The effect of strength training on the force of twitches evoked by corticospinal stimulation in humans

Carroll, T.J., Barton, J., Hsu, M. and Lee, M. (2009) The effect of strength training on the force of twitches evoked by corticospinal stimulation in humans. Acta Physiologica, 197 2: 161-173. doi:10.1111/j.1748-1716.2009.01992.x

Author Carroll, T.J.
Barton, J.
Hsu, M.
Lee, M.
Title The effect of strength training on the force of twitches evoked by corticospinal stimulation in humans
Journal name Acta Physiologica   Check publisher's open access policy
ISSN 1748-1708
Publication date 2009
Sub-type Article (original research)
DOI 10.1111/j.1748-1716.2009.01992.x
Volume 197
Issue 2
Start page 161
End page 173
Total pages 13
Editor Jan Henricksson
Place of publication Oxford
Publisher Wiley-Blackwell Publishing
Collection year 2010
Language eng
Subject 1109 Neurosciences
110603 Motor Control
920111 Nervous System and Disorders
Abstract Aim: Although there is considerable evidence that strength training causes adaptations in the central nervous system, many details remain unclear. Here we studied neuromuscular responses to strength training of the wrist by recording electromyographic and twitch responses to transcranial magnetic stimulation (TMS) and cervicomedullary stimulation of the corticospinal tract. Methods: Seventeen participants performed 4 weeks (12 sessions) of strength training for the radial deviator (RD) muscles of the wrist (n = 8) or control training without external load (n = 9). TMS recruitment curves were constructed from stimuli at five to eight intensities ranging between 15% below resting motor threshold and maximal stimulator output, both at rest and during isometric wrist extension (EXT) and RD at 10% and 50% of maximal voluntary contraction (MVC). Responses to weak TMS and cervicomedullary stimulation (set to produce a response of 10% maximal M wave amplitude during 10% MVC EXT contraction) were also compared at contraction strengths ranging from 10% to 75% MVC. Results: Isometric strength increased following strength training (10.7% for the RD MVC, 8.8% for the EXT MVC), but not control training. Strength training also significantly increased the amplitude of TMS- and cervicomedullary-evoked twitches during low-force contractions. Increases in the force-generating capacity of the wrist extensor muscles are unlikely to account for this finding because training did not affect the amplitude of twitches elicited by supra-maximal nerve stimulation. Conclusion: The data suggest that strength training induces adaptations that increase the net gain of corticospinal-motor neuronal projections to the trained muscles.
Q-Index Code C1
Q-Index Status Confirmed Code

Document type: Journal Article
Sub-type: Article (original research)
Collections: 2010 Higher Education Research Data Collection
School of Human Movement and Nutrition Sciences Publications
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Citation counts: TR Web of Science Citation Count  Cited 15 times in Thomson Reuters Web of Science Article | Citations
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Created: Wed, 25 Nov 2009, 13:33:48 EST by Deborah Noon on behalf of School of Human Movement and Nutrition Sciences