Effect of transcranial direct current stimulation on supramaximal intermittent exercise performance

Gilmar J Esteves,Rafael Pereira,Paulo E De A Pereira,Yuri L Motoyama,Guilherme H Elcadi,Paulo Henrique Silva Marques De Azevedo

doi:10.1590/10.1590/s1980-6574201900040215

Abstract

Abstract Aim: Our purpose was to determine whether Transcranial Direct Current Stimulation (tDCS) improves performance in untrained individuals for supramaximal intermittent exercise. Methods: In a cross-over design, 11 healthy male subjects (26.8 ± 4.6 years) performed four Wingate trials after 20 minutes of anodal or sham tDCS over the left Insular Cortex (IC). For performance indexes, Relative Peak Power (RPP), Relative Average Power (RAP) and Fatigue Index (FI) were computed. Also, a Rating of Perceived Exertion (RPE) and Electromyography (EMG) signal were used to assess central and muscle fatigue development. Results: There was a significant difference over trials on all performance indexes, but there were no significant condition x trial interactions for any of the indexes. RPE increased significantly over trials, but there was no condition x trial interaction. There was no significant difference over trials on EMG for the rectus femoris and vastus medialis muscles; however, EMG decreased over trials for the vastus lateralis muscle. Furthermore, there was no condition x trial interaction on the EMG signal for any of the muscles. Conclusion: Our findings suggest that the anodal tDCS technique has no impact on physical performance, perceived exertion nor muscle fatigue development for supramaximal intermittent exercise.

Highlights

The transcranial Direct Current Stimulation is a noninvasive and painless technique, which induces changes in the excitability of the cerebral cortex in humans[1]
analyses of variance (ANOVA) showed a significant difference of trials on all three performance indexes, Relative Peak Power (RPP) (F=5.86; P=0.003; observed power 0.92), Relative Average Power (RAP) (F=31.32; P < 0.001; observed power 1.00) and Fatigue Index (FI) (F=6.06; P=0.003; observed power 0.93)
There was no difference between conditions x trials interactions for any of the parameters, RPP (F=1.17; P=0.34; observed power 0.28), RAP (F=0.31; P=0.82; observed power 0.10) and for FI (F=0.13; P=0.83; observed power 0.06)

Summary

Introduction

The transcranial Direct Current Stimulation (tDCS) is a noninvasive and painless technique, which induces changes in the excitability of the cerebral cortex in humans[1]. The depth of the electric stimulus produced by tDCS can reach both the cortical and subcortical area[2]. This kind of stimulation produces a variation in the resting potential of the membrane, facilitating or hindering the neural firing depending on the polarity applied. When applied over Insular Cortex (IC) the tDCS modulated the Rating of Perceived Exertion (RPE) positively, and improved performance, in an incremental exercise test to exhaustion[5]. Some regions of the brain, such as the IC have been active and responded to afferent signals with an increase in RPE during exercise[6]. The IC along with other areas of the CNS can influence decisionmaking to maintain or stop the physical exercise[7]

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Methods

Results

Conclusion