Re: Aikido: The learning of natural movement
Re: the lowering back issue.
I think what you could do is this:
fix two spots on the ground with tape. Then put up a background with the distance marked on it (say in increments of 1 foot or maybe 6 inches. Then stand on the marks, and place the camera so that you were in profile.
______________Background with marks__________________
So then when you move, the amount you move your back relative to your feet (which are fixed in place) will be easy to measure. "X" marks the feet positioning.