Introduction: Learning from the Mistakes of Others
Ultra marathon running is a discipline where mistakes — in training, in race strategy, in nutrition management, or in gear selection — carry severe consequences. A nutrition mistake in a road marathon might cost you a personal best; the same mistake in a 24-hour ultra could cost you the race or put you in medical care. The good news is that most ultra running mistakes are highly predictable, widely documented in the running community, and entirely avoidable once you know what to watch for. This guide covers the most common mistakes ultra runners make — from beginners attempting their first 50K to experienced runners with multiple events behind them — and provides specific, actionable strategies to avoid each one.
Mistake 1: Starting Too Fast
Starting too fast is the single most common race day mistake in ultra running, and its consequences are severe. The excitement of race day, the adrenaline of the start, the presence of other runners moving quickly — all conspire to pull ultra runners out far too fast in the opening miles. In a marathon, going out too fast costs time. In a 24-hour ultra like the event contested at the Commonwealth Mountain & Ultra Distance Running Championships, going out too fast can make the final eight to ten hours essentially unrunnable. The fix is simple in principle but requires strong discipline in practice: start at a pace that feels almost embarrassingly easy, and hold it. Your race begins in the second half, not the first.
Mistake 2: Neglecting Strength Training
Many ultra runners — particularly those transitioning from road marathon backgrounds — view running mileage as the only training that matters and neglect the strength and conditioning work that prevents injuries and supports performance over extreme distances. The result is predictable: weakness in the glutes, hips, and stabilising muscles leads to IT band syndrome, knee pain, and ankle instability that cuts training programmes short or ruins race day. The fix: integrate two dedicated strength sessions per week throughout your training cycle, focusing specifically on posterior chain development, single-leg stability work, and the hip abductor strength that protects the knee during prolonged downhill running. Ten minutes of targeted strength work after each easy run also provides meaningful cumulative benefit.
Mistake 3: Under-Fuelling in Training and Racing
The endurance running world has long been influenced by a culture of dietary restriction and fear of weight gain that leads many athletes to undereat relative to their enormous training energy demands. This under-fuelling — known as Relative Energy Deficiency in Sport (RED-S) — impairs training adaptation, increases injury risk, disrupts hormonal function, and paradoxically reduces performance rather than improving it. In racing, failing to eat enough in the early stages of an ultra — before hunger or GI issues develop — leads to the catastrophic energy depletion that forces the majority of race retirements. The fix: fuel aggressively from early in both training and racing, treating nutrition as a performance input rather than an indulgence.
Mistake 4: Skimping on Sleep in Training
Sleep is the single most powerful recovery tool available to any athlete — and ultra marathon training’s high physical demands make it especially critical. Many ultra runners sacrifice sleep to fit in early morning training sessions, stay up late despite heavy training loads, and chronically accumulate a sleep debt that impairs performance, elevates injury risk, disrupts appetite regulation, and compromises immune function. Research consistently shows that athletes sleeping less than seven hours per night show significantly impaired physical performance compared to those sleeping eight or nine hours. The fix: treat sleep as the highest-priority recovery intervention, scheduling training around sleep commitments rather than the reverse, and using sleep extension (adding 60-90 minutes to your sleep duration during peak training weeks) as a deliberate performance strategy.
Mistake 5: Ignoring Mental Preparation
Ultra runners invest thousands of hours in physical preparation and often devote almost none to mental training — despite the fact that the deciding factor in the vast majority of ultra DNFs is mental, not physical. The body’s capacity to continue is typically far greater than the mind’s willingness to permit it. Mental preparation for ultra running includes: developing and rehearsing personal mantras that you can deploy during dark moments, visualising difficult sections of your race in detail during the weeks before race day, practising deliberate discomfort during training by finishing long runs in poor conditions rather than cutting them short, and building a clear, emotionally resonant list of reasons why you are running this race that you can access when the going is hardest.
Mistake 6: Over-Training and Ignoring Recovery Signs
The culture of ultra running celebrates toughness, volume, and relentless training — values that serve runners well when balanced, but that can become destructive when applied without recovery awareness. Over-training syndrome — the chronic accumulation of training stress without sufficient recovery — manifests through persistent fatigue, declining performance, elevated resting heart rate, mood disturbance, and increased injury frequency. Many ultra runners push through early over-training signs in the mistaken belief that feeling tired means they need to train more. The fix: monitor recovery systematically (resting heart rate, heart rate variability, subjective wellness), treat scheduled rest weeks as training non-negotiables, and understand that fitness is built during recovery from training, not during the training itself.
Mistake 7: Poor Aid Station Strategy
Aid station management in ultra races is a skill that separates experienced runners from beginners. Common aid station mistakes include: spending too long at stations chatting rather than efficiently fuelling, taking foods you have never eaten in training, losing mandatory kit items in the confusion of a busy aid station, and failing to execute pre-planned nutrition targets because emotional decision-making takes over. The fix: develop a written aid station plan before your race that specifies exactly what you will eat, drink, and check at each aid station. Rehearse this plan mentally during your taper. Aim to spend less than two to three minutes at aid stations in shorter ultras, slightly longer in 24-hour events. Treat your aid station plan as a race strategy document.
Mistake 8: Choosing the Wrong First Ultra Distance
Ambition is a virtue in ultra running — but choosing a first ultra event that significantly exceeds your current preparation can turn an exciting adventure into a miserable, potentially dangerous experience. Many first-time ultra runners are drawn by the prestige of extreme distances before they have built the base to support them. The result is frequently a DNF, an injury, or such a negative first experience that they never enter another ultra. The fix: choose your first ultra based on your current fitness, not your aspirational fitness. A 50-kilometre trail race with manageable elevation is an excellent first ultra for most runners. The experience of completing it successfully builds far more confidence and enthusiasm for progression than struggling through a much longer, more demanding event before you are ready.
Mistake 9: Neglecting Blister and Foot Care
Foot care is one of the least glamorous but most practically important aspects of ultra marathon preparation. Blisters caused by wet feet, ill-fitting shoes, or inadequate sock choices have ended more ultra races than most other single factors. The fix begins before race day: test your exact shoe and sock combination on long training runs in wet conditions. Apply anti-chafe products to feet before long runs and races. Change socks and dry feet at aid stations in wet weather races. Carry blister management supplies and address hot spots (pre-blister friction points) before they become full blisters. Taping known blister-prone areas prophylactically before races is standard practice among experienced ultra runners.
Conclusion: Mistakes Are Inevitable, but Avoidable Ones Aren’t
Every ultra runner makes mistakes — the athletes with the most miles behind them have simply made more of them and learned from each one. The mistakes covered in this guide are not obscure or unpredictable — they are the documented, widely recognised errors that the ultra running community has collectively accumulated enormous experience navigating. Approaching your ultra training and racing with awareness of these pitfalls gives you a genuine advantage over the runner who must discover each lesson through painful personal experience. Learn from the community, apply the fixes, and save your hard lessons for the genuine unknowns that ultra running always reserves for even the best-prepared athletes.