What an ultra is (and what ultra trail is)
An ultramarathon is any foot race longer than the classic marathon distance, 42.195 km. In practice, the field talks in bands: 50k, 100k and the classic 100 miles (about 161 km). There are also timed races, where you run a loop and count accumulated distance over 6, 12 or 24 hours.
Ultra trail is the mountain cut: a trail course with high accumulated elevation gain (the sum of everything you climb and descend). It is the elevation gain, not just the kilometers, that defines the brutality. A flat 100-mile race and a 100-mile race with 10,000 meters of climbing are almost different sports.
The real difficulties
What stops an ultrarunner is rarely the lungs. It is the sum of aggressions the marathon never gets to expose:
- Energy management: in races of many hours, keeping the refueling pace is decisive. The body cannot burn everything it spends, so starting too fast is paid for dearly at the end.
- Stomach: with blood diverted to the muscles, digestion slows. Nausea, cramps and sickness are among the most cited causes of dropping out as the distance grows.
- Feet: the blister is the most common medical problem in ultras. Hours of friction, moisture and swelling destroy the skin.
- Sleep: in races that go through the night, sleep deprivation is nearly inevitable and becomes a central factor in very long ultras. Poor vision, dozing off while moving and hallucinating are frequent reports.
- Muscular: long descents generate eccentric contraction that tears fibers. That is why the mountain destroys more than asphalt.
- Mental: the head decides. Knowing how to slice the race into small pieces and pushing through the bad moments usually separates those who finish from those who stop.
The training an ultra demands
Preparing for an ultra is not just running more. The pillars that show up in the training of those who finish these races:
- Progressive volume: the weekly base rises over months, without abrupt jumps, so the body can handle time on its feet without breaking.
- Back-to-back: long runs on consecutive days (for example, a long Saturday and a long Sunday) teach the body to run tired, simulating the race's accumulated fatigue without needing a single giant workout.
- Strength: strong legs and core protect against the muscle damage of descents and hold technique when fatigue arrives.
- Specific elevation: those who run ultra trail need to train climbing and, above all, descending, which is what destroys most. If there is no mountain nearby, stairs, ramps and the incline treadmill help.
- Night training: running with a headlamp, adapting the stomach to food in the early morning and knowing your own sleepiness before race day.
Preparation: race nutrition, gear and crew
The race plan itself is half the game. The other half is logistics:
- Fuel on the move: test in training what the stomach accepts after hours of running. What works at rest does not always go down at km 120.
- Gear: broken-in shoes with nothing new on race day, socks that do not chafe, hydration vest, headlamp with spare battery and layers for the cold of altitude and early morning.
- Crew and drop bags: in races that allow them, a support crew at the aid stations and bags with a change of clothes, food and supplies make a difference. In semi-self-sufficient races, you carry almost everything.
Reference races around the world
- UTMB (Chamonix, France): the main race has about 170 km and close to 10,000 meters of elevation gain, circling Mont Blanc through France, Italy and Switzerland. First edition in 2003. It usually takes place in late August. Kilian Jornet won it four times (2008, 2009, 2011 and 2022).
- Western States 100 (California, USA): 100.2 miles (about 161 km) in the Sierra Nevada, the oldest 100-mile trail race in the world, with the first on-foot edition in 1977. It happens on the last full weekend of June. A 30-hour cut-off to finish, and a silver buckle for those who do it under 24 hours.
Reference races in Brazil
- Brazil 135+ (Serra da Mantiqueira, SP/MG): 217 km (135 miles) along the hardest stretch of the Caminho da Fé, with a 60-hour limit. Considered one of the hardest ultras in the world. The edition usually takes place in January (next announced for January 07, 2027).
- KTR Ultra Serra da Canastra (MG): a stage-format ultra trail in the Serra da Canastra region, with 25, 50 and 100 km options. The 2026 edition took place in May, in a multi-day camp format.
- Ultra BM, formerly Bertioga-Maresias (SP coast): a traditional 75 km ultra between beaches, roads and trails of the São Paulo coastline, raced in solo and relay formats.
How Darwin follows an ultra season
Darwin helps organize volume, back-to-back long runs and strength blocks over the months, importing your activities from Strava and your watch to track internal load and flag fatigue. Mountain training is based on established techniques: the tool is the means, you operate the machine. Any nutrition and health adjustments must go through professionals.
