[BerntR]

Yes it is about keeping the left arm straight.

But there is more to it than that.

For once; You set up a rigid structure with the right arm, one that firms up things and resists slowdown during release and ball contact.

You also use extencior action to extend the hands away from the swing center. This increases the leverage of the pivot. You get to do more work per degree of shoulder turn.

But my current favourite is this: Creating a good muscle tension in the back, right under the left shoulder blade and right above the hip. These are the muscles that pulls the left arm through. The extencior action creates good connection between the pivot and the hands that assures that what you invest in the shoulder turn will pay off through the hands.

I now create this tension around 7-8 o'clock in the back swing as I set my wrists and when I've got everything synced and working 96%, I have a very direct connection between my footwork and the hands (and actually the club).