VMM 2026: Sa Pa, the Record Rain, and 5,300 People Searching for Their Own Limits

8 a.m., and mud

At 8 a.m. on September 18, 2026, in Sa Pa, Lao Cai province, the two longest distances of the Vietnam Mountain Marathon 2026 — 161 km and 100 km — started together. It was raining. Not a burst that falls and stops, but a rain that had seeped through the night, soaking into the topsoil, mixing with laterite and mountain gravel into a thick, clinging mass. Those at the front of the pack could not clearly see the start line; they saw a puddle of mud spreading like oil.

People usually describe Sa Pa through its clouds. This season, the clouds stayed on the ground. Fog sat at chest height, visibility sometimes collapsing to a few metres, and the entire course-marking system had to lean on tensioned rope and human wardens. For a mountain race with more than 5,300 runners from 54 countries, fog is not a backdrop. Fog is a variable in a safety equation.

I have followed VMM for years, but my day job is sitting with datasets from youth football and tennis. That is why I showed up here with a notebook rather than a pair of shoes. It is also why I look at a mountain race the way I look at a development curve: what already exists, what is forming, and what is being over-painted.

Every academy is an archaeological site. Every cohort is a cultural layer. I am only the one who takes notes. This year, that site sits at more than 1,500 metres above sea level.

Sa Pa is not a stadium, it is a geological layer

To understand VMM 2026, you have to understand the place before you understand the event.

The Hoang Lien Son range is the youngest and harshest part of northern Vietnam's mountain system. Its rock has not weathered long enough to become round. It remains sharp, loose, and slippery when wet. A dry slope in Sa Pa may simply be hard; the same slope after two days of rain is an entirely different technical test, demanding descending skill, terrain reading, and — most importantly — the clarity to know when to slow down.

According to documents published by the organisers, BTC VNM 2026, this year's event spans four days of competition, from September 17 to September 20, 2026. The 161 km and 100 km distances start together at 8 a.m. on September 18, 2026. That is an operational detail worth noting: two groups of runners with entirely different objectives are placed on the same course in the same window, and the entire resupply, checkpoint and rescue system must serve two different speeds simultaneously.

The organisers also confirmed that VMM has formally joined the World Trail Majors system. That detail matters more than it appears. When a trail race enters an international system, it accepts three things: higher safety standards, stricter course measurement, and a fixed calendar with little room for improvisation. All three raise organising costs, and all three are invisible from the outside.

5,300 people, 54 countries, and an uneven curve

Participation figures for 2026 record more than 5,300 runners from 54 countries. Looking at that number, the first reflex of anyone who works with statistics is to break it down.

5,300 people spread across several distances over four days. Most of them run short and medium distances — this is the group that creates the event's atmosphere, the group that brings families, that stays a few extra days in Sa Pa and spends money there. The 100 km and 161 km group is only a fraction, perhaps a few hundred people, but it is the group that determines the entire operational structure: they are the reason there are overnight aid stations, 24-hour rescue teams, and rope sections on slopes that short-distance runners never touch.

Based on my experience tracking matches and development-curve datasets, this structure looks very much like a football academy: large numbers at the entry level, thinning numbers as you move up, and a very small group at the decisive layer. The difference is that at an academy, people are culled by a coach's decision. On a mountain course, people cull themselves — by pace, by stomach, by knees, and by time.

54 countries is a telling number because it reflects something other than scenery. It reflects organisational capacity. A runner in Europe spends the equivalent of several weeks' wages, flies half the world, carries shoes, clothing, gels, electrolyte powder and a handwritten nutrition plan — that person is betting that the organisers will not leave them freezing on a mountain. The credibility of a mountain race is not in its beautiful course. It is in whether people get back to their hotel.

A sawtooth course and the illusion of the first 30 km

The defining feature of the VMM course is its sawtooth structure: up, down, up, down, repeated without any regular rhythm. For newcomers, this is the most underestimated aspect.

On a sawtooth course, total accumulated elevation does not tell the whole story. What decides is the length of each climb and the steepness of the descent immediately after it. A 5 km climb will drain a significant amount of glycogen, but the descent that follows is where the body pays: the quadriceps must act as a continuous brake, and every descending step is a stretch of muscle under load.

In the first 30 km, almost everyone feels strong. That feeling is a measurable physiological trap. Glycogen has not run out, the nervous system is still excited by the start, and morning temperatures are still low. Many runners go faster than planned in this section, and most of them will pay that debt somewhere between km 60 and km 80, when it is dark, when the last aid station is far behind, and when the brain starts calculating how many hours remain to the finish.

This is why a trail runner's race plan differs from a road marathoner's. On road, people split the distance in half. On mountain, people split by aid station, and each station is a separate negotiation. Arriving at a station, you do not ask yourself how many kilometres remain. You ask yourself how much water, how much salt, how many calories, and how much clarity remain.

The rope sections: where technique replaces physical capacity

In field reports, the organisers noted that this year's course included slopes so slick they resembled slides, requiring rope sections for runners to descend. This is the most important technical detail of the entire event, and it is often skipped by media because it is not photogenic.

A rope section is not a convenience. It is a statement about difficulty. Organisers install rope only when they judge that without it, the risk of injury or fall exceeds an acceptable threshold. It also means that in this section, speed is no longer decided by heart and lungs, but by skill.

On a rope section, the running order can invert. A runner who climbs well but has never descended on rope will lose more time than a slower runner with technical experience. This echoes tennis — a player with a powerful serve can still lose to a weaker server if the match falls into tiebreaks and the weaker server handles the pressure better. The same principle: when skill is elevated to a decisive role, a physical advantage is neutralised.

The organisers' decision to publicly disclose slippery sections and rope sections is also a deliberate communication act. It turns risk into information, and information into preparation. A mountain race does not hide its difficulty. It publishes its difficulty as part of the invitation.

Aid stations: a small economy running on trust

What almost no one sees at a mountain race is the back end of the aid station system. An overnight aid station needs hot water, easily digestible food, salt, fruit, blankets, lights, spare batteries, staff trained in first aid, and a clear procedure for handling dropouts.

At 161 km, this system is essentially a chain of small facilities strung along a trail, operating continuously for many hours, in rain. There are no grandstands. There is no cheering. There is a plastic table, a few barrels of water, a notebook for bib numbers, and a volunteer standing there from afternoon until the next morning.

When Covid closed the stadiums, I opened the data archive. Youth football never stopped beating. I found something similar here: when rain closes the trail, the logic is the same. A system is only trustworthy when it keeps operating at the moment no one is watching.

It is the aid station system that determines a mountain race's finish rate, not the beauty of the scenery. A poorly placed station, or one missing hot water during a rainy night, can push dozens of people to drop within a single hour. Outsiders read the final results and see the names. Insiders read the station distribution chart and know in advance who will quit.

Nutrition: the fourth sport no one trains

Across a mountain race, four sports take place at once: running up, running down, tolerating cold, and eating.

The fourth is the most underrated. A runner covering 100 km will burn calories that the body cannot fully replace while moving. Blood is diverted away from the digestive system to serve the muscles. As a result, much of the intake is not fully absorbed, and the greatest trap of ultra distances is not running out of energy but a stomach that refuses to cooperate.

That is why a serious trail runner's nutrition plan is written weeks before race day and tested in long training runs. Grams of carbohydrate per hour, salt tablets per hour, which gel is tolerated, which causes nausea — these are numbers nobody posts on social media, and they are the numbers that decide results.

In rain and cold like VMM 2026, the equation gets harder. The body burns extra energy to stay warm, while the sensation of thirst is suppressed by low temperatures. Runners tend to drink less than they need and skip food because of the cold. This is a category of mistake that causes no immediate pain. It only shows up at km 90, when it is far too late to fix.

The dropout curve: reading it like a scoreboard

At an event of this scale, the dropout rate at 161 km is usually not small, especially in record rain and on slick ground. But more telling than the total is the shape of the dropout curve.

People drop in three clusters. The first is early, when runners realise they were wrong about their fitness or their expectations. The second is mid-race, when stomach or foot problems appear and cannot be fixed at a station. The third — and the most painful — is very close to the finish, when the body has covered most of the distance but the mind no longer has the clarity to calculate what remains.

People call that an academy's failure. I call it a layer nobody has dug. A runner who drops at km 140 is not a finished story. He is an unread dataset: he covered 140 km in conditions most news readers cannot imagine, and he stopped for a specific reason that, if properly recorded, would help hundreds of others.

This is where sports media usually gets it wrong. We report on finishers and ignore those who stop. But in a training system or a competition system, it is precisely the dropout group that provides the most information about a course's real limits.

100 km and 161 km: two different sports wearing the same shirt

A common mistake among observers is to treat 161 km as 100 km plus 61 km. Physiologically, these are two different sports.

At 100 km, most experienced runners can still finish in daylight or dusk, meaning their circadian rhythm stays relatively normal. At 161 km, running through the night is almost certain. Night in the mountains is not merely a lack of light. It is falling temperatures, thick fog, narrow visibility, a disrupted circadian rhythm, and the emergence of psychological states that do not exist in daylight.

Both distances started together at 8 a.m. on September 18, 2026. That creates an interesting psychological effect: the 100 km group knows they will finish first, and the 161 km group knows they will be out there half again as long. Having both groups share the first stretch of course makes short-distance runners prone to being pulled along at the long-distance group's pace — one of the least-discussed causes of early dropout.

Read through a development-curve lens, this is the same error I still encounter in youth football scouting reports: people judge a 16-year-old by the standard of a 19-year-old, then draw the wrong conclusion about both. Same mistake. Same consequence.

Women at VMM 2026: the slowest-read part of the dataset

In trail running, the presence of female runners is one of the fastest-growing indicators and one of the slowest-analysed.

The issue is not numbers. The issue is how the story gets told. When a female runner finishes an ultra distance, media usually frames it as inspiration. That framing is not wrong, but it skips the hardest part: training, nutrition, and physiological-cycle structures for female ultra runners remain far less researched and far less shared than for men.

In a mountain race in rain, with low temperatures and slick ground, a small error in nutrition planning or equipment choice can create a far larger gap than in a road race. For female runners, fewer reference datasets mean more self-experimentation. That is a structural unfairness, not a matter of effort.

My view here mirrors how I view women's football. People tend to praise spirit before they praise expertise. But spirit is not what needs praise. It is what needs support — through infrastructure, through data, and through competitions with technical standards high enough that people are forced to learn the craft.

Actor Nhan Phuc Vinh and the celebrity trail-running dataset

One of the most-mentioned names during this edition is actor Nhan Phuc Vinh, known in artistic circles as a serious trail runner.

This is a data point worth more analysis than it appears. Celebrity participation in ultra races does not only generate media. It creates a new reference model for the public: if an actor can stand at the start line of a mountain race, then trail running is no longer seen as the preserve of a small group with freakish fitness.

But the rest of the dataset needs reading too. Celebrities entering an ultra are usually treated by media with a different standard — lighter on performance expectations, heavier on attention. That pressure can be fuel, but it can also be a source of bias in race planning.

What is worth noting is how this participation was recorded in field reports: as an endurance journey, not a performance. That is the right reading. But if Vietnamese trail running wants long-term growth, it needs more than famous names. It needs a semi-professional tier with income, coaches, insurance, and a year-round race calendar.

Record rain: a meteorological event or a media product

Throughout the event, rain was the most-discussed topic. On forums, users repeatedly expressed excitement and admitted admiration for the runners' endurance.

That emotion is real and entirely justified. But two things sitting side by side in the same story need separating.

First, the meteorological event: heavy rain, slick ground, limited visibility, slopes that required rope. This is a verifiable fact.

Second, how that event was packaged. Describing VMM as Vietnam's harshest race is a promotional definition, not a technical one. The harshness of a mountain race depends on total accumulated elevation, average gradient, weather conditions, and on-site support levels. There is no single index called harshest.

This does not diminish VMM. It simply places the number where it belongs. A race called harshest in a record-rain year is a good story. A race called harshest for ten straight years is a dataset.

The trap of romantic stories

There is a very common storytelling motif in endurance sport: humans overcoming nature, humans overcoming themselves, with nature cast as the opponent.

The motif is appealing because it is simple. But it hides three things.

First, it hides the resource gap. A runner with a coach, insurance, station support and money to fly to Sa Pa has a fundamentally different experience from a runner paying out of pocket, carrying all their own nutrition, and arranging their own accommodation. Both run the same course, but they are not running the same race.

Second, it hides the reality of sustainable operations. A mountain race with 5,300 people places pressure on a small locality like Sa Pa: traffic, water, waste, and the need for volunteer staff. These pressures do not appear in inspirational writing, but they exist, and they decide how many years the event can sustain that scale.

Third, it hides risk. When the story is told as a conquest, stopping becomes a personal failure rather than a correct decision. In heavy rain and on slick ground, the decision to stop is often the hardest and the most professional one.

I do not write reports. I excavate the memories of those who have never been told. Here, those never told are the people who stopped at km 60, and nobody writes about them.

Safety risk in a record-rain year

For a race with more than 5,300 people, running across four days, on mountain terrain, in heavy rain and thick fog, the safety question is not hypothetical. It is central.

Three risk groups need independent assessment.

First, terrain risk: slipping on muddy slopes, falling on natural descents, collisions with rolling rock. This is a risk group that can be mitigated by technical measures, and installing rope on slick slopes is a step in the right direction.

Second, physiological risk: hypothermia, dehydration combined with salt loss, and gastrointestinal problems. This is the hardest group to control because it happens inside the runner's body and only becomes visible when it is already late. In cold and rain, hypothermia is the leading danger over overnight ultra distances.

Third, organisational risk: rescue teams' ability to reach runners when visibility is limited, and the ability to handle multiple incidents simultaneously within the same window when the two longest distances run in parallel.

At international trail races, these three risk groups are usually assessed through a process that can be published. VMM joining an international system is a signal that these processes are being standardised. But standardisation is not a destination. It is a continuous process, and a record-rain year is a live test that no meeting room can simulate.

The final 20 minutes and the story of a war of attrition

There is a principle in endurance sport that I still find true in almost every discipline: the decisive part of a race is not the fastest section, but the section where a competitor has run out of backup plans.

In football, this principle shows up through substitutions. A team with a deep squad can make five changes in the second half, but that very fact turns the final 20 minutes into a war of attrition — the side with more reserve resources wins, and the side that has used up its options collapses. The entitlement increases, but so does the price.

In a mountain race, the same mechanism plays out from km 120 onward at 161 km. Before that, runners can compensate for mistakes in several ways: eat more, drink more, slow down, rest at a station. After km 120, backup plans disappear one by one. There is not enough time left to absorb nutrition. There is not enough strength left to run faster in compensation. And there is not enough clarity left to make good decisions.

This is why performance at ultra distances is decided not by top speed but by the ability to manage decline. A runner who finishes fast is not the fastest runner. They are usually the one who declines slowest.

The development system behind a mountain race

One thing rarely mentioned about VMM: behind 5,300 starters lies a training system that is mostly outside media view.

In Vietnam, most trail runners do not come through an academy pathway. They come from running clubs, community groups, gyms, or simply self-teaching online. Compared with a football academy that has selection and cohort-based development, the trail-running system here is far more spontaneous.

That cuts both ways. On the positive side, the entry threshold is low, so the participant pool is broad. On the limiting side, coaching quality is uneven, which means many runners enter ultra distances without having accumulated the necessary base mileage.

Read through the development-curve logic I still use in youth academy reports, this is the biggest bottleneck in Vietnamese trail running. A young footballer is assessed over years with continuous data. A trail runner in Vietnam is often assessed through just a few starts.

The World Cup is dazzling, but I keep looking down. Down there, gems are falling. At a mountain race, those gems are the mid-distance runners who will become the core of the ultra distances in three to five years. They do not appear on the results board. They appear in 5 a.m. training runs in the park.

Sa Pa and the question of what a destination is worth

You cannot discuss a race with 5,300 people from 54 countries without discussing local impact.

Sa Pa is a locality whose economy depends heavily on tourism. A four-day race in mid-September brings the area a significant volume of visitors outside peak season. This is a positive and measurable reality: hotel rooms, restaurants, transport services, and local staffing demand.

But a destination's value is not measured only in revenue. It is also measured in sustainability. A large mountain race places pressure on roads, water sources, waste handling, and especially on the volunteer force — people who often work overnight with limited support.

The correct way to read a tourism indicator is not the number of arrivals, but the return rate and the rate of local participation. If a mountain race runs for ten years while local runner numbers do not grow, it is an imported event, not a local one. This question deserves serious attention, and it cannot be answered by a press release.

What will be announced on September 19

According to the organisers' schedule, champions will be announced on September 19, 2026.

That date looks simple, but it carries important structural information. If the winner of the longest distance can be determined within a day of the start, it means the lead group's pace was high enough to complete most of 100 miles in just over 20 hours. That is an indicator of elite quality. On a sawtooth course with rope sections and slick mud, holding that pace matters far more than holding it on flat asphalt.

But the most interesting part of September 19 is not the winner. It is the gaps and times behind. The gap between first and tenth at an ultra usually says a great deal about competitive density. A large gap at the front can mean the course was harsh enough this year to punish mistakes severely, or that the lead group was clearly stratified.

This is the kind of analysis I still do with academy results tables. The final result is the least informative thing. The distribution in the middle is what tells the story.

What to track after the race

Three indicators will decide whether VMM 2026 is remembered as a step forward or as a one-off.

The first is the finish rate at 161 km. A sharp drop against previous years is a signal about course conditions, and that signal needs to be cross-checked against independent meteorological data.

The second is the share of Vietnamese runners at long distances. This is the most important long-term indicator, because it measures the maturity of the domestic trail-running community rather than the appeal of a destination.

The third is the number of medical incidents requiring intervention overnight. This is rarely published but is the most accurate measure of how well the organisers operated under harsh conditions.

None of these three indicators appears in a press release. All three need to be collected systematically and compared year over year. This is the least glamorous work in sport, and also the work that determines whether a race becomes a research site or just a shared event.

Closing

When the rain in Sa Pa ends, the trail will return to normal within a few weeks. The mud will dry. The ropes will be taken down. The footprints will fade after a few more rains.

What remains is not the course. What remains is the data: who finished. Who stopped. Where they stopped. Who came back the following year.

For someone whose work is reading development curves, the value of VMM 2026 is not how harsh it was. It is whether someone sits down, gathers those 5,300 rows of data, and begins sorting them into layers — newcomers, semi-professionals, elites, and those who will become elites five years from now.

The next brick has not been turned over yet. But it is already in someone's hands, and that someone could be you.