Anatomy Reference

Joint placement reference material. This is a good example because all the motion motion is done slowly and the camera angle is almost orthographic and she achieves a good broad range of motion.

I'm particularly interested in the spine area, both top and bottom, where it meets pelvis and neck.

Pivots

straight up

The pivot location for the pelvis and hips, the outer circle demonstrates the motion of the top of the legs as she bends over.

The torso rotates on this axis.







Bent over

The position of the pivot remains the same as she hasn't translated her axis in any direction, just rotated by around 90°, this illustrates the pivot is in the correct position.







Spine Mobility

She also hyper extends the spine (demonstrating how not to do the exercise) which show the backs manouverability in the lower region as the second joint translates out to form an arch shape.