The supine trunk rotation stretch is a good releasing exercise to help improve your ability to complete a stress-free backswing and follow-through. If the seated trunk-rotation test identified limitations in one or both directions, this exercise can help you gain flexibility in the proper region of your spine and enable a better turn.
Perform this releasing exercise as follows:
Lie on your back with your hips and knees bent so that your feet are flat on the floor and your arms rest comfortably away from your sides in the double "tray position".
Gently squeeze your shoulder blades and flatten your neck to the floor while you slowly and gently rotate your legs to the left.
Continue to slowly twist your body, keeping your right shoulder blade and forearm flat to the floor until you begin to feel a comfortable stretch in your spine and possibly in your right hip and the front of your right shoulder.
Hold this position for three to five minutes or until you feel a complete release of the gentle stretch in your body. You can enhance the stretch in this position by bringing your left hand down from the "tray position" and gently pressing down on your right thigh.
Slowly return to the neutral starting position and then repeat the stretch, this time rotating your legs to the right.
Practice this releasing exercise at least once a day for two to three weeks until you can stretch equally well in both directions. If your spine was more stiff or limited in rotation when turning to your right during the seated trunkrotation test, you should spend more time initially rotating your legs to the left. Likewise, if your trunk-rotation flexibility was more limited when turning to your left, then initially rotate your legs to the right in this exercise. Your ultimate goal is balanced rotation in both directions.