She trained with ChatGPT and ran a 2h43 Marathon Debut

In this Guest Series episode, we sit down with Ronja, a 23-year-old from the canton of Lucerne who came back to Switzerland in 2024 after a football scholarship in the US and started running almost by accident, mostly to clear her head.

Within a year she had won her debut marathon (SwissCityMarathon Lucerne, 2:43:38) off a longest training run of just 26K, and later run 2:38:48 for second at the Zürich Marathon, a U23 Swiss record.

We get into:

• How she actually used ChatGPT to build and adjust her training, and where AI coaching started to get risky
• Her move from self-coaching to a human coach, and then toward more science-based, data-driven training
• Why race fueling is the biggest piece of untapped potential in her running
• The mental side: kinesiology, racing through pain, and running with a smile as a performance tool
• Her road toward the World University Games and an Olympic goal for 2028 or 2032

It's a story about starting late, progressing fast, and the reminder that consistency, rest, and joy matter more than any single heroic session. Whether you coach or race yourself, there's plenty here on the promise and the limits of training with AI.

Follow Ronja: @ronja_hofstetter