SocketRocket
Ryder Cup Winner
Straightening the right leg in the back swing is used in the Stack and Tilt type swing, it assists to keep your centre forward on the front foot in the backswing. The hips then need to be pushed well forward with the head back to shallow out the plane on the down swing.
If you dont S&T then a flexed right knee is a better position to hold IMO as it keeps you more level and centered and stops you coming down on a steep plane that will encourage getting out to in and hitting Fats and Thins.
If you dont S&T then a flexed right knee is a better position to hold IMO as it keeps you more level and centered and stops you coming down on a steep plane that will encourage getting out to in and hitting Fats and Thins.