Biking and swimming are both popular forms of exercise. One fitness studio decided to combine the two.
"I bike, I run, I walk, I do everything," says Diane Morris.
And now the marathon runner is hitting the pool, but not to swim – to aqua cycle.
"You feel like you're peddling under water, you do, because of the resistance. Then you're using your upper body too. The resistance of the water with your upper body, you get a really good workout," says Ms Morris.
The speciality spin bikes are specifically designed for the water. The underwater workout has already made a splash in Europe.
Ester Gauthier saw that popularity and opened the first studio in the US.
It's now slowly creeping into the American exercise market.
Fitness trainers like Edouard Hall who are used to spinning on land, are now jumping into the pool.
"It's a great workout. It's fun for people who are serious about fitness, or just curious. There's such a large demographic of people it can appeal to," says Mr Hall.
"The resistance you get from the water and the hydrostatic pressure of when water is pressing back against you as you move through it makes it more challenging," he says.
For 67-year-old Diane, cross-training with aqua cycling has helped shed centimetres and tone her body even more.