This is a safe and effective way to train your abdominal muscles to stay flat and firm when you stand. Don't try to touch your feet to the floor right away; over time, you'll develop strength to lower them all the way to the floor.
-- Karen Voight 1Lie on a mat or a padded surface. Hold a foam roller lengthwise between your knees and ankles. Begin with your knees directly above your hips and rest your head on the floor. Bend your arms to the side with your elbows at shoulder level. Inhale, then exhale, and pull your navel toward your spine, tensing your abdominal muscles to flatten your midsection.