A new energy-capturing knee brace can generate enough electricity from walking to operate a portable GPS, a cell phone, a motorized prosthetic joint or an implanted neurotransmitter, research involving the University of Michigan shows.

"In a lot of places where it could be dissipating energy, it may actually be storing it and getting it back elastically. Your tendons act like springs. In many places, we're not sure whether the energy is really being dissipated or you're just storing it temporarily." -- Arthur Kuo, Associate Professor of Mechanical Engineering, Iniversity of Michigan