The Associated Press: Power From the People, a Step at a Time

The Associated Press: Power From the People, a Step at a Time: "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.
Max Donelan and colleagues reasoned that a device that helps the leg decelerate could generate power without requiring much additional energy from the person.
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"