What Marathoners Get Wrong About Ultramarathons

The transition from marathon to ultramarathon is more nuanced than simply running longer. In this episode, CTS Coach Cliff Pittman breaks down the biggest differences between marathon and ultra training, and what athletes actually need to change when making the jump.

We cover terrain, pacing, fueling, durability, gear, mental resilience, and the “Minimum Effective Change” model used while helping Olympic medalist Molly Seidel transition into trail ultrarunning.

HOST

Cliff Pittman is the Coaching Development Director at CTS, leading the Ultrarunning and Cycling Coaching staff with a specialty in guiding athletes from first-time ultrarunners to elite competitors at races like Western States 100, Leadville 100, and the Triple Crown of 200s. A competitive trail and ultra athlete himself, Cliff brings firsthand experience and a rare ability to turn complex training science into simple, actionable coaching.

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Transcript

Who This Ultra Transition Is For

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If you're a marathoner who has started wondering what's beyond 26.2, whether that's a 50K, a 50 miler, or 100k and beyond, this video is for you. Curiosity is common and the transition is far more nuanced than most people expect. The good news is that the fitness that you've built as a marathoner is a genuine asset if you know how to use it. I'm Cliff Pittman, Pro Ultrarunning Coach and Director of Coaching at CTS. I coach athletes from first-time ultrarunners to professional and world-class competitors. I want to start with something

Molly Seidel’s Blueprint For Switching

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important. The lessons in this video come largely from working with Molly Seidel, Olympic bronze medalist in the marathon and one of the most talented distance runners this country has produced. Molly won her first Ultra outright at Bandera 50K, setting a course record. She then earned a golden ticket to Western States with a fourth place finish of Black Canyon 100K and just her second ever Ultra. And she recently finished third at Canyon's 50K as a training race, not a peak performance, a stepping stone toward Western States. Now those results belong entirely to her. Her talent, her work, her willingness to step into unfamiliar territory and figure it out. What I can offer is the framework we used to navigate her transition and why that framework applies to any marathoner considering their first ultra.

Why An Ultra Is A New Sport

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Now let's start with the most important thing to understand about this transition. An ultra marathon is not simply a longer marathon. It's a different discipline entirely. Demands shift so significantly with the distance and duration that the skills, strategies, and preparation required to succeed look meaningfully different from what got you to a marathon finish line.

Five Differences That Change Everything

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So here are the five differences that matter most for your transition. Number one is terrain and environment. Road marathons are remarkably flat compared to most trail ultras, and even hilly road marathons do not prepare you for the biomechanical demands of sustained climbing, technical descending, and variable surfaces that define trail ultra running. In a single ultra, you might run on single track trail, forest service roads, jeep tracks, and pavement, sometimes in the same race. You might cross water, run through snow, or move through multiple microclimates as elevation changes dramatically. Western States gets up to over 9,000 feet in the Sierra Nevada with snow on the trail in June and descends into canyons with triple-digit heat later in the same race. Your preparation has to match that reality. Number two is pacing. In a road marathon, pace per mile is a very reliable tool. The surface is consistent, the terrain is predictable, and your splits mean something. In an ultra, pace becomes almost meaningless as a primary guide. Elevation, trail surface, technicality, all of it changes the relationship between effort and pace constantly. The tool that replaces pace in ultra running is RPE, rate of perceived exertion. Running through a rock garden is slower than running on a groomed gravel road, even when the effort level is identical. RPE keeps you within your physiological capacities regardless of those conditions. And learning to trust it in training is one of the most important skills you can develop as a transitioning runner. Number three is fueling and hydration. This is where most marathonners are least prepared and where races most often unravel. In a marathon, aid stations are frequent, carbohydrate is your primary fuel, and you can get away with mild dehydration or imperfect fueling without catastrophic consequences. In an ultra, the margin for error narrows significantly as hours accumulate. Aid stations can become hours apart and you're carrying your own fluids. You need to consume carbohydrates at rates that can exceed 60, even 90 grams per hour for many hours at a time. And perhaps most importantly, your appetite, your cravings, and your tolerance for food changes dramatically the longer that you run. What sounds good at mile 10 may be completely unappealing at mile 40 or 50. Fueling for ultras is a trainable skill though. You have to practice it in training deliberately, consistently, the same way you practice pacing or terrain. Number four is gear and biomechanics. In road marathons, running economy is critical performance variable. The more efficient your movement, the faster you run. In ultrarunning, we consciously trade some running economy for durability and comfort. Heavier trail shoes with more protection, a hydration vest that changes how you carry weight, sometimes even trekking poles that alter your gait and redistribute load across your upper body. These are not just gear decisions, they are biomechanical changes that affect how your body loads and recovers over many hours of movement. Becoming familiar with them in training is not optional. Number five, duration and mental resilience. A marathon is hard effort sustained for two to five hours. An ultra asks you to keep moving, making decisions, managing your body, maintaining effort for 8, 12, 20, or even more hours. The mental demands are a different kind, not just degree. And so success in Ultra requires knowing how to keep pushing when you think you have absolutely nothing left, how to problem solve when things go completely wrong, and how to stay patient when everything in you wants to either speed up or stop. These are skills that are developed in training. They matter as much as fitness when the race gets really long.

The Minimum Effective Change Model

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Now let's talk about how these differences shape the approach that we took with Molly and what that means for you. The most important framing principle behind her transition is what I call the minimum effective change model. When an elite athlete transitions disciplines, the temptation is to change everything all at once. More mileage, more vertical, more long runs, more intensity, and more stressors all at the same time. Now the minimum effective change model resists that impulse. It asks a simpler question: what already works? And what is truly missing? For Molly, the answer to what already works was almost everything on the fitness side. She had elite aerobicapacity, world-class lactate threshold, exceptional running economy, years of high volume training history. These were not developmental projects. They were already established strengths. So my job was to preserve them, not rebuild them. What was missing was the ability to express that fitness, that world-class fitness, under the specific demands of an ultra marathon. The durability over terrain and time and fueling at ultra volumes, as well as familiarity with gear and trail biomechanics. So we changed the architecture, not the volume. Instead

Back To Back Long Runs Done Right

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of adding more total mileage, we redistributed the stress. Back-to-back long runs became very intentional tools, and fatigue accumulation across consecutive training days was introduced carefully and progressively. A 20-mile road long run stresses the body very differently than a 15-mile trail effort followed by a 10-mile trail run the very next day, while also practicing 60 to 90 grams of carbohydrates per hour. The mileage might look very similar, but the stress profile is very different. And we also reinforced structured threshold work throughout the build early on. And threshold remains one of the strongest determinants of long duration performance. The ability to sustain high percentage of VO2 max efficiently underpins success when the race lasts two hours or even eight. So as we move toward race-specific preparation for Black Canyon, sessions start to shift to the back end of long runs, training her body to run at a quality effort when glycogen is already depleted and mental fatigue has started to set in. We got really good at running while tired. And that's specificity with purpose. And fueling became a very much a training variable in its own right. Long runs were fueling rehearsals. Carbohydrate targets were practiced repeatedly until gastrointestinal tolerance improved. We brought in Stephanie Howe to translate fueling science into simple, actionable behaviors. And simplicity improved compliance, and compliance improved consistency, and consistency improved performance. Now in race day at Black Canyon, nothing about Molly's physiology had been reinvented. She was still the same marathoner she's always been. But what changed has was her ability to manage those variables and determine whether elite fitness could survive the duration and distance of an ultra marathon. And she earned her golden ticket. That outcome is a reflection of her talent, her preparation, and her ability to handle adversity when it mattered most. Molly is exceptional at this and it showed.

Your Step By Step Ultra Framework

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But here's what this means for you as a marathon or considering your first ever ultra. You probably have more fitness than you think you need. The question isn't whether you're fit enough. The question is whether you can express that fitness you have under conditions that are genuinely new for you. So here's the framework. First, identify what already works and protect it. It's probably your aerobic base, your threshold fitness, your training consistency. All of these things transfer. So don't abandon them in a rush to add ultra specific volume. Second, introduce the new variables one at a time. Start with terrain, then back-to-back long efforts, then fueling at higher volumes, then gear and biomechanics. Stack them very deliberately, not all at once. Third, train your gut. Now this is a non-negotiable in ultrarunning. Practice fueling on every long run. Start at 50 or 60 grams of carbohydrate per hour, and then build up from there. Your GI system adapts, but only if you train it. Fourth is learn to pace by effort, not pace. RPE is your most reliable tool in trail and ultrarunning. And the sooner you trust it, your intuition, the better your races will go. And fifth, build mental resilience. Very deliberately. Put yourself in uncomfortable situations in training. Run while you're fatigued. Run in heat. Run when you don't feel like it. And even run slow. The ultra will ask you to keep going when everything else says stop. And the only way to prepare for that is to practice it. The transition from marathon to ultra running is not about becoming a different athlete. It's about extending what you already are and have into very new demands. Start where you are, change only what you need to change, and give it time to work. Now,

Next Video And Coaching Options

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if you want to go deeper on the durability work that underpins a successful ultra transition, the fourth variable durability video covers that in full. Watch that one next. And if you want coaching that guides your transition from marathon to ultra with a deliberate individualized plan, visit trainwright.com to connect with the CTS coach and subscribe for more coach driven ultra running education.