One of the best days of my golf swing was, when I figured out I was dropping my back shoulder (a lot) at setup. I had been doing this for years and wasn’t even aware. Once I leveled my shoulders and kept them level (and parallel to my hips) as I sat down to the shot, WOW Hugh difference. Now why it helps.
If you drop your back shoulder, it curves your spine and you can’t turn your shoulders freely. It also make you take the club inside (very bad). It also prevents you from pushing with the front shoulder on the takeaway straight back and up (where it should go as to not get trapped behind yourself). It also makes it more difficult to hold your front knee to restrict your lower body while the shoulders push on the takeaway (a must for the DUPLESSISGOLF swing)
So…At setup…Make sure your shoulders are level, square, parallel to hips, then maintain this relationship as you setup to the ball. Your chest will feel a little more in front of the ball…this is a good thing.
Oh, one last thing. Avoid letting your shoulders setup “Closed” to your hips. If they are natural, they will be in line and parallel to hips…. trust this… Ross