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26-week 100K ultra training plan (variations included)

A 26-week 100K ultra training plan with week-by-week time-on-feet structure, hills, back-to-backs, adaptation rules, and cutoff planning tools.

Last updated/Mar 20, 2026, 11:05 PM
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Start here

One decision, then execute

Pick the default variant, scan the phase map, then use one tool to lock pace and fueling numbers.

1. Choose a variant

4 days/week (Beginner-friendly)

Start with the recommended default. Customize only after two consistent weeks.

2. Scan the phase map

Base → build → peak → taper

Use the condensed view, then open the full week-by-week table only when you need detail.

Jump to week-by-week

3. Lock your numbers

Pace + fueling defaults

Run one calculator now so race week is execution, not improvisation.

Jump to tools

At a glance

Plan length

26 weeks

Built with phases, cutbacks, and a taper you can actually execute.

Weekly rhythm

47 days/week

Choose one variant and follow it for 2 weeks before tweaking.

Typical session time

Easy: ~50m • Long: ~220m

Prefer consistent minutes over heroic single sessions.

Readiness gate

  • You can complete 60–90 minutes easy without breaking down.
  • You’re willing to train by time-on-feet (not ego pace).

Default recommendation

4 days/week (Beginner-friendly)

Start here to reduce decision fatigue. Customize only after your first two weeks feel stable.

  • Consistency and durability first.

Safety first

This is general training information, not medical advice.

  • Recurring overuse pain under volume.
  • Inability to recover from long sessions (fix sleep/stress first).

Coaching beta

Want this adapted to your recovery?

Get coach-style adjustments when you miss sessions, sleep poorly, or feel fatigue signals.

Plan variants (days/week)

Pick a weekly rhythm you can repeat consistently. Start with the recommended default, then adjust only after your first two weeks feel stable.

4 days/week (Beginner-friendly)

4 days/week/Beginner
Recommended
  • Consistency and durability first.

5 days/week (Balanced default)

5 days/week/Intermediate
  • Includes one hills session and one long session focus.

6 days/week (Advanced)

6 days/week/Advanced
  • Only if recovery is stable; keep intensity controlled.

Week by week

Structure you can scan

Use this as your decision map: what matters this week, what the long run is doing, and where you should back off.

BaseJump

Weeks 18

Build time-on-feet and durability; keep it easy.

Long session: Long easy time-on-feet (trail/road) + hiking practice • Cutbacks: 2

BuildJump

Weeks 917

Add terrain specificity and back-to-back durability.

Long session: Back-to-back long sessions (scaled) + fueling rehearsal • Cutbacks: 2

PeakJump

Weeks 1823

Race-specific long sessions + cutoff-aware pacing.

Long session: Key long session with terrain focus + cutoff pacing practice • Cutbacks: 1

TaperJump

Weeks 2426

Reduce load; keep a touch of specificity; arrive healthy.

Long session: Shorter long session + mobility

View full week-by-week table
WeekPhaseFocusLong sessionKey workoutsNotes
1BaseBuild time-on-feet and durability; keep it easy.Long easy time-on-feet (trail/road) + hiking practiceHills (controlled) + hiking efficiency • Back-to-back long sessions (scaled)
2BaseBuild time-on-feet and durability; keep it easy.Long easy time-on-feet (trail/road) + hiking practiceHills (controlled) + hiking efficiency • Back-to-back long sessions (scaled)
3BaseBuild time-on-feet and durability; keep it easy.Long easy time-on-feet (trail/road) + hiking practiceHills (controlled) + hiking efficiency • Back-to-back long sessions (scaled)
4BaseBuild time-on-feet and durability; keep it easy.Long easy time-on-feet (trail/road) + hiking practiceHills (controlled) + hiking efficiency • Back-to-back long sessions (scaled)Cutback week
5BaseBuild time-on-feet and durability; keep it easy.Long easy time-on-feet (trail/road) + hiking practiceHills (controlled) + hiking efficiency • Back-to-back long sessions (scaled)
6BaseBuild time-on-feet and durability; keep it easy.Long easy time-on-feet (trail/road) + hiking practiceHills (controlled) + hiking efficiency • Back-to-back long sessions (scaled)
7BaseBuild time-on-feet and durability; keep it easy.Long easy time-on-feet (trail/road) + hiking practiceHills (controlled) + hiking efficiency • Back-to-back long sessions (scaled)
8BaseBuild time-on-feet and durability; keep it easy.Long easy time-on-feet (trail/road) + hiking practiceHills (controlled) + hiking efficiency • Back-to-back long sessions (scaled)Cutback week
9BuildAdd terrain specificity and back-to-back durability.Back-to-back long sessions (scaled) + fueling rehearsalHills (controlled) + hiking efficiency • Back-to-back long sessions (scaled)
10BuildAdd terrain specificity and back-to-back durability.Back-to-back long sessions (scaled) + fueling rehearsalHills (controlled) + hiking efficiency • Back-to-back long sessions (scaled)
11BuildAdd terrain specificity and back-to-back durability.Back-to-back long sessions (scaled) + fueling rehearsalHills (controlled) + hiking efficiency • Back-to-back long sessions (scaled)
12BuildAdd terrain specificity and back-to-back durability.Back-to-back long sessions (scaled) + fueling rehearsalHills (controlled) + hiking efficiency • Back-to-back long sessions (scaled)Cutback week
13BuildAdd terrain specificity and back-to-back durability.Back-to-back long sessions (scaled) + fueling rehearsalHills (controlled) + hiking efficiency • Back-to-back long sessions (scaled)
14BuildAdd terrain specificity and back-to-back durability.Back-to-back long sessions (scaled) + fueling rehearsalHills (controlled) + hiking efficiency • Back-to-back long sessions (scaled)
15BuildAdd terrain specificity and back-to-back durability.Back-to-back long sessions (scaled) + fueling rehearsalHills (controlled) + hiking efficiency • Back-to-back long sessions (scaled)
16BuildAdd terrain specificity and back-to-back durability.Back-to-back long sessions (scaled) + fueling rehearsalHills (controlled) + hiking efficiency • Back-to-back long sessions (scaled)Cutback week
17BuildAdd terrain specificity and back-to-back durability.Back-to-back long sessions (scaled) + fueling rehearsalHills (controlled) + hiking efficiency • Back-to-back long sessions (scaled)
18PeakRace-specific long sessions + cutoff-aware pacing.Key long session with terrain focus + cutoff pacing practiceHills (controlled) + hiking efficiency • Back-to-back long sessions (scaled)
19PeakRace-specific long sessions + cutoff-aware pacing.Key long session with terrain focus + cutoff pacing practiceHills (controlled) + hiking efficiency • Back-to-back long sessions (scaled)
20PeakRace-specific long sessions + cutoff-aware pacing.Key long session with terrain focus + cutoff pacing practiceHills (controlled) + hiking efficiency • Back-to-back long sessions (scaled)Cutback week
21PeakRace-specific long sessions + cutoff-aware pacing.Key long session with terrain focus + cutoff pacing practiceHills (controlled) + hiking efficiency • Back-to-back long sessions (scaled)
22PeakRace-specific long sessions + cutoff-aware pacing.Key long session with terrain focus + cutoff pacing practiceHills (controlled) + hiking efficiency • Back-to-back long sessions (scaled)
23PeakRace-specific long sessions + cutoff-aware pacing.Key long session with terrain focus + cutoff pacing practiceHills (controlled) + hiking efficiency • Back-to-back long sessions (scaled)
24TaperReduce load; keep a touch of specificity; arrive healthy.Shorter long session + mobilityHills (controlled) + hiking efficiency • Back-to-back long sessions (scaled)
25TaperReduce load; keep a touch of specificity; arrive healthy.Shorter long session + mobilityHills (controlled) + hiking efficiency • Back-to-back long sessions (scaled)
26TaperReduce load; keep a touch of specificity; arrive healthy.Shorter long session + mobilityHills (controlled) + hiking efficiency • Back-to-back long sessions (scaled)

Workout library

The sessions you repeat

You don’t need 50 workouts. You need a small library that you execute consistently, then progress safely.

Time-on-feet long session

Purpose: Build durable endurance without over-focusing on pace.

Prescription: 105–220+ minutes easy. Include hiking on climbs if terrain demands it.

Substitutions

  • Split into two sessions on high-stress weeks; keep total time similar.

Red flags

  • Sharp pain that changes form.
  • Needing multiple days to recover every week.
Back-to-back long sessions (scaled)

Purpose: Train durability and pacing under accumulated fatigue.

Prescription: Two consecutive days: long easy + medium easy. Keep both controlled and finish feeling stable.

Substitutions

  • If injury-prone: one long run + one long hike.

Red flags

  • Turning day 2 into a race.
  • Fatigue that spills into the entire next week.
Hills (controlled) + hiking practice

Purpose: Build climbing efficiency and downhill resilience safely.

Prescription: 6–12 × 2–4 min uphill at controlled effort; hike steep reps. Jog easy down.

Substitutions

  • Stair climbing or incline treadmill if needed.

Red flags

  • Knee pain on descents.
  • Over-striding downhill.
Cutoff pacing rehearsal

Purpose: Practice pacing that keeps you safe against cutoffs without burning matches.

Prescription: 60–120 min with segments at your cutoff-safe effort. Practice aid-station efficiency (quick in/out).

Substitutions

  • Do it as a hike-run combo on trails.

Red flags

  • Chasing pace on terrain that demands hiking.
  • Skipping fueling while ‘testing’ pace.
Fueling practice (GI-friendly)

Purpose: Train your gut and reduce race-day surprises.

Prescription: On long sessions: practice a simple schedule and adjust products if GI issues appear.

Substitutions

  • Lower intensity + smaller doses if tolerance is low.

Red flags

  • Repeated GI distress without changes.
  • Ignoring hydration in heat.
Strength durability (lower-body + trunk)

Purpose: Support downhill resilience and long-duration posture.

Prescription: 2×/week, 25–40 min: single-leg, posterior chain, calves, trunk. Avoid soreness spikes.

Substitutions

  • Travel circuit with step-ups, calf raises, core.

Red flags

  • DOMS ruining long sessions.
  • Sharp joint pain.

Adaptation rules

What to do when life happens

Most training failures are not fitness failures — they’re pacing, sleep, or scheduling failures. Use simple rules.

Missed workout

  • Protect the long session; drop extra intensity.
  • Don’t stack back-to-backs to ‘catch up’.

Low sleep week

  • Keep it easy; reduce long-session duration by 15–25%.
  • Replace hills with hiking if needed.

Fatigue signals

  • If legs feel dead, replace with easy hike and mobility.
  • Prioritize fueling and sleep; treat it like a cutback week.

Pain or injury

  • Pain that changes gait is a stop signal.
  • Swap to hiking/biking until pain-free; return gradually.

Travel week

  • Short sessions win: keep one long hike/run and one hills touch if possible.
  • Use time-based training and stay consistent.

Tools

Numbers to train with

Pick one tool, generate outputs, then plug them into your training week.

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Evidence (high level)

Why this structure works

  • Ultras reward time-on-feet and durability, not heroic pace sessions.
  • Back-to-back sessions train fatigue resistance safely when scaled.
  • Cutoff planning is a pacing skill; train it like a discipline.
  • Fueling and hydration are part of the training plan, not a race-week afterthought.

FAQs

Should I train by pace or time?

For ultras, time-on-feet is usually more useful than pace. Terrain changes pace; effort and durability are what transfer.

Do I need back-to-back long runs?

They can help, but they must be scaled and recovery-aware. If you’re injury-prone, use one long run and one long hike.

How do I prepare for cutoffs?

Use cutoff-safe effort in training, practice aid-station efficiency, and build margin for terrain and fatigue.

How much elevation training do I need?

Match the race demands. If the race is hilly, you need hills. If it’s flat, you still need durability.

How do I avoid GI issues?

Practice fueling early and often in long sessions. Adjust products and timing; don’t wait for race week.

What’s the biggest mistake?

Turning long sessions into races. Ultras reward staying consistent week after week.

Keep going

Sources