Quick Answer
First target distance: 50km — the most accessible entry point with 16–20 weeks of training from a marathon base. Key differences from marathon training: back-to-back long runs, deliberate uphill walking, 60g+ carbs per hour starting from 30–60 minutes in, time-on-feet priority over pace. Base required: one marathon completion (or consistent 35–45 miles/week) before starting ultra training. Most important single session: the long run, done at easy effort, practising race-day nutrition from week one.
The Base You Need Before Starting Ultra Training
Ultra training programmes assume a running foundation that marathon training doesn’t. Jumping into a 50km plan without having run a marathon — or at minimum, having been running consistently at 35–45 miles (55–70km) per week for several months — produces a training block where the early weeks are already too demanding for the runner’s current adaptation level. The fatigue compounds before the ultra-specific adaptations can take hold, and the result is usually injury or burnout before race day.
| Current running background | Recommended path to first ultra | Timeline |
|---|---|---|
| Beginner (under 1 year consistent running) | Build to marathon first; run the marathon; then consider 50km 6+ months later | 18–24 months to first 50km |
| Regular runner, no marathon | Complete a marathon; use that training cycle to assess recovery and volume tolerance before ultra training | 6–12 months to first 50km after marathon |
| Marathon finisher (1–2 marathons) | Ready for 50km training with 16–20 week plan; confirm comfortable at 40+ km/week | 4–5 months training block |
| Experienced marathon runner (3+ marathons, consistent training) | Well-prepared for 50km; can consider 50 miles with a longer build | 16-week plan is sufficient for 50km |
Relentless Forward Commotion’s coaching guidance recommends runners have a minimum of 35–40 miles per week of consistent training before beginning ultra-specific preparation — “not that you can’t train for an ultra in your first year or two, but having that experience gives you the best chances for success.” Our guide on building marathon mileage safely covers the foundation work needed before ultra training becomes appropriate — and our marathon training plans are the natural stepping stone for runners who aren’t quite at the base level yet.
The Core Shift: Time on Feet, Not Pace
The most important mental shift in ultra training is moving from pace-based thinking to time-on-feet thinking. In marathon training, pace per kilometre is central — you’re training at threshold pace, tempo pace, easy pace. In ultra training, especially for first-timers on trail courses, the terrain, elevation gain, and progressive fatigue make pace meaningless as a primary metric. A kilometre on a flat road and a kilometre up a mountain trail are not comparable training units.
The relevant metric is how long you’re on your feet and at what effort. Easy effort — genuinely easy, where you can hold a conversation — is the dominant intensity of almost all ultra training volume. Our guide on easy run effort covers this in detail, but the specific application for ultra runners is even more conservative than for road runners. Most ultra training should feel almost boringly easy in terms of effort, even when the duration is long. The volume and terrain provide sufficient stimulus; artificially increasing effort adds fatigue without proportional benefit. Our Zone 2 running guide covers how to calibrate this effort level precisely.
Trail Runner Magazine’s coach David Roche makes the point clearly: top ultra runners often train at lower weekly mileage than pro marathoners. Cat Bradley averaged 66 miles per week before winning Western States 100. The specific stress of long mountain efforts, back-to-back runs, and technically demanding terrain at easy effort is sufficient stimulus without the accumulated fatigue of very high mileage.
Back-to-Back Long Runs: The Ultra-Specific Training Tool
Back-to-back long runs are the structural element that most distinguishes ultra training from marathon training. Instead of one long run on the weekend, you run long on Saturday and run again on Sunday — on deliberately tired legs. This is what an ultra race demands beyond 60–70km: continuing to run (or move) when your body is fatigued from the previous hours of effort. Training this specifically is what prepares you for it.
A typical back-to-back structure for a 50km build might be 20km on Saturday followed by 14km on Sunday, or 24km and 16km later in the programme. The Sunday run should be genuinely easy — slower than a usual easy run, often feeling awkward and heavy in the first kilometre or two before settling. That heaviness is exactly the adaptation stimulus. The legs learn to keep moving under the glycogen depletion and muscle fatigue that the previous day’s run has created.
Introduce back-to-back runs gradually. For the first half of a 20-week programme, single long runs on the weekend are appropriate. Around 8–10 weeks before race day, begin alternating single long run weeks with back-to-back weekends. Never introduce them when you’re already carrying fatigue from illness, injury, or an unusually high training week. The long run on Monday, Wednesday, and Friday should remain easy — back-to-backs are the stress; the mid-week runs are the recovery.
Walking: Not a Concession, a Strategy
One of the biggest mindset adjustments new ultra runners need to make is about walking. In road running culture, walking during a race feels like failure. In ultra running, walking — particularly uphill walking — is deliberate race strategy used by virtually every competitor, including elite finishers. Fighting the urge to walk when the terrain demands it is how you blow up in the second half of a trail ultra.
The physics are straightforward: on a steep uphill, the difference in speed between running and walking hard is small. The difference in energy expenditure is significant. A runner who power-hikes steep climbs and runs everything else conserves enough energy over 6–7 hours to run much more effectively in the later kilometres. A runner who insists on running all climbs arrives at the halfway point of a 50km having spent far more energy per kilometre gained.
Practise walking uphills in training from the beginning. Find the gradient that makes walking more efficient than running — on trails, this is typically anything above about 15–20% grade — and walk those sections without guilt. Use a strong, purposeful stride with hands on thighs on very steep sections (a natural technique that most runners discover independently). Make walk breaks a trained skill rather than an emergency response.
Walking also applies to long flat sections when fatigue accumulates. In the final third of a long training run or race, 1-minute walk breaks every 8–10 minutes of running help manage heart rate and leg fatigue without the session or race falling apart. This is a mental skill as much as a physical one — accepting that a run-walk pattern in the late stages is faster and more sustainable than trying to maintain continuous running past the point of efficient movement.
Nutrition: The Critical Variable Most Runners Underestimate
Nutrition in ultra running is not optional extra-credit training. It’s a primary determinant of whether you finish. The body’s glycogen stores last approximately 90–120 minutes of exercise at moderate intensity. An ultra takes 5–30 hours depending on distance and terrain. The entire second half of every ultra race is a sustained glycogen management challenge.
The standard hourly framework: after the first 30–60 minutes, consume 200–300 calories per hour and target at least 60g of carbohydrate per hour. INOV8’s ultra coaching guidance uses 60g carbs/hour as the minimum target, noting it requires “trial and error to find what works individually.” Outside Online’s coaching source recommends starting at 200 calories per hour on your first long run and incrementally increasing until you find the upper tolerance limit.
Don’t eat by hunger signals in an ultra. Hunger during long efforts is a lagging indicator — by the time you feel genuinely hungry, you’re already behind on fuel and the deficit is difficult to recover from. Set a watch timer for every 20–30 minutes and eat on that schedule regardless of how you feel. Treat nutrition as fuel management, not eating for pleasure.
Real food becomes more appealing than gels after 4–5 hours. Most ultras and trail runs have aid stations with savoury foods — broth, potatoes, sandwiches — that sit better than constant gels at that point. Train your gut to handle both during long training runs at race pace. GI problems are the most common reason DNFs occur in ultras, and they’re largely preventable with gut training and appropriate food choices. Our guide on runner’s diarrhea covers the mechanisms behind GI distress during running and the specific foods to avoid in the days before long efforts. Our guide on running stomach cramps covers mid-run GI management in detail.
Hydration over many hours requires electrolyte management beyond plain water. Sodium loss through sweat compounds over hours, and hyponatremia (low blood sodium from excessive plain water intake) is a genuine risk in hot events. Drink to thirst but include an electrolyte source in any drink taken after the first hour. Our sweat test guide covers how to calculate your individual sweat rate and sodium losses — particularly valuable for long-duration training runs and races where these losses become significant.
Trail-Specific Training
If your target race is a trail ultra — which most 50km events are — a significant portion of your training needs to happen on trails. The specific demands of trail running differ from road running in several important ways. Uneven terrain loads the stabilising muscles of the ankle, hip, and core differently than flat road running. Downhill running — often overlooked in training — produces eccentric muscle loading in the quads that is unlike anything in road training, and severe quad soreness in the second half of a hilly ultra is almost always caused by insufficient downhill training. Uphill running and hiking uses the posterior chain differently from flat or road running.
Marathon Handbook’s 50km training guidance recommends aiming for at least 50% of training on trails when preparing for a trail ultra. This isn’t always practical for urban runners, but the principle is to include trail running frequently enough that race terrain isn’t novel. Hill repeats — which can be done on any appropriate slope — cover much of the uphill specificity needed. Finding a long trail for weekend long runs, even if mid-week runs are on roads, is a reasonable approach when full trail training isn’t accessible.
Technical terrain — rocks, roots, unstable surfaces — requires a different foot placement and core engagement than roads. This is partly a skill issue that improves with exposure, and partly a strength issue. Lateral hip and ankle stability work off the bike significantly reduces ankle roll risk on technical trails. Two strength sessions per week focusing on single-leg work (Bulgarian split squats, single-leg deadlifts, step-ups, calf raises) and core stabilisation addresses most of the trail-specific muscular demands.
How to Structure a Week of Ultra Training
| Day | Base phase (weeks 1–8) | Build phase (weeks 9–15) | Peak/taper (weeks 16–20) |
|---|---|---|---|
| Mon | Rest or very easy 30 min | Rest or very easy 30 min | Rest |
| Tue | Easy 60–75 min | Easy to moderate 75–90 min with hills | Easy 45–60 min |
| Wed | Easy 45–60 min | Easy 60–75 min | Rest or easy 30 min |
| Thu | Easy 60 min or hill repeats | Easy 75 min + strides or hills | Easy 45 min |
| Fri | Rest | Rest or short easy 30 min | Rest |
| Sat | Long run 18–24km (building) | Long run 24–36km (trail); back-to-back starts week 9–10 | Back-to-back if peak week; single long run (taper) |
| Sun | Easy 60–75 min or rest | Back-to-back run 14–20km (easy); or rest in single weeks | Easy 30–45 min or rest |
Cutback weeks every 3–4 weeks remain essential, exactly as in marathon training. Drop volume by 25–30% and reduce the long run by a similar proportion. This is where the adaptation from the preceding hard weeks consolidates — skipping cutback weeks in ultra training produces the same overuse injury pattern that it produces in marathon training, just with higher stakes given the longer training hours.
The Mental Side of Ultra Running
Every ultra runner will hit a low point. It’s guaranteed in any race beyond 50km and common in training runs that push toward 30km+. The difference between runners who push through and those who don’t is rarely physical capacity — it’s whether they’ve prepared for the mental experience of moving under deep fatigue.
Practise this in training. On your long back-to-back runs, include sessions where you continue through tiredness rather than cutting short. Not recklessly — always stop if something hurts genuinely — but experiencing the early-deep-fatigue feeling and learning that it passes is a training adaptation as real as a cardiovascular one. The body learns that the low periods resolve, that movement continues to be possible, and that there’s a different relationship with discomfort available than the one road runners are used to.
Many ultra runners are in their 40s and 50s, drawn to the sport by exactly this aspect — the mental challenge and the recalibration of what the body is capable of at an age when speed-based running becomes less rewarding. Our guide for older athletes covers how training principles adapt for runners over 50, including the recovery considerations that make ultra training particularly manageable at moderate volume for masters runners.
Train for Your First Ultra With Specialist Coaching
SportCoaching's ultra running coaches build training programmes around your specific distance, terrain, timeline, and work-life constraints — with the back-to-back structure, nutrition rehearsal, and progressive mileage that first-time ultra runners need to arrive at the start line ready.
FAQ: How to Train for Ultra Running
How do I start training for an ultramarathon?
Start with a solid marathon base — complete at least one marathon or be running 35–45 miles per week consistently before beginning ultra-specific training. The 50km is the recommended first ultra. A 16–20 week plan is appropriate from a marathon base; true beginners may need 20–24 weeks.
What are back-to-back long runs in ultra training?
Two long runs on consecutive days — Saturday and Sunday — designed to simulate running on fatigued legs, which is the defining challenge of racing beyond 50km. Introduced gradually around 8–10 weeks before race day. Sunday should be done at easy effort on genuinely tired legs from the day before.
How much should I eat during an ultramarathon?
200–300 calories per hour after the first hour, targeting at least 60g of carbohydrate per hour. Set a timer every 20–30 minutes and eat on schedule — don’t wait for hunger. Practice your exact race nutrition during training runs at race intensity, not just on easy sessions.
Is it okay to walk during an ultramarathon?
Not just okay — it’s deliberate strategy. Walking uphills is used by virtually all ultra runners including elites. The energy savings on steep climbs versus running are significant; the speed difference is small. Practice walking uphills from day one of trail training.
How many days a week should I train for an ultramarathon?
4–5 days per week for a first 50km. One or two long runs, two to three easy/moderate mid-week runs, at least one rest day, and optional strength or hill session. Recovery between long runs is as important as the long runs themselves.
Find Your Next Running Race
Ready to put your training to the test? Here are some upcoming running events matched to this article.
