Bilateral Dorsolateral Prefrontal Cortex High-Definition Transcranial Direct-Current Stimulation Improves Time-Trial Performance in Elite Cyclists

Abstract

Background: The effects of anodal transcranial direct-current stimulation (tDCS) on endurance exercise performance are not yet fully understood. Different stimulated areas and low focality of classical tDCS technique may have led to discordant results. Purpose: This study investigated the effect of a bilateral anodal high-definition tDCS (HD-tDCS) of the dorsolateral prefrontal cortex on the cycling time-trial (TT) performance and physiological and perceptual response at moderate intensity in elite cyclists. Methods: A total of 8 elite cyclists (maximal oxygen consumption: 72.2 [4.3] mL·min−1·kg−1) underwent in a double-blind, counterbalanced, and randomized order the experimental treatment (HD-tDCS) or control treatment (SHAM). After 20 minutes of receiving either HD-tDCS on the dorsolateral prefrontal cortex (F3 and F4) or SHAM stimulation, the participants completed a constant-load trial (CLT) at 75% of the second ventilatory threshold. Thereafter, they performed a simulated 15-km TT. The ratings of perceived exertion, heart rate, cadence, oxygen consumption, and respiratory exchange ratio were recorded during the CLT; the ratings of perceived exertion and heart rate were recorded during the TT. Results: The total time to complete the TT was 1.3% faster (HD-tDCS: 1212 [52] s vs SHAM: 1228 [56] s; P = .04) and associated with a higher heart rate (P < .001) and a tendency toward higher mean power output (P = .05). None of the physiological and perceptual variables measured during the CLT highlighted differences between the HD-tDCS and SHAM condition. Conclusions: The findings suggest that bilateral HD-tDCS on the dorsolateral prefrontal cortex improves cycling TT performance without altering the physiological and perceptual response at moderate intensity, indicating that an upregulation of the prefrontal cortex could enhance endurance exercise performance.

Acute effect of high-definition and conventional tDCS on exercise performance and psychophysiological responses in endurance athletes: a randomized controlled trial

“…Nonetheless, Pollastri et al 46 recently demonstrated a 1.3% faster 15 km time-trial in eight elite cyclists after bilateral HD-tDCS over the DLPFC (F3 and F4) with 1.5 mA for 20 min. As previously mentioned, the performance improvement shown by Pollastri et al 46 , despite seeming small may represent an important advantage considering the high level of performance of the sample 55 .…”

“…Nonetheless, Pollastri et al 46 recently demonstrated a 1.3% faster 15 km time-trial in eight elite cyclists after bilateral HD-tDCS over the DLPFC (F3 and F4) with 1.5 mA for 20 min. As previously mentioned, the performance improvement shown by Pollastri et al 46 , despite seeming small may represent an important advantage considering the high level of performance of the sample 55 . The difference between the present study and the study by Pollastri et al 46 may be explained by the different areas of stimulation, as HD-tDCS was applied over M1 in the present study and over the DLPFC in their study.…”

“…Thus, it would be reasonable to speculate that HD-tDCS could present greater effects on behavioral outcomes compared to conventional tDCS. So far, however, it remains speculative as only three studies used HD-tDCS 37 , 38 , 46 . Two of them for investigating exercise performance with low-intensity isometric contraction (30–35% of maximum isometric voluntary contraction) performed to exhaustion and found no change in performance 37 , 38 .…”

“…Two of them for investigating exercise performance with low-intensity isometric contraction (30–35% of maximum isometric voluntary contraction) performed to exhaustion and found no change in performance 37 , 38 . In a recent study, Pollastri et al 46 assessed the effect of a bilateral HD-tDCS over the DLPFC (F3 and F4) for 20 min on a 15 km time-trial performance in eight elite cyclists. The authors reported that the time to complete the time trial was 1.3% faster after HD-tDCS 46 .…”

“…In a recent study, Pollastri et al 46 assessed the effect of a bilateral HD-tDCS over the DLPFC (F3 and F4) for 20 min on a 15 km time-trial performance in eight elite cyclists. The authors reported that the time to complete the time trial was 1.3% faster after HD-tDCS 46 . However, none of these studies compared HD-tDCS to conventional tDCS.…”