Paul Wright, a smiling, impeccably jacked personal trainer, stared at me from the large screen mounted to the wall. He was waiting for me to start my next set of biceps curls.
The screen was part of a new weight-lifting machine from Tonal, a San Francisco start-up. The system combines software and an interactive LED screen with electromagnetic weights and cables to create an experience that does not rely on plates, barbells and gravity. Tonal had sensed that my last set of curls was too easy, and helpfully — perhaps sadistically — added more weight for the next set.
I grumbled about the weight, but realized Mr. Wright couldn’t hear me any more than Tamilee Webb could hear me griping through a “Buns of Steel” VHS tape in the 1990s. The video of him was a recording, too. But as I grimaced and sweated through the reps, I noticed they were precisely the right level of difficulty. The machine knew my strength better than I did. As I tested the machine in a Tonal office, the company’s chief executive, head of marketing, public relations representative and another trainer eagerly looked on.
The Tonal machine is very cool, I told them — and, at $2,995, very expensive.