Between-subject variability of muscle synergies during a complex motor skill

Frere, Julien and Hug, Francois (2012) Between-subject variability of muscle synergies during a complex motor skill. Frontiers in Computational Neuroscience, 6 . doi:10.3389/fncom.2012.00099


Author Frere, Julien
Hug, Francois
Title Between-subject variability of muscle synergies during a complex motor skill
Journal name Frontiers in Computational Neuroscience   Check publisher's open access policy
ISSN 1662-5188
Publication date 2012-12-01
Year available 2012
Sub-type Article (original research)
DOI 10.3389/fncom.2012.00099
Open Access Status DOI
Volume 6
Total pages 13
Place of publication Lausanne, Switzerland
Publisher Frontiers Research Foundation
Collection year 2013
Language eng
Formatted abstract
The purpose of the present study was to determine whether subjects who have learned a complex motor skill exhibit similar neuromuscular control strategies. We studied a population of experienced gymnasts during backward giant swings on the high bar. This cyclic movement is interesting because it requires learning, as untrained subjects are unable to perform this task. 9 gymnasts were tested. Both kinematics and electromyographic (EMG) patterns of 12 upper-limb and trunk muscles were recorded. Muscle synergies were extracted by non-negative matrix factorization, providing two components: muscle synergy vectors and synergy activation coefficients. First, the coefficient of correlation (r) and circular cross-correlation (rmax) were calculated to assess similarities in the mechanical patterns, EMG patterns and muscle synergies between gymnasts. We performed a further analysis to verify that the muscle synergies (in terms of muscle synergy vectors or synergy activation coefficients) extracted for one gymnast accounted for the EMG patterns of the other gymnasts. 3 muscle synergies explained 89.9±2.0% of the variance accounted for (VAF). The coefficients of correlation of the muscle synergy vectors among the participants were 0.83±0.08, 0.86±0.09, and 0.66±0.28 for synergy #1, #2, and #3, respectively. By keeping the muscle synergy vectors constant, we obtained an averaged VAF across all pairwise comparisons of 79±4%. For the synergy activation coefficients, rmax-values were 0.96±0.03, 0.92±0.03, and 0.95±0.03, for synergy #1, #2, and #3, respectively. By keeping the synergy activation coefficients constant, we obtained an averaged VAF across all pairwise comparisons of 72±5%. Although variability was found (especially for synergy #3), the gymnasts exhibited gross similar neuromuscular strategies when performing backward giant swings. This confirms that the muscle synergies are consistent across participants, even during a skilled motor task that requires learning.
Keyword Motor modules
Muscle Coordination
Nonegative matrix factorization
Motor primitives
Electromyography
Backward giant circle
Gymnastics
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Non HERDC
School of Health and Rehabilitation Sciences Publications
 
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Created: Thu, 29 Aug 2013, 01:59:48 EST by Francois Hug on behalf of School of Health & Rehabilitation Sciences