Words by Robert Birnbaum. Photography by Adrian Pirlet.

My weekly encounters with Antoine Charvolin are set in the homey annex of the On Lab in Zurich, where he and the testing crew investigate the latest prototypes down to the smallest detail. Almost two years ago, he first invited me to swing by and lend my sample-size feet to what he lovingly calls “the science”. There’s nothing special about my feet. However, they happen to be just the size of Antoine’s prototypes.

I had just joined On back then and so did Antoine. Well, at least in the office. Antoine had been representing On as a talented trail athlete for two years before that point. But if you just met him by the water cooler, you wouldn’t have guessed. Sure, he has the wiry build that allows him to pace up the steepest inclines with the ease of a mountain goat. Physiology aside, you wouldn’t think this gently humorous, humble Frenchman sees the podium almost as often as the office. 

Antoine doesn’t see his role as an On testing specialist as an extension of his sponsorship. What makes him a celebrity around the office isn't his athletic status but his infectious personality, drive and wisdom. He comes in, rolls up his sleeves and does the work like the rest of the team. Lunchtime is for training and refueling with characteristic smooth efficiency.

He makes it look easy but balancing pro-level training while working full time is a fine art. How does one find equilibrium – and excel – across both? How does one even become a pro trail runner to begin with? To get to know Antoine better, I tagged along for a day in his (athlete) life. Or at least for as long as I could keep up. Because trust me, the calmness Antoine exudes in his day job disappears as soon as he sets foot on the trail. Just like that moment when he disappeared behind a ridge that I wasn’t going to reach for another twenty minutes. Every now and then, I would find Antoine waiting by the side of the trail, grinning ear-to-ear as I pulled out my phone, drenched hands searching my notes, audibly struggling to go through the questions. He made me work for every single answer. But they were worth it.

“Growing up close to the French Alps in Grenoble, France, I always did something in the mountains. I started skiing at two or three-years-old. Or I went camping with my grandparents. There was always something,” he recalls in his distinctive French accent. In High School, Antoine began competing in cross-country skiing. It was through his skiing coach that Antoine discovered his passion (and talent) for trail running. 

Back then, Antoine – who embodies youthful energy like Bambi from the old Disney cartoons – split his time between the trails and a degree in mechanical engineering.  “Even before I went to school, my grandpa and I would build these small, wooden planes. I loved the planning. But also the tinkering, the actual building.”  After graduating, he had to decide whether to dedicate his life to the sport, or to start working as an engineer. And for a short period of time, it seemed like Antoine would choose the latter.

“I was doing a bit of work as an engineer and thought to myself, ‘Wow, that’s not what I really enjoy in life’. I enjoy the training, the running and improving, stuff like that. But after talking to other professional runners, it became clear to me that I don’t want to be just an athlete either.”

Antoine’s natural fit in the sports industry and his previous connection to On led him to Zurich – the home of On – to join the testing team. All the while, pursuing his passion of achieving as a pro trail runner.

Zurich, 2021

“The initial plan for me was to start in the testing team and then switch to the product development side. It turns out I enjoy my current work so much that I never made that switch. The testing team acts as the bridge between the consumer and the development team. But we don’t just take feedback and pass it on. We’re part of each product’s development. We find potential issues and work on the solutions.”

To find weak spots in new prototypes, Antoine calls upon his rich arsenal of internal and external testers – welcoming them into the testing space with chocolate and banana bread. Every now and then, he also hosts his infamous group test runs on our local Uetliberg mountain – the training ground he’s gotten to know best since moving to Zurich.

“I’ve collected some local legend Strava segments on Uetliberg, but there still are some trails that I’ve yet to explore. I still get lost sometimes.”

Even in his work, it seems like Antoine can’t keep his soles off the trails. Although a master of this balancing act, he’s aware that athletes who commit all their time to the sport can train more and recover quicker. A disadvantage? In some ways, yes. But Antoine sees the plus side.

“I knew that a full-time job would complicate the running part of my life. And it was challenging at times. Today, I don’t see it as a disadvantage, quite the opposite, actually. I might have less time to train. I might not be able to compete as often. But I don’t depend on race results to put food on the table. I show up on race day without any pressure to make the podium. For me, the start of a race signals ‘party time’. Just enjoying the time in the mountains with fierce competitors who have become good friends over the years. Training is 99 percent of your time, and it can be grueling. So the one percent that races represent should be as much fun as possible.”

It seems like Antoine’s discovered the sweet spot. He reaps the benefits of being a pro athlete, while enjoying the rewards of working alongside his testing team. He also retains more freedom to choose his races, mainly in the interest of sustainability.

“Loving the environment comes naturally with being a trail runner. If I was inside playing chess or video games, maybe I wouldn’t know the importance of protecting this beautiful world.” 

How does Antoine make sustainable choices? 

“A big part of your impact is the food you consume, so I largely avoid meat. Another part is the transport, especially if you take a plane or drive in a car by yourself. As athletes, we naturally strive to compete with the best in the world. But flying to the US for a race? The carbon emissions tied to that are just not worth it for me. Even in Switzerland there are countless trail races and I’m far from being the best here. So I choose to stay local for my competitions. Last year alone, I declined four race invitations because of the traveling required.”

Chamonix, 2023

Just a train ride away: the Marathon du Mont-Blanc is set in the dramatic landscape of Chamonix, France. Not only was this Antoine’s first ever trail race, but also his best race yet. After a surprising top-10 finish in 2022, the 2023 edition marks his key race of the year.

“I have a strong emotional connection to the Marathon du Mont-Blanc. I discovered trail racing there with the Youth Race. Last year, I finished in ninth place over the 42 km distance – my biggest success so far in a stacked field. This year, I’ve set my sights on the 90 km race – my first ultra trail race.” 

Recently, Antoine embarked on his first ultra challenge to discover what running for over 10-hours straight feels like. With a small film crew and his closest friends in tow, he set out to explore the route he’ll run at the race. 

“Running for that long is a physical challenge for sure, but it becomes a mental challenge too. You’re out there with only yourself and your thoughts. I’ve raced over the marathon distance for two years now. It was time to discover something else and I knew it had to be long distance stuff.”

With his races doubling in distance, Antoine’s training has followed suit. Two-hour sessions become four-hour ones. 20-minute intervals turn into 40-minute efforts. Sleep and nutrition follow a similar scheme.

“I feel good about how the preparation has been going. But the difference between training and racing is massive. Nevertheless, I’m quite confident, because I know one thing is sure: I will have a good day in the mountains, surrounded by friends, in a beautiful landscape.”

Nervous? 

“Yes, because so much of it is unknown to me. But I mainly feel excitement. And I plan to stay with ultra distances for the near future, no matter how the race goes. I simply enjoy the process so much, no matter if it ends up going well or not so well. If not, I’ll obviously have to try and improve.”

As we ventured back into the valley below Federispitz – one of Antoine’s favorite spots – I had discovered much more than my physical limitations. Despite working with Antoine regularly over the past two years, on our run I’ve been introduced to many other sides of him: his love for the environment, for shared adventures and for stroopwafel cookies (his go-to train snack). 

A relentless speed demon on the trails. A savvy testing specialist in the office. And calm, yet jovial presence everywhere he goes. This is Antoine Charvolin, our ‘little mountain goat’.