Device on knee can produce electricity

Call it the ultimate power walk. Researchers have developed a device that generates electrical power from the swing of a walking person's knee. With each stride the leg accelerates and then decelerates, using energy both for moving and braking. It's sort of like the way that some hybrid-electric cars produce electricity from braking.

With the device, a minute of walking can power a cell phone for 10 minutes, Donelan, of Simon Fraser University in Burnaby, British Columbia, said in a telephone interview. Other potential uses include powering a portable GPS locator, a motorized prosthetic joint or implanted drug pumps. (AP)