Ball Crunches

Another great abs move, according to the San Diego study: crunches on a fitness ball. Aim for three sets of 10 reps; keep your abs pulled in throughout the move.

Side Lifts

Lie on the floor on your side, legs stacked on top of each other. Prop your torso up on your bent forearm, with legs bent (easier) or straight (harder). Lift your hip off the floor so your body forms a straight line from shoulders to legs. Hold for a count of three; lower to floor. Repeat five to eight times; then switch sides and repeat. "You really have to use core muscles and obliques to do this, but you won’t think about the fact that you are working your abs," Kaehler says. "It’s a great way to sneak in some abdominal work."

Originally published in MORE magazine, March 2007.
Next: Are You Working Out Hard Enough

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