posted this earler--thought it applicable to this discussion:

Healthwatch- Parkinson's Treatment
Posted: Tuesday, June 12, 2007 at 4:16 PM

BACKGROUND: According to neuroscientist Jay Alberts, Ph.D., of the Cleveland Clinic, past animal studies have shown great benefits for exercise in terms of improving Parkinson's disease function. But these positive results haven't been replicated in human studies. Dr. Alberts says, "A lot of human studies haven't shown significant improvements in motor function using the various human interventions, such as weight training or other types of exercise training." But the animal studies used a paradigm called "forced exercise" -- where the animal is forced to exercise at a rate that's faster than its voluntary rate. After taking a group bike ride across Iowa in 2003, Dr. Alberts realized the concept of forced exercise may be the key to bridging the gap between the positive animal studies and the inconclusive human ones.

FORCED EXERCISE: During the Iowa bike ride, Dr. Alberts rode on a tandem bike with a person who had Parkinson's. The patient was forced to pedal much faster than she would have normally -- between 80 RPMs and 90 RPMs as opposed to between 50 RPMs and 60 RPMs. Dr. Alberts explains, "In many ways, this tandem was like a type of forced exercise paradigm that was being used in the tandem studies." Then in 2006, Dr. Alberts rode again with another Parkinson's patient. This patient depended on a surgically implanted device called deep brain stimulation to control his symptoms. If the device is turned off, his symptoms return immediately. Dr. Alberts and the patient went on a 50-mile tandem bike ride with the stimulator turned off, and to their delight, the patient had no symptoms. These observations led to Dr. Alberts testing the theory out clinically.