Transcranial direct current stimulation does not enhance cycling time-trial performance

Le résumé fourni par la source

Transcranial direct current stimulation (tDCS) to the primary motor cortex (M1) and dorsolateral prefrontal cortex (DLPFC) have separately been shown to increase performance during fixed-work time-to-exhaustion tasks. No studies have examined application of tDCS to these cortical sites in a single study or during self-paced tasks. Objectives: This study examined the influence of anodal-tDCS (A-tDCS) applied to M1 and DLPFC on cycling performance during a self-paced 16.1-km time trial (TT). Design: randomised cross-over design. Methods: Ten cyclists received 20 min of A-tDCS (1.5 mA) applied to M1, DLPFC or the visual cortex (V1; control), followed by a standardised 10-min warmup and a 16.1-km cycling TT. During the TT, heart rate and power output were continuously recorded and mean values for each quartile of the total TT duration were calculated. Ratings of perceive exertion (RPE) were collected at four, eight, 12 and 16.1 km. RESULTS: No differences were observed for the time-to-complete (p=0.07; BF10=1.24) or mean power output (p=0.09; BF10=1.11) during the 16.1-km TT between the M1 (1443.7±81.0 s and 274±44 W), DLPFC (1428.4±80.0 s and 280±39 W) and V1 (1434.8±9.6 s and 279±44 W) conditions. Both HR and RPE progressively increased from the first quartile of the TT with no differences observed between A-tDCS conditions. CONCLUSION: A-tDCS does not represents a viable method to decrease the physiological and perceptual stress during or enhance the performance of a self-paced cycling TT. Nevertheless, these findings should be viewed with respect to the inherent complexities between performance, fatigue and the brain.

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