FOUR DNFS AND A COURSE RECORD: HOW UTMB TIMES HAVE EVOLVED

Jim Walmsley arrived in Chamonix for the 2023 UTMB carrying four previous attempts. He had finished 5th in 2017. He had three DNFs after that — ankle injury, flat legs, mechanical suffering. He was the fastest ultra trail runner in the United States and arguably the world, and he could not get this race to cooperate.

On September 1, 2023, Walmsley ran 172 kilometers through France, Italy, and Switzerland in 19 hours, 37 minutes, and 43 seconds. The first American man to win UTMB, the new course record, a time that landed inside the top three fastest performances in the race's 21-year history. Four previous trips. One finish.

The gap between Walmsley's attempts and Walmsley's CR is not just a good story. It is a useful frame for understanding what UTMB is and why the course record progression looks the way it does: not a smooth decline over time, but a series of breakthrough moments separated by years of near-misses, modified courses, and weather-shortened editions.

The Course and Its Variables

UTMB circles Mont Blanc through three countries. The start and finish are in Chamonix, France. The course runs west into France, south into Italy through the Courmayeur section, then north into Switzerland through Champex-Lac and Trient before the long final descent back to Chamonix. Nominal distance: 172 km. Nominal elevation gain: approximately 10,000 meters. Time limit: 46 hours.

The "nominal" qualification matters. Only three times in the race's first ten years did runners complete the full advertised course as planned. Weather reroutes are embedded in UTMB's identity. In 2012 a weather-shortened 104 km edition was run. In 2025 a 2 km section in the Italian leg was cut due to snow and wind. Individual years involve minor variations. Comparing times across editions is, as a result, approximate rather than precise.

The 2003 inaugural course was 153 km. By 2023 it measured 172 km. The CR times span editions of different lengths.

The Men's Record Progression

Kilian Jornet won the first of his four UTMB titles in 2008. He won again in 2009 and 2011, by which point the sport had organized itself around the assumption that he would win any mountain ultra he entered. His 2011 winning time of 20:36:43 set a benchmark for the 170 km course — a race that, as UTMB's full history shows, had evolved dramatically from its 67-finisher inaugural edition just five years earlier.

Xavier Thévenard won in 2013 in 20:34:57 — a marginal improvement. Then François D'Haene arrived.

D'Haene won in 2014 in 20:11:44, erasing 22 minutes from the course record and winning by 45 minutes. He returned in 2017 to run 19:01:32 — a run that, if measured on the full official course, would be the fastest UTMB time in history. The discrepancy requires a note: UTMB records from years with route modifications are complex, and the official CR timeline does not consistently reflect D'Haene's 2017 time as the standing record. What is clear is that D'Haene ran approximately 19:01 that day and that no man ran faster in race history until 2025.

Jornet returned in 2022 — his fourth UTMB win, 14 years after the first — and ran 19:49:30 with COVID-19 contracted days before the race. The 2022 results article noted his run as breaking D'Haene's 2014 mark of 20:11:44, the discrepancy suggesting the 2017 run's record status was treated differently at the time.

Walmsley's 2023 CR of 19:37:43 is the current men's record on the official 172 km course. Tom Evans ran 19:18:58 at the 2025 edition on a course shortened by approximately 2 km due to Italian section conditions. That time is not treated as an official course record.

The Women's Record Progression

Krissy Moehl won the inaugural 2003 edition in 29:38 on the 153 km course. She returned in 2009 and won in 24:56 on the extended course — nearly five hours faster on a distance that had grown by 10 km. Both improvements reflect the combination of longer courses and faster runners.

Rory Bosio ran the most dramatic single performance in UTMB women's history at the 2013 edition. She covered the full course in 22:37:26 — erasing the previous record by approximately two hours and 20 minutes, and finishing 7th overall, ahead of the majority of the men's field. Bosio defended her title in 2014 but ran 23:23:20, slower than her own record.

Lizzy Hawker won five UTMB titles between 2005 and 2012, setting the standard for women's ultra trail performance in Europe before Bosio. Her 2011 winning time of 25:02:00 illustrates how dramatically the women's record has compressed — from 25 hours to 22 hours — over the following decade.

Courtney Dauwalter broke Bosio's record in 2021, running 22:30:54 on a course three kilometers longer than what Bosio had run in 2013. She won again in 2023 in 23:29:14, the third leg of her "Triple Crown" summer (Western States 100, Hardrock 100, UTMB) — the most concentrated run of ultra trail victories in modern history, though her 2023 UTMB time did not improve the record.

Katie Schide of the United States ran 22:09:31 at the 2024 edition — 21 minutes faster than Dauwalter's 2021 record. Schide's run is the current women's course record.

Why the Records Are Falling

UTMB records have declined faster in the past five years than in the prior fifteen, and the causes are the same as those reshaping road marathon times: better shoes, better fueling, and a deeper global talent pool.

Carbon-plated trail shoes arrived in meaningful form around 2022. HOKA introduced the Tecton X that year, the first major carbon-plate trail shoe designed specifically for the mixed terrain UTMB involves. Walmsley ran in an early version when he set the 2023 CR. Every major brand followed with their own carbon trail platform. The efficiency gains on soft and technical mountain terrain are smaller than on road surfaces, but they compound over 170 kilometers.

High-carbohydrate nutrition strategies — developed primarily in road marathon preparation — have transferred to ultra trail racing, enabling runners to maintain higher intensities across longer efforts. UTMB winners of 2023 and 2024 trained and fueled on protocols that did not exist in the field a decade earlier.

The competitive depth has also expanded. UTMB now draws the best ultra trail runners from across the Americas, Oceania, and East Africa in addition to the European base that originally defined the field. Schide and Walmsley are both Americans. The 2024 men's winner Vincent Bouillard is French. The 2025 men's winner Tom Evans is British. The winner list over the last five years shows no single nationality dominating.

The Walmsley Frame

The Walmsley story is the clearest illustration of what the course demands. He was not short of fitness across his four failed attempts — he was running the fastest 100-mile times in North America, setting course records at Western States. UTMB is not simply a test of running ability. It tests the intersection of fitness, mountain running skill, nutrition execution, and weather luck across 19 to 22 hours. Walmsley had the fitness in 2017. He ran the race wrong. In 2018 he was injured. In 2021 he had the wrong legs on the wrong day.

In 2023 everything aligned. His 19:37:43 was the product of a race executed correctly, on a day when the conditions cooperated, after enough failed attempts to understand what the course required.

That combination — not just ability, but accumulated understanding — is what makes UTMB course records rare and what makes them meaningful when they come.