the safe answer is to be able to pass an APFT on day 1. Push ups, sit ups and a 2 mile run. Thats the standard you will be judged on throughout your military career. beyond that, it is up to the cadre. just know that if you are in terrible shape and can't pass an APFT, you will attract a lot of negative attention... the good news, you will be able to pass one before you leave.