Article
C2 - 30402139
AN - SCOPUS:85062889381
VL - 2018
JO - Applied Bionics and Biomechanics
JF - Applied Bionics and Biomechanics
SN - 1176-2322
M1 - 5637568
ER -