I dont think thats it's quite right to directly compare push ups and bench presses. I view the push up an endurance type of excercise movement while the bench is mostly a power excercise. (of course it can be done with lighter wt and more reps as an endurance exercise.) So,just as "how much can ya bench?" is a measure of one type of strength, the number of pushups one can do is a measure of one type of endurance. IMHO. K-