Originally Posted by Soldier
A bodybuilder doesn't care about the weights, so he can continue to stimulate new growth through adding volume.
This isn't necessarily right. You cannot get bigger without getting stronger, and you cannot get stronger without getting bigger. At some point, your gains will cease to exist if you do not have both parts to the equation.
Matthew Perryman does an excellent job explaining muscle growth in his free e-book Maximum Muscle. There's a lot of solid information in that book. I'd recommend reading it if you're truly interested. You can download it from his website.