Have you signed up for a 100 km trail run and are in search of an effective training plan? This distance is a remarkable challenge in the world of trail running, firmly in the ultra-trail category. For mountain trails, most runners take between 15 and 24 hours to complete the course, often spending a night in the great outdoors. In contrast, ‘flat’ trails typically see completion times ranging from 8 to 15 hours. Thus, adopting a comprehensive 100 km trail training plan is crucial for maintaining endurance over such a long distance.
Whether you’re participating in the CCC at UTMB Mont-Blanc, tackling the 90 km of Mont-Blanc, embarking on the Raid 100 km of L’Ultra Marin, enduring the Templiers’ Endurance Trail, or any other 100 km trail event, here are essential tips to prepare you for success.
The short answer
- Allow at least 16 to 24 weeks of preparation, after having already run a 40 to 60 km trail race.
- The core of the plan: hike-and-run sessions of 4 hours or more, hills, downhills and strength work.
- Test your nutrition, gear and night running in training, never for the first time on race day.
- On a mountain 100 km, most runners take between 15h and 24h.
Contents
- Understanding the terrain profile of your 100km trail run
- Core elements of the 100 km trail running training plan
- How many weeks do you need to prepare for a 100 km ultra?
- Sample training week for a 100 km trail race
- Training to run at night
- Preparing your nutrition for the 100 km
- 100 km ultra preparation: frequently asked questions
- Your 100 km trail running training plan
Understanding the terrain profile of your 100km trail run
In challenging terrains like the Alps or other mountainous trails, 100 km routes often feature significant elevation gains, typically ranging from 5,000 to 6,000 meters, and sometimes even more. The higher the elevation gain-to-distance ratio, the greater the need for muscle strength training. Expect a slower pace due to the demanding nature of these elevations, where muscle strength becomes a critical factor. When permitted, using trekking poles is highly advisable to assist in these rigorous conditions.
Conversely, on flatter or smoother trails, the primary challenge lies in the repetitive nature of movements and the continuous impact on the body. Preserving muscle strength is equally important here to prevent fatigue. Neglecting this can lead to a scenario where, despite the comparatively easier course, you might find yourself walking during the final stages of the trail.
Comparing two ultras with effort kilometres
To compare courses, use effort kilometres: every 100 m of elevation gain adds 1 effort-km. A 100 km race with 6000 m of climbing is 160 effort-km, while an almost flat 100 km is barely more than 100. The two preparations have nothing in common. Learn more about how to calculate elevation gain.
Core elements of the 100 km trail running training plan
For a 100 km trail run, the key factors are endurance, running economy, and muscle strength.
Run-Hiking: a vital component for endurance
A critical aspect of your training plan should be run-hiking sessions lasting 4 hours or more. Run-hiking involves alternating between walking and running, aiming to maintain a moderate heart rate, ideally within zones 2 or 3. This method is not only effective for building endurance but also allows you to acclimatize to the varying intensities you’ll encounter during the race.
To maximize the benefits, try to simulate race conditions by choosing paths that mirror the terrain you’ll face on race day. This approach provides an excellent opportunity to test your race gear in real conditions. More importantly, it’s the perfect time to fine-tune your nutrition and hydration strategies. A general guideline is to aim for approximately 500 ml (or 50 cl) of water per hour of effort, but this can vary based on individual needs and environmental factors.
Working on resistance and muscle strength
To work on resistance and muscle strength, you can do short hill repeats, long hill repeats, as well as muscle strengthening exercises, including proprioception and specific exercises for trail running. Even more so than for shorter trails, cycling is an ally for working on endurance and strength while reducing impact.
Example of short hill repeats: 12×30 seconds with recovery jogging downhill.
Examples of long hill repeats: 4×8 minutes on hills.
To have a trail-specific muscle strengthening circuit, the RunMotion Coach app includes a complete and intuitive Strength and Conditioning Workouts module to perform at home.
Beyond uphill training, your 100 km trail running plan should also focus on downhill running. This prepares you to effectively handle negative elevations on race day. While races of these formats are rarely won on the downhill segments, unprepared runners can lose significant time or risk injuries in these sections, especially over 100 km distances. Therefore, it’s vital to ensure physical readiness for all aspects of the trail.
How many weeks do you need to prepare for a 100 km ultra?
Allow at least 16 to 24 weeks of specific preparation, and ideally a whole season to build up distance. Before your first 100 km, having run a 40 to 60 km trail teaches you how you react over a long effort: nutrition, pacing, muscle soreness. If you haven’t, schedule a race of that length 2 to 3 months before your goal. To progress step by step, read our advice on increasing your trail running distance. And when you are ready to step up to 100 miles, check out our 100-mile training plan.
Sample training week for a 100 km trail race
This example is for a runner training 4 to 5 times a week over 20 weeks, for a mountain ultra with 4000 to 6000 m of elevation gain. The durations are guidelines to adapt to your level and recovery.
| Phase | During the week | At the weekend |
|---|---|---|
| Base (weeks 1 to 8) | 1h easy run; short hills 12×30″; 30′ of strength work or cycling | Hilly long run of 2h30 to 3h |
| Specific (weeks 9 to 17) | Long hills 4×8′; easy run with 10 downhills of 1′; 4 rounds of strength and conditioning; 1 to 2 bike rides | Hike-and-run of 4h to 6h, sometimes over two days (intensive training weekend) |
| Taper (weeks 18 to 20) | Volume cut by 30 to 50%, short hill reminder | 2h hike-and-run, then race day |
Every 3 to 4 weeks, schedule a lighter week. In ultra running, accumulated fatigue is the main injury risk.
Training to run at night
On a mountain 100 km, you will very likely spend part of the night out on the course. Do at least two or three night runs during your preparation, on trails you know, to get used to your headlamp and to the drop in alertness. It is also the time to test what you can eat when your appetite fades: our tips on night-time nutrition for ultras.
Preparing your nutrition for the 100 km
Over 15 to 24 hours of effort, nutrition is part of training. Use every long hike-and-run to test what you will eat in the race, how often and with which drink. Also check what your race’s aid stations offer. Our guide on fuelling for a trail or ultra explains the method.
100 km ultra preparation: frequently asked questions
How many hours a week to prepare for a 100 km?
At the peak of their preparation, many amateur runners train 7 to 12 hours a week, long runs included. Consistency over several months matters more than one big isolated week.
What is the longest run before a 100 km?
One or two hike-and-run sessions of 5 to 6 hours, or an intensive weekend with two back-to-back long runs, 4 to 6 weeks before the race. Going further costs more in fatigue than it brings.
Can I run a 100 km without having done a long trail race?
It is risky. A 40 to 60 km trail before your first 100 km teaches you to manage pacing, nutrition and gear over a long effort. Our trail marathon training plan is a good step.
Do I need poles for a 100 km ultra?
On a mountain course they are often recommended when the rules allow them. Train with them during your hike-and-run sessions: running with poles.
Is there a 100 km trail training plan in PDF?
A fixed PDF plan takes neither your level nor your availability into account. The table above gives you the structure; the RunMotion Coach app then builds a personalised plan that adapts to your feedback.
Your 100 km trail running training plan
For your 100 km trail running training plan, you need to consider these elements and work on these varied areas. The simplest way is to download RunMotion Coach, as our algorithms will create your personalized training plan and Strength and Conditioning workouts (S&C workouts) circuits in addition to your running training. You can also add up to 2 cycling sessions per week.
Your training plan will be adapted to your goal, experience, and availability. Be sure to indicate the training terrains available to you (paths, mountains, hills, etc.). Your training plan will then evolve based on your feedback.
Among the sessions you can find in your 100 km trail running training plan:
- Run-hiking for 5 hours
- Hill repeats 12×30 seconds
- Long hill repeats 4×8 minutes
- 10 downhill runs of 1 minute each
- 4 sets of Strength and Conditioning workouts (S&C workouts) > single-leg squats, wall sits, proprioception drills, hamstring exercises,…)
In the Premium version of the app, you gain access to additional muscle strengthening sessions specifically designed for trail running. As you approach race day, the app also provides specialized advice, particularly on nutrition, to ensure you’re fully prepared.
The RunMotion Coach app, based in the Alps in Chambéry, supports runners of all levels globally. Our team, including enthusiasts of the 100 km distance, brings firsthand experience to the table. Julien Coudert, the creator of the S&C workouts, notably finished 15th in the CCC in 2013. Also, Guillaume and Romain Adam, who ran the CCC in 2019, contribute their insights and advice for the CCC.
We wish you a successful training experience with your 100 km trail running training plan!
