Ergogenic and Physiologic Effects of tDCS on Maximal Aerobic Performance: Protocol Description

Physical performance and means to improve it have been studied for a long time.
While there are numerous variables affecting one individual’s aerobic capacity, central
mechanisms are known to be strong restrictors. These include the output generated by the
motor cortex but also the mental fatigue or the perceived exertion. One way to act on these
cortically mediated processes is through transcranial direct current stimulation (tDCS), a
non-invasive neuromodulation method using weak electrical currents to modify neural
excitability. Previous studies showed that tDCS applied over the primary motor cortex can
improve maximal performance in cycling as well as sometimes decrease ratings of perceived
exertion. However, none of these studies controlled important performance-related
physiological parameters such as the evolution of oxygen uptake or blood lactate levels.
Additionally, no study investigated the ergogenic effects of tDCS in runners. Therefore,
we propose a new protocol to investigate the effects of motor tDCS on treadmill running
performance as measured by time-to-exhaustion trials. This randomized double-blind sham
controlled trial will compare the effects of active tDCS as compared to sham on time to
exhaustion. Psychophysiological responses to exercise, including rating of perceived exertion,
oxygen uptake, heart rate, and blood lactate concentration, will be measured continuously
during the time to exhaustion trials. These runs will be performed at 90% of the individual
maximal aerobic speed. This will be the first of its kind trial investigating the ergogenic and
physiologic effects of tDCS on running performance. The results will provide further insight
into tDCS mechanisms of action.