Delayed and reduced intralimb muscular coupling during postural reactions in individuals with incomplete spinal cord injury.

Autor: Pion CH; School of Rehabilitation, Faculty of Medicine, Université de Montréal, Canada; Centre for Interdisciplinary Research in Rehabilitation of Greater Montréal (CRIR), Canada., Masse W; Centre for Interdisciplinary Research in Rehabilitation of Greater Montréal (CRIR), Canada., Barthélemy D; School of Rehabilitation, Faculty of Medicine, Université de Montréal, Canada; Centre for Interdisciplinary Research in Rehabilitation of Greater Montréal (CRIR), Canada. Electronic address: dorothy.barthelemy@umontreal.ca.
Jazyk: angličtina
Zdroj: Gait & posture [Gait Posture] 2021 Jul; Vol. 88, pp. 84-93. Date of Electronic Publication: 2021 May 08.
DOI: 10.1016/j.gaitpost.2021.05.003
Abstrakt: Background: Postural strategies are enabled by rapid muscle activation sequences to prevent a fall. Intralimb muscular couplings underlie these postural strategies are likely impaired after incomplete spinal cord injury (iSCI), leading to inappropriate postural reactions and increased fall risk; yet, the nature of these changes is unknown.
Research Question: Identify changes occurring in intralimb coupling following a perturbation in individuals with iSCI.
Methods: Ten men with iSCI and eight age-matched controls (CTRL) stood on a force-platform that was randomly tilted forward or backward. Electromyographic (EMG) activity of the lower limb muscles was recorded, and coactivation or simultaneous facilitation/suppression between pairs of muscles was analyzed. Onset and duration of coupling latency, intralimb coupling delay, and amplitude ratios were measured in the distal (soleus [SOL]/tibialis anterior [TA]), proximal (biceps femoris [BF]/vastus lateralis [VL]), anterior (TA-VL), and posterior (SOL-BF) muscle couplings.
Results: In forward tilt, the main coupling was TA-SOL co-contraction for both groups, but the latency was longer and the duration shorter in SCI participants. In backward tilt, the TA-VL co-activation was the main coupling in CTRL (88 %), although it was also expressed by 60 % of SCI participant with a delayed latency. The facilitation/suppression of TA-SOL was the main coupling in SCI group (80 % vs 63 % in CTRL). Delayed coupling latencies were more pronounced in individuals with cervical iSCI and were correlated with the strength of lower limbs.
Significance: Similar muscular couplings are present in both groups but are delayed, which might contribute to postural reaction deficits in individuals with iSCI.
(Copyright © 2021 Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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