Sarcolemmal Excitability, M-Wave Changes, and Conduction Velocity During a Sustained Low-Force Contraction.

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Version: Final published version
License: CC BY 4.0
Serval ID
serval:BIB_4BE2BF112CCF
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Sarcolemmal Excitability, M-Wave Changes, and Conduction Velocity During a Sustained Low-Force Contraction.
Journal
Frontiers in physiology
Author(s)
Rodriguez-Falces J., Place N.
ISSN
1664-042X (Print)
ISSN-L
1664-042X
Publication state
Published
Issued date
2021
Peer-reviewed
Oui
Volume
12
Pages
732624
Language
english
Notes
Publication types: Journal Article
Publication Status: epublish
Abstract
This study was undertaken to investigate whether sarcolemmal excitability is impaired during a sustained low-force contraction [10% maximal voluntary contraction (MVC)] by assessing muscle conduction velocity and also by analyzing separately the first and second phases of the muscle compound action potential (M wave). Twenty-one participants sustained an isometric knee extension of 10% MVC for 3min. M waves were evoked by supramaximal single shocks to the femoral nerve given at 10-s intervals. The amplitude, duration, and area of the first and second M-wave phases were computed. Muscle fiber conduction velocity, voluntary surface electromyographic (EMG), perceived effort, MVC force, peak twitch force, and temperature were also recorded. The main findings were: (1) During the sustained contraction, conduction velocity remained unchanged. (2) The amplitude of the M-wave first phase decreased for the first ~30s (-7%, p<0.05) and stabilized thereafter, whereas the second phase amplitude increased for the initial ~30s (+7%, p<0.05), before stabilizing. (3) Both duration and area decreased steeply during the first ~30s, and then more gradually for the rest of the contraction. (4) During the sustained contraction, perceived effort increased fivefold, whereas knee extension EMG increased by ~10%. (5) Maximal voluntary force and peak twitch force decreased (respectively, -9% and -10%, p<0.05) after the low-force contraction. Collectively, the present results indicate that sarcolemmal excitability is well preserved during a sustained 10% MVC task. A depression of the M-wave first phase during a low-force contraction can occur even in the absence of changes in membrane excitability. The development of fatigue during a low-force contraction can occur without alteration of membrane excitability.
Keywords
conduction velocity, low-level contraction, membrane excitability, neuromuscular propagation, peripheral fatigue, submaximal contraction, sustained contraction
Pubmed
Open Access
Yes
Create date
09/11/2021 8:26
Last modification date
19/08/2022 6:09
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