The swimming happens in an indoor endless pool, and Blahnik said observations revealed that people don’t swim as well as they think they do. It turns out that even when people are pretty regular swimmers, it’s hard to measure a difference between, say, their crawl and breaststroke.

That’s not to say that everyone who comes into this data gym is going to partake in physical activity.

“One day you might show up and we’ll study how many calories you burn while you sit, because we need to understand that, too,” he said.

Blahnik spoke about Apple’s AI gym during a series of demos the company showed off to a small group of reporters in Los Angeles on Tuesday. The demos, presented by Apple itself and several outside developers, showed the Apple Watch’s newest and upcoming health and fitness capabilities—including a feature that wirelessly links the watch directly with a treadmill to track your workout, which will be available in the fall with the release of the new Apple Watch OS, WatchOS 4, and compatible gym equipment.