Paris-based personal trainer Stéphane Demouy has had a shape-shifting career that spans tennis, boxing, academia and entrepreneurship.

But if you ask him what keeps his clientele coming back — which, a quick scroll through his Instagram would reveal, ranges from Cindy Bruna and Izabel Goulart to Christina Milian and Luke Evans — he would say it’s his multidisciplinary point of view.

“The difference is my methodology,” Demouy says. “I have a diploma in sport, I do a check-up to understand how your body functions and how I can do your program, and I can use exercises that are special for you. Then, I have the result.”

Demouy, who started his professional career as a tennis pro — ranked fourth in France at the time, according to the trainer — went on to open a boxing gym after an injury sidelined him. From there, he went back to school, and has been a personal trainer ever since.

“The way he trains you is also following you every step of the way,” Bruna says. “It’s not just that you’re here for an hour and then it’s gone. He checks what you eat, he makes sure everything is aligned with what’s happening in your life. He will adapt the workout based on how I’m feeling and what’s going on. I’ve been with him for years and I’ve seen so much improvement.”

The model also finds the community-centric approach to his gym a key differentiator. “It’s not just a workout, it’s a vibe and a community,” she says. “For example, we just had Galette des Rois [king cake] together. We all know each other, and it’s such a good vibe.”

Demouy also has a concept gym in Cannes, France, though he’s looking to expand even further. “It’s called Voyagym,” Demouy says of the gym-on-the-go experience he’s piloting in mid-February. “That way, we can take the gym everywhere we travel.”

That entails travel equipment as well as a digital library of workout videos following Demouy’s program. “When you flash the QR code, you arrive on my platform, and you have 200 videos with different explanations, different parts of the body that you want to work [on], and if you want help with nutrition you can find that too,” he says. “It’s the future. We hear everyday about longevity, but for me, the secret is regularity, progress and intelligent methodology.”