I don't know if this is good or bad for you but this is what I have been doing. When I work out every other day, I do 400 push ups and 300 sit ups. I do 100 push ups, 100 sit ups, and keep alternating. The first set I do an APFT sort of. I use an [URL="http://www.online-stopwatch.com/bomb-countdown/full-screen/"]online stopwatch[/URL] and set it for 2:33. The :33 is to give me time to get into position. This seems to be working well. At last drill I did 71 push ups if I remember correctly. Just a few minutes ago I did 80 with about 5 seconds to spare.
It seems to be working for me. Try at your own risk. Time to do some sit ups now. HOOAH!