Leadville Trail 100
training plan
An adaptive 100 mile plan for a mountain course on trail, run in cool August conditions, built around the three things Leadville Trail 100 actually asks of you: thin air, cut-off times and running through the night. 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 thin air, cut-off times or running through the night.
On the ground, Leadville Trail 100 is a mountain course on trail, with 4,800 m of climbing in it. It is usually held in August, when conditions are usually cool, which is good racing weather but means a cold twenty minutes standing about beforehand. 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 more likely to help you than to hurt you. There will be a few hundred to a thousand starters out there with you.
- Profile
- Mountainous · trail
- Climbing
- 4,800 m · 48 m in every mile
- Usual conditions
- August · cool
- Race season
- Summer, northern hemisphere
- Field
- Small · a few hundred to a thousand
The air is thinner than the pace you trained at
At altitude the same effort produces a slower pace and a higher heart rate, and no amount of sea-level fitness argues with it. Going out on flatland numbers is the classic way to ruin the day.
The plan works in effort and heart rate rather than pace for Leadville Trail 100, keeps your goal honest about the elevation, and never asks you to hit a sea-level split on a course that will not give it to you.
The clock is a competitor
Intermediate cut-offs mean you have to reach specific points by specific times, usually after the section that hurt most. Slower runners can be pulled while still moving well.
The plan works from the cut-off structure you enter, builds the durability to hold pace late, and rehearses aid-station discipline so time is not lost standing still at Leadville Trail 100.
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 Leadville Trail 100 rather than during it.
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.
Small field
A small field means no pens and no queues, and nobody to tuck in behind when it gets hard, 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, cool conditions and a small 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 thin air, cut-off times and running through the night 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 Leadville Trail 100 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 Leadville Trail 100 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 cold-start rehearsal for conditions that are usually cool. The key session itself is written for running through the night. 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 | 10 mi1H30 |
| WED | Zone 2, easy | Cold-start rehearsal: race effort inside the first ten minutes, from cold | 9 mi1H25 |
| THU | Zone 3, steady | Strength: eccentrics & carries | 50' |
| FRI | Rest | Rest | |
| SAT | Zone 3, steady | Long mountain day: finish in the dark, with a headlamp | 34 mi7H00 |
| SUN | Zone 2, easy | Back-to-back hike with vert | 15 mi3H45 |
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 Leadville Trail 100?
Twenty-four weeks is the usual build for a 100 mile race like Leadville Trail 100, 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 thin air, cut-off times and running through the night first, and tells you plainly what it had to leave out.
When should I start training for Leadville Trail 100?
The date does not move: 21 to 22 August 2027. Count back twenty-four weeks from it and that is when a full-length 100 mile build opens: around late February for an August race, February through to August. If you are reading this later than that, the plan fits the block into what is actually left and names the sessions it dropped. 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 Leadville Trail 100?
There is 4,800 m of climbing in it, about 48 m in every mile. 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 thin air, cut-off times and running through the night, and none of the three gets dropped to make room for the others.
What kit do I need for Leadville Trail 100?
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 4,800 m of climbing in it, about 48 m in every mile. 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.
Do I need to train at altitude for Leadville Trail 100?
It helps and it is not available to most people, so the plan does not pretend otherwise. There is 4,800 m of climbing in it, about 48 m in every mile. Over twenty-four weeks the answer at sea level is sustained work at controlled effort rather than pace, arriving in August with a pacing plan that assumes you will be slower than your flat numbers say. Altitude affects people very differently; if you have a condition it touches, speak to a professional.
Will I be running in the dark at Leadville Trail 100?
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.
Is this an official Leadville Trail 100 training plan?
No. Adaptlete is an independent training-plan service with no affiliation to the organizers of Leadville Trail 100, 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.