Exercise Neuroscience Research Laboratory

The goal of our research program is to understand how the human nervous system controls powerful muscle contractions and fast movements and how this control is affected by Parkinson’s disease (PD), aging and exercise. We wish to develop the scientific basis for exercise practices to increase mechanical power and improve mobility in people with PD and older adults.

Mechanical power is the product of force and velocity, which one might equate to strength and speed. While maximal strength is critically important, maximal power is a better predictor of mobility. It is well known that the quantity of muscle tissue contributes to a person’s strength – people with more muscle tissue are stronger. The quality of muscle tissue also matters – people with more fast twitch muscle fibers can generate more speed and power. However, while the role of muscle in power production is well known, there is much to learn about how the nervous system controls speed and power in health and disease.

With aging, there are not only reductions in the amount and quality of muscle tissue but also reductions in the neural drive to muscle. In addition to the effects of aging, Parkinson’s disease adds further motor and sensory complications that result in abnormally slow and small movements – a symptom called bradykinesia. Bradykinesia is just one of several symptoms of PD and the primary focus of our research. Nevertheless, we are hopeful that scientific progress on the use of exercise to improve power and mobility in people with PD will carry over to other motor (e.g. balance) and non-motor (e.g. emotional well-being) symptoms.

In our exercise intervention studies, we test strategies to improve the neural excitation of muscle and these strategies have to be optimized for our populations of interest: older adults, new exercisers, people with cardiovascular risk factors and poor balance. Lifting heavy weights in the gym is one proven way to increase neural excitation, strength and power. However, high rates of neural excitation can also be achieved with high velocity movements against low force. Sayers (2009) described this as high-velocity power training. We want to use fast movements against low resistance activate the brain and any other part of the nervous system that limits power and mobility. Although we have adopted high-speed interval training on a stationary bicycle as our primary exercise mode, dance, boxing and exer-gaming are examples of other exercise modes that could be similarly effective.

Our research involves experiments with young adults, older adults, people with Parkinson’s disease and highly trained individuals. In addition to studying control mechanisms and how they change with age, disease and exercise, some of our research supports methodological development. The study of highly trained individuals provides an opportunity to understand optimal neuromuscular function.

DirectorChristopher A. Knight