May 3, 2017

Brain stimulation during exercise boosts strength, stamina and brain function

UOW researchers’ findings could benefit stroke victims, elite athletes and others

Researchers at the University of Wollongong (UOW) have shown that brain stimulation in conjunction with exercise not only improves muscle strength and cardiovascular function above that provided by exercise alone, but that it also improves brain function.

The research has a number of potential medical uses, for example to assist the elderly improve cardiovascular and neuronal function, to help stroke patients recover body movement, and could also be used to improve the performance of elite athletes.

Working in the Neural Control of Movement Laboratory in the Illawarra Health and Medical Research Institute (IHMRI), the research team of Dr Darryl McAndrew, Associate Professor Paul Stapley, Joel Walsh, David Hurley and Marc Brown measured the benefits of eccentric cycling both with and without brain stimulation.

Eccentric cycling involves the cyclist resisting a reverse motion of the pedals induced by electrical motors. It requires a lower workload than the traditional type of forward or concentric cycling. During eccentric muscle contractions, the muscle lengthens while it contracts in response to an opposing force; while during concentric muscle contractions the muscle shortens as it is contracted generate force.

Professor Stapley said brain stimulation during eccentric cycling provided “two benefits for the price of one”.

“Not only does that eccentric mode provide a good cardiovascular benefit at a lower cost, what our work shows is that the activation you get in the brain is greater for an eccentric mode than for a concentric mode,” he said.

When eccentric cycling is combined with stimulation of the specific area of the brain that controls the legs, the brain activation level is even higher.

“If you stimulate the brain after concentric cycling it produces a certain amplitude of activity. If you then stimulate exactly the same part of the brain after eccentric cycling it will give you a much larger amplitude,” Professor Stapley said.

“So eccentric cycling exercises the brain to a greater extent than concentric cycling does; you're producing connections in the brain that aren't produced by normal (concentric) cycling. And this is the first time that's ever been shown.”

The brain stimulation is applied non-invasively using a technique called Transcranial Magnetic Stimulation (TMS).

“We deliver a highly charged, very focussed magnetic field and stimulate the cortex non-invasively for one to five milliseconds,” Professor Stapley said.

The potential medical applications of the research are wide ranging.

“For people who’ve had a stroke, our results would suggest that if you couple eccentric cycling with repeated stimulation that this will be a way of exercising the person but also regaining some function in those muscles that have been affected by pathology, for example after stroke,” Professor Stapley said.

It could also be used to reduce the risk of falls in the elderly. As eccentric muscle actions are used to walk down slopes or stairs, an eccentric exercise program combined with TMS would train the brain to better control eccentric actions while also improving cardiovascular function and muscle strength.

Professor Stapley said the findings could be applied to elite athletes as well.

“If you couple TMS with eccentric cycling you get better overall training effects,” he said. “The muscles become stronger. They produce more force against the pedal simply by recruiting their brain to a greater extent. So it has a high performance component to it as well."  

The research team presented its results at the recent International Brain Stimulation conference in Barcelona, Spain. They also had two abstracts, covering different aspects of their research, published in this month’s Brain Stimulation journal (Short duration strength training increases corticospinal efficacy in healthy subjects and Corticospinal facilitation is enhanced post eccentric aerobic cycling in healthy subjects).

The team’s work has been supported by the Faculty of Science, Medicine and Health, who provided funds for the TMS equipment, and small grant funds for initiating the projects, and a Vice Chancellor’s International Visiting Scholar award to Professor Romuald Lepers from the Université de Bourgogne in 2016, who assisted in devising and initiating the experiments and with whom the laboratory has an ongoing collaborative relationship.