The Effects of tDCS on Endurance Parameters in Confirmed Athletes

INTRODUCTION:
Fatigue is a multifactorial, complex phenomenon that limits athletes’ performances. Transcranial direct current stimulation (tDCS) could be an interesting option to reduce supraspinal fatigue. However, to date, very little research has been done on the effects of tDCS on confirmed athletes. Our objective is to compare the effects of tDCS on endurance performance in confirmed athletes
METHODS:
Our study is a randomized, double-blind, cross-over study. 30 men aged between 18 and 30 years old were split into two groups (tDCS week 1 and sham week 2, or sham week 1 and tDCS week 2). All were right handed and footed, and had no positive answer on the TSST screening scale. They came to the University Hospital’s Isokinetic Lab twice to undergo a fatiguing protocol (30 maximal concentric repetitions over a 100° flexion amplitude at 180°/s). 20 min of either anodal or sham tDCS, with the anode over C3 and the cathode over FP2. We measured peak tork and work for both quadriceps and hamstrings in the dominant limb.
RESULTS:
There were no significant effects of tDCS compared to sham on quadriceps peak tork for the first 10, second 10 and final 10 repetitions (respectively 1,5%, 2% and 4,7% difference) or maximal work (respectively 1,5%, 2,5% and 5%), nor for first 10 repetitions of hamstring peak tork (2,5%) and work (3,6%). However, close to significant effects were seen on the second 10 contractions for peak tork values (p= 0,087, 4,75%) and significant effects were sean for the peak tork in the final 10 repetitions (7%), the maximal work in the second 10 repetitions (6,4%) and the final 10 repetitions (9%).
CONCLUSION:
Significant effects on hamstring fatigue were found after tDCS when compared to a sham treatment. These effects could potentially be explained by reducing supraspinal fatigue, or by decreasing perceived discomfort felt during the protocol.