The hips are all-important. They should be so open and relaxed that the knees have a life of their own. If not then the legs, simply by supporting your weight, will be constantly driving the pelvis and sacrum up and back, out of alignment. This gives us what we perceive as safe-distance but it is really a tragic disconnexion with ourselves. We do not inhabit our own space, we are always behind it, afraid of the spot-light, afraid of the plunge.