Full Swing · Mental Model

Coil back with your core, not your arms

The instructor explains that whatever you engage going back is what you tend to use coming down: swing back with your arms and you'll most likely hit the ball with your arms, but coil back with your core and you'll most likely drive through with those muscles. This is why taking it back with the arms and then trying to use the body on the way down forces you to completely stop and switch muscles, so the motion can't flow.