Does transcranial direct current stimulation (tDCS) improve sport performance? A systematic review and Meta-analysis

The ergogenic potential around neuromodulation techniques using transcranial direct current stimulation (tDCS) has increased in excitement over the years, however, research involving its potential use in sports performance has concluded mixed outcomes. This meta-analysis aims to synthesise the diverging opinions of whether tDCS may serve to benefit athletes’ performance. A systematic search was conducted using online databases and reference lists available until September 2019. Randomised full-text studies that examined the acute effects of tDCS compared to a sham/control condition on the outcome measures of physical endurance (isokinetic, isometric or dynamic indexes) or sport directed protocols on healthy adults were included following a prescribed eligibility criterion. A total of 36 studies were included in the review. The quantitative analysis found there to be a moderate effect favouring the control/sham condition suggesting tDCS has no effect on sports performance (SMD =0.31,95%Cl: 0.12,0.50, p=0.002). But a qualitative sub-analysis found there was a small effect favouring the tDCS condition, for isometric, dynamic and sports directed studies. The results suggest tDCS could be used as a potential ergogenic aid if used in conjunction with a training regime. The current synthesised evidence is insufficient to confidently support the use of tDCS in enhancing sports performance.