As one of the most recognizable names in ultrarunning, Jim Walmsley continues to redefine what it means to train with intention and precision—even in the heart of winter. With an eye on three major races in 2025, including Western States and the World Long Trail Championships, Walmsley sat down with us to talk about how he’s leveraging technology, dialing in perceived effort, and staying grounded between Flagstaff and France.
What’s new in your training — any changes in tech or workout types?
This training block during winter, I have really leaned into using the Wahoo KICKR RUN Treadmill. I’m trying to recalibrate my perceived efforts and feelings on the treadmill to use throughout this year. I’ve created a spreadsheet with gradient-adjusted paces for varying grades and speeds to run on the treadmill. This allows me to make up a threshold workout and plug in all sorts of variety with controlled grades and paces uphill.
What are you training for in 2025?
In 2025, my first goal race is the Chianti 125km race on March 22. This should allow for enough time to recover and start a new block towards Western States 100 mile at the end of June. Then Jess and I are looking to head back to Arêches-Beaufort, France, to start more training in the mountains towards the World Long Trail Championships in September. Those three races are my goal races for the year.
Is there a product playing a key role in your training this year?
I’ve started using the Wahoo TRACKR HEART RATE strap in October or November of 2024. This has been a really big game changer for me because it’s made the readings of my heart rate data a lot more reliable and now usable information for me to make training adjustments based off of. It’s also provided consistency in heart rate data across using my RIVAL watch or running without a watch on the treadmill.
Since you have spent most of the past 6 months in the U.S., what do you miss most about living and training in France?
Life in Arêches is slower and simple. There is a bit less for us to do day-to-day, so it makes for a slower pace of life than in Flagstaff. I’m kind of an old soul in that regard and enjoy a slow pace of life to enjoy the small events throughout the day.
Winner of the Chianti Ultra Trail 125km 🎉🎉🎉
Jim’s 2025 season is off to a dominant start. On March 22, he claimed a commanding victory at the Chianti Ultra Trail 125km in Tuscany, finishing in 9:59:48—nearly 30 minutes ahead of his closest rivals. Battling heavy rain, relentless hills, and some of the world’s best trail runners, Walmsley pulled away after the midway point and ran solo through the back half of the course. The muddy conditions made for a brutal day, but his performance confirmed what months of structured treadmill work and dialed-in training had been building toward: he’s back in top form.
Fresh off this win, Walmsley now sets his sights on Western States 100 in June, followed by a summer return to Arêches-Beaufort, France, to prepare for the World Long Trail Championships. From smart tech like the Wahoo TRACKR to carefully crafted threshold workouts on the KICKR RUN, his early-season prep has paid off in a big way—and the best may be yet to come.
