Start in a plank position. Keeping core engaged, spine extended, and weight evenly distributed with wrists below shoulders, step left foot up to outside of left hand without rotating torso. Cross left knee underneath body to touch right elbow, keeping hips and shoulders square to the floor. Thread left leg through to extend out beyond right side of the mat, opening to a side plank and extending right arm to the ceiling. Return to start position. Repeat on the opposite side, alternating sides for 12 reps total.