To challenge your core muscles and flatten a lower-ab pooch, take your abdominal workout up a notch with this bent-leg V-sit. It targets the deep (transverse) abdominal muscles that help pull in your midsection. It's a difficult exercise to do correctly, so remember to keep a short range of motion with your legs.

1 Sit on the floor with your legs bent and feet flat on the floor. Place your arms behind you and lean back on your elbows. On an exhale, try to round your lower back to touch the floor, pressing your navel toward your spine. Lift your feet off the floor, keeping your knees bent.

2 Without letting your abs relax, extend your legs just a few inches in front of you. Pause for three to six seconds as you continue to keep your abs drawn in toward your spine and your lower back slightly rounded. Release by bringing your knees into your chest, inhale and relax your abs. Repeat eight to 10 times.

This article originally appeared in the Los Angeles Times in the "Good Form" feature of the Health Section. "Good Form" is updated with a new Karen Voight article each Monday.