depends on if youre doing them right. you can look up the standards online, they are most likely the same for every branch though. you didnt specify which service you are talking about....some are a little more physically intensive than others. a good idea is to do other exercises that work ALL your arm muscles, not just push ups. dips, pull ups, tricep extensions, bench presses, chin ups, and working with free weights will all help build the muscles needed, while doing push ups correctly will help you with form. you can push all day but if you dont do them to standard, they wont count.