Stenson said the left-handed swings help him get a better feel for the path of his swing. “I sort of paint the path of the swing, and it’s easy to do that without the resistance of the clubhead,” said Stenson in his post-round press conference.
There are a litany of players who have an unusual pre-shot routine: For example, Chris DiMarco waggles the club back twice before he starts his swing, stopping when the shaft is parallel to the ground; and Mike Weir’s waggle is even longer, as he brings the shaft to a vertical position in his backswing to see that the club is on-plane.
These routines accomplish two things: 1) They assist in helping the player accomplish a certain swing motion or feel, so they can better execute the shot at hand; and 2) they allow the player to stay in the moment. This is why I think such routines are good for amateur golfers, especially under pressure situations where they’re trying to shoot a career-low score or playing in their club’s Member Guest. It keeps your mind focused on one specific thing so that you’re not thinking about the out of bounds to the left or the water short of the green. The more specific your intention, the easier it is to perform under pressure.