The 2025 UTMB is done and dusted, with Ruth Croft and Tom Evans winning via commanding performances. The weather certainly played a factor for many runners and fans enjoyed the numerous dynamic storylines as they unfolded during the 108-mile loop around Mont Blanc!
Before this year’s race, we published an article about some factors around pacing at UTMB. We analyzed past UTMB races and how strategies have shifted over the years, with a particular focus on how top finishers of the 2024 race paced themselves from start to finish.
Ruth Croft, the 2025 UTMB women’s champion. Photo: iRunFar/Eszter Horanyi
This article follows up on the first one by looking at this year’s UTMB pacing through the lens of top runners’ intensity factors and performance drops over the course of the event. We discussed these two terms in our first article in this series, as well as just below. Our goal is to gain insights into athletes’ pacing throughout the race.
As we know, Tom Evans and Ruth Croft both put on absolute masterclass performances, working through the adverse elements to come out on top. Both winners work with the same coach, Scott Johnston, whose training regimen clearly set these athletes up for success at the top level. It is also interesting to note that they both work closely with the same data scientist, Joseph Mestrallet. There are so many variables at play in a 100-mile mountain race, and it is interesting to think about the role of data in better understanding our physical limits and informing strategic decision-making.
Coach Scott Johnston with 2025 UTMB champions Ruth Croft and Tom Evans at the finish line. Photo: iRunFar/Bryon Powell
For this article, we focus on the UTMB event with data pulled from LiveTrail, the event’s live tracking system. We mainly focus on the metrics of effort, intensity factor, and performance drop:
- Effort: A grade-adjusted pace calculation. Gives us a view of what is happening on the ground.
- Intensity factor: The percentage of the maximum one-hour effort the runner is able to deliver based on their race performance. Gives us a view of what is happening inside the runner.
- Performance drop: Change in intensity factor over the course of the race.
Like our first UTMB pacing article last month, we collaborated with Zsolt Kovacs of Spectro.Life on this follow-up article. Spectro works with athletes to develop optimal race strategies based on custom running models. Thanks so much to Zsolt for this collaboration.
Let’s take a look at some of the data from this year’s event!
Maëlle Deruaz on her way to taking fifth at the 2025 UTMB. As we learn in this article, she had the lowest performance drop of all the top finishers, meaning she raced very efficiently. Photo: iRunFar/Eszter Horanyi
Finisher Rate and Performance Drop for All 2025 UTMB Runners
The weather made headlines at this year’s event, with images of runners pushing through adverse conditions. Many of the top contenders had to drop out, but this is something we’ve seen over the past years as the elites go out faster and faster, pushing the limits of what is possible. Looking at the overall numbers, we see the finish rate this year was higher than last year’s.
- 2025 Finisher Rate: 1,665/2,492 runners = 66.8%
- 2024 Finisher Rate: 1,760/2,761 = 63.74%
The U.K.’s Tom Evans climbing over the course high point at Grand Col Ferret in a storm during the 2025 UTMB. Most runners experienced around 12 hours of difficult weather during this year’s race. Photo: iRunFar/Eszter Horanyi
Looking at the average performance drop from 2024 to 2025, we see a small difference and a similar distribution.
- 2025 Performance Drop for All Runners: -50.51%
- 2024 Performance Drop for All Runners: -47.68%
The below graphs show the distribution of performance drops among finishers of UTMB last year and this year. We see that both distributions are uniform with the mean around -50% drop. As we will explore in more detail, many of the top finishers run efficient races with performance drops below -35%.
Performance Drop for all Finishers of the 2024 and 2025 UTMB
The performance drop for all finishers of the 2024 and 2025 UTMB.
This is to say that while the weather was a factor, it was just another in the myriad that exist in the context of a competitive, mountainous ultramarathon.
Camille Bruyas ran strong all of the 2025 UTMB to take second for the second time, following up on her similar 2021 performance. Photo: iRunFar/Bryon Powell
2025 UTMB Top Women’s Pacing
Let’s dive into the women’s race. Shown below is a graph of the effort (grade-adjusted pace calculation) of the top five women’s finishers plus 10th-place Courtney Dauwalter. Dauwalter and Croft both got off to very fast starts, pushing the pace on the first few kilometers and keeping it high into the first mountain climbs and descents. After Courmayeur, around 80k, we can see Croft had the energy and muscular endurance to keep pushing the pace, and ultimately took control of the race around 100k, running on to the win. Dauwalter slowed down significantly around this period but kept going to finish out a gutsy performance. Another notable line from the graph is Maëlle Deruaz, who started off the first few climbs conservatively and went on to finish out strong and claim an impressive top-five finish.
Effort of Top Women From the 2025 UTMB
The effort of selected top women from the 2025 UTMB.
Looking at the intensity factor of the top women, we see another part of the story. Dauwalter was pushing quite a high intensity for the conditions on this given day and could not sustain the effort throughout the race, and she finished with a performance drop of -58.4%. The top four women all started off fast and managed to keep their performance drop in the mid-30s to secure top spots. Deruaz had the lowest performance drop of this group of just -22.8%, putting together an efficient race.
Intensity Factors of Top Women From the 2025 UTMB
The intensity factors of selected top women from the 2025 UTMB.
2025 UTMB Top Men’s Pacing
On the men’s side, we can also look at similar graphs around effort and intensity factor. The notable takeaway from the ultimate winner, Evans, is that he did not let the high pace at the beginning influence his race strategy but kept a comfortable pace throughout so he could finish strong. The spikes on the initial downhills are sixth-place Ludovic Pommeret, who is known for his fast descents. He was going notably faster than other runners, but the efforts may have taken a bit of a toll in the later part of the race.
Effort of Top Men From the 2025 UTMB
The effort of selected top men from the 2025 UTMB.
Looking at the intensity factor of the top finishers, we get a more complete picture of how the runners performed. Evans had a very strong performance throughout the event, starting off comfortably and closing well. Ben Dhiman started off pushing and managed to hold on through to the end in a very impressive outing to take second. All the top men had quite low performance drops, with Pommeret’s being the greatest, perhaps suggesting the early, fast downhills did take a toll during the later stages of the race.
Intensity Factors of Top Men From the 2025 UTMB
The intensity factors of selected top men from the 2025 UTMB.
While some runners went out fast and kept the intensity up to finish at the top, others did not make it and DNFed. Here we plot the top finisher, Evans, with other top contenders who ended up DNFing. We really start to see variation around the 50k mark, with many folks dropping or losing momentum after Courmayeur, around 80k. Courmayeur seemed to be the turning point for many who pushed the pace too fast early on and weren’t able to maintain their effort levels.
Effort of the Top Man and Some Top Men Who DNFed the 2025 UTMB
The effort of the top man and some top men who DNFed the 2025 UTMB.
Conclusions
Having a clear and consistent pacing strategy continues to be the best way to complete these mountain ultra events. Among the top contenders, we often see them pushing up against their limits and not being able to finish out the race. Being well-trained can be a temptation to go out faster, but faster might be too fast to sustain throughout a 100-mile event.
In these races, we see significant performance drops, and figuring out how to limit this drop as much as possible is one key to success. Of course, there are countless factors that go into doing well at UTMB, and we hope that this article sheds some light on the importance of pacing and what it looked like at the 2025 UTMB.
Call for Comments
- Did you notice any interesting pacing strategies at the 2025 UTMB?
- What factors do you think might contribute to the performance drop of these athletes?
Ben Dhiman finishing in second at the 2025 UTMB. Photo: iRunFar/Bryon Powell
