I start basic training in in 2 months and wondered if anyone can advise me on how I can build up the muscle's you use when you do Pull Ups on the bar. I'm guessing its all about upper body strength, and push up's should help? I say this, as i'm ok for running, sit up's, push up's, but when it comes to pull up's, I end up swinging on the bar like a demented ape much to the amusement of the PTI's when I done selection. Is there a technique or is it just based on shear upper body strength? ...any suggestions would be welcome?