THURSDAY, Feb. 16 (HealthDay News) -- When it comes to helping Parkinson's disease patients retain vital motor function, weight training may be more effective than stretching or balance exercises, a new study concludes.

The findings "reconfirm our notions that exercise plays an important part in the treatment of Parkinson's disease," according to one outside expert, Dr. Nora Chan, director of the Movement Disorder Program at Winthrop-University Hospital, in Mineola, N.Y.

The research involved 48 people with Parkinson's who were randomly assigned to either a weight-training program or a workout routine that included flexibility, balance and strengthening routines. Both groups exercised for one hour, twice a week for two years.

The severity of the patients' motor symptoms, including tremors, was assessed after six, 12, 18, and 24 months of exercise. The symptoms were checked when the patients were not taking their medication.

Both groups showed improvements in motor symptoms at six months. But patients in the weight-training group had a 7.3 point improvement in their Unified Parkinson's Disease Rating Scale after two years, while the patients in the other group returned to the same scores they had at the start of the study.

The findings are being released early but will be presented at the American Academy of Neurology's annual meeting in New Orleans in April.

"While we have known that many different types of exercise can benefit Parkinson's patients over short time periods, we did not know whether exercise improves the motor symptoms of Parkinson's over the long term," study author Daniel Corcos, at the University of Illinois at Chicago, said in an AAN news release.

"Our results suggest that long-term weight training could be considered by patients and doctors as an important component in managing Parkinson's disease," he added.

Another expert, Dr. Andrew Feigin, said the study is one of many that seems to support the notion "that regular strenuous exercise may have long-term benefits for Parkinson's disease patients." However, participants knew which type of exercise they were being assigned, so that might have influenced their mood or motivation, according to Feigin, a neurologist specializing in Parkinson's disease at the Feinstein Institute for Medical Research in Manhasset, N.Y

For her part, Chan added that "further studies are needed to clarify whether certain exercises are more suitable for patients with different symptoms, in different stages of disease, how cost effective these various programs are, and the exact mechanisms by which exercise improves Parkinson's disease symptoms."

Findings presented at medical meetings are considered preliminary until publication in a peer-reviewed journal.

More information

The National Parkinson Foundation has more about Parkinson's disease and exercise.