1. Evolution of muscle coordination and mechanical output throughout four weeks of arm cranking submaximal training.
- Author
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Cartier, Théo, Rao, Guillaume, Viehweger, Elke, and Vigouroux, Laurent
- Subjects
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MATRIX decomposition , *EXTREMITIES (Anatomy) , *NONNEGATIVE matrices , *CROSS correlation , *PRODUCTION control , *ANAEROBIC capacity , *ARM muscles - Abstract
Muscle synergies are extensively studied to understand how the neuromusculoskeletal system deals with abundance. The synergies represent covariant muscles that act as building blocks for movement production. Nevertheless, little is known on how those synergies evolve after training, learning, and expertise. To this aim, this study reports the influence of 4-wk upper limb submaximal training with arm cranking on novice participants' muscle synergies. Twelve participants performed eight sessions of submaximal training for 4 wk. One session consisted of two 30-s maximal power tests followed by six 2-min bouts at 30% of maximal recorded power. Cranking torque and electromyogram (EMG) of 11 representative muscles were recorded during the entire protocol. After EMG normalization, muscle synergies were extracted with nonnegative matrix factorization (NNMF). Similarity was computed with cross correlation and cosine similarities, and statistical evolution across training days was tested by repeated-measures ANOVA. Although maximal power increased across training days, neither torque management, EMG, nor muscle synergies (4 synergies) were significantly affected by submaximal training. Nevertheless, results suggest slight modifications of muscle synergies across days despite nonsignificant differences. Despite the strong complexity of the upper limb anatomy, our results showed that training did not induce significant changes in movement realization (mechanical and coordination level). A low-dimensional organization of covariant muscles (muscle synergies) is selected from the first day and maintained through the following training days, despite slight but nonsignificant modifications. This study supports the hypothesis that motor control for movement production could be simplified by using low-dimensional building blocks (muscle synergies). Such building blocks allow stability in movement execution and are slightly adjusted to fit movement requirements with training. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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