From Devastating Back Injury at 17 to Going Pro at 32: Nina Derron's Triathlon Journey

This time on the podcast we sat down with Nina Derron, a professional triathlete from Switzerland who began her triathlon career at age 5, became Swiss Junior Champion in triathlon, duathlon, and the 10km road race, and then spent nearly three years away from the sport due to chronic back pain. She completed a PhD in Clinical Science from ETH Zurich while competing, and in 2025, at age 32, she qualified for the Ironman World Championship in Kona by finishing third at Ironman New Zealand.

We wanted to understand what it looks like to take a path this non-linear in professional sport, and what she learned along the way.

What she shared was candid and practical. Not a highlight reel, but a real account of injury, identity, recovery, and the decision to finally go all-in.

Below are some of the key things Nina shared with us during this conversation.

The back injury that changed everything

At 17, Nina was on a clear trajectory toward elite triathlon. Then a sharp back pain after a 10km race started a cycle that lasted almost three years. No clear diagnosis. Doctor after doctor. Physiotherapy that didn’t work. At one point, she was told to stop all movement entirely and was put on heavy pain medication.

“I kind of lost the dream to chase triathlon. My main hope was that someday my back pain would just be gone.”

She eventually took a gap year, started studying at ETH Zurich, tried alternative treatments, and slowly the pain faded. She started training again, not with professional goals in mind, but because swimming, running, and biking were simply what she had always known.

Bone density and what young athletes should know

Looking back, Nina believes a combination of factors contributed to her injury: the pressure of finishing high school alongside heavy training loads, and a genetic predisposition to low bone density that she and her sisters only discovered later.

All three Derron sisters were found to have lower than normal bone density. Nina’s recommendation is straightforward: get a DEXA scan early, especially if you are a young female endurance athlete. Her middle sister Michelle had the most significant issues, but the diagnosis and subsequent treatment helped all of them.

“The younger you can do something about it, the better.”

This is something we hear regularly on this podcast and it is worth repeating. Finding a doctor who understands endurance sports is not always easy, but it makes a real difference.

Training without data: Brett Sutton’s approach

Nina trains with the Trisutto squad under Brett Sutton, who also coaches the Chinese national triathlon team. The structure is unconventional by modern standards. Sessions are communicated day by day. Athletes rarely know what the next day holds until it arrives. And data plays a very small role.

The effort scale they use is simple: easy, moderate, medium, and mad. No power targets. No strict pace zones. Nina has a power meter on her bike but barely looks at it during sessions.

“It takes a lot of the stress about numbers away. Maybe your moderate is different on a day where you’re tired versus a day where you feel fresh. As long as you get your effort right, it’s still a successful session.”

She is clear that this approach is not for everyone. Some athletes need numbers to feel confident or to execute sessions correctly. But for her, training by feel has worked well, and the absence of data during sessions was a welcome contrast to the data-heavy nature of her PhD research.

Going full-time at 32

Nina completed her PhD while competing, running what she describes as a 70% academic workload alongside training. It was manageable, but left little room for anything else.

The decision to go fully professional came after watching her youngest sister Julie make the same shift and seeing the difference it made. She also felt that if she did not try it now, she never would.

“I’m 32. I won’t be doing this forever. If I don’t do it now, I might regret it.”

Her first full season as a professional yielded a podium at Ironman New Zealand, a Kona qualification, and a race win at Challenge Gdansk. She describes the win in particular as something different from a podium. She had not won a race in a very long time and it reminded her what that feeling is like.

Listen to the Full Episode

There is more in the full conversation that we did not cover here:

Growing up racing alongside her sisters and how the sibling dynamic shifted over the years
How the Derron family got into triathlon together
Nina’s pre-race routines and race day nutrition adjustments for long distance
What it was like racing against the Chinese national team athletes in training
Her thoughts on the Swiss sports culture and professional athletics

🎧 Listen on Spotify or Apple Podcasts

Connect with Nina

Instagram: @nina_derron

Connect with us

Instagram: @justbrunathings | @endurance_fabi

Coaching: www.jornadaendurance.com

Startup: www.augotraining.com