If you're training for semi-pro football, you should start conditioning in September or October. Even though it's called "semi-pro," it's still full-on contact, with hits as hard as in college and pro football. Your body needs to be able to dish out -- and take -- that kind of pain, so you need to be in the best physical shape possible.
If the team you're trying out for offers training camps, take advantage of them. If not, hit the weight room to build up your strength. Don't forget to add cardio training. Some teams are small, or they lose players throughout the season, and you may find that you're suiting up for both offense and defense. That means you'll have to build up your stamina to be able to play an entire game.
Just how fit do you need to be? We'll run through that next.