One Piece Turn

Using a wood, hold the club at opposite ends. Take the clubhead in your right hand. This will be a stretching drill. As with all stretching drills you should hold each position for 20-30 seconds.

Begin a slow backswing, keeping your arms close to the body, and turning the shoulders until you are looking over the left shoulder at an imaginary ball. Hold this position.

Swing through turning your shoulders and hips, finishing high. Let your right hand go down the target line and up through the imaginary target. Hold this position.

1. To encourage a full shoulder turn , follow-through and prevent casting. This full body release drill will reduce the likelihood of blocking or quitting on your shots. It will help keep you on line and prevent you from throwing the right shoulder out and across the target line ("casting"). It will help you add distance by increasing your flexibility, allowing a larger shoulder turn.
2. To develop a smooth takeaway. This drill helps build many good swing skills. It helps you turn fully, and gives you the feeling of going down and through the ball. A swing initiated with the upper and lower body, as opposed to just the arms, will insure a one piece takeaway allowing the full coiling of the entire body.
3. To reduce the tendency to be an "arm swinger". This drill helps make sure the body swing the arms, not the opposite. Imagine the inside (your trunk) swinging the outside (your arms). The body, arms, and shoulders must work together as a unit.

Do's and Don'ts
Start slowly because this is also a stretching exercise. If you feel any pain or discomfort move your hands further in form the ends of the club. This drill promotes a one piece takeaway, full release and complete turn. It's an excellent pre-game warm-up as well. 
written by Joe Davidson www.SimpleGolf.com