Free 16-Week Training Plan for Arc of Attrition by UTMB Arc 20K
Train for a winter coastal ultra: relentless short climbs, mud, wind, and long hours of darkness.
At 22.1 km with 744 m of elevation gain, this is a fast, punchy distance where speed and hill strength both matter. At 34 m of vertical per kilometer, much of the course is runnable — the plan focuses on building your aerobic cruising speed while preparing you for the steeper sections.
Race date: Sun, 24 January 2027Open entry22.1 km · 744 m
Race prep workspace
Continue Arc of Attrition by UTMB Arc 20K
Your race plan, next route workout, official GPX, fueling, cutoff, weather, and calendar link in one place.
I'm preparing for Arc of Attrition by UTMB Arc 20K. Here is the public training preview.
22.1 km · +744 m · 114 days to race day
Public preview only; my private routes and schedule changes are not included.
Plan: https://trailsplits.com/races/arc-of-attrition-by-utmb-arc-20k/training-plan?tier=strong-finish&strength=1&strength_track=no-gym&engine=unified&days=3
No account needed. A kept plan stays on this browser until its storage is cleared; find it under My kept plans, where you can also change single weeks.
Optional account and live calendar
Save it to your account, subscribe once, then adjust concrete dates as life changes.
Signed-in plan changes save automatically and update the same personal calendar URL.
Use the snapshot calendar without an account, or sign in for autosave.
Choose a subscription that refreshes, or download a one-time copy.
Terrain autopilot
Find a matching route near you
We'll look for a loop near you that matches your next run (40 min · ~5 km · +75 m)
and rehearses the 34 m/km demand of Arc 20K.
Terrain intel
South West Coast Path — cliff-top singletrack with constant short, steep climbs into and out of coves. The 100M gathers 5,507 m over 173 km with almost no flat running and very little runnable track.
Weather & kit
Late January on the Atlantic coast: gales, driving rain, mud, and temperatures near freezing with severe wind chill on exposed cliffs.
What this plan focuses on
Accumulate night hours — most of this race is run in the dark.
Train the repeated 50–100 m cliff climb-and-drop rhythm.
Rehearse cold, wet kit management and hypothermia prevention.
Practise eating and drinking in wind and rain without stopping.
Build ankle and foot resilience for mud and uneven coast path.
Unified race plan · beta
Uses the same load, recovery and taper rules as race discovery, with course-specific climbing only because this course has verified elevation.
Use it for race-effort sessions and race day. Easy runs stay easy whatever the goal; the plan's efforts come from how you run now.
Your starting point
Not stated. The plan assumes a typical starting week for this race and opens at 3h 00m of running.
Fit the plan to your recent training
This schedule opens at 3h 00m of running and 200 m of climbing in week one and peaks at 4h 15m and 575 m in a week; the longest planned outing is 1h 40m. These are prescriptions, not proof of readiness.
Adjust this plan
Swap concrete training days, or mark a day done/skipped without changing the race-specific template.
Calendar subscriptions refresh on the calendar app's schedule. This calendar export uses the selected start date and includes weekly summaries and any pre-base sessions. Use Keep this plan above for a fixed copy of the displayed race schedule.
Route-aware workouts
Key sessions include route buttons that deep-link into the Planner with pre-filled distance
+ elevation filters.
Little downhill to prepare for; general strength still helps.
Peak week target
575 m
4h 15m total training time
Cutoff pressure
Not listed
No cutoff in TrailSplits metadata.
Training emphasis: aerobic cruising speed, cadence control, and late-race leg speed.
Plan summary
The block begins on 2026-10-05, this coming week.
Duration
16 weeks
Start
2026-10-05
Peak weekly time
4h 15m
Peak weekly vert
575 m
Week 1Base Building
3h 00m ·
200 m vert
Mon · 2026-10-05rest
Rest
Effort: Rest
Rest or gentle mobility.
Tue · 2026-10-06hills
Easy hills + uphill strides
40 min · 75 m vert · ~5 km
Effort: Easy; strides strong but relaxed
Start with 10 minutes easy on rolling terrain. Then 6 x 20 seconds uphill strides, strong but relaxed, walking back down between them. Finish with at least 10 minutes easy; the rest of the run is easy on the hills.
Effort: Moderate: controlled reps, stop 1–2 short of failure
No-gym Session A: Bulgarian split squat, single-leg RDL, step-ups (bench/stairs), calf raises, side plank. Quality reps; stop well before failure. If 10 reps feels easy, add weight (backpack/water) so the last 2 reps feel challenging. In peak weeks, keep it short and easy.
Thu · 2026-10-08easy
Easy run
1h 10m · ~9.7 km
Effort: Easy
Conversational aerobic running. Keep easy days easy enough to support the key work.
Effort: Moderate: controlled reps, stop 1–2 short of failure
No-gym Session B: step-downs (slow 3–4s), lunges/sit-to-stand, soleus raises, carries (backpack), dead bug. Quality reps; stop well before failure. Keep the slow step-downs at least a day away from a long run; if this session falls the day before or after one, swap them for core work. In peak weeks, keep it short and easy.
Sat · 2026-10-10long
Long run
1h 10m · 125 m vert · ~8.9 km
Effort: Easy
Build relaxed time on feet at conversational effort.
Start with 10 minutes easy on rolling terrain. Then 6 x 20 seconds uphill strides, strong but relaxed, walking back down between them. Finish with at least 10 minutes easy; the rest of the run is easy on the hills.
Effort: Moderate: controlled reps, stop 1–2 short of failure
No-gym Session A: Bulgarian split squat, single-leg RDL, step-ups (bench/stairs), calf raises, side plank. Quality reps; stop well before failure. If 10 reps feels easy, add weight (backpack/water) so the last 2 reps feel challenging. In peak weeks, keep it short and easy.
Thu · 2026-10-15easy
Easy run
1h 10m · ~9.7 km
Effort: Easy
Conversational aerobic running. Keep easy days easy enough to support the key work.
Effort: Moderate: controlled reps, stop 1–2 short of failure
No-gym Session B: step-downs (slow 3–4s), lunges/sit-to-stand, soleus raises, carries (backpack), dead bug. Quality reps; stop well before failure. Keep the slow step-downs at least a day away from a long run; if this session falls the day before or after one, swap them for core work. In peak weeks, keep it short and easy.
Sat · 2026-10-17long
Long run
1h 10m · 125 m vert · ~8.9 km
Effort: Easy
Build relaxed time on feet at conversational effort.
Start with 10 minutes easy on rolling terrain. Then 6 x 20 seconds uphill strides, strong but relaxed, walking back down between them. Finish with at least 10 minutes easy; the rest of the run is easy on the hills.
Effort: Moderate: controlled reps, stop 1–2 short of failure
No-gym Session A: Bulgarian split squat, single-leg RDL, step-ups (bench/stairs), calf raises, side plank. Quality reps; stop well before failure. If 10 reps feels easy, add weight (backpack/water) so the last 2 reps feel challenging. In peak weeks, keep it short and easy.
Thu · 2026-10-22easy
Easy run
1h 15m · ~10.4 km
Effort: Easy
Conversational aerobic running. Keep easy days easy enough to support the key work.
Effort: Moderate: controlled reps, stop 1–2 short of failure
No-gym Session B: step-downs (slow 3–4s), lunges/sit-to-stand, soleus raises, carries (backpack), dead bug. Quality reps; stop well before failure. Keep the slow step-downs at least a day away from a long run; if this session falls the day before or after one, swap them for core work. In peak weeks, keep it short and easy.
Sat · 2026-10-24long
Long run
1h 15m · 150 m vert · ~9.4 km
Effort: Easy
Build relaxed time on feet at conversational effort.
Start with 10 minutes easy. Then 6 x 20 seconds relaxed strides, with 1 minute easy between repeats. Finish with at least 10 minutes easy; any remaining time is easy.
Effort: Moderate: controlled reps, stop 1–2 short of failure
No-gym Session A: Bulgarian split squat, single-leg RDL, step-ups (bench/stairs), calf raises, side plank. Quality reps; stop well before failure. If 10 reps feels easy, add weight (backpack/water) so the last 2 reps feel challenging. In peak weeks, keep it short and easy.
Thu · 2026-10-29easy
Easy run
1h 05m · ~9 km
Effort: Easy
Conversational aerobic running. Keep easy days easy enough to support the key work.
Effort: Moderate: controlled reps, stop 1–2 short of failure
No-gym Session B: step-downs (slow 3–4s), lunges/sit-to-stand, soleus raises, carries (backpack), dead bug. Quality reps; stop well before failure. Keep the slow step-downs at least a day away from a long run; if this session falls the day before or after one, swap them for core work. In peak weeks, keep it short and easy.
Sat · 2026-10-31long
Long run
55 min · 125 m vert · ~6.8 km
Effort: Easy
Build relaxed time on feet at conversational effort.
Start with 10 minutes easy on rolling terrain. Then 6 x 20 seconds uphill strides, strong but relaxed, walking back down between them. Finish with at least 10 minutes easy; the rest of the run is easy on the hills.
Effort: Moderate: controlled reps, stop 1–2 short of failure
No-gym Session A: Bulgarian split squat, single-leg RDL, step-ups (bench/stairs), calf raises, side plank. Quality reps; stop well before failure. If 10 reps feels easy, add weight (backpack/water) so the last 2 reps feel challenging. In peak weeks, keep it short and easy.
Thu · 2026-11-05easy
Easy run
1h 20m · ~11.1 km
Effort: Easy
Conversational aerobic running. Keep easy days easy enough to support the key work.
Effort: Moderate: controlled reps, stop 1–2 short of failure
No-gym Session B: step-downs (slow 3–4s), lunges/sit-to-stand, soleus raises, carries (backpack), dead bug. Quality reps; stop well before failure. Keep the slow step-downs at least a day away from a long run; if this session falls the day before or after one, swap them for core work. In peak weeks, keep it short and easy.
Sat · 2026-11-07long
Long run
1h 15m · 175 m vert · ~9.2 km
Effort: Easy
Build relaxed time on feet at conversational effort.
Start with 10 minutes easy on rolling terrain. Then 6 x 20 seconds uphill strides, strong but relaxed, walking back down between them. Finish with at least 10 minutes easy; the rest of the run is easy on the hills.
Effort: Moderate: controlled reps, stop 1–2 short of failure
No-gym Session A: Bulgarian split squat, single-leg RDL, step-ups (bench/stairs), calf raises, side plank. Quality reps; stop well before failure. If 10 reps feels easy, add weight (backpack/water) so the last 2 reps feel challenging. In peak weeks, keep it short and easy.
Thu · 2026-11-12easy
Easy run
1h 20m · ~11.1 km
Effort: Easy
Conversational aerobic running. Keep easy days easy enough to support the key work.
Effort: Moderate: controlled reps, stop 1–2 short of failure
No-gym Session B: step-downs (slow 3–4s), lunges/sit-to-stand, soleus raises, carries (backpack), dead bug. Quality reps; stop well before failure. Keep the slow step-downs at least a day away from a long run; if this session falls the day before or after one, swap them for core work. In peak weeks, keep it short and easy.
Sat · 2026-11-14long
Long run
1h 20m · 200 m vert · ~9.7 km
Effort: Easy
Build relaxed time on feet at conversational effort.
Start with 10 minutes easy. Then 4 x 6 minutes uphill at a hard but repeatable effort, with 2 minutes easy between repeats. Finish with at least 10 minutes easy; any remaining time is easy.
Effort: Moderate: controlled reps, stop 1–2 short of failure
No-gym Session A: Bulgarian split squat, single-leg RDL, step-ups (bench/stairs), calf raises, side plank. Quality reps; stop well before failure. If 10 reps feels easy, add weight (backpack/water) so the last 2 reps feel challenging. In peak weeks, keep it short and easy.
Thu · 2026-11-19easy
Easy run
1h 15m · ~10.4 km
Effort: Easy
Conversational aerobic running. Keep easy days easy enough to support the key work.
Effort: Moderate: controlled reps, stop 1–2 short of failure
No-gym Session B: step-downs (slow 3–4s), lunges/sit-to-stand, soleus raises, carries (backpack), dead bug. Quality reps; stop well before failure. Keep the slow step-downs at least a day away from a long run; if this session falls the day before or after one, swap them for core work. In peak weeks, keep it short and easy.
Sat · 2026-11-21long
Long run
1h 25m · 225 m vert · ~10.3 km
Effort: Easy
Build relaxed time on feet at conversational effort.
Start with 10 minutes easy. Then 6 x 20 seconds relaxed strides, with 1 minute easy between repeats. Finish with at least 10 minutes easy; any remaining time is easy.
Effort: Moderate: controlled reps, stop 1–2 short of failure
No-gym Session A: Bulgarian split squat, single-leg RDL, step-ups (bench/stairs), calf raises, side plank. Quality reps; stop well before failure. If 10 reps feels easy, add weight (backpack/water) so the last 2 reps feel challenging. In peak weeks, keep it short and easy.
Thu · 2026-11-26easy
Easy run
1h 10m · ~9.7 km
Effort: Easy
Conversational aerobic running. Keep easy days easy enough to support the key work.
Effort: Moderate: controlled reps, stop 1–2 short of failure
No-gym Session B: step-downs (slow 3–4s), lunges/sit-to-stand, soleus raises, carries (backpack), dead bug. Quality reps; stop well before failure. Keep the slow step-downs at least a day away from a long run; if this session falls the day before or after one, swap them for core work. In peak weeks, keep it short and easy.
Sat · 2026-11-28long
Long run
1h 05m · 175 m vert · ~7.8 km
Effort: Easy
Build relaxed time on feet at conversational effort.
Start with 10 minutes easy. Then 4 x 6 minutes uphill at a hard but repeatable effort, with 2 minutes easy between repeats. Finish with at least 10 minutes easy; any remaining time is easy.
Effort: Moderate: controlled reps, stop 1–2 short of failure
No-gym Session A: Bulgarian split squat, single-leg RDL, step-ups (bench/stairs), calf raises, side plank. Quality reps; stop well before failure. If 10 reps feels easy, add weight (backpack/water) so the last 2 reps feel challenging. In peak weeks, keep it short and easy.
Thu · 2026-12-03easy
Easy run
1h 15m · ~10.4 km
Effort: Easy
Conversational aerobic running. Keep easy days easy enough to support the key work.
Effort: Moderate: controlled reps, stop 1–2 short of failure
No-gym Session B: step-downs (slow 3–4s), lunges/sit-to-stand, soleus raises, carries (backpack), dead bug. Quality reps; stop well before failure. Keep the slow step-downs at least a day away from a long run; if this session falls the day before or after one, swap them for core work. In peak weeks, keep it short and easy.
Sat · 2026-12-05long
Long run
1h 30m · 250 m vert · ~10.8 km
Effort: Easy
Build relaxed time on feet at conversational effort.
Start with 10 minutes easy. Then 4 x 6 minutes uphill at a hard but repeatable effort, with 2 minutes easy between repeats. Finish with at least 10 minutes easy; any remaining time is easy.
Effort: Moderate: controlled reps, stop 1–2 short of failure
No-gym Session A: Bulgarian split squat, single-leg RDL, step-ups (bench/stairs), calf raises, side plank. Quality reps; stop well before failure. If 10 reps feels easy, add weight (backpack/water) so the last 2 reps feel challenging. In peak weeks, keep it short and easy.
Thu · 2026-12-10easy
Easy run
1h 20m · ~11.1 km
Effort: Easy
Conversational aerobic running. Keep easy days easy enough to support the key work.
Effort: Moderate: controlled reps, stop 1–2 short of failure
No-gym Session B: step-downs (slow 3–4s), lunges/sit-to-stand, soleus raises, carries (backpack), dead bug. Quality reps; stop well before failure. Keep the slow step-downs at least a day away from a long run; if this session falls the day before or after one, swap them for core work. In peak weeks, keep it short and easy.
Sat · 2026-12-12long
Long run
1h 30m · 275 m vert · ~10.6 km
Effort: Easy
Build relaxed time on feet at conversational effort.
Start with 10 minutes easy. Then 4 x 6 minutes uphill at a hard but repeatable effort, with 2 minutes easy between repeats. Finish with at least 10 minutes easy; any remaining time is easy.
Effort: Moderate: controlled reps, stop 1–2 short of failure
No-gym Session A: Bulgarian split squat, single-leg RDL, step-ups (bench/stairs), calf raises, side plank. Quality reps; stop well before failure. If 10 reps feels easy, add weight (backpack/water) so the last 2 reps feel challenging. In peak weeks, keep it short and easy.
Thu · 2026-12-17easy
Easy run
1h 20m · ~11.1 km
Effort: Easy
Conversational aerobic running. Keep easy days easy enough to support the key work.
Effort: Moderate: controlled reps, stop 1–2 short of failure
No-gym Session B: step-downs (slow 3–4s), lunges/sit-to-stand, soleus raises, carries (backpack), dead bug. Quality reps; stop well before failure. Keep the slow step-downs at least a day away from a long run; if this session falls the day before or after one, swap them for core work. In peak weeks, keep it short and easy.
Sat · 2026-12-19long
Long run
1h 35m · 300 m vert · ~11.1 km
Effort: Easy
Build relaxed time on feet at conversational effort.
Start with 10 minutes easy. Then 6 x 20 seconds relaxed strides, with 1 minute easy between repeats. Finish with at least 10 minutes easy; any remaining time is easy.
Effort: Moderate: controlled reps, stop 1–2 short of failure
No-gym Session A: Bulgarian split squat, single-leg RDL, step-ups (bench/stairs), calf raises, side plank. Quality reps; stop well before failure. If 10 reps feels easy, add weight (backpack/water) so the last 2 reps feel challenging. In peak weeks, keep it short and easy.
Thu · 2026-12-24easy
Easy run
1h 20m · ~11.1 km
Effort: Easy
Conversational aerobic running. Keep easy days easy enough to support the key work.
Start with 10 minutes easy. Then 4 x 5 minutes on familiar, controllable terrain at controlled hard, with 2 minutes easy between repeats. Finish with at least 10 minutes easy; any remaining time is easy.
Effort: Moderate: controlled reps, stop 1–2 short of failure
No-gym Session A: Bulgarian split squat, single-leg RDL, step-ups (bench/stairs), calf raises, side plank. Quality reps; stop well before failure. If 10 reps feels easy, add weight (backpack/water) so the last 2 reps feel challenging. In peak weeks, keep it short and easy.
Thu · 2026-12-31easy
Easy run
1h 25m · ~11.8 km
Effort: Easy
Conversational aerobic running. Keep easy days easy enough to support the key work.
Start with 10 minutes easy. Then 4 x 5 minutes on familiar, controllable terrain at controlled hard, with 2 minutes easy between repeats. Finish with at least 10 minutes easy; any remaining time is easy.
Effort: Moderate: controlled reps, stop 1–2 short of failure
No-gym Session A: Bulgarian split squat, single-leg RDL, step-ups (bench/stairs), calf raises, side plank. Quality reps; stop well before failure. If 10 reps feels easy, add weight (backpack/water) so the last 2 reps feel challenging. In peak weeks, keep it short and easy.
Thu · 2027-01-07easy
Easy run
1h 25m · ~11.8 km
Effort: Easy
Conversational aerobic running. Keep easy days easy enough to support the key work.
Start with 10 minutes easy. Then 3 x 2 minutes at controlled race effort, with 1 minute easy between repeats. Finish with at least 10 minutes easy; any remaining time is easy.
Run the 22.1 km as planned: start controlled and use the fuelling and kit rehearsed in training.
Cutoff check
If your race has a time limit, this estimates the minimum average pace and whether your
target finish time clears the cutoff.
Result
Enter a cutoff to see the required pace.
Exports
Use the personal subscription URL for a live saved plan. Calendar links regenerate from their parameters and may reflect updated race facts or engine fixes. A kept plan and its downloads remain unchanged.
Disclaimer: this plan is general information, not medical advice. Adjust based on fatigue,
experience, and injury history.
About the Arc of Attrition by UTMB Arc 20K course
At 22.1 km with 744 m of elevation gain, this is a fast, punchy distance where speed and hill strength both matter. At 34 m of vertical per kilometer, much of the course is runnable — the plan focuses on building your aerobic cruising speed while preparing you for the steeper sections.
This training plan adapts the 16-week structure specifically for 22.1 km with 744 m of elevation gain,
scaling weekly volume and vert targets so your body is ready for race-day demands.
Shorter trail races reward aggressive pacing and strong climbing. The plan emphasises quality intensity — hill repeats, tempo efforts, and race-pace sessions — while building enough endurance to finish strong on tired legs.
Training phases for Arc 20K
The current 16-week schedule has these phases for 22.1 km and 744 m of climbing:
Weeks 1–6 — Base Building: Establish consistent aerobic training and introduce course-like terrain gradually.
Weeks 7–11 — Vert Accumulation: Increase course-specific climbing while rehearsing easy effort and fueling.
Weeks 12–14 — Peak Volume: Practise the longest planned outings and race equipment without adding extra sessions.
Week 15 — Taper: Reduce training load while retaining a small amount of familiar intensity.
Week 16 — Race week: Reduce training and follow the race-day plan.
Pacing a runnable course
At 34 m of vertical per kilometer, much of the Arc of Attrition by UTMB Arc 20K course is runnable.
Training should emphasise aerobic cruising speed — tempo runs on rolling terrain, sustained effort on moderate climbs, and efficient flat-to-uphill transitions.
The biggest risk on a runnable course is starting too fast; practice negative-split long runs to build discipline.