Originally posted by horseback:
An average guy (under 35) in good shape should
be able to run a single mile in approximately six minutes, two in 13:30 or so, and three in 20 to 21 minutes. If he has a masochistic streak, he should be able to knock those times down considerably.
Most people are NOT in good shape.
If you're in shape, 4 minutes of maxing out on your pushups and situps will not affect your time in a three mile run. They are anaerobic exercises, working muscles you use only peripherally to run; they won't sap your endurance, and they aren't going to be sore until the next day (which they won't be at all if you are in GOOD shape).
By the bye, I ran my Navy 1.5 mile fitness run in a bit over 8 minutes at age 27 (I pushed it a bit so that I could lap <1/2 mile laps> LT McCartney, who was and probably still is a horse's patoot). The requirement for an old guy like me at that time (1980) was something like 17 minutes.
This was two hours before my daily 4k swimming workout. My thighs and calves cramped up on me big time, so do not try that at home. The look on Mr. McCartney's face made it well worth it though.
PS- I'd have scored 100s across the board, according to jarink's link