When Erin Arbuckle takes ballet class wearing her New York City Marathon shirt, teachers often ask her, "You didn't actually run that, did you?" She did, twice, and she's running again this year on November 5.

Arbuckle, 28, a graduate of School of American Ballet and a freelance dancer who has performed with Ballet Next and Emery LeCrone Dance among others, is a rare ballerina who not only runs but has taken on the challenge of a marathon.

"If I can run 26 miles, I can handle a two-minute variation," she says.

Ballet dancers are taught to save their bodies for dance and avoid injury from other activities. While low-impact cross-training like swimming is encouraged, running is generally considered too high impact.

"I was told it would give me huge calves and thighs and damage my knees," Arbuckle says.

Her two foot surgeries were from dance injuries though, not running, and her body is holding up well despite what she was told to expect.

Marika Molnar, director of physical therapy at New York City Ballet, generally advises dancers to run only as a warm up. "Running for 5 to 10 minutes before ballet class to move the large muscles of the body is useful," she said. "Beyond that, you start to have risks."