There’s a particular kind of suffering that ultramarathon runners know intimately: the miles past the point where the race was supposed to end. When the legs are done, the glycogen is gone, and what’s left is the decision to keep moving anyway. OCR athletes at longer formats know a version of this too — it surfaces somewhere on a Spartan Beast, or in the final stretch of a Savage Ultra, when the obstacles stop feeling like obstacles and start feeling like tests of something deeper than fitness.
The training methodologies that ultramarathon runners have developed over decades — built specifically to prepare athletes for that exact territory — are more transferable to OCR than most obstacle racers realize. Not all of it translates directly, and the gaps are worth understanding. But the frameworks for building volume, managing fatigue, and teaching the body to perform late in a long effort are directly applicable to the demands of longer OCR formats. Here’s how to use them.
The Ultra Foundation: Why Volume Matters Differently
Ultramarathon training is, at its core, a volume-management discipline. The goal isn’t just to get the athlete fit — it’s to get them accustomed to sustained movement under accumulating fatigue, over a period long enough that the brain begins to normalize the discomfort. The body adapts, but so does the mind. The athlete who runs 60 miles in a training week isn’t just building cardiovascular output; they’re building a baseline expectation of what sustained effort feels like. That baseline changes what’s hard.
For OCR athletes competing in formats that run an hour or longer — and especially those targeting 21K, Ultra, or multi-lap formats — this concept is directly relevant. The athletes who fall apart late in a long OCR event usually aren’t undertrained for pace. They’re undertrained for duration. They’ve done their speed work and their strength work, but they haven’t spent enough time in the uncomfortable middle space where the body is fatigued but the race isn’t close to over.
Borrowing from ultra training here means building a weekly long run that’s genuinely long — not 90 minutes, but three, four, or more hours at low intensity. The pace is almost irrelevant. The duration is the stimulus. Over a 12–16-week cycle, this kind of session fundamentally changes what late-race effort feels like.
Back-to-Back Long Efforts: The Ultra Secret Weapon
One of the most distinctive elements of ultramarathon training is the back-to-back long run: a long effort on Saturday, followed by another long effort on Sunday, both at low intensity. The second session is run on pre-fatigued legs — and that’s precisely the point. It teaches the body to perform when it isn’t fresh, which is the state it will always be in during the later stages of any long race.
For OCR athletes, this concept has an obvious application: combine a long run day with a strength and obstacle-practice day the following morning. Not a crusher session — a moderate, obstacle-focused workout that forces the athlete to practice technical movements under accumulated fatigue. Rope climbs on tired arms. Monkey bar sequences on a grip that’s already been tested. Carries with legs that logged miles the day before. The simulation isn’t accidental. It’s the training.
This is where many OCR athletes who come from a running or fitness background leave performance on the table. They train their strength fresh and their running fresh and their obstacles fresh — and then on race day, everything arrives at once, together, in a degraded state. The back-to-back model introduces that degraded state intentionally and repeatedly, so race day isn’t a shock. It’s a familiar environment.
Perceived Effort Over Pace: The Ultra Mindset Shift
Ultramarathon runners train primarily by effort, not pace. Heart rate or perceived exertion — not GPS speed — governs most sessions. This is partly practical (trails and terrain make pace meaningless) and partly physiological (intensity needs to be managed over time to avoid burning out the aerobic system before the training cycle peaks). The result is athletes who are extremely well-calibrated to their own internal states — who know what sustainable effort feels like at hour six versus hour one.
OCR athletes tend to race more instinctively. They run hard, they hit obstacles, they push through. That approach works fine on a 5K sprint. On a Beast or Ultra format, it’s often the thing that leaves them bonking at kilometer 18 wondering where everything went wrong. Introducing effort-based training — even for a 10-week block — develops exactly the kind of internal throttle that long-format OCR demands. The athlete learns to read their own body accurately enough to pace the effort across four or five hours rather than burning it in the first ninety minutes.
The skeptic’s view is worth acknowledging here: ultra training volume isn’t appropriate for every OCR athlete. Someone competing primarily in Sprint or 10K formats doesn’t need a 50-mile-week training block. The caloric demands are significant. The time commitment is real. And OCR’s strength and technical obstacle requirements mean that pure running volume can crowd out the work that actually makes athletes better on course. The ultra-borrowing should be selective, not wholesale.
Nutrition Strategy: Fueling for Duration, Not Just Intensity
Ultra nutrition is a science unto itself, and the core lesson is this: eating on the move is a skill, not an afterthought. Ultramarathon runners practice consuming calories at regular intervals during training runs — not just on race day — so that the gut is trained to absorb energy under duress. They experiment with formats, timing, and volume over months of training, not in the final week before a big race.
Long-format OCR athletes face the same demand but often train as though nutrition is a race-day logistics problem rather than a training adaptation. It isn’t. The gut that can absorb 200–250 calories per hour at race effort in a five-hour event needs to have practiced that. Real-food options, gels, chews, liquid calories — all of these behave differently under sustained effort, and the body needs reps to figure out what it can handle.
Integrating fueling practice into long training efforts, the way ultra runners do, is one of the highest-leverage adaptations an OCR athlete targeting long formats can make. It’s not glamorous, and it doesn’t show up in any fitness metric — but it can be the difference between a strong finish and a death march to the medical tent.
Putting It Together: A Practical Borrowing Framework
You don’t need to run a hundred miles a week to benefit from ultra methodology. The goal is selective adoption — taking the elements of ultra training that address OCR’s specific late-race demands without abandoning the strength and technical work that makes the sport what it is. A practical approach for OCR athletes targeting long formats:
- One true long effort per week: Build to 3–4 hours at low effort over a 12-week cycle. This is the aerobic base investment that pays dividends in hours 3 and 4 of a long race.
- Monthly back-to-back sessions: Pair your long run day with an obstacle-practice session the next morning. Keep the second session moderate — the stimulus is fatigue management, not fitness accumulation.
- Train by effort, not pace: At least one session per week should be governed by heart rate or perceived exertion rather than GPS pace. This calibrates the internal throttle that long-format racing demands.
- Practice fueling every long session: Eat on the move during any session over 90 minutes. Experiment. Keep notes. Race-day nutrition is a trained adaptation, not a plan.
- Protect the strength work: Ultra-borrowing should supplement OCR-specific training, not replace it. Two quality strength sessions per week minimum. The obstacles don’t care about your mileage.
The Bottom Line
OCR and ultramarathon racing are different sports with meaningfully different demands. But the ultramarathon community has spent decades solving the exact problem that longer OCR formats present: how to prepare an athlete to perform well, technically and physically, in the hours when most people are just trying to survive. The solutions — volume, back-to-back fatigue exposure, effort-based training, practiced nutrition — are not complicated. They’re just disciplined. Which, in the end, is what separates the athletes who finish strong from the ones who finish.
This article was researched with the help of AI tools and reviewed and edited by Hilton Campbell. Original reporting and quotes are our own.