New prosthesis makes walking easier

2010-02-26
Newsfeed

Engineers have designed a prosthetic foot they say will help amputees walk easier by cutting the extra energy they have to spend between steps by nearly half.

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Engineers have designed a prosthetic foot they say will help amputees walk easier by cutting the extra energy they have to spend between steps by nearly half.

A certain amount of energy is always wasted when the foot hits the ground and the ankle pushes up as force is exerted with each step. But the base of an artificial foot is typically not as efficient as a normal ankle so people using them have to spend more energy.

University of Michigan professor Art Kuo explains: "For amputees, what they experience when they're trying to walk normally is what I would experience if I were carrying an extra 30 pounds."

His team from the university's departments of Biomedical Engineering and Mechanical Engineering measured the energy spent using a conventional prosthetic at 23% higher than natural gait. Their new prototype, which incorporates an improved energy recycling system, has managed to reduce this to 14%.

Mr Kuo said: "We know there's an energy penalty in using an artificial foot. We're almost cutting that penalty in half."

In their paper published in the journal PLoS ONE, the researchers explain: "All prosthetic feet store and return energy, but they don't give you a choice about when and how. They just return it whenever they want.

"This is the first device to release the energy in the right way to supplement push-off, and to do so without an external power source."

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