Mountain ultra-trailing is a very demanding challenge, both physically and mentally. To embark on it with serenity and efficiency, a methodical, individualized preparation compatible with one's personal life is essential.
Adapt training to your life, not the other way around
The first common mistake is to base your schedule on a rigid training plan. However, ultra-endurance requires long-term regularity rather than brutal and temporary volume. You must therefore build a plan that respects your professional, family, and social constraints. The training plan must therefore be personal and adapted to your constraints. Before signing up for a race, it is important to conduct a thorough cost-benefit analysis. An ultra-trail requires:
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A weekly investment of 8 to 15 hours of training (Léger, 2008)
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Planned active and passive recovery,
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Material, nutritional, and medical logistics.
Small tip: Keep a journal for two weeks to objectively assess the time available for training, recovery, and sleep. Also include your projects for the coming year, so that all information is visible.
1. Develop aerobic endurance: the fundamental basis
Aerobic endurance is the ability to sustain effort below the lactate threshold for long durations. It represents the foundation of all ultra performance.
Why?
• It improves energy efficiency (Friedmann et al., 2003)
• It promotes the use of fat as a substrate.
• It allows for maintaining a constant pace in difficult terrain.
How to train it?
• Specific long trail runs, at low intensity or with some pace variations
• Regular jogging sessions
• Polarized training: 80% at low intensity, 20% at high intensity (Seiler, 2010) — warm-up and cool-down periods are included in the 80%
• Gradually increase volume, planning your season and load
• Take advantage of long outings to test poles, equipment, nutrition, and dietary strategy
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2. Work on VMA and uphill VMA
VMA (Maximum Aerobic Speed) helps raise the performance ceiling. Its "uphill" version (on slopes >15%) is a good indicator of mountain performance.
Vernillo et al. (2015) show that the most successful ultra-trail runners have better uphill running economy.
Why is it useful?
• Better ability to climb quickly
• Improved tolerance to intense effort at altitude
• Optimization of the power-to-weight ratio
How to train?
• Specific VMA sessions on hills or steep slopes (>15%) — e.g.: 2 x (6 x 1’/1’ full effort on the slope)
• Fartlek sessions in mountainous terrain
• Intervals integrated into long runs to work on pre-fatigue
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3. Prepare the body for heat and humidity
Thermoregulation is often underestimated. However, in summer ultra-trails (UTMB, Diagonale des Fous, Grand Raid des Pyrénées), heat and humidity can be decisive.
Why worry about it?
• Thermal stress reduces muscular and cognitive abilities (Nybo et al., 2014)
• Dehydration alters blood flow and potentially increases the risk of cramps
Preparation methods
• Passive acclimatization: sauna after workouts (20 min, 2 to 3 times/week)
• Active acclimatization: runs in heat with progressive load (Racinais et al., 2015)
→ It is possible to maintain your classic training plan, monitoring intensity with a heart rate monitor (reduced pace and power zones)
• Adapted clothing and hydration strategy tests
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4. Test your nutrition and train your glucose tolerance
In ultra-running, failure is often digestive before it is muscular. The digestive system must be trained just as much as the legs.
In-race nutrition goals
• Provide 60 to 90g of carbohydrates per hour (Jeukendrup, 2014), or more if tolerated. Best tolerated ratio: 1:0.8 (Maltodextrin-Fructose)
• Avoid gastrointestinal problems
• Prevent hypoglycemia
Pyrène DrinkMix is particularly suitable with its highly digestible and non-nauseating formula.
How to train the digestive tract?
• Incorporate carbohydrate intake during training (gels, drinks, bars)
• Test a variety of textures and temperatures
• Gradually increase the amount of carbohydrates consumed during training (Stellingwerff, 2020)
⚠️ Certain intolerances (FODMAPs, lactose, etc.) must be identified beforehand via a food diary.
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5. Strength training: a lever for performance and injury prevention
Too often neglected by trail runners, strength training is nevertheless an essential tool, especially in the mountains, where biomechanical constraints are high (elevation changes, unstable terrain, long descents, extreme fatigue).
Why incorporate strength training?
For performance:
• Improves running economy (amount of energy required at a given speed) (Balsalobre-Fernández et al., 2016)
• Strengthens the ability to generate force on uneven ground
• Delays the onset of muscular fatigue and protects against prolonged muscle degradation (Millet & Lepers, 2004)
For injury prevention:
• Addresses certain muscle imbalances
• Improves joint stability (knee, ankle, pelvis) (Lauersen et al., 2014)
• Strengthens connective tissues (tendons, ligaments), reducing the risk of overuse injuries
How to integrate it?
• 1 to 2 sessions/week in the development phase (winter, early season)
• 1 session/week in the maintenance phase (specific period)
• Moderate to heavy load with a focus on technique and control
• Progressive integration of plyometrics
To avoid: sessions too close to long runs or intense workouts, to limit cumulative fatigue.
Tip: a strength training session can be coupled with a 45 min to 1 hour jog a few hours later.
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In conclusion
Preparing for a mountain ultra-trail isn't just about "running more." It's a fine orchestration between:
• A schedule compatible with real life
• Progressive development of endurance and power
• Adaptation to environmental conditions
• Personal mastery of nutrition during long efforts
• Reasoned integration of strength training
Ultra-running is an adventure.
But an adventure that is won first in training — and even before that, in planning.
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References
• Seiler, S. (2010). What is best practice for training intensity and duration distribution in endurance athletes? Int. J. Sports Physiology and Performance.
• Jeukendrup, A. (2014). A step towards personalized sports nutrition: carbohydrate intake during exercise. Sports Medicine.
• Vernillo, G., et al. (2015). Physiological characteristics of trail running athletes. J. Sports Med. Phys. Fitness.
• Racinais, S., et al. (2015). Optimizing training and performance in hot environments. Scand. J. Med. Sci. Sports.
• Nybo, L., et al. (2014). Performance in the heat—physiological factors of importance for hyperthermia-induced fatigue. Comprehensive Physiology.
• Millet, G.P., et al. (2011). Ultra-endurance running and the role of pacing, nutrition, and training. Sports Medicine.
• Stellingwerff, T. (2020). Training the Gut for Athletes. ACSM’s Health & Fitness Journal.
• Balsalobre-Fernández, C., et al. (2016). Effects of strength training on running economy in highly trained runners: A systematic review with meta-analysis. J. Strength Cond. Res.
• Millet, G.Y., & Lepers, R. (2004). Alterations of neuromuscular function after prolonged running, cycling and skiing exercises. Sports Medicine.
• Lauersen, J.B., et al. (2014). The effectiveness of exercise interventions to prevent sports injuries: a systematic review and meta-analysis. Br. J. Sports Med.
Written by: Romain Bonzom, Coach & Physical Trainer.
