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Here's a direct route to the oblique muscles. "They're the stabilizers of your torso," Greene says. "Strong obliques ensure good posture, and they allow the rest of your workout to be more effective." Oprah is enthusiastic about this move.
"The thing about each one of these exercises," she says, "is that the more you do them, the better you get. It's quite an accomplishment to see and feel your body getting stronger. You'll start to notice a difference after about three weeks."