Imagine your gym workout didn’t just fuel your day, but also helped fuel a boat down a river.

Well, this is the idea behind the floating gym, designed by Italian architects Carlo Ratti Associati.

The Paris Navigating Gym will be powered down the Seine River by human energy, as people exercise, according to indy100.com.

The glass bubble design ensures that gym-goers get a good look at the Eiffel Tower as they toil away.

The “human-powered Gym Boat” is 20 metres long, and can hold up to 45 people. It features bikes and cross trainers, and displays realtime information about the Seine’s environmental condition