Lie flat with both knees bent into the chest. Before you curl up, be sure your box or frame is square and then activate your powerhouse.
Curl the upper body off the mat and hold the left leg, reaching the left hand to the ankle and the other to the knee. Extend the right leg 45º. Control the torso as you switch legs, inhaling on one side and exhaling on the other. Continue switching for 8 repetitions. Bend both knees to finish. Rest your head.