Self Powering Energy

So currently batteries are the primary source for energy in a lot of electronic products such as ipods. The batteries eventually break however and are thrown away. This article talks about how this can be changed simply by walking around. By attaching some wires to your knee straps (also part of it) you can use the motion of your leg going up and down to turn a lever which in turn powers a generator. Imagine if this was integrated into many other products, energy needs would be met and america might not as obese anymore.