Definition - What does Sphinx Roll-Up mean?
Sphinx roll-up is a basic variation of sphinx pose that engages the core muscles.
Beginning in sphinx – prone with the tops of the feet, lower body and forearms pressing into the ground and the chest lifted – the yogi bows the head while pushing the hips up and keeping just the tops of the feet and the forearms on the mat.
Yogapedia explains Sphinx Roll-Up
Sphinx roll-up targets the deep core muscles, building strength in the abdominals and lower back. By doing so, the pose improves posture and lays the foundation for more challenging asanas that require a strong core. Sphinx roll-up also serves as a good counter-pose to sphinx, which is a chest-opening backbend. In addition, sphinx and sphinx roll-up prepare yogis for such fundamental postures as upward- and downward-facing dog poses.
For beginners or yogis with ankle problems, the knees may remain on the ground as the hips lift. Yogis with shoulder problems should skip sphinx roll-up.