The kick is supposed to be slower. Trust me, I’ve tried throwing a really fast kick. You end up hurting yourself more instead of your opponent. And I said, moving your arm back doesn’t increase the power of your punch unless you’re fighting southpaw. So it doesn’t really do much though it can increase power. But not enough that anyone finds use of doing it to make their punches slower but somewhat harder. Not by much though. Bringing your arm back is not good for quick punches, it’s hard on muscles like the biceps. It’s irritating to punch like that so much that you’re likely will weakening your punch.