Brain stimulation has been demonstrated to be an effective way to improve endurance in cyclists, in a small placebo-controlled study from the University of Kent. The findings are expected to advance our understanding of the brain's role in endurance exercise, how it can alter the physical limits of performance in healthy people and add further evidence to the debate on the use of legal methods to enhance performance in competition.
The research, which was conducted by Dr Lex Mauger and colleagues at Kent's School of Sport and Exercise Sciences (SSES), set out to investigate how endurance limits are a matter for the mind as well as the body.
By testing cycling time to task failure (TTF) in a group of 12 active participants in a placebo controlled study, Mauger discovered that stimulating the brain by passing a mild electrical current (transcranial direct current stimulation [tDCS]) over the scalp to stimulate it increased the activity of the area associated with muscle contraction. This decreased perception of effort and increased the length of time participants could cycle for.
The team explained this is because the exercise felt less effortful following stimulation. tDCS has been used to enhance endurance performance but how it achieved this was previously unknown and this study has helped identify the mechanisms.
Other researchers involved in the study were Dr Luca Angius, Dr James Hopker, and Professor Samule Marcora, University of Kent, with Professor Alvaro Pascual-Leone, Berenson-Allen Centre for Non-Invasive Brain Stimulation, division of cognitive neurology, Beth Israel Deaconess Medical Centre and Dr Emiliano Santarnecch, Harvard Medical School.
Abstract
Background: Transcranial direct current stimulation (tDCS) has been used to enhance endurance performance but its precise mechanisms and effects remain unknown.
Objective: To investigate the effect of bilateral tDCS on neuromuscular function and performance during a cycling time to task failure (TTF) test.
Methods: Twelve participants in randomized order received a placebo tDCS (SHAM) or real tDCS with two cathodes (CATHODAL) or two anodes (ANODAL) over bilateral motor cortices and the opposite electrode pair over the ipsilateral shoulders. Each session lasted 10 min and current was set at 2 mA. Neuromuscular assessment was performed before and after tDCS and was followed by a cycling time to task failure (TTF) test. Heart rate (HR), ratings of perceived exertion (RPE), leg muscle pain (PAIN) and blood lactate accumulation (ΔB[La−]) in response to the cycling TTF test were measured.
Results: Corticospinal excitability increased in the ANODAL condition (P < 0.001) while none of the other neuromuscular parameters showed any change. Neuromuscular parameters did not change in the SHAM and CATHODAL conditions. TTF was significantly longer in the ANODAL (P = 0.003) compared to CATHODAL and SHAM conditions (12.61 ± 4.65 min; 10.61 ± 4.34 min; 10.21 ± 3.47 min respectively), with significantly lower RPE and higher ΔB[La−] (P < 0.001). No differences between conditions were found for HR (P = 0.803) and PAIN during the cycling TTF test (P = 0.305).
Conclusion: Our findings demonstrate that tDCS with the anode over both motor cortices using a bilateral extracephalic reference improves endurance performance.
Authors
L Angius, AR Mauger, J Hopker, A Pascual-Leone, E Santarnecchi, SM Marcora
[link url="https://www.kent.ac.uk/news/science/15403/brain-stimulation-can-improve-athletic-performance"]University of Kent material[/link]
[link url="http://www.brainstimjrnl.com/article/S1935-861X(17)30931-2/fulltext"]Brain Stimulation abstract[/link]