Effects of Bilateral Dorsolateral Prefrontal Cortex High-Definition Transcranial Direct-Current Stimulation on Physiological and Performance Responses at Severe-Intensity Exercise Domain in Elite Road Cyclists

Abstract

Purpose: To investigate the effects of bilateral dorsolateral prefrontal cortex high-definition transcranial direct-current stimulation (HD-tDCS) on physiological and performance responses during exercise at the upper limit of the severe-intensity exercise domain in elite-level road cyclists. Methods: Eleven elite-level road cyclists (VO2peak: 71.8 [3.1] mL·kg−1·min−1) underwent the HD-tDCS or SHAM condition in a double-blind, counterbalanced, and randomized order. After 20 minutes of receiving either HD-tDCS on dorsolateral prefrontal cortex (F3 and F4) or SHAM stimulation, participants completed a 10-minute constant-load trial (CLT1) at 90% of the first ventilatory threshold and a 2-minute CLT (CLT2) at peak power output. Thereafter, they performed a simulated 2-km time trial (TT). Maximal oxygen uptake, respiratory exchange ratio, heart rate, and rating of perceived exertion were recorded during CLT1 and CLT2, whereas performance parameters were recorded during the TT. Results: In 6 out of 11 cyclists, the total time to complete the TT was 3.0% faster in HD-tDCS compared to SHAM. Physiological and perceptual variables measured during CLT1 and CLT2 did not change between HD‐tDCS and SHAM. Conclusions: HD-tDCS over the dorsolateral prefrontal cortex seemed to improve cycling TT performance within the upper limit of the severe-intensity exercise domain, suggesting that an upregulation of the prefrontal cortex could be critical even in this exercise intensity domain. However, the limited dimension and the high interindividual variability require further studies to test these putative ergogenic effects.

A Single Anodal Transcranial Direct Current Stimulation Session to Enhance Sport-Specific Performance in Trained Individuals? A Systematic Review and Meta-Analysis

“…Sample sizes of included studies ranged from 8 to 36 participants (13.6 ± 6.6). Athletes were experienced in various sports disciplines: cycling [16, 29, 35, 36, 41], swimming [37, 39, 43], triathlon [30], rowing [41, 42], bodybuilding [31], resistance training [38], basketball [40], parkour [3], taekwondo [17, 32] and pistol-shooting [33]. Additionally, some studies reported that athletes competed at the regional [39], national [17, 32, 37, 42, 43] and/or international level [17, 30, 32, 37].…”

“…For an overview of investigated sport-specific motor performances in each study, please see Table 1. Sport disciplines were categorized in the following performance domains: endurance (cycling [16, 29, 35, 36, 41], swimming [37, 39, 43], triathlon [30], rowing [41, 42]), strength (bodybuilding [31], resistance training [38]) & visuomotor skill (basketball [40], parkour [3], taekwondo [17, 32], pistol-shooting [33]).…”

“…All studies applied tDCS prior to sport-specific performance. Cortical target areas of tDCS were clustered in 4 groups: M1 [3, 17, 30-32, 34, 38, 40-42], TC [29, 31, 43], PFC [3, 16, 35-37, 39] and CB [33]. Current intensity was set at 2 - 2.2 mA in most studies (78 %) or 1.5 mA (22%).…”

“…Functional roles of prefrontal subdivisions such as dorsolateral prefrontal cortex (dlPFC) and orbital prefrontal cortex (oPFC) extend from cognitive control of motor behavior [60] to the disengagement of motor activity [61], and fatigue [62]. Six studies included in this meta-analysis stimulated the PFC [3, 16, 35-37, 39]. Given the inhibitory control of the PFC during motor activity, a common rationale of studies aiming to employ PFC stimulation is based on the assumption that an upregulation of PFC excitability leads to a reduction in effort for inhibitory control during motor activity.…”

“…In addition, a Google Scholar search identified one study that was not indexed in the searched databases because of its recent publication date. Finally, a total of 18 studies were deemed eligible for inclusion in the qualitative synthesis [3,16,17,[29][30][31][32][33][34][35][36][37][38][39][40][41][42][43]. An overview of the study selection process is depicted in the PRISMA flow diagram (Figure 1).…”