Doing the right kind of exercises, power cleans, dead lifts, squat, pull up, chin up, as opposed to bicep curls and working 'beach muscles' is the key to a successful bulk. To be honest tho, you can do all the excerises in the world-but if you don't nail the diet,it's a pointless slog.
I wouldn't even consider comparing AFL and Gaelic Players fitness, AFL players are infinity fitter and stronger by virtue of being professionals - they look the part no doubt in those tight shirts, but they are functional athletes too. I've read some stories about what some of those fella's can do, I'm sure Irish players would be able to do it too, but Australia is far superior to Ireland in the field of athleticism and sports science.
I didn't mean to point out Gormley in a bad way, it's just some of the common thought that is stated in Tyrone.