Here are 4 more effective -- not to mention safer -- ways to get a stronger, more sculpted midsection.
The 4 Best Exercises for Your Core That Aren't Crunches
Bent-Knee Pilates Hundred(01 of04)
Open Image ModalPlank with Arm and Leg Raise(02 of04)
Open Image ModalHigh Knee March(03 of04)
Open Image ModalWhy 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. (credit:Courtesy of Michele Olson)
One-Knee Side Lift(04 of04)
Open Image ModalWhy do it: This yoga-inspired move is a variation on the side plank, which Olson found is 47 percent better at working the external obliques on the sides of your body and slightly better at toning the rectus abdominus (those muscles that make the 6-pack).
Starting position: Sideways: Lie on your right side with your right forearm on the floor, your hips and legs stacked.
How to do it: Press into floor, straightening left arm upward and lifting hips toward ceiling. For stability and balance, bend your right knee so that your shin makes contact with the ground. Hold for a count of "one Mississippi," then lower. Lift again and repeat. Complete 15 reps on each side. (credit:Courtesy of Michele Olson)