Muscle Function Improves With Resistance Exercise Program: Study
A program of supervised resistance exercise can improve muscle function — including in muscles needed to breathe — for adults with late onset Pompe disease (LOPD), a small study suggests.
“Our findings encourage use of supervised exercise and inspiratory muscle training for improving physical function and health to improve generalized muscle weakness and particularly respiratory weakness which remains the primary cause of morbidity and mortality in LOPD,” the researchers wrote.
The study, “Safety and effectiveness of resistance training in patients with late onset Pompe disease – A pilot study,” was published in Neuromuscular Disorders.
Resistance training is a type of exercise that involves moving muscles against a force — lifting weights is a well-known type of resistance training. Pompe disease is characterized by muscle weakness, and the standard treatment is enzyme replacement therapy (ERT), which involves administering a version of the enzyme whose defect causes Pompe.
In this study, 10 adults with LOPD underwent a 24-week exercise program consisting of supervised resistance training three times per week. Participants also were given devices to do respiratory training at home six days a week. Respiratory training is designed to work the muscles needed to move air in and out of the lungs.
“To our knowledge, this is the first study to examine the therapeutic efficacy of combined resistance training and respiratory training as an adjunct therapy to ERT in subjects with LOPD to prevent the loss of muscle mass and function,” the researchers wrote.
The 10 participants ranged in age from 41 to 71; two females and eight males. Nine were Caucasian, and one was of Asian ethnicity. All but one of them were on ERT at the study’s enrollment.
Throughout the study, the participants underwent a number of physical function and muscle strength tests. The changes in these values over time were compared with natural history data (what would be expected for LOPD in the absence of treatment) from six patients.
The average distance that participants could walk in six minutes (6MWT) decreased not significantly by less than 2 meters (about 6 feet). Natural history data suggested that the average decrease would have been nearly 7 meters (more than 20 feet).
The average maximum inspiratory pressure (MIP) increased significantly, by 8.5 cm H2O. MIP is a measure of the strength of the muscles that pull air into the lungs when someone inhales. The exercise program did not alter the trajectory of changes in forced vital capacity (FVC), a measure of lung function based on how much air a person can exhale in a full breath.
“The 6MWT [six-minute walk test] distance and FVC in upright position diminished significantly over time during the natural history period, and the exercise study significantly improved the trajectories of MIP and 6MWT outcomes but as expected, not the FVC,” the researchers wrote.
Analyses of muscle strength in the participants’ knees and elbows showed significant increases over the course of the study.
“There was a significant improvement in the leg extensors and elbow flexors muscle strength, the muscle groups that were targeted in this study,” the scientists wrote.
The exercise regimen was generally well tolerated in the study. One participant developed back pain related to the exercises, though upon review it was revealed that he had been performing extra exercises at home, which likely contributed.
“These results suggest that exercise training has a positive effect on muscular strength and functional capacity in patients on ERT with late-onset Pompe disease,” the researchers concluded.