SACH-SAWCH

the pelvis thus have a fixed spatial mechanical relationship to the spine is an important evolutionary step which was needed to utilize evolving better movement neurological computation. Above, we see the height of the center of mass near where pelvis attaches to the spine. The hips can go up on right while down on left (or the reverse) which does not displace the center of mass. A stiff line from center of mass to a point on the floor (long peg leg) arcs over a circle path with sharp up to down at the ends of the arc. A small savings is that it does not have to travel the full height as seen in the arc above. Hips can go up and down without the center of mass moving as much. But, we need more. The FOOT. The single most functional bone in the

ankle/foot is the talus (seen prominently in white in inset above). The talus is key to all foot & ankle movement; and yet, it has no muscles or tendons attached to it. It is a spatial adaptive link with several planes of motion with interesting shapes & properties. The cylinder shaped mortise is seen opened here. The Achilles passes the talus to attach to the heel. Others also pass the talus en route to their attachment points. The talus thus moves within an envelope of tension generated by a sheath of passing muscle tendons whose forces (interacting with those generated by ground impact) average and

smooth body travel. It reacts mechanically to change from best guess adaptation to approximated anticipated ground conditions [hard, soft, slippery, tilted etc]. It is a mechanical capacitor averaging oddities, especially of contour. But, what if the forces of unexpected angularity exceed what it can yield to? It breaks. Or, the containing envelope of constraints sprain or break.