Photos: Power-generating leg brace goes for a walk

The Biomechanical Energy Harvester uses sensors and a real-time control system to assist the hamstring muscles in slowing the knee motion. The system only turns on power generation at the end of the walker's swing phase, just before the foot hits the ground, according to a university release.

Donelan believes his device will have applications for military and medical fields, as well as consumer markets.

He said: "Portable electricity represents much more than just a convenience to some people. It allows a soldier to communicate, navigate and get home safely. It dramatically improves the quality of life for stroke victims, amputees and others who rely on power-assisted medical devices to get around."

The device is featured in this week's issue of the journal Science.

Photo credit: Greg Ehlers/Simon Fraser University