I've participated in many threads regarding the human energy concept and way too often the OP plus a number of the people in them get all uptight about the realities behind just how dismal of power sources we are.... and that doesn't take into account the human energy used to plant, tend and harvest the "free" food. Never mind. He can't tend his crops since he is generating all of that "free" power.
Oh, and did you notice that the Olympic athlete wasn't reading a book or doing research on the Internet while toasting that slice of bread? He is such a slacker.
I will say it again about human power proponents. What idiots!!
p.s. I will add to this the fools that think they can get free energy by putting a generator in a backpack or shoes. Not only are you getting the energy conversion inefficiencies but you a wearing a backpack that rides like it is filled with rocks or shoes that feel like you are walking barefoot on cobble stones.
Why? Imagine for a moment that the padding in you backpack was perfect. No matter how much you jump up and down you would not feel the backpack. If you can't feel the backpack then you are not pushing against it to transfer energy. No energy transfer means no power generated. The only way to get motion to the backpack is to reduce the padding.
Almost always it some persons wanting to go off grid that thinks that if they just have the right generator on their exercise bike they can live a rather normal electronics based lifestyle pedal powering all their electronics toys up to full charge every day.
The reality is most people couldn't pedal power recharge their cell phones once a day. Then there are the others who seem to think that going off grid and going pedal power for all their electrical needs would be better and cheaper for them 'since utility power is too expensive' for them to afford. They don't have a clue how much energy they use let alone how many hours a day they would be pedalling their brains out just to keep their computers up and running for a hour or so.