Many of us have done thousands and thousands of presentations from the holster during dry fire and live fire. Often when we do we are flat footed and don't have to move until we have the gun presented at the target. Here are some stills of what it looks like when you need to move as you draw. So much for economy of motion. Both of these guys are experienced shooters, the bottom like is that under during dynamic movement all body angles change and so will your draw. Both shooters are drawing in response to a visual stimuli. The second shooter first had to panic push the target that is laying down before engaging the second target.