Banca de DEFESA: EVERTON BORGES DA SILVA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : EVERTON BORGES DA SILVA
DATE: 25/08/2025
TIME: 09:00
LOCAL: LABEX
TITLE:

EFFECT OF DIFFERENT INTENSITIES OF TRANSCRANIAL DIRECT CURRENT STIMULATION ON CEREBRAL HEMODYNAMICS, COGNITIVE PERFORMANCE, AND ENDURANCE IN TRAINED CYCLISTS AND THEIR POSSIBLE PREDICTORS

KEY WORDS:

Neuromodulation, Physical performance, Neuroscience

PAGES: 103
BIG AREA: Ciências da Saúde
AREA: Educação Física
SUMMARY:

Introduction: The central nervous system plays a crucial role in physical performance, particularly in endurance. In this context, transcranial direct current stimulation (tDCS) may exert a neuromodulatory effect and enhance performance. However, findings in the literature remain inconsistent. One possible reason could be related to the current intensity used, which has been limited to 2 mA. Studies suggest that higher intensities are required to induce neuromodulatory effects and compensate for interindividual differences, producing results of greater magnitude and, possibly, more consistent effects. However, this has not yet been experimentally tested. Therefore, we aimed to evaluate the effect of tDCS with different intensities targeting the dorsolateral prefrontal cortex (DLPFC) on brain activity, cognitive and endurance performance, and psychophysiological responses in trained cyclists.

Methods: Eighteen trained male cyclists (36.0 ± 8.52 years old; 8.53 ± 5.94 years of cycling experience; 10.83 ± 3.03 training hours/week; maximum oxygen uptake 58.82 ± 8.16 ml·kg⁻¹·min⁻¹; peak power 301.89 ± 44.49 Watts) underwent a maximal incremental test and three 20-km time trials (TT-20km). Before the TT-20km, participants received randomized and counterbalanced tDCS at 2 mA, 4 mA, or sham (placebo). Before tDCS, after tDCS, and after the TT-20km, participants were assessed for cerebral hemodynamics using functional near-infrared spectroscopy (fNIRS) and cognitive performance (Stroop test). During the TT-20km, performance parameters (power, cadence, time), heart rate (HR), and cerebral hemodynamics were continuously monitored, and participants reported psychophysiological responses [rating of perceived exertion (RPE), affective response, and arousal] every 4 km. Data were analyzed using Generalized Mixed Models (GMM) and Bonferroni post hoc tests, with significance set at p<0.05.

Results: Sensations and perceptions related to tDCS did not differ between conditions, indicating effective blinding. There was no effect of tDCS on cognitive performance or resting cerebral hemodynamics (all ps >0.05). However, tDCS at 2 mA resulted in higher mean power and shorter time in the TT-20km compared to sham (ps<0.001) and 4 mA (ps<0.05), with no difference between 4 mA and sham (ps>0.15). During the TT-20km, no differences were found between experimental conditions for HR, cerebral hemodynamics, RPE, affective response, or arousal (ps>0.05).

Conclusion: The results suggest that tDCS over the DLPFC at 2 mA, but not 4 mA, may improve endurance performance in trained cyclists, even without changes in cerebral hemodynamics, cognitive performance, or psychophysiological responses. These findings indicate that there may be an optimal intensity for tDCS to exert its neuromodulatory effects.

COMMITTEE MEMBERS:
Presidente - 1277591 - DANIEL GOMES DA SILVA MACHADO
Interno - 1793257 - ARNALDO LUIS MORTATTI
Externo à Instituição - UIRASSU BORGES