newVideoPlayer("kneebrace_giz.flv", 475, 376,""); A knee brace that generates enough electricity to power 10 cellphones was demonstrated by scientists recently. The brace harvests the energy of a person’s knee braking after taking a step, similar to the way hybrid car brakes collect energy to charge their batteries. The device only weighs 1.6kg, and does not need the intense effort that other human-powered energy generators such as hand cranks require. And while the mobile phone measurement given by the creators is pretty useless, they do have several practical applications in mind.