For 68-year-old Robert Kennedy, a retired Florida Power and Light foreman, the secret to managing his Parkinson symptoms is movement.
"Once you stop moving, the disease takes over," he said.
To that end, he swims daily and plays ice hockey twice a week. He has also joined the latest study at the University of Miami's Max Orovitz Laboratory of Neuromuscular Research and Active Aging titled "Comparison of Neuromuscular and Functional Adaptations to 10% and 30% Velocity-Loss Threshold Resistance Training in Persons with Parkinson's Disease."
The goal of the study is to compare two approaches to resistance training that may help people with Parkinson's disease improve their strength, power, mobility and physical function, the researchers said.
Parkinson's is a progressive neurological disease that causes problems with movement, balance and other bodily functions as nerve cells that make dopamine in the brain deteriorate. The disease tends to affect more men than women.
The randomized study will enroll 20 adults between ages 50 and 85 with mild to moderate Parkinson's disease. Participants will complete five weeks of supervised resistance training.
"This study varies from others we have done because instead of focusing on how heavy a load a person can lift, the aim is to see if they can maintain that velocity without becoming fatigued," said Joseph Signorile, professor and director of the laboratory and the study's principal investigator.
Muscle weakness and slowed movement can reduce power and contribute to mobility limitations and falls among people with Parkinson's disease, the researchers said.
Although previous research indicates that high-speed resistance training can improve physical performance, researchers say it remains unclear how much fatigue should be allowed during each set.
Prior to the training, participants are evaluated to measure changes in strength, movement speed, power, muscle size and quality, as well as walking speed, balance and sit-to-stand ability.
Each exercise session is personalized according to the person's ability and needs, said Ethan Elkins, a third-year graduate student in the Exercise Physiology program at the School of Education and Human Development. The study is his thesis.
"We are looking at short-term fatigue response through different exercise," said Elkins. "This is important because fatigue can worsen the symptoms of Parkinson's."
Elkins said they are looking at what dose (how much load or force in each exercise) should be used with each participant to help them with their symptoms.
The research focuses on "velocity loss," or the reduction in movement speed that occurs as muscles become fatigued during a set of exercises.
Participants will be assigned to stop sets of leg presses and chest presses when their movement speed declines by either 10 percent or 30 percent.
Stopping at a 10 percent decline will result in fewer repetitions and may preserve faster movements while reducing fatigue. Allowing a 30 percent decline will produce more repetitions and a greater overall training volume, which could provide a stronger stimulus for changes in muscle size and quality, said Elkins.
Participants will perform the same exercises with the same progression in resistance using several machines that include leg and chest presses.
The study is designed to determine whether limiting fatigue produces better gains in speed and power or whether completing more repetitions leads to greater muscular adaptations.
For Raul Busto, 68, who was diagnosed with Parkinson's in 2006 and uses a walker, the study has been very beneficial. On a recent Thursday morning, he was doing leg pushes on a machine at the lab.
He joined the study because he feels that after completing the exercises, he feels more confident.
"The Parkinson's has affected my mobility and balance," he said. "But the exercises give me something to strive for, and I hope it can ultimately help me with all the symptoms of Parkinson's."
