Ultra du Saint Jacques 2026: Building Your Race Strategy with Segly

134 km, 6,022 m of positive elevation gain, an evening start from Saugues and a finish in full sunshine at Le Puy-en-Velay: the Ultra du Saint Jacques 100M 2026 is one of the most committing ultra-trails on the UTMB calendar. On Friday 12 June at 19:10, several hundred runners will set off into the Auvergne night to reach this legendary cathedral. Here's how to build a race strategy to finish in 25h05 — and how you can customise this plan for your own goals.

Understanding the course before building your strategy

The Ultra du Saint Jacques is above all an exceptional course. With 6,022 m of positive elevation and 6,335 m of negative over 134.85 km (Segly data), the profile is as technical as it is demanding. But what makes this race truly unique is the combination of three factors:

• The evening start: setting off at 19:10 from Saugues, the first 60 km are run in darkness, which calls for a different effort management and heightened vigilance on technical sections.
• The variety of segments: the course alternates between long rolling sections (S1, 24 km almost flat), dry, steep climbs (S5, +5.0% average gradient over 6.5 km) and long descents towards the valley (S2, −2.6% over 15 km).
• The late-afternoon finish: for a 25-hour goal, you reach Le Puy-en-Velay on Saturday at around 20:15 — after a full night and a full day of racing.

The Segly breakdown reveals a course in three main phases: a first, relatively rolling night section (S1→S2), a sustained, progressive climb through the massif (S3→S7), then a gradual return to the valley to the finish (S8→S11). Knowing these phases in advance changes everything about effort management.

How I built my race plan with Segly

By importing the GPX file of the Ultra du Saint Jacques 100M into Segly, the app automatically analyses the course and proposes a split into segments that takes elevation and gradient into account. I kept a split into 11 segments, aligned with the official aid stations and life bases.

The goal: 25 hours

25h05, an average speed of 5.42 km/h — that's the target chosen. Realistic for a very well-trained runner in ultra distances, it leaves a comfortable margin before the maximum allowed time of 30h50. It's also a goal you can adapt: by customising the Segly analysis, you can target 22 hours, 28 hours or any other value.

The fatigue factor at 15%

This is Segly's central concept. The fatigue factor measures the degradation of your speed between the first and second half of the race. Here, 15% means you'll run 15% faster in the first half than in the second. It's not pessimism — it's clear-headedness.

The data confirms it: winners of major ultras such as the UTMB typically show a fatigue factor of 10 to 15%. Planning too low a factor often means starting too fast and collapsing in the final segments. With 15%, you absorb the night, the afternoon heat and the muscular fatigue of the last 40 kilometres.

The key segments to watch

Not all segments are equal. Here are the 3 sections that will make or break your race:

S3 — Prades → Monistrol (km 40 → 54): the muscular wake-up call

996 m of positive elevation over 14.56 km. It's the most elevation-heavy segment of the entire race — and it arrives between 2 and 5 a.m. Climbing this at night, with the fatigue of the first third already accumulated, demands real pace discipline. Walk the climb, run the flats: this is often where the second half of the race is decided.

S5 — Saint Privat → Saint Jean Lachalm (km 63 → 70): the steepest

+5.0% average gradient over 6.53 km with 668 m of D+ and sections at 50% — the most demanding segment in terms of gradient. Estimated at 1h31, this stretch is run at dawn (Saint Jean Lachalm around 08:12). The body is in full transition between night and day: an ideal moment to eat, drink and manage pace by instinct.

S7 — Alleyras → Lac du Bouchet (km 81 → 97): the decisive segment

15.42 km, 825 m of D+, +3.0% average gradient — almost 3 hours of effort between 10:27 and 13:26. This is the middle of the day, potentially the heat. It's also the moment when your legs already have 80 km in them. This segment is the real test: if you reach Lac du Bouchet (life base, km 97) on time, the finish is within reach.

Split times to finish the Ultra du Saint Jacques in 25h

Here is the complete race plan for a 25h05 goal, starting from Saugues on Friday 12 June 2026 at 19:10. This table is the ideal communication tool with your crew — if you reach Monistrol 30 minutes late at 05:20, the signal is clear.

Build your own race strategy

The full analysis of the Ultra du Saint Jacques 100M — the 11 segments, the 15% fatigue factor, the 25-hour goal — is available directly here:

See the Segly analysis for the Ultra du Saint Jacques — 25-hour goal →

This link gives you access to the full strategy in read-only mode. By clicking "Customise the analysis", you can:

• Change your time goal (20h, 22h, 27h...)
• Adjust the fatigue factor to your level (10% for a very strong runner, 20–25% for a first ultra)
• Adapt the times of each segment based on your knowledge of the terrain
• Export your plan as a PDF and share your personalised link with your crew

The GPX analysis is completely free on segly.vo2run.app. No account required. 10 minutes of preparation for hours of peace of mind on race day.

Conclusion

The Ultra du Saint Jacques 100M 2026 is 134 km and 6,000 m of elevation between Saugues and Le Puy-en-Velay — an adventure that only good preparation can turn into success. A serious ultra-trail race plan, realistic split times, a well-informed crew: the ingredients are simple, but they make all the difference when your legs start to feel heavy between Bains and the Dolaizon.

On Friday 12 June 2026 at 19:10, the headlamps will switch on in Saugues. In 25 hours (or a little more), the cathedral of Le Puy-en-Velay awaits you. Build your plan, share it with your team, and run with confidence.