Muscles from the same muscle group do not necessarily share common drive: evidence from the human triceps surae

Hug F, Del Vecchio A, Avrillon S, Farina D, Tucker K (2021)

Publication Type: Journal article

Publication year: 2021

Journal

Journal of Applied Physiology American Physiological Society

Book Volume: 130

Pages Range: 342-354

Journal Issue: 2

DOI: 10.1152/JAPPLPHYSIOL.00635.2020

Abstract

It has been proposed that movements are produced through groups of muscles, or motor modules, activated by common neural commands. However, the neural origin of motor modules is still debated. Here, we used complementary approaches to determine: 1) whether three muscles of the same muscle group [soleus, gastrocnemius medialis (GM), and gastrocnemius lateralis (GL)] are activated by a common neural drive, and 2) whether the neural drive to GM and GL could be differentially modified by altering the mechanical requirements of the task. Eighteen human participants performed an isometric standing heel raise and submaximal isometric plantarflexions (10%, 30%, and 50% of maximal effort). High-density surface electromyography recordings were decomposed into motor unit action potentials and coherence analysis was applied on the motor unit spike trains. We identified strong common drive to each muscle but minimal common drive between the muscles. Further, large between-muscle differences were observed during the isometric plantarflexions, such as a delayed recruitment time of GL compared with GM and soleus motor units and opposite time-dependent changes in the estimates of neural drive to muscles during the torque plateau. Finally, the feet position adopted during the heel-raise task (neutral vs. internally rotated) affected only the GL neural drive with no change for GM. These results provide conclusive evidence that not all anatomically defined synergist muscles are controlled by strong common neural drive. Independent drive to some muscles from the same muscle group may allow for more flexible control to comply with secondary goals such as joint stabilization. NEW & NOTEWORTHY In this study, we demonstrated that the three muscles composing the human triceps surae share minimal common drive during isometric contractions. Our results suggest that reducing the number of effectively controlled degrees of freedom may not always be the strategy used by the central nervous system to control movements. Independent control of some, but not all, synergist muscles may allow for more flexible control to comply with secondary goals (e.g., joint stabilization).

Authors with CRIS profile

Alessandro Del Vecchio Juniorprofessur für Neuromuscular Physiology and Neural Interfacing

Involved external institutions

University of Queensland AU Australia (AU) Université de Nantes FR France (FR) Imperial College London / The Imperial College of Science, Technology and Medicine GB United Kingdom (GB)

How to cite

APA:

Hug, F., Del Vecchio, A., Avrillon, S., Farina, D., & Tucker, K. (2021). Muscles from the same muscle group do not necessarily share common drive: evidence from the human triceps surae. Journal of Applied Physiology, 130(2), 342-354. https://doi.org/10.1152/JAPPLPHYSIOL.00635.2020

MLA:

Hug, François, et al. "Muscles from the same muscle group do not necessarily share common drive: evidence from the human triceps surae." Journal of Applied Physiology 130.2 (2021): 342-354.

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