Researchers at the University of Michigan have created a prosthesis that makes walking much easier on amputees than current options. The trick: an artificial foot that recycles the kinetic energy generated by walking.

The device works by mimicking the natural push-off of a human ankle, using a microprocessor to control the device and capture the energy normally dissipated by the leg:

In tests on subjects walking with an artificially-impaired ankle, a conventional prosthesis reduced ankle push-off work and increased net metabolic energy expenditure by 23% compared to normal walking. Energy recycling restored ankle push-off to normal and reduced the net metabolic energy penalty to 14%.

That means less cumbersome dragging of an artificial limb and a more natural walking sensation. It also only requires a small battery to operate, running off of less than one watt of power.

It's just a prototype for now, but assuming the current round of testing goes well, there's no reason not to expect a commercial application in the not too distant future. [PLoS ONE via Inhabitat]