The first and second phase of the muscle compound action potential in the thumb are differently affected by electrical stimulation trains

Sarcolemmal membrane excitability is often evaluated by considering the peak-to-peak amplitude of the compound muscle action potential (M-wave). However, the first and second M-wave phases represent distinct properties of the muscle action potential, which are differentially affected by sarcolemma properties and other factors such as muscle architecture. Contrasting with previous studies in which voluntary contractions have been used to induce muscle fatigue, we employed repeated electrically-induced tetanic contractions of the adductor pollicis muscle and assessed the kinetics of M-wave properties during the course of the contractions. Eighteen participants (25±6 years) underwent 30 electrically-evoked tetanic contractions delivered at 30Hz, each lasting 3s with 1s intervals. We recorded the amplitudes of the first and second M-wave phases for each stimulation. During the initial stimulation train, the first and second M-wave phases exhibited distinct kinetics. The first phase amplitude showed a rapid decrease to reach ~59% of its initial value (p<0.001), whereas the second phase amplitude displayed an initial transient increase of ~19% (p = 0.007). Within subsequent trains, both the first and second phase amplitudes consistently decreased as fatigue developed with a reduction during the last train reaching ~47% of its initial value (p<0.001). Analysing the first M-wave of each stimulation train unveiled different kinetics for the first and second phases during the initial trains, but these distinctions disappeared as fatigue progressed. These findings underscore the interplay of factors affecting the M-wave and emphasize the significance of separately scrutinizing its first and second phases when assessing membrane excitability adjustments during muscle contractions.

Medienart:

E-Artikel

Erscheinungsjahr:

2024

Erschienen:

2024

Enthalten in:

Zur Gesamtaufnahme - year:2024

Enthalten in:

Journal of applied physiology (Bethesda, Md. : 1985) - (2024) vom: 21. März

Sprache:

Englisch

Beteiligte Personen:

Lanfranchi, Clément [VerfasserIn]
Rodriguez-Falces, Javier [VerfasserIn]
Place, Nicolas [VerfasserIn]

Links:

Volltext

Themen:

Fatigue
Journal Article
M wave
Sarcolemmal excitability
Tetanic contraction

Anmerkungen:

Date Revised 21.03.2024

published: Print-Electronic

Citation Status Publisher

doi:

10.1152/japplphysiol.00861.2023

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM370007905