The spine is in axial extension; the work is to maintain the spinal curves in this relationship to gravity, balancing the abdominal action with the back extensors. If abdominal support is lacking, the extensors will overwork, and the spin will arch excessively.

Gravity draws the unsupported side of the pelvis towards the floor. Generally, you don’t need to use adductors to do this; instead, the ability of the abductors and external rotators to lengthen with control is essential (otherwise the pelvis is lifted away from the floor).

If hamstrings are tight, bending the standing leg is better than rotating the pelivs.