By RunDoyen.
Featuring coaching insights from Addi Zerrenner.
RunDoyen connects runners with expert online running coaches and race-focused training plans built around real goals, real schedules, and long-term progress.
TL;DR
- An ultramarathon is any race longer than 26.2 miles, with common distances including 50K, 50 miles, 100K, and 100 miles.
- Trail ultras are not just “longer marathons.” Terrain, elevation, fueling, gear, aid stations, and recovery all change the preparation.
- Back-to-back long runs are one of the most useful tools for building time-on-feet durability.
- Train on terrain that resembles your race, especially if the course includes steep climbs, long descents, or technical trails.
- Ultra nutrition is highly individual, but you need to practice eating more and fueling for a much longer day.
- Recovery should be planned before race day, not improvised after you are exhausted.
If you are moving from road racing into ultras and want a plan that accounts for terrain, fueling, life schedule, and long-term progression, RunDoyen can help you Get Matched with an online running coach.
Table of Contents
- What counts as an ultramarathon?
- Why trail ultras require different preparation
- The three biggest training priorities
- A practical ultramarathon training framework
- Fueling, aid stations, and race-day logistics
- Strength, mobility, and durability for trails
- Recovery after an ultramarathon
- Common mistakes
- Safety and when to get help
- Final thoughts
What Counts as an Ultramarathon?
An ultramarathon is any race longer than the standard marathon distance of 26.2 miles. The most common entry point is the 50K, which is roughly 31 miles. From there, many runners move toward 50 miles, 100K, 100 miles, and sometimes even longer distances.
That definition sounds simple, but the training demands can vary dramatically.
A road 50K may feel like a slightly extended marathon, especially for an experienced marathoner. A hilly trail 50K, however, can feel like a completely different sport. The distance is only one part of the challenge. Surface, elevation, weather, technical footing, aid station spacing, gear needs, and time on feet can all change how you prepare.
That is why ultramarathon training should start with the race itself. Before you decide how many miles to run, study the course. Ask:
- Is the race on roads, smooth trails, technical trails, mountains, desert, or mixed terrain?
- How much climbing and descending are involved?
- How far apart are aid stations?
- Will you need a pack, bottles, poles, lights, or extra layers?
- Is your goal to finish, compete, or simply experience the distance well?
The answers shape your training more than the distance alone.
Why Trail Ultras Require Different Preparation
Trail ultras require a broader view of preparation than many road races. You still need aerobic fitness, consistency, and a long-run progression, but you also need durability, patience, problem solving, and comfort with changing conditions.
On trails, pace becomes less useful as the primary guide. A mile with steep climbing, rocky footing, or technical descending may take far longer than a flat road mile. Effort, breathing, hiking efficiency, and total time on feet often matter more than hitting a specific split.
Elevation is one of the clearest examples. Standard hill repeats can help, but they are not the same as preparing for a course with repeated climbs and descents. A runner training for a trail 50K with major uphills and hard downhills needs to condition the body for both directions. The climbing taxes the calves, glutes, hamstrings, and lungs. The descending can beat up the quads and ankles.
For deeper context on how hill work supports race preparation, RunDoyen’s guide to hill training for runners is a useful supporting resource.
Trail ultras also change the rhythm of the race. In a road marathon, aid stations are often quick: grab fluid, take a gel, keep moving. In an ultra, an aid station may involve sitting down, refilling bottles, putting ice around your neck on a hot day, changing socks, addressing blisters, eating real food, or checking in with a support crew.
That does not mean you should linger at every aid station. It means you should train for the reality of the event.
The Three Biggest Ultramarathon Training Priorities
A good ultramarathon training plan can include easy mileage, long runs, trail runs, hills, strength training, and sometimes tempo or longer interval work. But three priorities sit at the center.
1. Time on feet through long runs
The long run matters in almost every endurance plan, but it becomes even more important in ultra preparation. You need to get used to moving for a long time, managing fatigue, eating while active, and staying mentally engaged when the effort stops feeling exciting.
For many ultra runners, back-to-back long runs are especially useful. Instead of relying on one very long effort every weekend, you might run long on Saturday and moderately long again on Sunday. This helps create the feeling of running on tired legs without making every single long run excessively demanding.
For example, a runner might build toward a weekend such as 20 miles one day and 10 miles the next, or 15 and 15, depending on background, race distance, terrain, and recovery capacity.
2. Terrain specificity
If your race is on trails, run trails. If your race has climbing, climb. If your race has long descents, practice descending.
There is no perfect substitute for the terrain you will race on. Strength training and treadmill incline can help when access is limited, but they do not fully recreate the muscular load, balance demands, and decision making of trail running.
This is especially important for technical courses. Roots, rocks, uneven footing, sharp turns, and cambered trail sections can leave runners sore even when the elevation is modest. The body has to learn how to stabilize, react, and absorb impact from different angles.
3. Nutrition practice
Ultra nutrition can make or break the day. The longer the race, the more you need to practice taking in calories, fluid, and electrolytes while moving.
A simple starting point is taking a gel roughly every 45 to 60 minutes during earlier long runs, then gradually testing more substantial foods as runs get longer. Once trail long runs reach roughly 15 to 16 miles or more, many runners begin experimenting with real food.
Common examples include peanut butter pretzels, applesauce, soda, cookies, or other easy-to-handle foods. Some runners tolerate sweet foods well. Others need salty or more solid options. There is no universal formula, so practice is the plan.
RunDoyen’s guide to nutrition for runners gives additional context on fueling, hydration, and recovery habits.
A Practical Ultramarathon Training Framework
The right training structure depends on your background, race distance, timeline, injury history, and course. A marathoner moving to a road 50K may need a different build than a newer runner aiming for a technical trail 50K.
Still, most ultra plans include the same building blocks.
1. Build gradually
If you already have a strong running background, a trail 50K may require at least four months of focused preparation. Six months is a common planning window for many runners. For someone starting from a low mileage base or with little distance-running experience, the timeline may need to be much longer.
The goal is not to cram miles. The goal is to arrive prepared.
That means building mileage, absorbing the work, practicing terrain, and tapering before race day. RunDoyen’s training plans hub can support runners looking for structured race preparation across different distances and goals.
2. Use back-to-back long runs carefully
Back-to-back long runs are valuable, but they are also demanding. They should be introduced gradually.
A runner might begin with a normal long run followed by a short easy run the next day. Over time, the second day can grow. The purpose is not to race both runs. The purpose is to develop durability and confidence while tired.
For most runners, these weekends should be followed by real recovery. Easy days need to be easy. Mileage should not increase aggressively at the same time that terrain, elevation, and long-run duration increase.
3. Practice race-like terrain
Course simulation matters. If your race has long climbs, include sustained climbing when possible. If it has steep descents, practice controlled downhill running. If it is technical, spend time on trails that force you to watch your footing.
A useful workout is a longer hilly trail run where the focus is not pace, but steady movement over repeated climbs and descents. This can prepare the legs better than short hill repeats alone.
4. Keep some variety
Ultra training does not have to be only slow mileage. Some runners benefit from occasional tempo work, longer intervals, strides, or controlled faster running, especially when they tolerate it well.
The key is dosage. Speed and tempo work should support the larger goal, not compromise the long runs, terrain practice, or recovery. For many runners, one faster session every week or every other week is enough.
Extractable Element: 7-Step Ultramarathon Training Checklist
- Define the race demands: distance, terrain, elevation, weather, aid stations, gear, and cutoff times.
- Build a long-run progression that increases time on feet without forcing huge jumps.
- Add back-to-back long runs once your body can handle the basic long-run load.
- Train on race-like terrain, including climbs, descents, uneven footing, and technical trails when relevant.
- Practice fueling early, then test real foods during longer trail runs.
- Include strength and mobility work for calves, hamstrings, glutes, hips, ankles, and posture.
- Plan recovery before race day, including full rest, unstructured running, hydration, and enough calories.
The main takeaway: ultramarathon training is not only about running farther. It is about preparing for the specific demands of the event. The better your training matches the course, the more confident you can be when the race gets difficult.
Fueling, Aid Stations, and Race-Day Logistics
In many road races, aid stations are brief. In trail ultras, they can become part of your strategy.
You may need to refill fluids, restock calories, cool down with ice, change socks, check your feet, manage blisters, or adjust gear. For longer events, some runners may eat what feels more like a small meal than a race snack.
This is why long runs should include logistics practice. Do not wait until race day to learn whether your stomach handles gels after four hours, whether your vest rubs, whether your shoes cause blisters on descents, or whether salty foods sit better than sweet ones.
Practice:
- Carrying fluids in the same way you will on race day
- Eating while hiking or running
- Opening wrappers with tired hands
- Refilling bottles quickly
- Changing socks if your race may require it
- Knowing what foods calm your stomach and what foods upset it
Ultra fueling is partly physiology and partly problem solving. The best plan is one you have tested under fatigue.
Strength, Mobility, and Durability for Trails
Running is still the most important part of ultramarathon training. But if your schedule allows, strength training can be a major advantage.
For trail ultras, the posterior chain is especially important: calves, hamstrings, and glutes all help with climbing, stabilizing, and absorbing load. Hip and ankle mobility also matter because trails rarely give you perfectly flat footing.
Upper body strength should not be ignored either. Arm drive, posture, shoulder position, and trunk control can all matter late in a long race. As fatigue builds, runners often collapse through the upper body, which can make breathing and efficient movement harder.
A balanced strength plan for ultrarunners may include:
- Calf raises and lower-leg strength
- Glute and hamstring work
- Single-leg stability
- Core and trunk control
- Hip mobility
- Ankle mobility
- Upper body pulling and pushing movements
For a broader framework, see RunDoyen’s guide to strength training for runners.
Recovery After an Ultramarathon
Recovery from a trail ultra deserves the same respect as the training build.
After a trail 50K, a cautious minimum is one full week with no running, cross training, or exercise. For many runners, two weeks of full rest is better. After that, the next couple of weeks can be unstructured: short, easy running only when the body feels ready.
That creates roughly a month of rest and low-pressure movement before returning to structured training. Longer ultras may require much more recovery. Some runners take many weeks before feeling ready to train again.
Nutrition matters here too. Keep calories coming in. Prioritize enough protein, fats, carbohydrates, and fluids. The body has done a lot of work, especially if the race involved long descents, technical terrain, heat, or a very long time on feet.
If you are returning from a major endurance effort, RunDoyen’s marathon recovery plan offers useful recovery principles that can be adapted conservatively for longer efforts.
Common Mistakes in Ultramarathon Training
- Treating a trail 50K like “just five more miles” than a marathon, without accounting for terrain and time on feet.
- Relying only on short hill repeats when the race includes sustained climbs and long descents.
- Waiting until race day to test real foods, fluids, gear, socks, shoes, or a hydration vest.
- Increasing mileage, elevation, and technical trail exposure all at the same time.
- Running back-to-back long runs too hard instead of using them to build durability.
- Ignoring downhill preparation, then getting crushed by quad soreness late in the race.
- Skipping recovery because the race pace was slower than a road marathon pace.
- Choosing an ultra timeline based on excitement rather than current fitness and training history.
Safety and When to Get Help
Ultramarathons ask a lot from the body and mind. Blisters, lost toenails, swollen feet or ankles, stomach issues, cuts, scrapes, and deep fatigue can all happen during or after trail ultras. Longer-term challenges may include prolonged exhaustion, low motivation, immune stress, or signs that the body is not recovering well.
This article is general guidance, not medical advice. Do not ignore sharp pain, worsening symptoms, dizziness, chest pain, fainting, confusion, severe swelling, or ongoing health concerns. Stop, seek appropriate support, and consult a qualified medical professional when symptoms are concerning or do not improve.
Runners with a history of injury, low energy availability, menstrual changes, recurring illness, or difficulty recovering should be especially cautious. More training is not always better. Sometimes the smartest move is to reduce load, recover, and rebuild gradually.
Final Thoughts
Ultramarathon training is a different kind of challenge. It rewards patience, specificity, and self-awareness. The goal is not only to become fit enough to cover the distance, but to become prepared for the course, the terrain, the fueling demands, the mental low points, and the recovery that follows.
Start with the race demands. Build time on feet. Practice back-to-back long runs carefully. Train on terrain that resembles the course. Test nutrition before race day. Strengthen the body for climbs, descents, and uneven footing. Know your reason for being out there when the race gets hard.
For runners who want expert guidance through the jump from road racing to trail ultras, RunDoyen’s coach network lets you Browse Coaches and find support that fits your goals, background, and schedule.
FAQ
How long does it take to train for a trail 50K?
For a runner with a solid background, at least four months is a reasonable minimum, while six months is often a better planning window. A newer runner may need much longer, especially if they have not built toward marathon-level endurance first.
Is a 50K much harder than a marathon?
It depends on terrain. A road 50K may feel like an extended marathon for an experienced runner. A trail 50K with elevation, technical footing, and longer time on feet can feel much harder than the distance difference suggests.
Should ultramarathon training include back-to-back long runs?
Often, yes. Back-to-back long runs help runners practice moving on tired legs without making one single long run excessively long. They should be introduced gradually and followed by real recovery.
What should I eat during an ultramarathon?
There is no perfect universal answer. Many runners start with gels, then test real foods such as pretzels, applesauce, soda, or other easy-to-digest options during longer runs. The key is to practice before race day.
Do I need to train on trails for a trail ultramarathon?
Yes, whenever possible. Trails create demands that roads do not: uneven footing, turns, climbs, descents, rocks, roots, and changing rhythm. If trail access is limited, use hills, strength training, and occasional destination trail runs to close the gap.
Is speed work useful for ultramarathon training?
It can be, but it should not compromise the long runs, terrain work, or recovery. Some runners benefit from tempo work, longer intervals, or strides once per week or once every two weeks, depending on experience and fatigue.
How can an online running coach help with ultramarathon training?
An online running coach can help match your training to your race course, current fitness, schedule, injury history, and fueling needs. This is especially useful for ultras because terrain, logistics, recovery, and long-run structure vary so much from race to race.
How much time should I take off after an ultramarathon?
After a trail 50K, one full week off from running and exercise is a cautious minimum, with two weeks often better. The next couple of weeks can be unstructured and easy. Longer ultras may require a longer recovery window.
