Core A. Sit down and place your hands just outside your hips, with fingers pointed forward and legs straight out in front of you. Bend your arms and lean back, while you lift your feet a few inches off the floor and stare straight ahead. B. Exhale and crush your knees and upper body together (making a V shape), pulling your belly button in and keeping your chest lifted. continue for 15 reps. Rest for 30 seconds, then do 2 more sets.