The history of golf certainly has shown and continues to show that there are many ways to swing. Nowhere is that more true than in the backswing. It seems to me that many instructors today are very against lateral motion in the backswing. I’m not sure why because most of the players in the hall of fame utilized lateral motion. Some had giant moves off the ball, some not so much. I see many younger players working on swings that seem too centered almost to the point of a reverse pivot. I’m afraid many of these players have back and hip injury in their future.
Obviously swaying onto the outside of the trail foot can cause a host of impact problems as does a reverse pivot. Most of the greats did have lateral motion going back but most definitely had a re-centering move before reaching the top.
Going back some players moved / “swayed” their upper body / head back ie: Tiger, Strange, Hagen.
Some great players made a big shift back with their lower spine / hips ie: Monty, Couples, Inkster.
My preference is to see a bit of lateral motion with a strong re-centering move. This is a natural athletic motion and can become a key element to rhythm and balance. Practice throwing a ball to get the feel.