The amount of energy you have to expend to draw back a bow is not simply a function of the peak weight but of the entire force/draw curve. A 60 pound peak bow with a 1.0 stored energy to peak ratio (on the low side) will of course require the archer to expend 60 ft/lbs of mechanical energy equivalent to pull it back. If that same 60 pound peak bow had a s.e.p. of 1.4 (relatively hard cam) it would require 40% more or 84 ft/lbs. Same peak weight but the 2nd bow would be much harder to draw. The 2nd bow would also throw an arrow much faster.