Get off the line. Every attack is from point A (his hand or foot) to point B (your body). If you start to backpedal, I can chase you from here to Kentucky but I will get you. If you step to the side, all kinds of opportunities appear aside from you not getting hit. I trained my studends in this with a big wall and a tennis ball. I don't throw where thI think they are moving, just where they are standing (point A to B). They learned the concept of getting off the line.