power walking

Excerpt from the article: Device Gives New Meaning to “Power Walking” | By Devin Powell | Science NOW Daily News | 7 February 2008

“The latest fad in self-powered wrist wear is the kinetic watch, a device that converts the momentum of a swinging arm into milliwatts. But researchers have unveiled a new accessory for your knees that puts the trendy timepiece to shame. Generating more than 1000 times more energy, the “Biomechanical Energy Harvester” may provide a green way to power the portable devices of the future.

Every time you take a step, you use two different groups of powerful muscles connected to the knee. The first group pushes to kick the lower leg out. Just before full extension, the second group pulls to put the brakes on. But for Max Donelan, director of the Simon Fraser University Locomotion Laboratory in Burnaby, Canada, and his colleagues, this braking process is just useful energy going to waste. His team has created a modified knee brace with a drive train that converts the mechanical energy into electricity. “A similar principle is used in hybrid cars to make electricity when you press the brakes; it’s called generative braking,” says Donelan.”

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