Louis Osselaer on HYROX Running Volume and Sled Pull Dominance

For a recent episode of the Rox Lyfe podcast, we sat down with Louis Osselaer, one of Belgium’s top HYROX athletes and a qualifier for the 2026 HYROX World Championships in the Elite 15 Singles, Elite 15 Doubles, and Belgium relay team.

Louis has enjoyed a breakthrough season, progressing from age group world champion to one of the fastest-rising athletes in the Elite 15. Along the way, he’s developed some of the strongest sled pull and lunge stations in the sport, balanced elite-level training with a full-time job, and overcome challenges both on and off the race course…

From Athletics and CrossFit to HYROX

Unlike many Elite 15 athletes, Louis didn’t come from a traditional endurance background. His sporting journey included athletics, javelin throwing, baseball, triathlon ambitions, and six years of CrossFit before eventually committing fully to HYROX.

Although he won his age group at the 2022 HYROX World Championships in Las Vegas, he initially returned to CrossFit before eventually deciding to focus on HYROX.

A back injury ultimately pushed him toward more endurance-focused training, and he quickly realised he enjoyed that style of training far more.

Balancing Elite 15 Competition With a Full-Time Job

While many of the top athletes in HYROX are now training full-time, Louis continues to work as an educator at a boarding school while also coaching athletes online.

Despite those commitments, he regularly trains between 16 and 20 hours per week, with some peak weeks reaching 25 hours.

One thing he believes separates him from many athletes is his flexibility.

“I really like to base my training by feel.”

Rather than forcing sessions when his body isn’t responding, Louis is happy to adjust, reduce volume, or even stop a workout entirely if recovery is needed.

Building One of the Best Sled Pulls in HYROX

Louis recorded the fastest sled pull split in the Elite 15 race in Warsaw and has become known as one of the strongest athletes on the station.

Interestingly, he doesn’t credit that success to traditional strength training.

Instead, he focused on repeated exposure to race-specific work.

” By just doing a lot of sled pull, making sure the mechanics are there, I think you can come a long way.”

Inspired by advice he heard from Jon Wynn, Louis built sessions around combinations of sled work and airbike efforts to simulate race fatigue while maintaining quality movement patterns.

He rarely trained with loads heavier than race weight, preferring instead to become more efficient at competition-specific loads.

The Running Volume Behind His Improvement

One of the biggest changes in Louis’ training has been a significant increase in running volume.

This season he built up to 100-kilometre weeks, although he emphasises that the progression took more than two years and was approached gradually.

“I do think that’s needed, but I also think you should give yourself some time to get there.”

His running is programmed by a specialist coach, while Louis handles his own HYROX-specific and strength work.

Rather than chasing arbitrary mileage targets, he focuses on consistent progression and staying healthy.

“I’d rather lose two or three weeks than lose two or three months.”

Solving Serious Race-Day Digestive Issues

After experiencing significant gastrointestinal problems during competition, he began researching sports nutrition and gut health to identify potential triggers.

Through extensive testing, he discovered that fructose was a major issue during high-intensity racing. He also adjusted his race-week nutrition, simplified food choices, reduced pre-race meal sizes, and refined his fuelling strategy.