I don’t even know what to say here. It’s very hard for my lower back to flex. I have the coordination to do the rocking motion, BUT my lower back doesn’t flex more, so I’m a bit at a loss here. I can only work with the range I presently have. With everything else, I've seen progress rather quickly. My body usually adapts to the training demands, but with the Rocks and JCs, I feel I am going no where. It may take light years to “unlock” my lower back. Not sure if it’s even possible as I’ve been told some of the stiffness is ligamentous, structural…
Parting thought: If I had gigantic spoon, I could easily rock, hold position and go with the flow.