Euskal Trail 130 — Segly vs the Clock: 17 Checkpoints, 3 Phases, 2-Minute Gap

20 hours and 57 minutes. That's how long it took me to complete the Euskal Trail 130 — 128 km and 7,500 m of elevation gain in the mountains of the Basque Country. And what struck me most at the finish wasn't the exhaustion, nor the pride of a top-20 overall placing. It was that number: a 2-minute gap with the Segly plan.

Before the start, I had built a full strategy on Segly — 15 segments split manually, fatigue factor set at 15%, Plan A target of 21 hours. The app had predicted 20h59. I crossed the line at 20h57.

Over 21 hours of effort, 7,500 metres of climbing, 17 official checkpoints — a 2-minute gap. That's not luck. It's what proper preparation based on GPX analysis makes possible. But beyond the final result, the race told me a much more interesting story: a first half with a progressively growing lead, a second half that ate into that cushion, and a finish line reached exactly on plan. In this article, I break down the 17 checkpoints one by one, the 3 phases of the race, and what the data reveals about my actual fatigue factor.

The Euskal Trail 130: a race with character

The EuskalTrail doesn't mess around. The course winds through the Basque Country — committed passes, ridges exposed to the wind, technical descents that eat up the quadriceps. Over 128 km and 7,500 m of positive elevation between France and Spain, the course never really lets up: climbs follow one another without respite, and descents demand concentration and caution.

The 2026 edition, held on 15 May, gave us capricious weather — humidity and cool temperatures — with even snow on the summits, enough to heighten the adventure of an ultra. Difficult but manageable conditions, which allowed me to focus on race strategy while managing temperature.

The start was at 5 a.m., in the dark, in the rain. The first kilometres cross very damp forest areas before tackling the first Basque ridges (Iparla).
17 checkpoints, each a milestone for measuring the gap between plan and reality in ultra-trail split times. 18th overall with an average speed of 6.36 km/h — that's the raw result. But the numbers behind that result are far more telling than the ranking alone.

Preparing my ultra-trail with Segly

Five days before the start, I published an article detailing how I built my strategy on Segly: GPX import, split into 15 segments, fatigue factor calibration. I refer you to that article for the full methodology.

In short: I had gone for the Plan A at 21 hours, with a fatigue factor of 15%. That figure meant I planned to run the second half of the race 15% slower than the first — not pessimism, but a clear-headed recognition of the reality of ultra-trail. Segly gave me a forecast time of 20h59. I had also prepared a Plan B at 23 hours, shared with my crew through the app's read-only share link. On 15 May, at 5:00, I started the stopwatch. Here's what really happened.

The 3 phases of the race

The race can't be understood by looking only at the final result. It reads as three distinct phases, each with its own logic.

Phase 1 — Building up (0 → 72 km, Urepel)

I came out of the start faster than planned. By Jara (km 6.5), I was already 12 minutes ahead of the plan. The lead built up gradually: −31 min at Gaztiparlepoa (km 19.5), −36 min at Elorrieta, −34 min at Les Aldudes. I reached the Urepel checkpoint (km 72.2) with a 1h02 lead on the Segly plan — the peak of the positive gap.

What the data reveals: on this first stretch, my actual trail fatigue factor was around 22% — above the 15% planned for a total of 21 hours of racing. I was in my zone, the terrain suited me, and I capitalised on the muscular freshness of the early hours.

Phase 2 — Fatigue sets in (72 → 115 km, Col Ahartza)

From Urepel, the story changed. The lead melted checkpoint after checkpoint: −52 min at Lindus (km 84.7), −43 min at Auzai, −18 min at Banca (km 108.5). At Col Ahartza (km 115.2), I was at +1 minute — back within the Segly plan, and even slightly behind it. That's the classic sign of an ultra: accumulated fatigue exceeding the planned scenario. A sign of starting too fast in the first part? Probably. But a controlled start — not an explosion of pace, just insufficient vigilance over 70 km.

Phase 3 — Back on plan (115 → 128 km, Finish)

The last 13 kilometres were a surprise. The gap stabilised, mental strength took over, and I finished 2 minutes ahead of the Segly plan. An almost perfect return to the announced times. Plan A held despite an atypical race — and it's the most convincing demonstration of the value of a good trail race plan.

Segly vs timing: the segment-by-segment comparison

Here is the full table of the 17 checkpoints — Segly forecast time versus official timing:

Reading the segments reveals several lessons. The maximum lead reached at Urepel (km 72.2), at −1h02, falls precisely at mid-race. The sharpest reversal occurs between Banca and Col Ahartza (6.7 km): the gap goes from −18 min to +1 min — the hardest segment of my race, in the middle of the night, with legs that refused to cooperate. The final climb back between Munhoa and the finish shows that my mind held out to the end.

Trail fatigue factor: what the race revealed

I had planned a fatigue factor of 15%. Reality was more nuanced — and that's precisely what this kind of analysis brings to light after the fact.

On the first half (up to Urepel, km 72), I built a lead on the estimate, thinking I could hold the pace and do better than 21 hours. I was slowing down less than planned — the terrain and conditions were in my favour. I took advantage of the muscular freshness to build a substantial credit on the Segly plan.

On the second half, the picture changed: fatigue climbed. Freshness on the passes, muscular fatigue and probably a calorie deficit all did their work. I lost most of my lead over this stretch.

The fatigue factor came out at around 22% — above the 15% planned, but within a coherent range. What's remarkable is that the Segly plan absorbed this gap thanks to the credit accumulated in the first part. The final result doesn't reflect the internal turbulence of the race.

For my next ultra-trail preparation, the lesson is clear: try to respect split times better in the first half of the race, for a more controlled second half. Segly precisely allows this kind of fine-tuning, segment by segment.

What Segly taught me about my ultra-trail race strategy

Finishing a 130 km race 2 minutes from a plan built 5 days earlier is rare. But Segly's real value isn't in the precision of the final result — it's in the quality of the preparation that led to it.

Thanks to the segment-by-segment GPX analysis, I had concrete reference points throughout the race. At every checkpoint, I knew whether I was ahead or behind, and by how much. No anxiety, no improvisation — just information to make the right decisions on the course.

My crew had access to my full plan via the Segly share link. They knew exactly where to wait for me, what to have ready, and at what time to start worrying if I didn't arrive. That level of organisation changes the dynamics of an endurance race.

I recommend that every runner preparing an ultra-trail invest time in their Segly analysis before the start. 10 minutes of preparation for hours of peace of mind on the course.