It's come from France, it's been to the States, and history dictates it won't be long till it's on these shores - but are you going to try Aqua Cycling?
Already a craze in New York, it's nothing more than a spin class when you're up to your chest in water, but it's billed as having all sorts of health benefits not usually ascribed to cycling.
"Aqua cycling is a marriage between yoga and regular cycling," Esther Gauthier, who created New York's AQUA Studio after exporting the idea from France, told Business Insider.
"It's the intensity of cycling, but then there's something about the water that's so soothing and adds the relaxation of yoga."
Although enthusiasts say the downsides are the bike rocking about as you pedal, and not being able to hear the instructor over the splashing, they reckon it's great for people who usually find it hard to exercise, including the overweight, the pregnant and those who've suffered an injury.
Raynham Athletic Club in Massachusetts also offers the classes, with special rust-proof marine-grade stainless steel bikes.
“There’s less stress on the joints and back,” instructor Kerri Mathieu told the Taunton Gazette.
“Although you’re working really hard, just being in the water is very soothing,” she said.
After an unpromising start, having to be bribed by her parents to learn to ride without stabilisers, Sarah became rather keener on cycling in her university years, and was eventually persuaded to upgrade to proper road cycling by the prospect of a shiny red Italian bike, which she promptly destroyed by trapping a pair of knickers in the rear derailleur. Sarah writes about about cycling every weekend on road.cc.