Perceived smoothness probably has a lot to do with how each of us draws, and our physical makeup. I have some rotator cuff problems that give me pain early in the draw. If I can get the draw through the first 8-10" , I can finish it.

I' m also quite sure I use both my shoulder and back muscles throughout the whole draw. Different areas of the shoulder and back are used, depending on what point in the draw I' m at. Once I get to a certain point in the draw, the weakened muscles in my shoulder are not in use, and I can get it the rest of the way back easily.