Well, I hope this helps. With the exception of the initial p.t. tests, you will never do more than 25 push ups at a time, 5 chin ups, your probably not going to do any sit ups, and as for running it has been covered about 1000 times on this board. If you pay attention to how I described what you will do, you will know that being able to do 70 pushups means absolutely nothing and you are wasting your time trying to increase that number, you will however have to do thousands of sets of 25 pushups. So make sure you can do 25, stand up, get in trouble for something else, do another 25, stand up, hit the deck again for another 25 and so on, you wont do very many chinups, but during one of your classes, you will be using those muscles a lot more than you ever thought you could, try doing a chin up, and holding your chin above the bar for as long as you can, then under control come back down, do it again, then try it holding your legs out in front of you, bent at the waist at as close to 90 degrees as you can, and hold it. See if you can stay with your chin up past the bar for eventually 10 minutes, 15. As for situps, with the exception of the test at the start and occasionally during P.T., your not going to do them, instead you might want to read up on the 5 points of flight procedure, particularly the 5th point. Also to make your life easier when you get there, try this, take a rope, loop it around one of your shoulders, down beside your groin, (make sure it is the same side as the shoulder that you started from), from there go across your back over the other shoulder and down on the other side of your "area". Sit down and bring your chest to your thighs, tighten the rope and tie it off. Stand up, if you can, now try the pushups and situps and running. Imagine wearing it everyday for 3 weeks, and you will be gold. Do not let the requirements for the P.T. test lead you to believe that this course will be easy in any way. Good luck and I hope I helped at least a little bit.