Effects of Multifocal Transcranial Direct Current Stimulation Specifically Activating the Motor Cortex on Cycling Endurance Performance

Objective: This study examined how endurance cycling performance was affected by multifocal transcranial direct current stimulation（tDCS） that simultaneously stimulates the prefrontal cortex and motor cortex. Methods: Functioning near-infrared spectroscopy was used to monitor hemodynamic responses in the PFC and motor cortex to identify the target cortical regions while participants performed incremental exercise test on a cycling ergometer. Subsequently, multifocal tDCS was used to stimulate these regions, the effects of stimulation were assessed by recording the lower-limb root mean square amplitude（RMS） and cycling performance. Results: 1) There were significant correlations between cycling time and FC1h, FC2h, C1h and C2h in motor cortex;2) after multifocal tDCS, heart rate significantly decreased compared with before stimulation, while mechanical work and cycling speed increased compared with Sham; 3) during the propulsion phase, RMS of the rectus femoris, vastus medialis（VM）, vastus lateralis, and tibialis anterior decreased following multifocal tDCS compared to pre-stimulation levels, while RMS of the biceps femoris showed significant lower activation compared with Sham; during the pulling phase, RMS of the biceps femoris significantly decreased following multifocal tDCS, while compared with Sham group, the RMS of vastus medialis showed significantly higher activation and the RMS of gastrocnemius lateralis showed significantly lower activation. Conclusions: Multifocal tDCS specifically activating the motor cortex improves cycling endurance performance and enhances adaptability to training regime, indicating its effectiveness as an augmentation method to increase endurance exercise performance.