In order to achieve maximum clubhead speed at impact, you must be behind the ball at impact.
If the balance point of your body, which I believe is right at the base of the back of your neck, is moving laterally, the face of your club will not be square at impact and you will not be able to finish your swing on balance.
There are three things you must do before you start your swing that are key to being a good striker of the ball. I refer to these as the three B’s. They are:
1) Set up behind the ball.
2) Turn your lead shoulder behind the ball.
3) Stay behind the ball.
To set up behind the ball on a full shot you must be balanced with your weight evenly balanced on both feet between the balls of your feet and your heels with your nose behind the ball and your hands even with the ball.
To turn behind the ball, the swing starts from the ground up by initiating the backswing with the left shoulder, and the right hand coiling against the inside of your right knee and leg, so that your left shoulder is positioned behind your left knee at the top of your backswing. It’s just the opposite for left-handed golfers.
To stay behind the ball at impact, start the down swing by rotating your hips out of the way and finish with almost a 100 percent of your weight on your left leg and foot. Your right knee will almost be touching your left leg when you finish on balance.
Refrain from turning your shoulders with your hips on the downswing. Your chest and upper body will be facing the ball for a millisecond at impact.
When you do this properly you will see the ball leave the tee or see the divot being made.