Contraction intensity-dependent variations in the responses to brain and corticospinal tract stimulation after a single session of resistance training in men

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The aim of this study was to determine the effects of acute resistance training (RT) intensity on motor evoked potentials (MEPs) generated by transcranial magnetic brain stimulation and on cervicomedullary motor evoked potentials (CMEPs) produced by electrical stimulation of the corticospinal tract. In four experimental sessions, 14 healthy young men performed 12 sets of eight isometric contractions of the elbow flexors at 0 (Control session), 25, 50 and 75% of the maximal voluntary contraction (MVC). Before and after each session, MEPs, CMEPs, and the associated twitch forces were recorded at rest. MEPs increased by 39% (P < 0.05 vs. 25% and control condition, ES = 1.04 and 1.76 respectively) after the 50% session and by 70% (P < 0.05 vs. all other conditions, ES = 0.91 - 2.49) after the 75% session. In contrast, CMEPs increased similarly after the 25%, 50%, and 75% sessions with an overall increase of 27% (P < 0.05 vs. control condition, ES = 1.34). The amplitude of maximal compound muscle action potentials (Mmax) was unchanged during the experiment. The MEP- and CMEP-associated twitch forces also increased after RT, but training intensity affected only the increases in MEP twitch forces. The data tentatively suggest that the intensity of muscle contraction used in acute bouts of RT affects cortical excitability.

TidsskriftJournal of Applied Physiology
Udgave nummer4
Sider (fra-til)1128-1139
Antal sider12
StatusUdgivet - 2019

Bibliografisk note

CURIS 2019 NEXS 337

ID: 226825698