UTMB
training plan
An adaptive 100 mile plan for a mountain course on trail, run in unpredictable August conditions, built around the three things UTMB actually asks of you: relentless vertical, running through the night and technical descending. Twenty-four weeks written two at a time, from what you actually did in the two weeks before, and rewritten the moment you travel, get ill or something starts hurting.
This page describes the race and what its course, climate and date ask of a build. On Pro, the plan itself is written for you, from your experience, your weekly hours and your date, so two athletes entered in this race get different plans.
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Three demands, three answers
A generic 24-week 100 mile plan gets you to the start line. It has no idea about relentless vertical, running through the night or technical descending.
On the ground, UTMB is a mountain course on trail, with 10,000 m of climbing in it. It is usually held in August, when the weather is genuinely unpredictable, and two editions running rarely feel the same. So over a 100 mile race, the vertical is the event and the distance is how long you are out in it, and the weather is the variable you prepare for, because nobody can plan around it. There will be one to ten thousand starters out there with you.
- Profile
- Mountainous · trail
- Climbing
- 10,000 m · 62 m in every kilometer
- Usual conditions
- August · unpredictable
- Race season
- Summer, northern hemisphere
- Field
- Mid-sized · one to ten thousand
The vertical is the event
Measured in miles this looks manageable. Measured in vertical gain it is a different sport. You get hours of climbing, hiking where running stops making sense, and a descent bill on the other side of every summit.
Training is built around vertical gain and time on feet instead of mileage, with hiking programmed as a real session. On UTMB you will be hiking for a large part of the day.
Part of this happens in the dark
Moving through the night is a separate skill: depth perception goes, pace slows, the low point at 3am arrives on schedule, and everything you did not practice with a headlamp becomes a problem.
Night sessions programmed into the build rather than left as a surprise, with the kit, the fueling and the wakefulness rehearsed before UTMB rather than during it.
Descending here is a skill you have to practice
Loose, steep or rocky descents ask for balance, braking control and nerve. Treated as recovery they cost you time and shred your legs for whatever comes after.
Repeated descent practice on terrain like the course, and eccentric strength so the legs holding you back at the end of UTMB are still the ones you started with.
Getting in, and getting to the line
Adaptlete has no involvement in entry, allocation or ballots for any race. This is what the format asks of your planning.
Ballot
Places usually go by ballot, which makes the honest sequence place first, plan second. If the draw goes against you, the same block moves to another race without being rewritten. Twenty-four weeks back from August puts the first week in late February.
Mid-sized field
A mid-sized field clears inside the first mile, so the pace you settle into is genuinely yours, and on a mountain course the queue forms at the first singletrack and never fully clears. Over a 100 mile race, that is a long time to be running somebody else's race.
Trail
Trail, so the long sessions have to happen on ground like it. Footing, poles, descending and eating while you move are skills, and none of them are learnable on a treadmill in the last two weeks. The peak week puts climbing intervals on it, months before August.
You will be training through the northern spring
Work backwards and a twenty-four-week block for an August race opens around late February, running February through to August. That is the northern spring, and it is the half of the job most plans never mention. The light comes back a little faster than the weather does, so the first block is still winter and the last one is not. It is the easiest season to train in and the easiest one to overreach in, because everything suddenly feels good at once. And the last block lands in August, with mountainous ground, unpredictable conditions and a mid-sized field waiting at the end of it.
So the plan holds the ramp down while the evenings open up, and puts the biggest weeks where the daylight actually supports them rather than where enthusiasm wants them. Whatever the season takes out of two weeks, the work for relentless vertical, running through the night and technical descending is what the rebuild puts back first.
- Weeks 1-10 February-May the weather turns mid-block; the ramp holds steady anyway
- Weeks 11-16 May-June early starts and heat; the long sessions move to the cool hours
- Weeks 17-24 · peak and taper June-August
Months assume UTMB keeps its usual August slot and that you take the full 24 weeks. Adaptlete builds from the date you enter.
A real week from a UTMB build
This is the shape of the biggest week in 24: 6 sessions a week, 14H 30M of training, and one session that matters more than the rest. Two of them are here because of this course and not the distance: climbing intervals for the mountainous profile, and a weather rehearsal for conditions that are usually unpredictable. The key session itself is written for relentless vertical. For an August race, week 17 lands in June. Your version is written from your hours, your history and how far out you are.
- Every session says what it is for, in plain language
- Intensity you can scan down the week without reading
- Move any session to any day without breaking the block
| Day | Intensity | Session | Distance and duration |
|---|---|---|---|
| MON | Rest | Rest | |
| TUE | Zone 4, threshold | Climbing intervals: 4 × 10 min, hiking the steep sections | 16 km1H30 |
| WED | Zone 2, easy | Weather rehearsal: it goes ahead in whatever the day hands you | 14 km1H25 |
| THU | Zone 3, steady | Strength: eccentrics & carries | 50' |
| FRI | Rest | Rest | |
| SAT | Zone 3, steady | Long mountain day: built around the vertical | 55 km7H00 |
| SUN | Zone 2, easy | Back-to-back hike with vert | 24 km3H45 |
Something will go wrong.
That is the part we built for.
Nobody finishes a twenty-four-week build without missing a week, and February through to August is a long time to stay lucky. The plans that fail are the ones that carry on as if nothing happened.
A work trip in week 13
Hotel treadmill, nothing else? Those days get rewritten around it.
Flu in May
The block rebuilds and ramps you back. Nothing is deleted.
A niggle at week 20
Loading comes off it, the rest of your week stays. And go see someone.
Questions people actually search
How many weeks do I need to train for UTMB?
Twenty-four weeks is the usual build for a 100 mile race like UTMB, at 6 sessions a week. Counted back from an August race that opens the block around late February and runs it February through to August. Coming from a lower base, give yourself longer. With fewer weeks than that the plan compresses. It builds what it can from where you are, protects the work for relentless vertical, running through the night and technical descending first, and tells you plainly what it had to leave out.
When should I start training for UTMB?
UTMB is usually held in August, and the next edition an athlete could realistically build for is Late August 2027. Count back twenty-four weeks from whatever date you enter and the block opens around late February, running February through to August. Adaptlete builds backwards from your date, so the whole 100 mile plan lines itself up the moment the date is confirmed. Entry runs on a separate clock (places here are allocated by ballot), and the training deadline is the one you control.
Do I need hills to train for UTMB?
There is 10,000 m of climbing in it, about 62 m in every kilometer. That is mountainous ground on trail, over a 100 mile race, and it is trainable without moving house. The peak week carries climbing intervals and loads the long session the way the course does. Train somewhere flat and the plan substitutes sustained-effort and eccentric work that loads the same tissue, and tells you it has done so. It is one of relentless vertical, running through the night and technical descending, and none of the three gets dropped to make room for the others.
What kit do I need for UTMB?
Trail, so the long sessions have to happen on ground like it. Footing, poles, descending and eating while you move are skills, and none of them are learnable on a treadmill in the last two weeks. There is 10,000 m of climbing in it, about 62 m in every kilometer. Over twenty-four weeks the plan puts the long sessions on ground like it and asks you to use the same pack, poles, shoes and food you intend to use in August. Check the organizers' own mandatory kit list. It is theirs, it changes, and we do not publish it.
Will I be running in the dark at UTMB?
Almost certainly, and for longer than you think. A 100 mile race on trail over mountainous ground puts most people out for at least one full night. The plan schedules head-torch sessions on real terrain rather than leaving them to the last two weeks, and the twenty-four-week block finishes long days in the dark on purpose so August is not the first time.
How long will I be out on the course at UTMB?
Long enough that the plan works in time on feet. There is 10,000 m of climbing in it, about 62 m in every kilometer. Over mountainous trail in August that turns a 100 mile race into a day of moving, eating and problem-solving, so the twenty-four-week block builds back-to-back long days and rehearses relentless vertical, running through the night and technical descending at the effort you can hold for hours.
Is this an official UTMB training plan?
No. Adaptlete is an independent training-plan service with no affiliation to the organizers of UTMB, and none is implied. We name the race because the plan is built around what its course, its format and its date ask of you.