To add on to the shape language idea ^
These are great studies to understand the proportions and general directionality of a body. The shapes (circles/ovals) used to quickly describe sections of the body like the head, torso, and hips might not be communicative enough to inform you or the viewer. The practice of preemptively plotting these significant sections of a skeleton is great though! Maybe try thinking about the actual shapes of the bones of these areas. The ribcage has a specific shape that isn't a tall oval, the hips are boxy, the head isnt quite circular.