If you’ve ever found yourself in a quandary over whether to sweat off your extra pounds in spin class or take a few heart-pumping laps through the pool, French entrepreneur Esther Gaultier has the answer to your prayers: aquacycle. It’s exactly what it sounds like — exercise bikes in a swimming pool — and the 31-year-old New York resident is responsible for bringing this fast-growing exercise trend across the Atlantic.

“I discovered aquacycling at the Maison Popincourt” — a chic fitness center and spa — “during a trip to Pairs. I realized that no one was offering it in New York yet,” says Gautier, who came to New York in 2006 to work for a fashion photographer. Interested parties can get in on the action at Gauthier’s Aqua Studio in Tribeca, and she also has plans to open branches in New York and Los Angeles.

And she’s not the only one cashing in on the American aquacycle revolution: Laurent Bouhier, another French entrepreneur has started Aqua Wellness World, a company based in Westchester that supplies equipment for the sport. “We sell aquacycling bikes to pools, hotels and sports clubs and we organize classes on-demand. My wife is an aquacycling teacher. I think that the sport has a lot of growth potential here,” says the expat who, until last year, was promoting aquacycling in the Caribbean.

Gauthier’s Tribeca facility is a small swimming pool filled with specially-deisgned bikes all in a trendy loft space, complete with exposed brick. Each aquacycle class lasts 45 mintues, during which a teacher suggests different movements and rhythms to the pleasant beat of pop music. Participants leave relaxed… and exhausted. “It’s a sport that physical without being high-impact, so it’s excellent for the joints. In New York, people associate intense effort with pain, but you can absolutely exercise without getting hurt and without being sore the next day,” says Gauthier.

In its first 8 months since opening, Aqua Studio has done remarkably well considering that New Yorkers are not particularly hot on water sports. About 6,000 people have tried it out, thanks in no small part to US media coverage of the phenomenon which originated in Italy. “It’s caused a lot of curiosity and we’re beginning to have more and more regular clients,” Gauthier says.

Now that spring has finally arrived, maybe it’s time to dive in and start working that bikini body in your bikini.