You're Correct!

A golf swing is a rotary movement. You create a position at address to make this rotary action from. As you create your posture, or the angle that you tilt you spine forward at, this becomes a fixed point that you then need to turn your body around and rotate.

The rotation around your spine creates power for you to then utilize when you swing the golf club back towards the ball, allowing you to create club head speed and therefore distance to your golf shots. Maximum rotation in your body will help you to create maximum distance.

To ensure that you create enough shoulder rotation, or upper body rotation in the back swing, you need to turn or rotate your shoulders/upper body 90 degrees to the right (for right handed golfers) of the starting position. Your shoulders should be set parallel to the target line in your address position and therefore you want to work on turning them 90 degrees to the right of this position, so that your upper back is turned and flat to the target.

A great exercise to work on to help you learn to rotate your upper body to a maximum is to set up as though you are going to hit a golf ball. Place the golf club across the front of your shoulders. This club should be parallel to the target line. Turn your shoulders and the club to the right until the left end of the club is pointing towards the golf ball. The club should be angled downwards towards the ball on the left end of the club as you rotate if you are holding your spine angle.

If you find you are unable to rotate a full 90 degrees to the right doing this, then allow your left heel to rise from the ground and you should find that you are able to turn further. Lifting your left heel allows your hips to rotate more and this in turn allows your shoulders to rotate further around your spine. However, if you are able to turn your shoulders 90 degrees to the right without lifting your left heel, keep your left heel on the ground for more power – only lift it to achieve the correct 90 degree shoulder turn if necessary.

If you make a lifting action with your arms and spine during your back swing rather than a rotary movement, you will not create the full power that you could. Lifting the club into position only allows you to use the strength in your arms, not the strength in your arms and body as a rotary movement permits.

Keeping your left heel on the ground as you make your back swing will create more torque, twisting in your body, or coil. This will create more power but only if you have achieved the rotation in your shoulders. If you can not turn your shoulders 90 degrees right with your left heel on the ground, then allow it to lift. Your shoulder turn is the priority.

In order to rotate and turn well during your back swing, you need to be flexible. If you are getting tight and tense in your upper body before you swing back, then this will restrict your movement. Work on relaxing and keeping your shoulders and upper body loose and you will achieve a great shoulder rotation.