The best 3 core exercises for perfect abs.

We all want a toned, flat stomach. No surprise there. But since many women are still relying on crunches to get it, we want to make one thing clear: Crunching is not the most effective abs workout. "Crunches work only the muscles on the front and sides of your abdomen, but it's important to target all the muscles of the core to get more defined abs—including lower back, hips, and upper thighs," says Lou Schuler, co-author of The New Rules of Lifting for Abs.

Here's the best 3 core exercises you've never done, and they'll reveal the abs you never knew you had.

1- KETTLEBELL PULLOVER:

HOW TO DO IT: Lie on your back and raise your legs. Bend your knees 90 degrees and spread them apart while keeping the bottoms of your feet together. Lift a kettlebell straight above your head, holding the sides of the handle in both hands. Lower the weight behind you, stopping a foot off the floor. Hold for 30 seconds, and lift it back above your head. That's 1 rep. Do 5.

WHY IT WORKS: "Pulling things overhead while lying on your back is what you did when you were a baby," says Hartman. "It's a natural movement that perfectly aligns your extremities and loads your trunk, activating and strengthening your core."

2- PLANK CABLE ROW:

HOW TO DO IT: Attach a handle to the low pulley of a cable station and face it in a plank position, resting your weight on your forearms. Grab the handle in your right hand with your arm outstretched. This is the starting position. Pull the handle toward your right side, stopping when your elbow touches your ribs. Return to the starting position. Do 3 sets of 10 reps per arm.

WHY IT WORKS: "Pulling weight toward you in a plank engages your lats, abs, and obliques," says Tony Gentilcore, C.S.C.S., a trainer at Cressey Performance in Massachusetts. "That not only rocks your core and boosts torso stability but also helps you build a better-looking back."

3-  HALF-KNEELING VERTICAL PALLOF PRESS:

HOW TO DO IT: Attach a triceps rope to a cable machine and turn away from it while holding the ends of the rope in your hands on either side of your head. Drop into the bottom position of a lunge, with your front knee bent 90 degrees and your rear knee touching the floor. Brace your core and press the ends of the rope overhead until your arms are fully extended. Pause, and lower them. Do 3 sets of 8 reps.

WHY IT WORKS: "This move forces your abs to battle against the backward pull of the weight stack," says Gentilcore. "That's a new stimulus for most guys, making it a good core builder that also smokes your shoulders."