I' m not 100% up to speed on this topic, I must admit. BUT, I do know this: the area under the force/draw curve is the stored energy available when you reach full draw. It is measured in FOOT-POUNDS. (Not just pounds.) That means that the FOOT component contributes along with the POUNDS component. (i.e., you can get an energy total higher than the pounds of pull because the energy is a product of pounds over distance.)

How " efficient" your total system is depends not just on the design of the bow, but how well your arrow can absorb the energy that the bow releases during the shot.

I think I remember learning somewhere that the most efficient compound design is a wheel bow. It seems like the wheels provided the best mechanical advantage, storing more energy for less work. This does not mean they' re faster. The area under a " hard cam" curve is greater, and the cams store more energy, BUT you' ve got to pull up a MUCH steeper force/draw curve. This means that they' re less comfortable to draw, etc.