The Trail Running Briefing

An ultrarunner doesn't just need a powerful aerobic engine. They need a flexible one.

In this episode of The Trail Running Briefing, we explore metabolic flexibility: the body's ability to adjust its use of fat and carbohydrate according to exercise intensity, duration and fuel availability.

Fat provides an enormous energy reserve during prolonged, lower-intensity exercise, while carbohydrate becomes increasingly important when the demands rise, whether during a steep climb, a technical section or a hard finish.

But does becoming better at burning fat automatically make us better ultrarunners?

We examine the scientific evidence, including research showing that low-carbohydrate, high-fat diets can substantially increase fat oxidation without necessarily improving endurance performance. We also explain why metabolic adaptations don't always translate into better race results.

Most importantly, we discuss how to develop metabolic flexibility through consistent aerobic training, appropriate carbohydrate availability, effective fuelling strategies and gut training.

Metabolic flexibility isn't about burning as much fat as possible. It's about developing the capacity to use the right fuel, at the right time, for the right effort.

Because even in a 100-mile race, your body doesn't operate at one intensity, and your training and nutrition should reflect that.

Key references:

1. Burke et al. (2017) — Low carbohydrate, high fat diet impairs exercise economy and negates the performance benefit from intensified training in elite race walkers.

2. Burke et al. (2020) — Crisis of confidence averted: Impairment of exercise economy and performance in elite race walkers by ketogenic LCHF diet is reproducible.

3. Impey et al. (2018) — Fuel for the Work Required: A Theoretical Framework for Carbohydrate Periodization and the Glycogen Threshold Hypothesis.

4. Gejl and Nybo (2021) — Performance effects of periodized carbohydrate restriction in endurance trained athletes — a systematic review and meta-analysis.

5. Tiller et al. (2019) — International Society of Sports Nutrition Position Stand: Nutritional considerations for single-stage ultra-marathon training and racing.

6. Systematic review (2023) — The Effect of Gut-Training and Feeding-Challenge on Markers of Gastrointestinal Status in Response to Endurance Exercise.

7. Systematic review (2024) — The Effects of Ketogenic Diets and Ketone Supplements on the Aerobic Performance of Endurance Runners.

Why do your legs sometimes give up during an ultramarathon when your breathing feels comfortable and your aerobic fitness suggests you could keep going?

In this episode of the Trail Running Briefing, we explore ultra durability, the ability to maintain muscular strength, running efficiency and movement quality as fatigue accumulates over hours of running.

Drawing on recent scientific research, we examine why muscle damage and neuromuscular fatigue can become major performance limiters in long mountainous ultras, particularly during repeated climbs and descents.

We also explore the difference between building a powerful aerobic engine and developing the muscular resilience needed to support it.

Most importantly, this episode provides practical, evidence-based guidance on how to improve durability through progressive strength training, downhill conditioning, race-specific long runs, intelligent pacing, fuelling and recovery.

Ultra performance isn't just about how fast or efficiently you run when fresh. It's about how much of that performance you can preserve when fatigue arrives.

Train your engine. Strengthen your chassis. Build the durability to reach the finish line.

Key references:

1. Tiller & Millet (2025). Decoding Ultramarathon: Muscle Damage as the Main Impediment to Performance. Sports Medicine.

2. Muñoz de la Cruz et al. (2026). Decoding Neuromuscular Fatigue in Trail Running: A Systematic Review Across Distances and Sex Differences. International Journal of Sports Physiology and Performance.

3. Zanini et al. (2025). Strength Training Improves Running Economy Durability and Fatigued High-Intensity Performance in Well-Trained Male Runners. Medicine & Science in Sports & Exercise.

4. Giandolini et al. (2016). Effect of the Fatigue Induced by a 110-km Ultramarathon on Tibial Impact Acceleration and Lower Leg Kinematics.

5. Vernillo et al. (2015). Energy Cost and Kinematics of Level, Uphill and Downhill Running: Fatigue-Induced Changes After a Mountain Ultramarathon. Journal of Sports Sciences.

6. Bontemps et al. (2025). Muscle Soreness but Not Neuromuscular Fatigue Responses Following Downhill Running Differ According to the Number of Exercise Bouts. European Journal of Sport Science.

7. Llanos-Lagos et al. (2024). The Effect of Strength Training Methods on Middle-Distance and Long-Distance Runners' Athletic Performance: A Systematic Review with Meta-analysis. Sports Medicine.

8. Hunter et al. (2025). Durability as an Index of Endurance Exercise Performance: Methodological Considerations. Experimental Physiology.

9. Garbisu-Hualde & Santos-Concejero (2020). What Are the Limiting Factors During an Ultra-Marathon? A Systematic Review of the Scientific Literature.

Can too much training take away your love of running?

In this episode of The Trail Running Briefing, we explore athlete burnout, why trail and ultra runners are particularly vulnerable, and how the constant pursuit of improvement can sometimes become counterproductive.

Drawing on the latest scientific research, we explain the difference between normal training fatigue, overtraining and burnout, and explore how accumulated training demands, insufficient recovery, psychological pressure and everyday life stress can affect both performance and motivation.

More importantly, we discuss practical strategies to recognise the early warning signs, reduce the risk of burnout and maintain a healthy balance between training, recovery and personal life. We also explore how to recover when burnout has already developed and rediscover the enjoyment of running.

Because sustainable ultrarunning isn't about how much training you can tolerate. It's about becoming stronger while protecting your health, wellbeing and love of the sport for years to come.

Key references:

1. Lin, C.-H., et al. (2025). Re-examining Athletes’ Stress-Burnout Relationship: A Systematic Review and Meta-Analysis. International Sports Studies, 47(2), 110–156.

2. Dišlere, B. E., et al. (2025). A Scoping Review of Longitudinal Studies of Athlete Burnout. Frontiers in Psychology, 16, 1502174.

3. Reardon, C. L., et al. (2026). Mental Health in Elite Athletes: International Olympic Committee Consensus Statement (2026). British Journal of Sports Medicine, 60(15), 1083–1130.

4. Glandorf, H. L., et al. (2026). Athlete Burnout, Biomarkers, and Mental and Physical Health: A Longitudinal Examination of Physiological Mechanisms and Processes. Sport, Exercise, and Performance Psychology, 15(3), 299–319.

5. Mountjoy, M., et al. (2023). 2023 International Olympic Committee's Consensus Statement on Relative Energy Deficiency in Sport (REDs). British Journal of Sports Medicine, 57(17), 1073–1097.

6. Saw, A. E., Main, L. C., & Gastin, P. B. (2016). Monitoring the Athlete Training Response: Subjective Self-Reported Measures Trump Commonly Used Objective Measures: A Systematic Review. British Journal of Sports Medicine, 50(5), 281–291.

7. Walsh, N. P., et al. (2021). Sleep and the Athlete: Narrative Review and 2021 Expert Consensus Recommendations. British Journal of Sports Medicine, 55(7), 356–368.

In Episode 36 of The Trail Running Briefing, I take you through the ARC100 by UTMB from the perspective of someone who has raced it twice, in 2025 and 2026.

This episode is designed as a practical course guide for runners preparing for the race. I break down the key sections of the route, including the wet and boggy terrain around Lizard Point and Mullion, the runnable stretches towards Penzance, the technical section from Mousehole to Porthcurno, and the importance of using Land’s End as a chance to reset.

I also focus on what I consider the toughest part of the race: Pendeen to Lelant. This long, technical section can take many hours, so carrying enough water and nutrition and preparing mentally for slow progress is essential.

Along the way, I share lessons from my own experience, including foot management, accepting wet conditions, using barrier cream, training with wet feet, pacing the runnable sections sensibly, and which parts of the course are most worth recceing.

The key message is simple: don’t race the distance, race the terrain in front of you.

Cross-training can be a valuable tool for ultrarunners, but it should always serve a clear purpose.

In this episode of The Trail Running Briefing, I explore why specificity still matters, especially for mountain ultrarunners. A long ultra is not simply one discipline: it involves running uphill, running flats, running downhill and, very importantly, power-hiking steep climbs.

We look at why uphill walking can be one of the most race-specific forms of “cross-training”, how cycling can build additional aerobic volume with less impact, and where swimming can be useful during recovery, injury management or high-load periods.

I also explain why strength training should not really be considered cross-training at all, but rather an essential part of ultramarathon preparation.

The key question is not: “What is the best cross-training?”

It is:

“What adaptation am I trying to create, and what is the most specific way to achieve it without adding unnecessary fatigue?”

Train the engine but train the movement too.

Key references:

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Endurance Coach GmbH et al. (2026). Cross-training between running and cycling: effects on VO₂max and running performance — a systematic review and meta-analysis. Frontiers in Sports and Active Living.

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Finiel, L., Carron, S., Margot, C., et al. (2026). Energetic cost of locomotion closely aligns with the preferred uphill walk-run transition at constant vertical speed in runners. European Journal of Applied Physiology.

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Martinez-Navarro, I., Vicente-Mampel, J., López-Grueso, R., et al. (2026). Uphill Walking Economy and Maximal Oxygen Consumption in Trail Runners: Relationship with Ultra-Trail Performance. International Journal of Sports Medicine.

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Brill, J.W. & Kram, R. (2021). Does the preferred walk-run transition speed on steep inclines minimize energetic cost, heart rate or neither? Journal of Experimental Biology, 224, jeb233056.

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Vernillo, G., et al. (2020). Steep (30°) uphill walking vs. running: COM movements, stride kinematics, and leg muscle excitations. European Journal of Applied Physiology.

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Tanaka, H. (1994). Effects of cross-training: transfer of training effects on VO₂max between cycling, running and swimming. Sports Medicine.

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Reilly, T., Morris, T. & Whyte, G. (2009). The specificity of training prescription and physiological assessment: a review. Journal of Sports Sciences.

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Eihara, Y., et al. (2024). Effect of Strength Training Programs in Middle- and Long-Distance Runners' Economy at Different Running Speeds: A Systematic Review with Meta-analysis. Sports Medicine.

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Recent umbrella review (2025). The Effect of Strength Training on Endurance Performance Determinants in Middle- and Long-Distance Endurance Athletes.

Mental toughness in ultrarunning is often misunderstood.

It isn’t about ignoring pain, refusing to walk, or proving how much suffering you can tolerate. Current research suggests the more useful skill is how you respond when things become difficult.

In this episode, I look at what the evidence tells us about mental toughness, pain coping, resilience and self-efficacy in ultra-endurance running and why stubbornness should not be confused with toughness.

We also explore a simple practical framework:

Acknowledge. Assess. Act.

Recognise what is happening, work out what you can control, and take the next useful action.

Because sometimes mental toughness means pushing. Sometimes it means slowing down, eating, walking, adapting the plan or fixing a problem early.

The goal isn’t to become unbreakable.

Mental toughness isn’t about suffering more. It’s about responding better.

Key references:

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Song, Q., & Song, Y-G. (2026). Psychological Traits Associated with Mental and Performance Resilience in Long-Distance and Ultra-Endurance Runners: A Systematic Review. Frontiers in Psychology, 17, 1919146. DOI: 10.3389/fpsyg.2026.1919146.

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Delalay, M., & Hotz Boendermaker, S. (2026). Mental Pain Responses of Ultramarathon Runners: A Scoping Review. Sports, 14(2), 72. DOI: 10.3390/sports14020072.

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Paley, C. A., & Johnson, M. I. (2025). Human Resilience and Pain Coping Strategies: A Review of the Literature Giving Insights from Elite Ultra-Endurance Athletes for Sports Science, Medicine and Society. Sports Medicine, 55, 2137–2146. DOI: 10.1007/s40279-025-02277-4.

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Alschuler, K. N., Krabak, B. J., Kratz, A. L., Jensen, M. P., Pomeranz, D., Burns, P., Bautz, J., Nordeen, C., Irwin, C., & Lipman, G. S. (2020). Pain Is Inevitable But Suffering Is Optional: Relationship of Pain Coping Strategies to Performance in Multistage Ultramarathon Runners. Wilderness & Environmental Medicine, 31(1), 23–30. DOI: 10.1016/j.wem.2019.10.007.

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Brace, A. W., George, K., & Lovell, G. P. (2020). Mental Toughness and Self-Efficacy of Elite Ultra-Marathon Runners. PLOS ONE, 15(11), e0241284. DOI: 10.1371/journal.pone.0241284. Studied 56 elite HURT100 runners.

Episode 33 explores running injuries through a simple risk-management lens: Risk = Probability × Impact. The central idea is that ageing does not automatically make runners fragile or guarantee a higher injury risk, but the consequences of a significant injury can become more costly because rebuilding lost strength, fitness, tendon capacity and race-specific durability may take longer and disrupt a larger proportion of our training.

The episode argues that our risk appetite should evolve with age. Rather than becoming overly cautious, masters runners should become more selective about which risks are worth taking. Hard training, long runs, strength work, hills and race-specific stress still matter but unnecessary risks such as aggressive progression, excessive racing, poor recovery or ignoring persistent niggles offer little return.

The key message is simple: protecting consistency is itself a performance strategy. Train hard where the adaptation justifies the risk, reduce avoidable injury risk, and spend your “risk budget” wisely.

Key references:

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Mckendry J, et al. (2018). Muscle morphology and performance in master athletes: A systematic review and meta-analyses. Ageing Research Reviews.

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Delabastita T, Bogaerts S, Vanwanseele B. (2018). Age-Related Changes in Achilles Tendon Stiffness and Impact on Functional Activities: A Systematic Review and Meta-Analysis. Journal of Aging and Physical Activity.

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Svensson RB, et al. (2016). Effect of aging and exercise on the tendon. Journal of Applied Physiology.

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McCrum C, et al. (2018). Alterations in Leg Extensor Muscle-Tendon Unit Biomechanical Properties With Ageing and Mechanical Loading. Frontiers in Physiology.

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Jones MD, et al. (2021). Sex Differences in Adaptations in Muscle Strength and Size Following Resistance Training in Older Adults: A Systematic Review and Meta-analysis. Sports Medicine.

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Hayes EJ, et al. (2023). Recovery from Resistance Exercise in Older Adults: A Systematic Scoping Review. Sports Medicine – Open.

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Saragiotto BT, et al. (2014). What are the main risk factors for running-related injuries? Sports Medicine.

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van Poppel D, et al. (2021). Risk factors for overuse injuries in short- and long-distance running: A systematic review. Journal of Sport and Health Science.

In this episode of The Trail Running Briefing, we explore cardiac drift: why heart rate can gradually rise during long runs even when pace or effort appears unchanged.

We explain the relationship between heart rate and stroke volume, why heat, dehydration and prolonged exercise increase cardiovascular strain, and how this matters specifically for ultrarunners.

We also look at aerobic decoupling and durability, and discuss how pacing, consistent aerobic training, progressively longer runs, sensible hydration and heat acclimation can help reduce excessive drift.

The key message is simple: the same pace does not always mean the same physiological cost.

Key references:

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Coyle, E.F. & González-Alonso, J. (2001). Cardiovascular drift during prolonged exercise: New perspectives. Exercise and Sport Sciences Reviews, 29(2), 88–92.

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Fritzsche, R.G., Switzer, T.W., Hodgkinson, B.J. & Coyle, E.F. (1999). Stroke volume decline during prolonged exercise is influenced by the increase in heart rate. Journal of Applied Physiology, 86(3), 799–805.

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Montain, S.J. & Coyle, E.F. (1992). Influence of graded dehydration on hyperthermia and cardiovascular drift during exercise. Journal of Applied Physiology, 73(4), 1340–1350.

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González-Alonso, J., Calbet, J.A.L. & Nielsen, B. (1998). Muscle blood flow is reduced with dehydration during prolonged exercise in humans. The Journal of Physiology, 513(3), 895–905.

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Maunder, E., Seiler, S., Mildenhall, M.J., Kilding, A.E. & Plews, D.J. (2021). The Importance of 'Durability' in the Physiological Profiling of Endurance Athletes. Sports Medicine, 51(8), 1619–1628.

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Smyth, B., Maunder, E., Meyler, S., Hunter, B. & Muniz-Pumares, D. (2022). Decoupling of Internal and External Workload During a Marathon: An Analysis of Durability in 82,303 Recreational Runners. Sports Medicine, 52, 2283–2295.

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Tyler, C.J., Reeve, T., Hodges, G.J. & Cheung, S.S. (2016). The Effects of Heat Adaptation on Physiology, Perception and Exercise Performance in the Heat: A Meta-Analysis. Sports Medicine, 46(11), 1699–1724.

Peak form is not simply about being as fit as possible. It is the point where high fitness meets low fatigue, allowing an athlete to fully express the adaptations built over weeks and months of training.

Hard training develops aerobic fitness, strength, durability, climbing and descending ability, but it also creates fatigue. This means runners can sometimes be getting fitter while temporarily feeling slower or heavier. Tapering works by reducing that fatigue while preserving the fitness already developed.

Research supports substantially reducing training volume before an important race while maintaining some intensity. The purpose is not to create new fitness at the last minute, but to reveal the fitness already there.

Peak form should also be viewed as a window rather than a permanent state. Fitness can be maintained for relatively long periods, but the ideal combination of fitness, freshness, race specificity and psychological readiness cannot be held indefinitely.

After an A-race, the goal should therefore not be to stay at your peak, but to repeat the cycle:

RECOVER → REBUILD → DEVELOP → TAPER → PEAK AGAIN.

The key message of the episode is simple:

Training builds the fitness. Tapering reveals it.

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Wang, Z., Wang, Y., Gao, W., & Zhong, Y. (2023).Effects of tapering on performance in endurance athletes: A systematic review and meta-analysis. PLOS ONE, 18(5), e0282838.DOI: 10.1371/journal.pone.0282838

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Bosquet, L., Montpetit, J., Arvisais, D., & Mujika, I. (2007).Effects of tapering on performance: A meta-analysis. Medicine & Science in Sports & Exercise, 39(8), 1358–1365.

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Mujika, I., & Padilla, S. (2003).Scientific bases for precompetition tapering strategies. Medicine & Science in Sports & Exercise, 35(7), 1182–1187.DOI: 10.1249/01.MSS.0000074448.73931.11

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Calvert, T. W., Banister, E. W., Savage, M. V., & Bach, T. (1976).A systems model of the effects of training on physical performance. IEEE Transactions on Systems, Man, and Cybernetics, 6(2), 94–102.DOI: 10.1109/TSMC.1976.5409179

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Spiering, B. A., Mujika, I., Sharp, M. A., & Foulis, S. A. (2021).Maintaining Physical Performance: The Minimal Dose of Exercise Needed to Preserve Endurance and Strength Over Time. Journal of Strength and Conditioning Research, 35(5), 1449–1458.DOI: 10.1519/JSC.0000000000003964

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Millet, G. Y., Tomazin, K., Verges, S., Vincent, C., Bonnefoy, R., Boisson, R. C., et al. (2011).Neuromuscular Consequences of an Extreme Mountain Ultra-Marathon. PLOS ONE, 6(2), e17059.DOI: 10.1371/journal.pone.0017059

In Episode 30 of The Trail Running Briefing, we explore why ultrarunners sometimes stop improving even when they are training consistently and working harder.

A plateau doesn’t always mean you need more mileage or more intensity. It can mean your body has adapted to the same training stimulus, accumulated fatigue is hiding your fitness, recovery or fuelling is insufficient, or your training is no longer targeting the qualities that actually limit your performance.

We look at the importance of purposeful progression, keeping easy runs genuinely easy, strength training, durability, recovery weeks, adequate fuelling and race-specific preparation.

The key message is simple: training is not about collecting more kilometres, it is about creating adaptation. Before doing more, understand what needs to change.

Key References:

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Zanini, M., Folland, J. P., & Blagrove, R. C. (2026).Regular Long Runs and Higher Training Volumes Are Associated with Better Running Economy Durability in Performance-Matched Well-Trained Male Runners.Medicine & Science in Sports & Exercise, 58(1), 162–173.

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Zanini, M., Folland, J. P., Wu, H., & Blagrove, R. C. (2025).Strength Training Improves Running Economy Durability and Fatigued High-Intensity Performance in Well-Trained Male Runners: A Randomized Controlled Trial.Medicine & Science in Sports & Exercise, 57(7), 1546–1558.

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Tiller, N. B., & Millet, G. Y. (2025).Decoding Ultramarathon: Muscle Damage as the Main Impediment to Performance.Sports Medicine, 55(3), 535–543.

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Llanos-Lagos, C., Ramirez-Campillo, R., Moran, J., & Sáez de Villarreal, E. (2024).Effect of Strength Training Programs in Middle- and Long-Distance Runners' Economy at Different Running Speeds: A Systematic Review with Meta-analysis.Sports Medicine, 54(4), 895–932.

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Sperlich, B. et al. (2023).The Proportional Distribution of Training by Elite Endurance Athletes at Different Intensities During Different Phases of the Season.Frontiers in Sports and Active Living, 5, 1258585.

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Oliveira, P. S. et al. (2024).Comparison of Polarized Versus Other Types of Endurance Training Intensity Distribution on Athletes' Endurance Performance: A Systematic Review and Meta-analysis.

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Mountjoy, M. et al. (2023).2023 International Olympic Committee's (IOC) Consensus Statement on Relative Energy Deficiency in Sport (REDs).British Journal of Sports Medicine, 57, 1073–1097.

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Meeusen, R., Duclos, M., Foster, C., Fry, A., Gleeson, M., Nieman, D., Raglin, J., Rietjens, G., Steinacker, J., & Urhausen, A. (2013).Prevention, Diagnosis, and Treatment of the Overtraining Syndrome: Joint Consensus Statement of the European College of Sport Science and the American College of Sports Medicine.Medicine & Science in Sports & Exercise, 45(1), 186–205.

Ultra running demands far more than just mileage. Long runs, back-to-backs, strength work, fuelling, recovery, work, family and everyday stress all contribute to the total load an athlete carries.

In this episode, I explore burnout in ultrarunning, how it differs from normal fatigue or overtraining, and why it can gradually turn something we love into something that feels like an obligation.

We look at the key warning signs, physical and emotional exhaustion, declining motivation, reduced sense of achievement and losing enjoyment in the sport, and most importantly, what runners can do to reduce the risk.

The central message is simple: your real training load is training plus everything else happening in your life.

Sustainable ultra running isn’t about doing the maximum training you can survive. It’s about training at a level you can repeatedly absorb while protecting your motivation, health and love for running.

Key references:

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Raedeke, T. D., & Smith, A. L. (2001). Development and preliminary validation of an Athlete Burnout Measure. Journal of Sport & Exercise Psychology, 23(4), 281–306.https://doi.org/10.1123/jsep.23.4.281

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Gustafsson, H., DeFreese, J. D., & Madigan, D. J. (2017). Athlete burnout: Review and recommendations. Current Opinion in Psychology, 16, 109–113.https://doi.org/10.1016/j.copsyc.2017.05.002

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Lonsdale, C., Hodge, K., & Rose, E. A. (2009). Athlete burnout in elite sport: A self-determination perspective. Journal of Sports Sciences, 27(8), 785–795.https://doi.org/10.1080/02640410902929366

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Kellmann, M., Bertollo, M., Bosquet, L., et al. (2018). Recovery and Performance in Sport: Consensus Statement. International Journal of Sports Physiology and Performance, 13(2), 240–245.https://doi.org/10.1123/ijspp.2017-0759

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Cresswell, S. L., & Eklund, R. C. (2005). Changes in athlete burnout and motivation over a 12-week league tournament. Medicine & Science in Sports & Exercise.

Episode 28 explores how ultra training should evolve with age without lowering ambition. The central idea is the recovery budget: every long run, hard session, strength workout and race creates stress, while sleep, work, nutrition and life commitments affect how quickly that budget is restored.

As runners get older, training does not necessarily need to become easier, but it should become less crowded and more purposeful. This means allowing more recovery between demanding sessions, maintaining strength training, using intensity selectively and treating races as major training loads rather than casual additions to the calendar.

The episode also stresses that sustainable training matters at every age. Younger runners may tolerate poor decisions for longer, but repeated overload can still lead to injury, fatigue and burnout. The key message is:

Do not ask how much training you can survive. Ask how much training you can absorb and repeat for years.

Key references:

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Tanaka H, Seals DR. Endurance exercise performance in Masters athletes: age-associated changes and underlying physiological mechanisms. The Journal of Physiology. 2008;586(1):55–63. doi: 10.1113/jphysiol.2007.141879

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Borges N, Reaburn P, Driller M, Argus C. Age-related changes in performance and recovery kinetics in Masters athletes: a narrative review. Journal of Aging and Physical Activity. 2016;24(1):149–157. doi: 10.1123/japa.2015-0021

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Valenzuela PL, Maffiuletti NA, Joyner MJ, Lucia A, Lepers R. Lifelong endurance exercise as a countermeasure against age-related VO₂max decline: physiological overview and insights from Masters athletes. Sports Medicine. 2020;50(4):703–716. doi: 10.1007/s40279-019-01252-0

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Fragala MS, Cadore EL, Dorgo S, et al. Resistance training for older adults: position statement from the National Strength and Conditioning Association. Journal of Strength and Conditioning Research. 2019;33(8):2019–2052. doi: 10.1519/JSC.0000000000003230

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Llanos-Lagos C, Ramirez-Campillo R, Moran J, Sáez de Villarreal E. Effect of strength-training programs on middle- and long-distance runners’ economy at different running speeds: a systematic review with meta-analysis. Sports Medicine. 2024;54(4):895–932. doi: 10.1007/s40279-023-01978-y

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Herbert P, Hayes LD, Sculthorpe NF, Grace FM. HIIT produces increases in muscle power and free testosterone in male Masters athletes. Endocrine Connections. 2017;6(7):430–436. doi: 10.1530/EC-17-0159

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Soligard T, Schwellnus M, Alonso JM, et al. How much is too much? Part 1: International Olympic Committee consensus statement on load in sport and risk of injury. British Journal of Sports Medicine. 2016;50(17):1030–1041. doi: 10.1136/bjsports-2016-096581

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Doering TM, Reaburn PR, Phillips SM, Jenkins DG. Postexercise dietary protein strategies to maximize skeletal-muscle repair and remodeling in Masters endurance athletes: a review. International Journal of Sport Nutrition and Exercise Metabolism. 2016;26(2):168–178. doi: 10.1123/ijsnem.2015-0102

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Tiller NB, Millet GY. Decoding ultramarathon: muscle damage as the main impediment to performance. Sports Medicine. 2025;55(3):535–543. doi: 10.1007/s40279-024-02127-9

After a DNF, remember this sequence:

Feel it. Separate it. Learn from it. Then move forward.

Feel the disappointment without shame. Separate the facts from the story you are telling about yourself. Extract a small number of useful lessons. Then rebuild through ordinary, consistent action.

A DNF is painful because the goal mattered. But it is a result, not an identity. It records where one race ended; it does not decide where your running ends.

So keep this sentence for the difficult days after an unfinished race:

“I did not finish this race—but this race has not finished me.”

Key references:

• Mosewich, A. D., Crocker, P. R. E., Kowalski, K. C., & DeLongis, A. (2013). Applying self-compassion in sport: An intervention with women athletes. Journal of Sport & Exercise Psychology, 35(5), 514–524. DOI: 10.1123/jsep.35.5.514
• Ceccarelli, L. A., Giuliano, R. J., Glazebrook, C. M., & Strachan, S. M. (2019). Self-compassion and psycho-physiological recovery from recalled sport failure. Frontiers in Psychology, 10, 1564. DOI: 10.3389/fpsyg.2019.01564
• Zhang, N., Huang, J., & Yao, J. (2023). Athletes’ self-compassion and emotional resilience to failure: The mediating role of vagal reactivity. Frontiers in Psychology, 14, 1192265. DOI: 10.3389/fpsyg.2023.1192265
• Kuchar, A. L., Neff, K. D., & Mosewich, A. D. (2023). Resilience and Enhancement in Sport, Exercise, & Training—RESET: A brief self-compassion intervention with NCAA student-athletes. Psychology of Sport and Exercise, 67, 102426. DOI: 10.1016/j.psychsport.2023.102426
• Neumann, D. L., & McInnes, M. (2025). A brief writing intervention assists athletes to cope with performance failures. PsyCh Journal, 14(5), 787–798. DOI: 10.1002/pchj.70026
• Alipour Ataabadi, Y., Cormier, D. L., Kowalski, K. C., Oates, A. R., Ferguson, L. J., & Lanovaz, J. L. (2022). The associations among self-compassion, self-esteem, self-criticism, and concern over mistakes in response to biomechanical feedback in athletes. Frontiers in Sports and Active Living, 4, 868576. DOI: 10.3389/fspor.2022.868576

Durability is the ability to preserve your performance as fatigue accumulates during prolonged exercise. While fitness describes what you can do when fresh, durability determines how much of that fitness remains after many hours of running.

In a 100K or 100-mile race, pace can decline because of muscular damage, worsening running economy, reduced force production, poor fuelling and mental fatigue. A durable runner still becomes tired, but their deterioration is slower and more manageable.

Durability is developed through consistent training volume, progressive long runs, selective back-to-back sessions, race-specific terrain, downhill conditioning and strength training. Long runs should also be used to practise realistic pacing, hiking, nutrition and equipment.

The common mistake is trying to prove durability through excessively long or exhausting sessions. Durability is not built by destroying the body in one weekend. It comes from months of sustainable training that can be repeated consistently.

Fitness may carry you through the first half of an ultra. Durability determines what remains for the second.
Key References:

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Maunder, E., Seiler, S., Mildenhall, M. J., Kilding, A. E., & Plews, D. J. (2021). The Importance of “Durability” in the Physiological Profiling of Endurance Athletes. Sports Medicine, 51, 1619–1628. DOI: 10.1007/s40279-021-01459-0.

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Jones, A. M. (2024). The Fourth Dimension: Physiological Resilience as an Independent Determinant of Endurance Exercise Performance. The Journal of Physiology, 602, 4113–4128. DOI: 10.1113/JP284205.

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Millet, G. Y. (2011). Can Neuromuscular Fatigue Explain Running Strategies and Performance in Ultra-Marathons? The Flush Model. Sports Medicine, 41, 489–506. DOI: 10.2165/11588760-000000000-00000.

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Millet, G. Y., Tomazin, K., Verges, S., et al. (2011). Neuromuscular Consequences of an Extreme Mountain Ultra-Marathon. PLOS ONE, 6, e17059. DOI: 10.1371/journal.pone.0017059.

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Tanda, G., & Knechtle, B. (2015). Effects of Training and Anthropometric Factors on Marathon and 100 km Ultramarathon Race Performance. Open Access Journal of Sports Medicine, 6, 129–136. DOI: 10.2147/OAJSM.S80637.

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Bontemps, B., Vercruyssen, F., Gruet, M., & Louis, J. (2020). Downhill Running: What Are the Effects and How Can We Adapt? A Narrative Review. Sports Medicine, 50, 2083–2110. DOI: 10.1007/s40279-020-01355-z.

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Llanos-Lagos, C., Ramírez-Campillo, R., Moran, J., & Sáez de Villarreal, E. (2024). Effect of Strength Training Programs in Middle- and Long-Distance Runners’ Economy at Different Running Speeds: A Systematic Review with Meta-analysis. Sports Medicine, 54, 895–932. DOI: 10.1007/s40279-023-01978-y.

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Knechtle, B., & Nikolaidis, P. T. (2018). Physiology and Pathophysiology in Ultra-Marathon Running. Frontiers in Physiology, 9, 634. DOI: 10.3389/fphys.2018.00634.

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Clark, I. E., Vanhatalo, A., Thompson, C., et al. (2019). Dynamics of the Power-Duration Relationship During Prolonged Endurance Exercise and Influence of Carbohydrate Ingestion. Journal of Applied Physiology, 127, 726–736. DOI: 10.1152/japplphysiol.00207.2019.

In this episode, we cover why carb loading is not about eating a huge bowl of pasta the night before a race, but about arriving at the start line with full fuel stores. For trail and ultra runners, glycogen is the body’s fast-access fuel, and starting underfuelled can make the later stages of a race much harder.

The key message is simple: carb loading should be planned, practised, and spread across the final 24–48 hours before race day. A good target for long endurance events is often around 8–12 grams of carbohydrate per kilogram of body weight per day, depending on the runner, the race, and gut tolerance.

The episode also explains what runners often get wrong: relying on one big meal, eating too much fibre or fat, trying new foods, or worrying about small increases in body weight caused by glycogen and water storage.

The practical advice is to use familiar, easy-to-digest carbohydrate foods, reduce gut stress before race day, and rehearse the strategy before key long runs or lower-priority races.

Main takeaway: Carb loading fills the tank before the race; race fuelling keeps topping it up. You cannot fully compensate during the race for arriving underfuelled.

Key references:

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Thomas, D. T., Erdman, K. A., & Burke, L. M. — “Nutrition and Athletic Performance.”

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Burke, L. M., Hawley, J. A., Wong, S. H. S., & Jeukendrup, A. E. — “Carbohydrates for training and competition.”

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Wallis, G. A. — “Dietary Carbohydrate and the Endurance Athlete: Contemporary Perspectives.”

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Vitale, K., & Getzin, A. — “Nutrition and Supplement Update for the Endurance Athlete.”

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Kerksick, C. M. et al. — “International Society of Sports Nutrition Position Stand: Nutrient Timing.”

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Mata, F. et al. — “Carbohydrate Availability and Physical Performance.”

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Naderi, A. et al. — “Carbohydrates and Endurance Exercise: A Narrative Review.”

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Thomas / ACSM position statement — race-day fuelling section

In this episode, we look at one of the most important skills in ultrarunning: managing the low points. Every runner will face dark moments during an ultra, but a low point is not necessarily the end of the race. It is usually information: you may need fuel, fluids, sodium, cooling, warmer clothing, slower pacing, or simply a mental reset.

The key message is: do not make big decisions from a low point. Instead, use the simple process: Check. Fix. Wait. Check what may be causing the problem, fix one or two obvious things, then give yourself 15 to 30 minutes before judging the race again.

The goal is not to feel good all day. The goal is to stay functional when things feel bad.

Key references:

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Pageaux, B. - “The psychobiological model of endurance performance”

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Marcora et al. - “Mental fatigue impairs physical performance in humans”

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Blanchfield et al. - “Talking yourself out of exhaustion: the effects of self-talk on endurance performance”

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Burgum et al. - “Reduced mood variability is associated with enhanced performance in ultramarathon running”

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Bieleke et al. - “If-then planning”

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Tiller et al. - “International Society of Sports Nutrition Position Stand: Nutritional considerations for single-stage ultra-marathon training and racing”

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Hew-Butler et al. - “Exercise-Associated Hyponatremia: 2017 Update”

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Cao et al. - “Head, face and neck cooling as per-cooling during exercise in the heat”

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Bongers et al. - “Cooling interventions for athletes”

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Costa et al. - “Nutrition for Ultramarathon Running: Trail, Track, and Road”

In this episode, we explain the difference between heat acclimatisation and heat acclimation. Acclimatisation usually refers to adapting naturally to a hot environment, while acclimation is a more controlled process using tools like hot-water immersion, sauna, or structured heat exposure.

The key message is that heat adaptation is not just about “getting used to suffering.” It creates real physiological changes: lower heart rate at a given pace, earlier and more efficient sweating, better temperature regulation, reduced perceived effort, and improved tolerance when racing or training in warm conditions.

For ultrarunners, this matters because heat can compromise pacing, hydration, fuelling, digestion, decision-making, and overall race performance. However, heat work should be treated as training stress, not recovery.

The episode gives practical starting points for both hot-water immersion and sauna: begin with short exposures of 10–15 minutes after easy runs, then gradually build towards 20–30 minutes, and only progress further if well tolerated. It also highlights precautions: avoid heat exposure when ill, dehydrated, dizzy, very fatigued, or medically vulnerable.

The main takeaway: do not wait until race day to discover how your body responds to heat. Train the heat response before the weather tests you.

Key references:

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Racinais et al. 2015 — Consensus Recommendations on Training and Competing in the Heat

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Racinais et al. 2023 — IOC Consensus Statement on Recommendations and Regulations for Sport Events in the Heat

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Zurawlew et al. 2018 — Post-exercise Hot Water Immersion as a Practical Heat Acclimation Strategy

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Zurawlew et al. 2019 — Hot Water Immersion, Retention of Heat Adaptations

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Scoon et al. 2007 — Post-exercise Sauna Bathing and Endurance Performance in Competitive Runners

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Casa et al. 2015 — National Athletic Trainers’ Association Position Statement: Exertional Heat Illnesses

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Roberts et al. 2021/2023 — ACSM Expert Consensus Statement on Exertional Heat Illness

In this episode, we explore one of the most important principles for sustainable ultrarunning progress: using the minimum intensity needed to create the right adaptation.

The goal of training is not to suffer as much as possible. The goal is to apply the right stimulus, recover from it, and repeat it consistently over time. Whether we are doing intervals, hill work, downhill sessions, strength training, or long runs, the same principle applies: enough stress to adapt, but not so much that it disrupts the rest of the training block.

The episode compares training intensity with a doctor prescribing medication. The best dose is not the highest dose; it is the dose that works with the fewest side effects. In running, too much intensity can create unnecessary fatigue, soreness, injury risk, and poor recovery. Too little does not create adaptation. The sweet spot is the smallest useful dose.

For ultrarunners, this means progressing gradually, respecting recovery, and judging sessions not only by how hard they feel, but by whether they allow consistent training afterwards.

Key message: Train hard enough to adapt, but not so hard that the cost is greater than the benefit.

Key references:

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Androulakis-Korakakis et al. — The Minimum Effective Training Dose Required to Increase 1RM Strength in Resistance-Trained Men

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Schoenfeld et al. — Resistance Training Volume Enhances Muscle Hypertrophy but Not Strength in Trained Men

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Hughes et al. — Adaptations to Endurance and Strength Training

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Spiering et al. — Maintaining Physical Performance: The Minimal Dose of Exercise Needed to Preserve Endurance and Strength Over Time

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Rosenblat et al. — Polarized vs Threshold Training: Systematic Review and Meta-analysis

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Muñoz et al. — Does Polarized Training Improve Performance in Recreational Runners?

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Oliveira et al. — Comparison of Polarized Versus Other Types of Endurance Training Intensity Distribution

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Tallis et al. — Repeated Bout Effect of Downhill Running on Physiological Markers and Muscle Soreness

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Assumpção et al. — A Single Bout of Downhill Running Attenuates Subsequent Exercise-Induced Muscle Damage

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Martinez-Navarro et al. — Downhill Running-Induced Muscle Damage in Trail Runners

Elite trail runners do not descend faster simply because they are braver. They descend faster because they brake less.

Downhill running creates a lot of muscle damage because the quadriceps are working eccentrically: they produce force while lengthening to control the body against gravity. Every downhill step is like a small controlled landing. When runners overstride, lean back, tense up, and land heavily, the quads act like emergency brakes. This feels safer in the moment, but over a long race it destroys the legs.

Elites are better because they descend with more rhythm, better posture, quicker steps, and less unnecessary braking. Their feet land closer under the body, their upper body stays relaxed, and they read the terrain earlier. This allows them to move faster while creating less damage.

The practical message is that downhill running must be trained gradually. Start with short, controlled downhill efforts, focus on light feet and quick cadence, then build towards longer descents and descending on tired legs. Strength work also helps, especially controlled eccentric exercises like step-downs, split squats, lunges, and slow squats.

Main takeaway: Do not train downhill just to prove toughness. Train downhill to reduce the cost of descending. The best descent is not the one where you feel heroic at the top; it is the one that leaves you with legs at the bottom.

Key references:

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Bontemps, B. et al. (2020). Downhill Running: What Are The Effects and How Can We Adapt? A Narrative Review. Sports Medicine.

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Bontemps, B. et al. (2020). Full-text review via PMC.

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Tallis, J. et al. (2024). Repeated Bout Effect of Downhill Running on Physiological Markers of Effort and Post-Exercise Perception of Soreness in Trained Female Distance Runners. Sports.

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Coratella, G. et al. (2024). Downhill running increases markers of muscle damage and alters jump performance.

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Martínez-Navarro, I. et al. (2026). Downhill Running-Induced Muscle Damage in Trail Runners: An Exploratory Study Regarding Training Background and Running Gait. Sports.

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Genitrini, M. et al. (2022). Downhill Sections Are Crucial for Performance in Trail Running.

Caffeine is one of the most evidence-supported supplements for endurance performance, but ultrarunners need to use it strategically rather than simply taking more.

The key message is that caffeine is not fuel. Carbohydrates provide energy for the muscles; caffeine mainly helps with alertness, focus, motivation, and perceived effort. This makes it especially useful in long ultras, where mental fatigue, sleepiness, low mood, and poor decision-making can become as limiting as physical fatigue.

For shorter races, caffeine before the start can be useful. But in longer ultras, especially races lasting over 8–15 hours or through the night, it is often better to delay caffeine until the second half, the night section, or the final third, when its benefits are more valuable.

A practical starting point is 25–50 mg per hour once caffeine use begins, adjusted based on tolerance. Some runners may tolerate more, but higher doses increase the risk of stomach issues, anxiety, jitters, and sleep disruption.

The episode emphasises that caffeine should never replace proper fuelling. When energy drops, the first question should be: have I taken enough carbohydrates?

Main takeaway: Fuel with carbohydrates. Focus with caffeine. Caffeine is not the engine; it is the light you switch on when the road gets dark.

Key references:

• Guest, N. S. et al. (2021). International Society of Sports Nutrition Position Stand: Caffeine and Exercise Performance. Journal of the International Society of Sports Nutrition. Australian Institute of Sport. Caffeine: Performance Supplement Guide.
• Wang, Z. et al. (2022). Effects of Caffeine Intake on Endurance Running Performance and Time to Exhaustion: A Systematic Review and Meta-analysis. Nutrients.
• Shen, J. G. et al. (2019). Establishing a relationship between the effect of caffeine and duration of endurance athletic time trial events. Journal of Science and Medicine in Sport.
• Goldstein, E. R. et al. (2010). International Society of Sports Nutrition Position Stand: Caffeine and Performance. Journal of the International Society of Sports Nutrition.
• Benchetrit, S. et al. (2024). The effects of sleep deprivation and extreme exertion on cognitive performance in ultra-marathon runners.
• Martinez Gonzalez, B. (2022). Sleep Deprivation and Ultra-endurance Performance. University of Kent thesis.
• Office of Dietary Supplements, NIH. Dietary Supplements for Exercise and Athletic Performance: Health Professional Fact Sheet.