Originally Posted by
mr_pedro
120 lbs is indeed the average force required to do 600W @ 60 RPM. But 600W is a lot, a 185lbs person would need a 20% grade to do 6.5 mph at 600W. So in practice, if you can do 600W, you are not struggling up a hill doing 60 RPM at running speeds. For all real life purposes, you do not need but a fraction of your body weight in strength to go up any hill.
But considering the facts that you can only (for the most part) push with one leg at a time and the fact that peak power (within a single revolution) is certainly higher than average power, I would say that you do (on an instantaneous basis) sometimes exert forces that are closer to your maximum leg strength than "never anywhere near your maximum leg strength".
dave