The effect of tDCS on improving physical performance and attenuating effort perception during maximal dynamic exercise in non-athletes

Objectives: This study aimed to test the effects of transcranial direct current stimulation (tDCS), using different electrode positioning and montages, on physical performance in maximum incremental tests of healthy non-athlete subjects.

Design: A double-blinded, crossover, sham-controlled study.

Method: Fifteen subjects (aged 25.8 ± 5 years, nine women) received one of five different tDCS protocols: (i) anodal tDCS on the primary motor cortex (M1) (a-tDCS/M1), (ii) anodal tDCS on the left temporal cortex (T3) (a-tDCS/T3), (iii) cathodal tDCS on M1 (c-tDCS/M1), (iv) cathodal on T3 (c-tDCS/T3), or (v) sham tDCS. The protocols were assigned in a random order in separate sessions. After tDCS, the volunteers performed the maximal incremental exercise test (MIT) on a cycle ergometer in each session. The following measures were used to evaluate physical performance (primary outcome) during MIT: time to exhaustion (TE), maximum power (MAX-P), and Borg Rating of Perceived Exertion (RPE) scale. In addition, as a secondary outcome measure, we assessed the lower-limb corticospinal excitability and electrical muscular activity.

Results: tDCS applied over T3 or M1 did not influence electrical muscular activity or increase physical performance during MIT in healthy non-athlete subjects. However, our data confirmed that a-tDCS on the M1 increases lower-limb cortical excitability.

Conclusions: Our results suggest that tDCS is not effective in improving performance during maximal dynamic exercise in non-athletes. However, we confirmed that the a-tDCS M1 protocol used in this study might increase cortical excitability in the lower limb motor cortex.