Standing Core Rotation

Don't let the pics fool you; this exercise is way more challenging than it looks, hitting the transverse abdominis and obliques to a degree that you'll be hard-pressed to achieve with other moves, she says.

How to do it: Attach a handle to a cable station* (or firmly tie a resistance band around a sturdy object) at sternum-height from a standing position. Holding the handle with both hands, with your arms fully extended in front of your body, take a few steps back from the station until you feel tension in the cable. Still holding the handle in the same position, make a quarter-turn away from the station to the right, with feet hip-width apart and knees slightly bent; this is your starting position. (The cable should be pulling your arms, still extended, slightly toward the station.) Squeeze your core and rotate your torso away from the station. Pause for one second, then slowly reverse the movement to return to the starting position. That's one rep. Do 12 to 15 reps, then repeat on the opposite side, making a quarter-turn away from the station to the left to start. Perform two to three sets.

*The cable station weight should be enough to allow you to just squeeze out your last rep with proper form.