Neuroplastic alterations in common synaptic inputs and synergistic motor unit clusters controlling the vastii muscles of individuals with ACL reconstruction

Nuccio S, Germer CM, Casolo A, Borzuola R, Labanca L, Rocchi JE, Mariani PP, Felici F, Farina D, Falla D, Macaluso A, Sbriccoli P, Del Vecchio A (2024)

Publication Type: Journal article

Publication year: 2024

Journal

Journal of Applied Physiology American Physiological Society

Book Volume: 137

Pages Range: 835-847

Journal Issue: 4

DOI: 10.1152/japplphysiol.00056.2024

Abstract

This cross-sectional study aims to elucidate the neural mechanisms underlying the control of knee extension forces in individuals with anterior cruciate ligament reconstruction (ACLR). Eleven soccer players with ACLR and nine control players performed unilateral isometric knee extensions at 10% and 30% of their maximum voluntary force (MVF). Simultaneous recordings of high-density surface electromyography (HDEMG) and force output were conducted for each lower limb, and HDEMG data from the vastus lateralis (VL) and vastus medialis (VM) muscles were decomposed into individual motor unit spike trains. Force steadiness was estimated using the coefficient of variation of force. An intramuscular coherence analysis was adopted to estimate the common synaptic input (CSI) converging to each muscle. A factor analysis was applied to investigate the neural strategies underlying the control of synergistic motor neuron clusters, referred to as motor unit modes. Force steadiness was similar between lower limbs. However, motor neurons innervating the VL on the reconstructed side received a lower proportion of CSI at low-frequency bandwidths (<5 Hz) compared with the unaffected lower limbs (P < 0.01). Furthermore, the reconstructed side demonstrated a higher proportion of motor units associated with the neural input common to the synergistic muscle, as compared with the unaffected lower limbs (P < 0.01). These findings indicate that the VL muscle of reconstructed lower limbs contribute marginally to force steadiness and that a plastic rearrangement in synergistic clusters of motor units involved in the control of knee extension forces is evident following ACLR.NEW & NOTEWORTHY Chronic quadriceps dysfunction is common after anterior cruciate ligament reconstruction (ACLR). We investigated voluntary force control strategies by estimating common inputs to motor neurons innervating the vastii muscles. Our results showed attenuated common inputs to the vastus lateralis and plastic rearrangements in functional clusters of motor neurons modulating knee extension forces in the reconstructed limb. These findings suggest neuroplastic adjustments following ACLR that may occur to fine-tune the control of quadriceps forces.

Authors with CRIS profile

Alessandro Del Vecchio Juniorprofessur für Neuromuscular Physiology and Neural Interfacing

Involved external institutions

Università degli Studi di Roma "Foro Italico" IT Italy (IT) Universidade Estadual de Campinas (UNICAMP) / University of Campinas BR Brazil (BR) University of Padua / Universita degli Studi di Padova IT Italy (IT) Fédération Internationale de Football Association FIFA CH Switzerland (CH) Imperial College London / The Imperial College of Science, Technology and Medicine GB United Kingdom (GB) University of Birmingham GB United Kingdom (GB)

How to cite

APA:

Nuccio, S., Germer, C.M., Casolo, A., Borzuola, R., Labanca, L., Rocchi, J.E.,... Del Vecchio, A. (2024). Neuroplastic alterations in common synaptic inputs and synergistic motor unit clusters controlling the vastii muscles of individuals with ACL reconstruction. Journal of Applied Physiology, 137(4), 835-847. https://doi.org/10.1152/japplphysiol.00056.2024

MLA:

Nuccio, Stefano, et al. "Neuroplastic alterations in common synaptic inputs and synergistic motor unit clusters controlling the vastii muscles of individuals with ACL reconstruction." Journal of Applied Physiology 137.4 (2024): 835-847.

BibTeX: Download