Best way to get fit on a treadmill in a short amount of time...?

Hi.My guess is that when you do join the army,they will make you run outside not inside. Running outside is different then being on a treadmill believe it or not. I suggest actually running outside instead. You could possibly switch it up if you want to like on cold days do running inside. Warm days outside. Check to see how fast you have to run that 1.5 mile in. I think they time you each time. I do a 5.5 to 5.7 speed myself while running. If I really want to beat a certain mile time then I go faster which is about 6.2