Within the Bujinkan you often speak about Koppo, to have Koppo is when you have a structure a base to use and to use Koppojutsu is when you attack someones else structure.
My understanding of Koppo is when the bones are stacked on top of eachother in a perfect way. The muscles then are what helps the bones to move around and if a person whould stand still no muscles would be needed as the structure supports itself.
Within the Feldenkrais they speak alot of the same, the bones should be the base and the muscles are there to support.
I was thinking of this the other day in my yoga class when coming out of Rabbit. Then I had worked my back muscles nice and loose on both the front and back and I got this sensation when there was one point there was no need to use the muscles, I could just sit there straight and effortless.
I have no other word on this feeling than Koppo.