Lay on the floor with a neutral pelvis, hands behind your head, and your feet together on the chair. If you don't have a rolling chair, just put your legs in the air.
Engage your abdominal muscles on an exhale to curl your head and shoulders off the ground while keeping your elbows pointed toward the arms of the chair.
Inhale to extend your legs, rolling the chair away from you, and lower the shoulders back to the floor. Exhale to curl back up while rolling the chair back in.