Fitness doesn't have to be about hauling weights and pounding treadmills.

Instead of grunting and aching their bodies into shape, some happy souls strengthen the core by tripping the light fantastic. And many experts believe that the current craze for all things dance is fueled by television.

"I definitely think that 'Dancing with the Stars,' 'So You Think You Should Dance,' etc., have had a huge impact on the dance world," Ginny Nicholson, who manages Triangulo, a New York City studio devoted to Argentine tango, said of the popular realty TV shows.

"The tango scene in New York City has grown from a few milongas (tango parties) a week ... to at least two milongas on any given night," she said in an interview.

Tango is not the only dance craze on the upswing, according to Patricia Klausner, spokeswoman for Steps on Broadway, which offers instruction in everything from ballet to jazz to hip hop.

"I think reality TV shows have sparked a great interest in and fascination for dance," she said. "Some of the dancers and choreographers on 'So You Think You Can Dance' have trained and taught here."

Steps, a New York institution, has been instructing all levels of amateurs and professionals since 1979. But Klausner said beginner enrollment has been particularly strong of late.

Along with TV, Marc Santa Maria of Crunch, a nationwide chain of health clubs, credits the Internet, specifically YouTube and Facebook, with broadening cultural, and therefore dance, horizons.

"What has increased is more diversity in dance," Santa Maria, Group Fitness Director for the fitness chain, which claims 100,000 members, explained.

"People are definitely more open to styles that may not have been as common in fitness a few years ago."

This season dance classes at Crunch range from barre and jazz to something called Cardiac Go Go, a Los Angeles invention inspired by the white-booted go-go girls of the 1960's.

Another, dubbed Rock of Ages, fuses traditional musical theater dance with pole dancing and rock music.

And Masala Bangra, billed as "the traditional Indian dance workout set to hip-hop, disco, salsa, techno, house and rap music" has gained numbers thanks to the soundtrack from the Academy Award winning film "Slumdog Millionaire," Santa Maria said.

"Everyone wants to have fun, and dance is freeing and a great release," he said. "It is also highly social and folks love that-especially when things like the economy are bringing people down."

Santa Maria, who trained as a dancer, says it's a great workout: "You engage all muscle groups and can really push the cardio," he said.

Klausner agrees: "Dance is a great way to get into shape, stay in shape. Muscles stay long and lean rather than bulky. Besides that, dance helps with posture and grace as well as self-confidence."

So why doesn't everyone do it?

"The biggest barrier for beginners is fear of being judged by others and/or failing," Klausner said. "(Truth is) that no one in class cares. They are so busy dealing with their own challenges."

Indeed, as no less a purveyor of self-consciousness than Irish playwright Samuel Beckett advised: "Dance first. Think later. It's the natural order."

Or as Fred crooned to Ginger, "Hea-ven."