
Trail 50K Training Plan: 20 Weeks, Beginner, Heart Rate
A structured, progressive 20-week heart-rate plan to get you to the finish line of your first trail 50K healthy and confident. It builds your aerobic base, climbing and descending strength and race-day routines step by step, with an easier week every fourth week.
The Race
A typical trail 50K: 50 km (31 mi) with about 1,200-2,500 m (4,000-8,200 ft) of climbing. Your first ultramarathon. Six to ten hours for most first-timers, with long climbs, long descents, aid stations and the need to eat and drink all day. The plan works for any trail race of this distance: the race day is set as an event on the final Saturday.
Who It Is For
You have finished a trail 30K, half marathon or longer, run 3-4 times a week (about 3.5-4 h) and can run 75 min on trails.
Your 20 Weeks
- Phases: Preparation weeks 1-2, Base weeks 3-8, Build weeks 9-13, Specific weeks 14-18, Taper week 19, race week 20.
- Weekly: 4 runs and 2 strength sessions, about 3.6 h rising to 7.6 h of running.
- Long runs: 1h15 to 4h00, with back-to-back runs up to 1h30.
- Climbing: about 400 m rising to 1250 m a week.
- Trail skills: hill repeats, power hiking, downhill technique, fueling practice and a dress rehearsal.
- Strength: two RunForce 45-min sessions built in the TrainingPeaks Strength Builder (A: Force & Posterior Chain; B: Single-Leg & Mountain Durability), with a demonstration video for every exercise.
Heart Rate Training

Every run is prescribed in RunForce heart-rate zones (% of max HR), with a field check in week 1. Workouts explain how to use heart rate on climbs, on short efforts and in the heat.
The RunForce Beginner Trail Series
Seven progressive plans: 10K, 20K, 30K / 20 Miles, 50K, 75K / 50 Miles, 100K and 100 Miles, each in Heart Rate, RPE and Pace versions. Finish one, recover for 2-4 weeks, then start the next distance. This plan is also available in RPE and Pace versions. Search "RunForce Beginner Trail" in the TrainingPeaks store.
Your Coach: Adrien Thévenet

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.