Sustained cycling exercise increases intracortical inhibition

Sidhu, Simranjit K., Lauber, Benedikt, Cresswell, Andrew G. and Carroll, Timothy J. (2013) Sustained cycling exercise increases intracortical inhibition. Medicine and Science in Sports and Exercise, 45 4: 654-662. doi:10.1249/MSS.0b013e31827b119c

Author Sidhu, Simranjit K.
Lauber, Benedikt
Cresswell, Andrew G.
Carroll, Timothy J.
Title Sustained cycling exercise increases intracortical inhibition
Journal name Medicine and Science in Sports and Exercise   Check publisher's open access policy
ISSN 0195-9131
Publication date 2013-04
Year available 2013
Sub-type Article (original research)
DOI 10.1249/MSS.0b013e31827b119c
Volume 45
Issue 4
Start page 654
End page 662
Total pages 9
Place of publication Philadelphia, PA, United States
Publisher Lippincott Williams & Wilkins
Collection year 2014
Language eng
Formatted abstract
Purpose: In the current study, we measured EMG suppression induced by subthreshold transcranial magnetic stimulation (TMS) in order to investigate the effects of sustained cycling exercise on intracortical inhibition.

Methods: Sixteen subjects cycled at 75% of their maximum workload (Wmax) for 30 min, during which subthreshold TMS was applied at a defined crank angle where vastus lateralis (VL) electromyography (EMG) amplitude was increasing and approximately 50% of its recorded maximum. Sub-threshold TMS was also applied during nonfatiguing control cycling bouts at 75% and 37.5% of Wmax prior to sustained cycling.

Results: Although EMG in VL during control cycling at 37.5% Wmax was approximately half that during cycling at 75% Wmax (P ≤ 0.05), the amount of EMG suppression was not different between workloads (P > 0.05). EMG amplitude in VL recorded in the last 5min of sustained cycling was not different from the first 5 min (P > 0.05), whereas the amount of EMG suppression at the end of the sustained cycling was significantly greater than that at the start (P ≤ 0.05).

Conclusions: The increase in TMS-evoked EMG suppression during sustained cycling implies an increase in the excitability of the intracortical inhibitory interneurons during the exercise. The observed increase in intracortical inhibition is similar to that observed during sustained single joint contractions, suggesting that changes in the responsiveness of intracortical inhibitory interneurons are similar during locomotor exercise and static single joint contractions.
Keyword Transcranial magnetic stimulation
Motor cortex
Inhibitory interneurons
Locomotor fatigue
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2014 Collection
School of Human Movement and Nutrition Sciences Publications
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Created: Fri, 18 Jan 2013, 10:24:08 EST by Deborah Noon on behalf of School of Human Movement and Nutrition Sciences