Originally Posted by
Adam Skillin
You almost definitely can use a 4" for squats and presses, and if you can, you should. The 3" or 2.5" is better for deadlifts for many people, and as far as I can tell, it's a matter of personal preference for bench. I'm a short guy with a short torso, and I squat and press in a 4" and bench and deadlift in a 2.5" I've coached maybe 3 people for whom a 4" was too wide even for squats. While we may still debate the exact mechanism of the action of the muscles' interaction with the belt, I think everybody agrees that you want as much support as possible.