Set up: Lie on your back with legs hip distance apart, knees bent and feet flat on the floor. Arms alongside the body, palms flat.
Inhale, engage the abdominals.
Exhale, bring one knee over the hip with the shin perpendicular to the thigh.
Exhale, re-engage the abdominals as the second leg comes up.
Inhale, expand the rib cage. Exhale, lower the abdominals to return the feet to the floor one at a time.