Effects of acute resistance training modality on corticospinal excitability, intra-cortical and neuromuscular responses

Latella, Christopher; Teo, Wei Peng; Harris, Dale M.; Major, Brendan; VanderWesthuizen, Dan; Hendy, Ashlee M.

doi:10.1007/s00421-017-3709-7

Cited by 37 publications

(57 citation statements)

References 56 publications

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“…A single session of ST increases the responses to corticospinal tract stimulation at rest or during low‐level isometric contractions suggesting , increases in cortical or α‐motoneuron excitability or an increased efficacy of the corticospinal‐motorneuronal synapse . Our results are in line with previous studies by showing ~47% increase in CSE measured at 5% background MVC in the BB of the trained arm only after ST at 75% MVC.…”

Section: Discussionsupporting

confidence: 92%

“…Regarding SP, past results have been inconsistent with studies showing increases set by set during an ST session and decreases after an acute ST session. Here, we found no change after unilateral acute ST at a low or high intensity.…”

Section: Discussionmentioning

confidence: 87%

“…These results combined with the SICI data suggest that, although chronic ST could lead to reductions in SICI and SP, just a single session of isometric ST does not reduce the efficacy of the GABAa and GABAb receptor–mediated inhibitory intracortical circuits projecting to the cortical excitatory neurons. Acute reductions in intracortical inhibition could be a compensatory mechanism to diminish the effect of peripheral fatigue on force output . However, the ramped isometric contractions we used did not require participants to hold the target force, minimizing any peripheral fatigue (discussed below).…”

Section: Discussionmentioning

confidence: 99%

“…In fact, chronic ST tends to decrease short‐interval intracortical inhibition (SICI) and silent period (SP) duration, suggesting that a release of intracortical inhibition could be one mechanism underlying the chronic increases in cM1 excitability and in the effectiveness of the motor command to increase MVC force. However, the time course of such adaptations is unclear because results from acute studies are inconsistent . In addition to reductions in SICI or SP, an increase in intracortical facilitation (ICF) could also contribute to the increase in CSE.…”

Section: Introductionmentioning

confidence: 99%

“…ICF is thought to involve corticocortical pyramidal cells with glutaminergic synapses projecting to the cortical neurons that activate the corticospinal tract . However, little is known about changes in ICF after an acute session of ST, with two studies showing little or no changes …”

Section: Introductionmentioning

confidence: 99%

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Training intensity‐dependent increases in corticospinal but not intracortical excitability after acute strength training

Colomer‐Poveda

Hortobágyi

Keller

et al. 2019

Scandinavian Med Sci Sports

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The purpose of this study was to determine whether the increases in corticospinal excitability (CSE) observed after one session of unilateral isometric strength training (ST) are related to changes in intracortical excitability measured by magnetic brain stimulation (TMS) in the trained and the contralateral untrained biceps brachii (BB) and whether such changes scale with training intensity. On three separate days, 15 healthy young men performed one ST session of 12 sets of eight isometric contractions of the right elbow flexors at 0% (control session), 25%, or 75% of the maximal voluntary contraction (MVC) in a random order. Before and after each session separated at least by 1 week, motor evoked potential (MEP) amplitude, short‐interval intracortical inhibition (SICI), contralateral silent period (SP), and intracortical facilitation (ICF) generated by TMS were measured in the trained and the untrained BBs. Compared with baseline, MEPs recorded from the trained BB increased by ~47% after training at 75% of MVC (P < .05) but not after training at 0% (~4%) or 25% MVC (~5%, both P > .05). MEPs in the untrained BB and SICI, SP, and ICF in either BB did not change. Therefore, acute high‐intensity but not low‐intensity unilateral isometric ST increases CSE in the trained BB without modifications in intracortical inhibition or facilitation. Thus, increases in corticospinal neurons or α‐α‐motoneuron excitability could underlie the increases in CSE. Regardless of contraction intensity, acute isometric ST did not modify the excitability of the ipsilateral primary motor cortex measured by TMS.

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Section: Discussionsupporting

confidence: 92%

Section: Discussionmentioning

confidence: 87%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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