Tuesday, July 30, 2013

Brain stimulation: does it enhance sports performance?


Brain stimulation has been introduced more than 100 years ago initially in animal studies and later in clinical studies involving humans. This method was initially designed to help patients with brain injuries but it is now being used in other areas too (for example in exercise physiology research & in skill acquisition studies).

What is brain stimulation?
Brain stimulation uses constant, low current delivered to the brain area of interest via surface electrodes. Research in healthy participants has shown that brain stimulation can improve cognitive performance on a variety of tasks depending on the area of stimulation.

Potential applications in sports
Based on the current evidence it seems that brain stimulation can be used to enhance exercise training-induced benefits and maximize sports performance.
Indeed, studies have shown that skill acquisition rate may improve with brain stimulation and this might have implications for training. If the players/athletes learn better and faster when brain stimulation is being used this will result in improved performance in the long term. Reis et al (2009) had their participants to perform a simple motor task on the computer while receiving transcranial direct current stimulation over the primary motor cortex (experimental condition) or without it. Measurements were performed before the experiment at 5 days of training and at 3 months post training. The results showed better performance for the experimental trial, even at 3 months post-training, compared to the control condition. 
Other studies have shown that time to fatigue and response time is improved immediately after stimulation and for the following 20-60 min. If this is true in real life situation, players/athletes might feel less tired towards the end of the game if they receive brain stimulation. Brain stimulation might also help the players/athletes to feel less tired the days between matches. However, it must be noted that this is only speculation and there is no scientific evidence in favor of this hypothesis.

Possible limitations
Studies with brain stimulation have been contacted in non-experts and we don’t know what would be the benefits in elite athletes.
Results so far are on simple motor tasks and we don’t know the response with more complex tasks as is the scenario in sports.

Health risks
As experts state some health risks may arise when brain stimulation is used outside safety parameters.

For further reading
Cogiamanian et al (2007). Improved isometric force endurance after transcranial direct current stimulation over the human motor cortical areas. Eur J Neurosci 26:242-249.
Jang et al (2009). The effect of transcranial direct current stimulation on the cortical activation by motor task in the human brain: an fMRI study. Neurosci  Lett 460:117-120.
Reis et al (2009). Noninvasive cortical stimulation enhances motor skill acquisition over multiple days through an effect on consolidation. PNAS 106:1590-1595.

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