20-Week 100K Ultramarathon Training Plan
A 100K on 4 training days: weekend back-to-backs carry the volume, midweek stays short and focused. A structured 20-week plan by RunForce.
Who Is This For
Experienced trail runners who can train only 4 days a week but want to finish a 100K well.
Plan at a Glance
- Distance: 100K, 100 km (62 mi)
- Duration: 20 weeks
- Level: Intermediate
- Training days/week: 4 (4 runs, strength on run days)
- Peak training: about 10.9 h of running a week, long run 5h30, back-to-back 2h30
- Terrain: Hilly trail, some night running
- Elevation profile: Built for 100K courses with 2,500-4,500 m (8,000-15,000 ft) of climbing. Weekly climbing in the plan: 650 m (2,100 ft) rising to 2,300 m (7,500 ft).
How the Structured Workouts Work
- Targets: heart rate as a % of max HR, with a range for every step (warm-up, reps, recoveries, cool-down). Enter your max HR in TrainingPeaks; week 1 includes a field check.
- Zones: Z1 60-70% (RPE 2-3), Z2 70-78% (RPE 3-4), Z3 79-86% (RPE 5-6), Z4 86-91% (RPE 7-8), Z5 91-100% (RPE 8-9).
- RPE: each target also shows its 1-10 effort, for short reps, heat, altitude or running without a heart-rate monitor.
- No pace targets: pace means little on climbs and technical trail.
- Devices: workouts sync to compatible watches (e.g. Garmin, COROS, Suunto, Apple Watch). A chest strap is recommended.
- Strength: Strength Builder sessions with videos, sets, reps and a target RPE.
Prerequisites
A finished 50K or 50-miler, running 4 times a week (about 5 h), a 1:45 trail long run.
What Is Included
- 20 weeks of structured workouts: Foundation weeks 1-2, Aerobic Development weeks 3-8, Strength & Muscular Endurance weeks 9-12, Race-Specific weeks 13-17, Taper weeks 18-19, race week 20. An easier week every 3-4 weeks.
- Purposeful long runs, back-to-backs and a dress rehearsal, plus a fueling lesson on every long run.
- Race day set as a TrainingPeaks event on the final Saturday, with pacing, fueling and checklist.
- RunForce Strength Builder sessions with exercise videos, sets, reps and RPE: 2 a week in the foundation phases, 1-2 in the specific phases, none in the final 10 days.
Your Coach: Adrien Thévenet
UESCA-certified Ultrarunning Coach. Endurance coach since 2011, working with elite athletes, professional endurance athletes, major race winners, and a Spartan National Champion across road, trail, and mountain running.
Certifications:
-25 Years of Endurance Sports Experience
-TrainingPeaks Level 2
-UESCA Ultrarunning
-RRCA Certified
-STRYD Power Coach
-ACE Certified
With 25 years in endurance sports, I offer tailored coaching for diverse runners - from beginners to sub 3-hour marathoners. Emphasizing well-being, we collaborate on a program that fits your life keeping you motivated.