How to Train for an Ultramarathon: The Fundamentals
When Courtney Dauwalter crossed the finish line at the Ultratrail Lago d'Orcia in Chianti, she did what she's done repeatedly across the sport: make something brutally hard look almost effortless. That kind of performance tends to spark a specific question in runners watching from the outside. Could I do that?
Key Takeaways
- Ultra training requires at least 6 months of progressive base building
- Back-to-back long runs simulate ultra fatigue better than single long efforts
- Nutrition accounts for up to 50% of ultramarathon success
The honest answer is that more runners are capable of finishing an ultramarathon than they think. But the training demands a different mindset than anything you've done before, including the marathon. Here's what you need to understand before you start building your plan.
What Counts as an Ultramarathon
Any race longer than the standard 26.2-mile marathon distance qualifies as an ultra. In practice, the most common entry-level distances are 50 kilometers (31 miles) and 50 miles. Beyond that, you're looking at 100-kilometer and 100-mile events, the latter being the format that has made Dauwalter a household name in endurance sports.
Most first-timers target a 50K. It's long enough to require serious preparation, but short enough that completing a marathon puts you within striking range of the finish line.
The Base You Need Before You Begin
You shouldn't start an ultramarathon training block from scratch. A solid aerobic foundation matters more here than in almost any other running discipline. Most coaches recommend having at least one marathon under your belt and consistently running 30 to 40 miles per week for several months before beginning a dedicated ultra plan.
If your weekly mileage is significantly lower than that, spend three to six months building your base first. Rushing the process is the fastest route to injury, and injuries in ultra training tend to cost you weeks, not days.
Time on Feet Over Pace
This is the single most important mental shift you'll make as a new ultra runner. Pace becomes largely irrelevant. What matters is duration. Your long runs should be measured in hours, not miles, and your goal during those sessions is to keep moving, not to hit a target split.
Research consistently shows that the majority of ultra runners, including experienced ones, incorporate run-walk intervals throughout their races. Learning to walk efficiently, especially on uphills, isn't a sign of weakness. It's a core skill. Practice it during training so it feels natural on race day.
Build Weekly Mileage Gradually
The standard rule of not increasing weekly mileage by more than 10 percent applies here, and it applies strictly. Ultra training plans typically run 16 to 24 weeks for a 50K, and 20 to 30 weeks for a 50-miler.
Most plans follow a three-weeks-up, one-week-down structure. You build volume for three weeks, then pull back by roughly 20 to 30 percent in the fourth week to let your body absorb the training load. Don't skip recovery weeks. That's where adaptation actually happens.
Peak weekly mileage for a 50K training block typically lands between 50 and 70 miles, depending on your experience level and how your body responds to volume.
Back-to-Back Long Runs
One of the defining features of ultra training that separates it from marathon prep is the back-to-back long run. Instead of a single long effort on the weekend, you run long on both Saturday and Sunday. The second run teaches your body to perform on already-tired legs, which is exactly the condition you'll be in during the later miles of a race.
A typical example for a mid-cycle weekend might be a 16-mile run on Saturday followed by a 12-mile run on Sunday. The pace on both days should be conversational. If you can't hold a full sentence, you're moving too fast.
Elevation and Trail-Specific Training
If your goal race has significant elevation gain, you need to train on hills. Most ultras are run on trails, and the demands of technical terrain and climbing are completely different from road running. Your cardiovascular system adapts to road mileage, but your ankles, hips, and stabilizing muscles need specific exposure to uneven ground.
Try to do at least one run per week on the type of terrain your race will cover. If you live somewhere flat, treadmill incline work is a legitimate substitute for building climbing strength. Some runners also use weighted hikes on rest days to accumulate vertical without the impact of running.
Nutrition Is Training Too
You cannot outrun poor fueling at ultra distances. At race pace, most runners burn between 400 and 600 calories per hour. Over a 10-hour race, that's a significant deficit that you have to actively manage. Ultramarathon nutrition relies heavily on real food, not just gels. Aid stations at major races stock items like broth, boiled potatoes, peanut butter sandwiches, and fruit.
Practice eating during your long runs from the start of your training block. Your gut needs to be trained to process food while your body is under stress. Many ultra runners report GI problems as their primary reason for dropping from a race, and the majority of those issues are preventable with consistent fueling practice during training.
Recovery and Injury Prevention
Sleep is your most underrated training tool. Studies in endurance sports link consistent sleep of seven to nine hours per night with faster recovery, better performance, and reduced injury rates. Prioritize it the same way you'd prioritize a long run.
Strength training, particularly single-leg exercises and hip work, protects you from the repetitive stress injuries that end ultra training blocks early. Two sessions per week of 20 to 30 minutes is enough to build meaningful durability without compromising your running volume.
Finding the Right Race and Plan
Choose a first race with a generous cutoff time, ideally 12 hours or more for a 50K. That buffer removes pressure and lets you focus on completing the distance. Look for events with well-stocked aid stations and manageable elevation profiles if you're targeting a debut.
Free and paid training plans from organizations like iRunFar and experienced ultra coaches give you a structured framework to follow. You don't need to build your own plan from scratch, especially for a first attempt.
The ultra community is notably welcoming to newcomers. Ask questions, connect with local trail running clubs, and don't underestimate what you're capable of. Dauwalter started somewhere too.
Frequently Asked Questions
How long to prepare for a first ultra?
A minimum of 6 months of specific training, ideally after a year of regular running and a completed marathon. Progress must be very gradual.
What weekly training volume for an ultra?
Most plans peak at 60-100 km per week. Back-to-back long runs on Saturday and Sunday simulate ultra fatigue better than one very long run.
How do you manage nutrition during an ultra?
Aim for 200-300 calories per hour with a mix of solid and liquid carbohydrates. Test everything in training, never on race day.