Setting up with slack in your arms causes you to extend towards the ball when you swing and hit the ball with the heel of the club
Our main concept in golf fitness is to understand how your body works with your golf swing, looking at the dysfunctional areas of your body and how they effect your swing
Start with a neutral grip making sure that your left hand is not turned over or under the shaft, this will prevent you from manipulation the clubface at the top of the backswing