I think this is an awesome question. I have a background in martial arts and lately, I've been training with a bag two or three day a week.
If you box, endurance, speed and accuracy are you best friends. Train with at least one heavy bag, a speed bag, and if you can find one - a double cable speed bag.
One thing about boxing is that it's so physically demanding, it'll whittle you down to a twig (a very powerful and athletic twig with a well-defined physique) but a twig nonetheless. Unless you are very tall, having Ronnie Coleman's physique will not help you become a better pugilist... of course, that's if you're thinking about competing. If you want to retain the bulk or your bulk, you're going to have to pay considerable attention your diet.
And since I'm not qualified to say any more but I can relate, I'll ask the question:...
I was also bulking before I began pounding the bag and in the past couple of weeks I have lost five lbs. I can't afford body comp testing so I am not convinced that all I am losing is fat. I drink more water, supplement and eat around a training session as I would a weight-lifting session, and still devote the same amount of time to lifting.
For anyone with more experience, how do you engage in something as physically demanding as bag training WHILE trying to put on mass? I could stand to lose some fat, but once I get to the point where I can see abs (which may be another month or two) I am going to want to see my weight increase.
I have a feeling the answer has something to do with dieting to keep my body in an anabolic state. Help appreciated, and also let me know if you agree/disagree with my response to atomsk.
DWK