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Advanced

100K Trail Training Plan

20 weeks to a 100K: long mountain days up to 5½ hours, back-to-backs, strength and cross-training.

20 weeks

Plan length

13h 40m

Peak week

5h 30m

Longest run

3,600 m+

Peak climbing

See the scheduleFind a race

The four phases

Weeks 1–7

Base

Build the habit and your aerobic engine with easy volume, short hills and strength foundations.

Weeks 8–13

Build

Longer mountain days and hill repeats, plus back-to-back runs for ultras: the bulk of the training.

Weeks 14–17

Peak

The biggest weeks: long runs with your race gear and fueling, and sustained climbs at race effort.

Weeks 18–20

Taper

Less volume, same rhythm: arrive at the start line rested and sharp.

Week by week

Monday to Sunday. Open a week to see each day; durations are total time.

Adjust your plan

Plan length
Which one should I choose?
Easy runs

Move them to your machine if you are coming back from an injury or want less pounding. The long run and the hills stay running: that is the specific work.

Weekly load

Minutes each week by kind of work. Tap a week to open it.

14% of the time low-impact
RunningLow-impactStrength
148121620
BaseBuildPeakTaper
Week 17· Peak week13h 40mRunning 11h 30mLow-impact 1h 40mStrength 30 min
Mountain dayHillsEasy runStrengthLow-impact aerobicRest
Week 1Base5h 25m · 1,400 m+
MonRestRest or 20 min of mobility
TueHillsEasy run with 6–8 short uphill strides45 min · 300 m+
WedBike or indoor trainerContinuous zone 2, by heart rate50 min
ThuStrengthSquats, lunges, step-ups and core40 min
FriEasy runEasy, conversational paceOr low-impact: Bike or indoor trainer35 min
SatMountain dayLong trail run with climbing2h · 1,100 m+
SunEasy runEasy recovery run or hikeOr low-impact: Bike or indoor trainer35 min
Week 2Base6h · 1,550 m+
MonRestRest or 20 min of mobility
TueHillsEasy run with 6–8 short uphill strides50 min · 300 m+
WedBike or indoor trainerContinuous zone 2, by heart rate55 min
ThuStrengthSquats, lunges, step-ups and core40 min
FriEasy runEasy, conversational paceOr low-impact: Bike or indoor trainer40 min
SatMountain dayLong trail run with climbing2h 15m · 1,250 m+
SunEasy runEasy recovery run or hikeOr low-impact: Bike or indoor trainer40 min

Unlock weeks 3–20

Sign in for free to see the whole plan day by day, all the way to race day.

Week 3Base6h 15m · 1,700 m+Week 4BaseEasier week5h 05m · 1,350 m+Week 5Base7h 10m · 1,950 m+Week 6Base7h 20m · 2,100 m+Week 7Base7h 55m · 2,250 m+Week 8BuildEasier week6h 30m · 1,750 m+Week 9Build9h 20m · 2,500 m+Week 10Build9h 50m · 2,700 m+Week 11Build10h 10m · 2,800 m+Week 12BuildEasier week7h 40m · 2,200 m+Week 13Build11h 15m · 3,050 m+Week 14Peak12h 15m · 3,200 m+Week 15Peak12h 50m · 3,350 m+Week 16PeakEasier week8h 45m · 2,600 m+Week 17Peak13h 40m · 3,600 m+Week 18Taper9h 15m · 2,900 m+Week 19Taper7h · 2,150 m+Week 20TaperRace week2h 10m · 250 m+

The training days

Mountain day

Your long run on trails with climbing, the key session of the week. Keep an easy, conversational effort, walk the steep climbs and practise your fueling.

Hills

Uphill work for climbing strength: strides, repeats or sustained climbs depending on the phase. Hard going up, easy coming down.

Easy run

Short, relaxed runs that add volume without fatigue. If you can’t talk, slow down. Being pure aerobic work, you can also do them low-impact on your machine.

Strength

Legs, hips and core: squats, lunges, step-ups and single-leg work that make you stronger on climbs and steadier on descents.

Strength training guide
Low-impact aerobic

Zone 2 aerobic volume without the pounding of running. The bike is only one option: the elliptical, a stair climber, a rowing machine or aqua jogging work too, each for a different goal.

Choose your machine
Rest

A day off or gentle mobility. This is when your body adapts to the training.

How do you do your low-impact aerobic day?

The bike is not the only way to add aerobic volume without impact. Pick the machine you use and the plan adapts every week, or leave it on “By phase” to follow our recommendation.

Go by heart rate. On a machine you are less used to, your muscles tire before your heart: stay in zone 2 by heart rate to make sure the work is really aerobic.

Match it to your goal. For climbing, prioritise the elliptical with resistance and the stair climber; for a break for your joints, the bike and aqua jogging are better.

Upcoming races for this plan

See all races
Oct 2, 2026 · 100KTransJeju by UTMBJeju Island, South KoreaOct 2, 2026 · 105KUltra-Trail des Montagnes du JuraLancrans, Jura, FranceOct 2, 2026 · 100KSalomon Ultra PirineuBagà, Barcelona, SpainOct 8, 2026 · 100KKodiak Ultra Marathons by UTMBBig Bear Lake, California, United StatesOct 9, 2026 · 105KGran Trail PeñalaraNavacerrada, Madrid, SpainOct 15, 2026 · 106KGrand Raid RéunionRéunion Island, France

Gear for your 100K trail race

Picked for the distance from the products we compare.

Hoka Mafate 5
Hoka Mafate 5Shoes
Nike ACG Zegama Trail
Nike ACG Zegama TrailShoes
Altra Olympus 7
Altra Olympus 7Shoes
norda 001A
norda 001AShoes
Salomon ADV Skin 12
Salomon ADV Skin 12Vest
Maurten Gel 100
Maurten Gel 100Nutrition
LEKI Ultratrail FX.One SL
LEKI Ultratrail FX.One SLPoles

Frequently asked questions

How long does it take to train for a 100K trail race?

Plan around 20 weeks if you already run three or four times a week. 20 weeks can work if you are already fit; take 24 if you are building up from less running.

How many hours a week should I train for a 100K trail race?

This plan starts at about 6 hours a week and builds to around 12 at its peak, with an easier week every fourth week so your body absorbs the work.

How long should my longest training run be for a 100K trail race?

About 5h 30m on trails with climbing, a few weeks before the race. You don’t need to cover the full distance in training: weekly climbing (up to 3600 m+ at the peak) and consistency matter more.

What cross-training should I do for a 100K trail race?

One low-impact aerobic session a week, in zone 2 by heart rate. Pick it for your goal: the elliptical or a stair climber for climbing-specific work, the bike or aqua jogging to rest your joints, and a rowing machine to strengthen the back, shoulders and core you use on technical descents and with poles.

Do I need strength training for a 100K trail race?

One or two short sessions a week for legs, hips and core make you stronger on climbs, steadier on descents and less prone to injury. The plan keeps them light in the last weeks.

Other training plans

Trail Running Plan for Beginners10K Trail Training PlanTrail Half Marathon Training Plan25K Trail Training Plan30K Trail Training PlanTrail Marathon Training Plan50K Trail Training Plan50 Mile Training Plan100 Mile Training Plan

These plans are general guidance for healthy runners. Adapt them to your level and how you feel, and check with a doctor or coach before increasing your training.