Anatomical Function: The Oblique musclesrotate the torso.
The oblique muscles (light blue in the diagram at right) are used for all rotational activity around the spine.
The oblique muscles will only work at their optimum strength when their insertion points are stable. That mean that we need to keep the base / arc stable while using the obliques. Do not yank or hurl shoulders or the free leg to initiate rotation, as this will destabilize the base.