Is exercise the next new source of renewable energy?

If you take a minute to think about it, the idea's been around for quite a while. Old fashioned crank phones, hand-cranked radios -- people have been using elbow grease to create electricity for years. But eco-savvy gym rat Doug Woodwring and others like him want us to start harnessing the energy created from everyday workouts and convert it into usable power.

He mentioned his idea to the management at California Fitness in Hong Kong, and soon the gym had 13 elliptical trainers hooked up to a car battery. The machines power a few TVs and a couple of lights, but the excitement it and other potential projects like it have created is spreading. Imagine creating power just by walking through the subway, dancing on a dance floor, or even carrying a backpack. The concept is known as a "parasitic generator" and it makes use of the energy we create by going about our everyday lives. It could even bring electricity to far out places to refrigerate vaccines or lighten the battery load of soldiers.

Pretty cool, I think, though most of the ideas are still in development. At the moment, the biggest hurdle seems to be that it costs an enormous amount of money to generate only small amounts of power. But California Fitness says they'll consider going worldwide with their newly adapted elliptical machines if the project works. Who knows, you may soon be helping to light up the world with your next workout!