It's even harder if you're hunched over, which restricts your turn. You've got to free your body up for a big coil by standing tall at address. The easiest way to make a big turn is with your shoulders on a horizontal plane, which means standing straight up. Of course, you can't stand completely straight and hold a golf club at the same time, but to make a big turn, you should stand as tall as possible. Long-hitting pros like Fred Couples and Davis Love III are good examples.
Love is tall, but both stand very erect at address.
This lets them make a big turn of the shoulders on a nearly horizontal plane while their arms swing up on a more vertical one. It's no coincidence that they are two of the longest hitters on tour. At address, flex your knees slightly, and, keeping your back straight, bend forward from the hips only until your arms are hanging in front of your legs. This erect position will free you up to make a big turn on the backswing. Extend your arms fully into impact for maximum power.