THIS is the woman responsible for Madonna's arms.
Tracy Anderson pulls down on resistant elastic bands strung across the ceiling; dances around the room; endlessly circles her arms. She moves her torso back and forth and sideways to strengthen the abdominals, and then lies on her -- of course -- taut belly for a series of butt-toning leg lifts.
To spend an hour working out with Ms. Anderson, with an iPod blasting and the heat cranked up, is to get a taste of what it's like to prepare for a grueling concert tour, striving for that sinewy muscle tone. Or so you can tell yourself. Maybe this is how it feels to sweat like Gwyneth Paltrow, bopping around your blond-wood home gym in the Hamptons, losing the pregnancy pounds with Ms. Anderson's mat exercises and dance routines. "You really are how you move," Ms. Anderson said.