ab exercises that aren't crunches

Photo: Courtesy of Michele Olson

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High Knee March
Why do it: Sure, this standing move works both your abs and your lats (the muscles that pull in your waist). But its real advantage over crunches is that it works the front and back muscles in harmony—a feat that, Olson says, helps you build overall core strength and makes you less likely to get injured when picking up heavy objects.

Starting position: Stand tall with feet hip-width apart and hands behind your head, elbows out.

How to do it: Tighten your abs and lean slightly forward as you bring your right knee up toward your belly button. Lower the right leg and return to start; repeat on opposite side for 1 rep. Alternate legs; do 12 reps total.