In the 1970s and early 1980s, Roy Callender was at the top of the bodybuilding world.

He became Mr. Canada in 1977 and finished third in Mr. Olympia the next year. His success meant he spent a lot of time working out with Arnold Schwarzenegger.

“We trained together before I went to the states,” Callender told CTV News. “We trained together in London, that’s where I picked up all my desire. He had a different mindset.”

At 78 years old, Callender is taking up a new challenge. He’s co-founded a fitness app called RC3.

“We kind of found this blind spot,” Carlos Benfeito, RC3 co-founder, said. “What happens when you’re not with your personal trainer?”

RC3 records your workout and analyzes your movements. The app gives feedback on posture and technique. A personal trainer is then able to look at your activities.

“You get to see every workout that you’ve done and the replays of those workouts, and you see your performance throughout those workouts,” Benfeito said.

Bodybuilder Roy Callender, 78, has developed an app that uses AI to track workouts. (CTV News/Matt Grillo)

The app is free to download, but will eventually cost $50 a month.

Callender says he used to have clients calling him and asking questions about posture and specific exercises.

“I don’t have to worry about the client calling me now,” Callender said. “When they use the app and they mess up, I get a notification. I go in right away. I look for the client, look for the exercise, make the note, post it on the client program page.”