University of Michigan researchers are working on an artificial foot prototype (prosthesis) that would allow its user to walk without any extra effort. As the equipment comes with a microprocessor and a 1-watt battery to capture the kinetic energy generated by walking, the effort during the ankle push-off is reduced by recycling and reusing this wasted energy. What it culminates in is a net metabolic energy reduced by 14 percent required to walk.
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%.