Some golfers just don’t know when to stop. Their backswing, that is.
Once they begin the backswing turn, it keeps going and going until reaching an unplanned, unspecified point – usually the point at which they can no longer rotate the shoulders. Even then, the hips and legs might continue moving away from the ball, compounding the issue. Any power built up by coiling the upper body against the lower body is lost.
When should the backswing stop? While there’s no specific answer and every golfer is different, the general rule of thumb holds that the club – and therefore the body – should not go past the point where it’s parallel to the ground. (A little farther is OK with longer clubs like the driver, provided your lead arm and wrist don’t buckle.)
Another axiom states that the shoulders should rotate until they’re perpendicular to the target line, with the hips turned at a 45° angle. If this is beyond your flexibility, strive for a 2:1 ratio of shoulder-to-hip rotation.
This drill will teach you to keep the lower body quiet while the upper body works away from the ball, shortening your swing and creating torque between the two parts. No need to use a ball when practicing this one:
This is an excellent drill to improve your flexibility and works well as a pre-round stretching routine.