There are at least 3 things preventing you from increasing club speed through the impact zone:

  1. Overturning your hips in the backswing. This effects your downswing speed because your muscles are not building up enough torque to be released on your downswing. Think of muscle torque as stored up power waiting to be released. When your hips turn nearly as much as your shoulders there is nothing much to be released.
  2. Elbows losing magnetism for each other. Separating your elbows slows down your swing because they are not working together to row your boat in the same direction. When your right elbow bends in your backswing it is moving away from your left elbow—and your upper body—which of course creates far too much distance between them. This distance is GUD. Geographically Undesirable. Your arms will swing much faster when you keep your elbows together as much as possible. This also applies to the forward swing after impact. You will note in the graphics that your left elbow is moving away from your right one and again creating a lot of GUD distance. It may not feel awkward now because you’ve committed it to muscle memory, however when you train yourself to keep them together you will then notice that your new muscle memory will provide you with a smoother and faster swing speed. See video below.
  3. Weight transfer outside the box. At first when watching your left hip shift down the target line it appeared that your upper body was staying inside the box. However, the photos reveal this is not true. The vertical lines I’ve drawn on the graphics start inside your instep and rise straight up creating the vertical box. We talked about the box during your lesson. You definitely have a good shift with your left hip toward the target line to start your downswing, however it is bringing with it your upper body. The reason I thought you were staying in the box is because your head actually does create an illusion that your upper body is too. When your body travels away from the ball and from your center of gravity, it slows your swing down, as well. When body is outside the box on one side that is considered a sway on that side. When your body is out of the box in both directions that is a sway on both sides. Sways are known power killers. Sere video below on hip turn.