Training for Ultramarathons: How to Prepare for the Ultimate Test of Endurance
Ultramarathons are a different beast. Whether it’s 50K, 100 miles, or a 24-hour race, the challenge goes beyond fitness. It’s about durability, efficiency, mindset, and execution. As someone who has represented Great Britain at the 24-hour distance, Wales at 100km, and coached athletes to some of the toughest ultra finishes on the planet, from Badwater and Spartathlon to The Spine and Marathon des Sables, I can tell you this: training for ultramarathons requires a smarter, more disciplined approach than simply running more miles.
In this article, I’ll share the key principles that every runner whether you’re a beginner stepping up from marathons or an experienced athlete chasing a new distance, needs to understand about ultramarathon training.
Why Training for Ultramarathons Is Different
A marathon demands endurance and speed. An ultramarathon demands those too but layered with fuelling, fatigue management, and mental resilience. You can be the fittest runner on the start line and still fall apart if you haven’t trained your gut, prepared your mind, or conditioned your legs for the relentless pounding of hour after hour on the trail or road.
Training for an ultramarathon is not just about who can run the most it’s about who can recover, adapt, and keep going when everything in their body wants to stop. That’s why a good ultramarathon coach looks at more than just mileage, they help you balance training stress with recovery, adapt nutrition to your needs, and prepare you mentally for the inevitable lows.
Building the Aerobic Engine
The foundation of all successful ultra training is aerobic development. This means lots of easy running. A principle I use with my athletes is the 80/20 rule: around 80% of training should be at a truly easy effort, with only 20% devoted to harder sessions.
Why? Because ultras are not won in the pain of intervals they’re won with an efficient aerobic system that can go for hours without breaking down. Easy miles condition your muscles, joints, and nervous system to handle long durations, while also improving fat metabolism, a key factor in ultra performance.
If you’re new to the distance, start by gradually increasing weekly mileage and extending your long run. More experienced runners can build towards higher volumes, but always with recovery in mind.
The Long Run and the Back-to-Back
The long run remains the cornerstone of ultra training. Unlike marathon prep, where one long run a week might be enough, ultramarathon training often requires back-to-back long runs. For example:
• Saturday: 20–25 miles at an easy effort
• Sunday: 15–20 miles on tired legs (often hilly)
This approach trains fatigue resistance, the ability to keep moving efficiently when your legs are already depleted. It’s one of the biggest performance factors in ultra racing.
Strength and Specificity
Ultra running isn’t just about running. Hills, uneven terrain, and long descents demand strength. That’s why I encourage athletes to train with:
• Hill repeats for strength and efficiency
• Downhill running to condition quads eccentrically
• Strength training (single-leg work, core, posterior chain), Leg circuits, etc.
Specificity matters too. If your race is mountainous, train on mountains. If it’s flat and fast, simulate race pace in long efforts. An ultramarathon coach will tailor these details to your goal race.
Recovery: The Hidden Training Session
Every hard run is only as effective as the recovery that follows. Many runners push too hard, too often, and end up overtrained before race day.
Key recovery pillars:
• Sleep: 7–9 hours a night, plus naps if possible
• Nutrition: Carb-protein mix within 30 minutes post-run
• Active recovery: Easy cycling, swimming, or walking to promote circulation
• Listening to your body: If you’re overly fatigued, take the extra rest day
Remember: fitness is built in recovery, not in training stress alone.
Fuelling: Training the Gut
One of the biggest mistakes I see is athletes who train well but fail on race day because of poor fuelling. You can’t wing nutrition in an ultra.
• Aim for 50-80 grams of carbs per hour initially
• Include real food (bananas, wraps, trail mix) alongside gels and drinks (if you can)
• Practice fueling in training runs, not just races
• Hydrate consistently
Your gut is just as trainable as your legs, ignore it, and even the best training plan will fail you.
The Mental Game
No ultramarathon is without its dark patches. Mental toughness is what carries you when your body says “stop”.
Practical mindset strategies:
• Break the race into sections (aid station to aid station)
• Use mantras like “strong and steady”
• Expect discomfort, embrace it as proof you’re pushing your limits
• Visualise yourself handling adversity before race day
As someone who’s run 24-hour races and coached athletes to world-class finishes, I can promise you: mental training is as important as physical training.
Do You Need an Ultramarathon Coach?
While it’s possible to finish an ultra with a DIY plan, working with an experienced ultramarathon coach accelerates progress, reduces injury risk, and ensures training fits your lifestyle. I’ve coached complete beginners to their first 50K, and I’ve guided athletes to British records and podium finishes in some of the hardest ultras in the world.
The common thread? Structure, accountability, and smart planning. An ultramarathon coach doesn’t just write miles, they help you execute a strategy that balances training with recovery, prepares you nutritionally, and builds the mindset needed to succeed.
Final Thoughts
Training for ultramarathons is about more than just running longer. It’s about building a resilient body, training your gut, managing recovery, and developing an unbreakable mindset. With the right structure and guidance, you can go further than you ever thought possible.
