I think you are absolutely right, what it feels like is happening now is that concentrating on the arm and shoulder rotation and a more forward pointing back knee is causing me to lose my board feel. Previously I used to wiggle my way down the line using board feel even foot pressure and no drive. Now I am see-sawing between too much weight on the back foot and having to compensate with too much on the front. Then there is getting my butt down to the wave - the instructor was saying something to that effect when I was on the surf skate....
MR J - From what I see, you have to much weight on the front foot. This causes "rail dig", and you don't get the drive you want. More legs, less upper body. If you can get your butt in the wave on your bottom turn, you will feel the speed!
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Its feeling all a bit alien at the moment.
This is a frame grab from the turn prior to having too much weight on the front. Too much weight on the back.