Turn the lead shoulder across the chest, don't pick up
The coach says 'picking the club up' with the hands is 'no shoulders'; to improve ball striking, get the lead shoulder moving across the chest in the backswing. To feel it, he extends both arms straight off the body, keeps them straight, and swings them back until the hands point at the camera, which moves the shoulder across the chest.
Channel: SagutoGolf
Watch official source at 69:07