Tracy Anderson left her Indiana hometown at 18 with dreams of becoming a ballet dancer in New York.
The dancing career never panned out, but after more than two decades of work, Anderson has established herself as a prominent fitness trainer to the stars.
The pint-sized training guru now presides over a fitness empire worth $35 million, and counts Jennifer Lopez, Gwyneth Paltrow and Kim Kardashian as clients.
Despite her success, Anderson doesn't think of herself as an entrepreneur -- she just wanted her students to get fitter and feel better.
"I didn't set out to start a business first," she said. "I want to help people, and I want to create tools to help people."
Anderson's tools include more than 170 fitness DVDs and five gyms in New York and Los Angeles, with three more on the way.
Her business stretches into retail too, with lines of sportswear and exercise equipment. A new line of nutritional bars and supplements is to be sold at retail giant Target (TGT).
Related: America's fitness heavyweights want you
Anderson traces the roots of her business to a time when she was struggling to stay in shape for ballet.
"I had a lot of talent, I was in a school for dance, [but] my body was not that of a dancer and I couldn't get it there," she recalled.
Anderson was inspired by a doctor who was treating her ex-husband, a professional basketball player, for back problems. The doctor's research involved strengthening small muscle groups to ease the strain on larger ones.
From there, it took her four years to develop the "Tracy Anderson Method," which focuses on fitness movements, instead of traditional resistance weight training.
It's a training program that has been criticized by some fitness experts as unscientific.
But as word of the high intensity workouts spread, stars like Madonna and Paltrow started knocking on Anderson's door.
"There was a huge hole in the fitness industry when I came into it," Anderson said. "It hadn't been changed for many, many years, and it was very focused on just working the large muscles."
Related: On the road and eating badly
Anderson is now devoted to training the masses, but she still works with a number of stars. Paltrow has even appeared in some of Anderson's DVDs.
"I feel really blessed that she's trusted me for 10 years with designing her muscles," Anderson said of the movie star.
And when it comes to running a successful business, Anderson's advice is to know your passion and not waste time on anything else.
"Don't stay in a business that you don't 100% believe in," she said.
