Sway is not necessarily a bad thing. It is a swing characteristic. What matters is that for whatever distance you move away from the target, you must move back before impact. A look at the illustration shows a golfer at the top of their backswing. The green represents the original swing arc from the address position. Once moved into the back swing, there is an evident sway as indicated by the head movement, and that action has changed the bottom of the swing arc to be 4-5 inches behind the ball.
If there is no correction, the impact of the clubface will be that distance behind the ball, resulting in a divot and a shot hit “fat” or “chunky.” I am not here to prevent the sway. After the things my body has went through in the military, I have this exact dilemma in my swing, and I have owned it. The long-term goal is to increase range of motion in the thoracic spine to keep my head more centered on the ball. This is an uphill battle, and one that requires mobility training twice, if not three times a day. In the meantime, for good golf, I press my lead foot into the ground for the start of my backswing and before I reach the top, I press the equal amount, if not more, from the trail foot. This ensures that my iron striking is down on the ball and if I had a swing thought, it would be to get my weight to the lead side of my body towards the target as soon as I start my backswing. The faster the weight is shifted to the lead side, the better the result.
For those with a little confusion, I’ll break it down like this. No backswing has ever moved the ball forward. The existence of the backswing is to wind up TO UNWIND in the downswing. If your worry is how great your backswing is, you’re missing the point of forward energy to the target, through the ball. We are loading to unload, that is the purpose. Most amateurs load so much that they restrict the unloading, so if your backswing takes the club all the way past your lead shoulder, and you cannot get the body weight transferred to the lead side before impact, then you need a shorter backswing.
So, the moral of this story is what you take away from positioning in the address before you swing, you have to put back before impact to ensure crisp, solid contact.
-David