The Trail Running Briefing

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:

1. 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.

2. 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.

3. 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.

4. 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.

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

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

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

8. 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.

9. 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:

1. 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.

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

3. 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.

4. 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.

5. 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:

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

• 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.

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

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

• 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.

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

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

• 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:

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

• 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.

• 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.

• 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.

• 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.

• 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.

• 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.

1. 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

2. 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.

3. 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

4. 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

5. 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

6. 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:

1. 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.

2. 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.

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

4. 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.

5. 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.

6. 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.

7. 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.

8. 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:

1. 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.

2. Gustafsson, H., DeFreese, J. D., & Madigan, D. J. (2017). Athlete burnout: Review and recommendations. Current Opinion in Psychology, 16, 109–113.

3. 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.

4. 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.

5. 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:

1. 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

2. 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

3. 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

4. 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

5. 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

6. 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

7. 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

8. 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

9. 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:

1. 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
2. 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
3. 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
4. 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
5. 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
6. 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:

1. 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.

2. 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.

3. 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.

4. 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.

5. 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.

6. 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.

7. 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.

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

9. 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.