Dr. Alberts was intrigued by the connection between the motor control improvement in his friend's arms, and how it could be connected to forced leg movement - the key word being "forced." /*Forced exercise*/ requires the patient to peddle faster than they would peddle voluntarily, and with the tandem bike, a trainer regulates the pedaling rate, creating a tough workout.
"There was a 35 percent improvement in motor functioning for those patients who did the forced exercise compared to the voluntary exercise," said Dr. Alberts.
Researchers think the forced exercise on a bike could be triggering the release of some chemicals that may actually improve motor function.
ABC News contributed to this report.