In the future, when you need to charge your cell phone, all you’ll need to do is to go for a walk. Researchers at Simon Fraser University Locomotion Laboratory in Burnaby, Canada, have created an accessory that attaches to your knee to generate power with every step that you take.

Every time that you take a step, your leg both accelerates and decelerates. Two groups of muscles, work towards making this happen. The first group pushes your leg forward, so that a step can be taken. Just as the leg is close to being fully extended, the second group starts pulling back your leg, braking your leg. And it is this braking mechanism which Max Donelan, leader of the research team, saw as completely wasted energy. He thus modified a knee brace, which was outfitted with a drivetrain, essentially a generator, that was able to absorb that wasted energy and turn it into electricity, in a manner much akin to the braking system of some hybrid vehicles, which are capable of recuperating energy as they are braking.

The device can be used to power small devices, such as cellphone, GPS receivers and can even assist to power a motorized prosthetic joint. Naturally, you may wonder how this device feels, as the fact that you are generating power would mean that there should be some resistance in the device. The entire rig weights around 1.6kg and test users haven’t found it too uncomfortable. Furthermore, and according to the project team, the device can actually assist people with walking better, as the extra braking provided by the device mean that less effort is being put on the muscles of the leg.

Create electricity and lose weight while doing it. Is there anything not to like?

+ Device Gives New Meaning to “Power Walking” @ ScienceNOW