I have a question about the pelvis. I'm posting it here, but part of my question can be seen in the videos on spine anatomy. When Skelly bends over to touch his toes, the entire pelvis is pushed backward. I'm having trouble wrapping my head around why this happens. I know the spine can lean forward or arch forward without that happening, but It seems impossible for normal forward bending over to happen without this pushing back kind of cupping motion of the pelvis and I'm not sure how to really understand what is causing that to happen. Maybe its the innervation the muscles to cause this motion to happen. It feels like the gluteal muscles have to relax and the knees have to lock, but Im trying to understand this motion better as it directly effects imagining the pose of the pelvis correctly. Any help is indeed appreciated.