Step by step instructions
Begin in a full plank position with hands on the edge of a chair seat, arms lined up directly below shoulders, feet together. Brace abs tight and point left foot. Extend left leg behind hip, and avoid letting hips sag.
Bend left knee into chest, rounding spine, and scooping abs deep into spine. Bring nose to knee. Extend leg back behind hip and repeat. Repeat on the other side to complete the set.