WHY DO 36% OF ATHLETES NOT FINISH THE UTMB?

2,761 competitors took part in the UTMB in 2024.

1,001 of them never reached the finish line in Chamonix.

These aren't statistics. These are a thousand stories about systems that fell apart. About guts that said "enough." About legs that gave out. About minds that made one bad decision too many.

Because 100 miles UTMB is a test not of your muscles and mind, but of the entire ultra-system that you have built for yourself.

And you know what? Athletes don't drop out because they're weak. They drop out because something breaks. Most often, sooner than they think. Most often, for reasons that could have been predicted. Most often, because someone didn't learn their lesson from the ultra process.

1. PACE FROM THE START. THE FIRST SIN THAT KILLS AT KILOMETERS 80.

The most common and common reason for a DNF. And the easiest to avoid.

The UTMB starts at 6:00 PM, downtown Chamonix, thousands of fans, music, adrenaline pumping. Runners set off too fast because they "feel great." They're reacting to the crowd. To the energy. To the euphoria. They're trying to "stock up."

And UTMB doesn't forgive energy debt. Every percentage point above the plan comes back with interest after 100-120 km.

The crisis doesn't start on the Grand Col Ferret. It starts in Chamonix, in the first hour, when you feel indestructible.

2. THE GUT SAYS "ENOUGH". TOP 1 REASON FOR DNF (ALSO APPLIES TO THE ELITE)

I hear competitors complaining after UTMB that "the water at the UTMB checkpoints is weird", "I must have eaten something rotten at the checkpoint because I threw up for 3 hours afterwards." "It's because of the soup!" "It's because of the cheese!"

NO.

In 90% of cases, it wasn't just food from a food source. It was exertional endotoxemia. It sounds like something out of a medical horror movie. And it kind of is.

What is endotoxemia?

Normally, the intestinal wall is a tight barrier. Bacteria stay inside, where they belong. The blood is clean. The system functions.

But during prolonged, intense exercise, your body makes a brutal decision: muscle or gut. And it chooses muscle.

Blood flows away from the intestines and into the working legs. Up to 80% less blood flow. The intestine suddenly receives too little oxygen and too few nutrients. It begins to suffer.

And then the intestinal wall becomes leaky. In the literature, this is called leaky gut, but the name is misleading, because these aren't large holes. They're microscopic gaps between cells that are normally sealed shut.

Fragments of bacteria that should never have entered the blood begin to penetrate through these gaps.

Body reaction: red alert

Your immune system isn't stupid. It recognizes invaders and responds, as it does to any threat, by triggering inflammation.

Fever. Nausea. Vomiting. Diarrhea. Chills. A general feeling that "something is very wrong."

Sound familiar? It sounds exactly like food poisoning. Because the mechanism is similar. Except the source isn't food from a convenience store. The source is your own gut bacteria, which have gotten into a bad place.

Exertional endotoxemia isn't bad luck. It's a sign that your system has failed. And unless you change your approach, it will fail again.

Now the next time someone tells you they're "obsessed" with it, you know what it really was like.

Why does the intestine refuse to cooperate?

Too aggressive a pace at the beginning. Blood flows away from the intestines and into the muscles. The intestines get the signal: "We're in survival mode, digestion can wait." And they wait. For hours. While you try to shove gel after gel into yourself.

No gut training before the race. Yes, the gut gets training. Just like muscles. If you haven't trained your gut to absorb 60-90g of carbohydrates per hour in the months leading up to the race, don't expect it to suddenly do so under the pressure of a race.

Poor sodium and fluid management. Hyponatremia (too low sodium), dehydration, and overhydration—all of these conditions can end a race equally effectively.

3. FOURS THAT ARE FADED OUT. PHYSIOLOGY KNOWS NO COMPROMISE.

UTMB involves 10,000 meters of elevation gain and very long, sometimes technical descents. The quadriceps muscles work eccentrically for hours, slowing the body down on steep descents.

I see this regularly with athletes who write to me. Someone comes back after a failed ultra and says, "My legs just gave out. My head wanted to, but my legs wouldn't listen."

It's not a matter of character. It's a matter of tissue preparation.

Lack of eccentric training. Lack of overall strength. Lack of adaptation to long descents. And then the surprise when, at the 80th kilometer, my knees give out.

If you don't train in the mountains, when was the last time you stepped off the box at the gym and onto the ground? Preferably with your own bodyweight, then with additional weights? - Exactly.

4. WEATHER. LITTLE THINGS THAT KILL.

UTMB is night, cold, rain, wind, scorching heat in the valleys, and freezing cold on the passes. Often, all in one race.

In 2024, the organizers announced a mandatory "Hot Weather Kit." In the heat of 2015, with temperatures ranging from 14-25°C, as many as 43% of competitors failed to finish. In the colder 2017, only 33%.

Ten percentage points difference. It's just because of the weather—and weather is something you can prepare for! Yes, you can learn to run better in the heat.

Competitors are eliminated because they choose the wrong clothing. Because they can't manage their heat. Because they freeze for hours or overheat and lose sodium through sweat.

These are small things. But over 100 miles, it all adds up and eliminates the race.

6. HEAD, BUT NOT IN THE WAY YOU THINK.

And this is where we get to the point where most articles start talking about "mental strength" and "winning character."

I won't.

Because it's not the lack of a "strong head" that usually ends a race, but the lack of a plan B, C, D. Panic at the first crisis. Reacting impulsively instead of strategically.

Athletes who complete the UTMB don't fight every crisis as if it were an enemy. They manage them. Calmly. Methodically. Because they have a plan. Because they knew the crisis would come. Because they prepared for it instead of hoping it would pass them by.

COURMAYEUR: CEMETERY OF DREAMS

There is one checkpoint that collects 17.7% of all DNFs for the entire race.

Courmayeur. Kilometer 81. Supposedly halfway through the route. But in reality, only a third of the difficulty and a gigantic trap.

You arrive at the point, exhausted from the pace and digestive issues—and it's warm here. Safe. You can get some sleep. Eat a hot meal.

And it's very easy to convince yourself that giving up "is a wise decision", because you still have Grand Col Ferret ahead of you at 2,537 m above sea level, the highest point of the route.

Interesting data: DNFs at mountain checkpoints are only 8% of the total, even though they constitute 40% of checkpoints. It's easier to give up where a warm bed awaits than on a windy pass.

Men tend to give up early, with 34% dropping down to Lac Combal at kilometer 67. Women are more persistent at the beginning, with only 29% giving up by that point.

So if you want to finish UTMB - just get out of there, don't sit back, do your thing and run.

CHAMPEX-LAC: POINT OF NO RETURN

There is one moment in UTMB that changes everything.

Champex-Lac. Kilometer 134.

If you get here and out of there, you have a 94% chance of finishing. That leaves "only" 47 km.

Interestingly, runners over 50 have a higher DNF rate overall. But once they leave

Champex-Lac, have even better chances of reaching Chamonix than the younger ones.

Experience teaches us that the hardest part isn't running. The hardest part is getting out of a warm spot when everything hurts. When your body is screaming. When your bed is right there.

And that's precisely why this isn't a test of character. It's a test of the system. A decision-making system that works even when you're tired, hungry, and sore.

WHAT DOES THIS ALL MEAN?

A 36% DNF isn't a failure of character. It's a failure of the system.

The pace was bad from the start. My gut wasn't trained. My muscles weren't ready for the descents. Packing my drop bag failed. The conditions exceeded my preparation. Decisions were chaotic instead of strategic.

UTMB doesn't test who's tough. Everyone who steps onto the starting line for a 100-mile race is tough. That's not the question.

UTMB tests who has their system in order. Who has done their homework on their own biology. Who knows what to do when their gut gives out. When their legs give out. When their head starts whispering, "Let it go."

And this is exactly what the MojeUltra philosophy is about: not heroism, not "strong head", not "pushing with character". A system based on knowledge, experience and knowledge of one's own body.

Because true finishers don't fight their bodies. They work with them.

Do you have a crisis management system, or are you hoping the crisis will pass you by?