You should sit back on the ball.
Power comes more from pivot foot triggering the hips which triggers the shoulder which, etc.
He may feel the need to step back because he's not well balanced to start with. He may lack confidence - i.e. it's an unconscious move away from the ball to give himself more time. There's no way the leg can move back, and he may get a better sense of his contact position out over the plate on the ball. Display summaries of other articles about hitting . Search the Web.