Vietnamese Athletics Is Missing Split Data: The Result Is There, the Story Is Not

Last June, I downloaded the results sheet of an athletics meet inside Vietnam's national competition system. The sheet had three columns: name, performance, place. In the men's long jump, the winner was listed at 7.4x metres. No wind reading. No mark flagged as a foul. No note on surface, temperature or wind direction.

In Japan, where I live and work as a sports data analyst, a long jump result always carries two figures. The first is distance. The second is wind speed, in metres per second, recorded to one decimal place. The allowable limit for ratifying a record is +2.0 m/s. Above that, the mark is still recorded, but it sits in a different drawer of the file.

The distance between those two sheets is not measured on the track. It sits wherever the data is left behind once the competition ends.

The Result Exists, the Story Does Not

Vietnamese athletics has results. At recent SEA Games, Vietnam's athletics team has consistently finished among the leading nations in the sport, with names that have become brands: Nguyen Thi Oanh in the middle distances and the 3,000m steeplechase, Quach Thi Lan and Nguyen Thi Huyen in the 400m and 400m hurdles, Bui Thi Thu Thao in the long jump, Hoang Nguyen Thanh in the marathon.

But when I opened the file for a national meet to understand how an athlete ran a 1,500m, I found a single final time. No 400m, 800m or 1,200m splits. No reaction time. No lap-by-lap finish data. A prefectural-level meet in Japan, meanwhile, publishes all of those columns, along with the name of the timing official.

Across nine years of watching athletics and football through data sheets, I have drawn one dry conclusion: the quality of a sporting nation is not measured by its medal count, but by the number of columns in its results file.

Three Numbers That Taught Me to Read What Is Missing

On 2 July 2026, in Rostov-on-Don, Japan led Belgium 2-0 and lost 2-3 in the World Cup round of 16. I was 17, writing every phase into a notebook. Japan held 55% of possession and touched the ball inside the opponent's penalty area 7 times. Belgium touched it 21 times. Both teams had the same share of the ball, but a threefold gap in where the ball was touched.

I wrote my first analytical piece on those two numbers, arguing that Japan's late push up the pitch was a structural error. The piece was heavily criticised. I did not change my mind, because I still had my notebook. On that Russian night, I watched data shatter before my eyes — and learned that a single well-placed metric can overturn an entire commentary narrative.

In 2026, when the J-League was suspended for four months, I could not go to Yodoko Sakura Stadium to watch Cerezo Osaka. I took match footage from the 2026 season and logged every pressing situation myself. The result was a dataset of 1,240 situations, enough to calculate PPDA — the number of passes a team allows before pressing. From it, I predicted Cerezo would drop off when the league resumed because they had lost home advantage. I placed them second. They finished fourth. My model was wrong.

The cause I found later had nothing to do with pressing. I had failed to measure the crowd variable: empty stadiums removed Cerezo's home advantage, but they also removed opponents' away-day pressure. An empty stadium, yet the numbers were still full of noise. A variable you do not measure does not disappear; it simply comes back to break your model at the end of the season.

The third number arrived in the January 2026 transfer window. I analysed more than 200 players moving from the J-League to Europe and found a correlation coefficient of 0.67 between kilometres covered per match and success rate in the Bundesliga. Midfielder Ao Tanaka was covering 11.8 km per match, the highest in the J-League. I sent the data to a German scout. He moved to Fortuna Düsseldorf on loan. The contract is only the ending; the opening chapter is written in the spreadsheet.

What Is Being Thrown Away in Vietnam

Those three stories share a common denominator: in each case, the decisive variable was measurable, and it had already been measured — by someone willing to publish it.

Vietnamese athletics sits exactly at that junction. Electronic timing systems at domestic meets record splits for every lap; that is how the equipment works. In the 400m hurdles, the system records every 100m marker. In the marathon and half marathon, 5km stations timestamp every athlete. In the long jump, a wind gauge is mandatory equipment in official competition under World Athletics rules.

The data exists. It simply does not reach the finish line.

The consequences are technical, and they can be calculated. Without splits, no analyst can compute closing speed over the final 400m of a 1,500m. That is the only metric that shows whether an athlete distributed effort correctly, and it predicts the next round reasonably well. Without 400m hurdle splits, you cannot measure rhythm decay between the first and tenth hurdle — the thing that separates an athlete with stable technique from one with pure speed. Without a wind reading, a 7.4x metre jump can neither be placed in the personal-best column nor removed from it.

You might ask why such a metric can predict the future at all. The answer lies in measurement stability. An athlete who closes the final 400m 1.2 seconds faster than rivals across three consecutive meets is a structured signal, not luck. A single burst is not.

In the 400m hurdles, splits also reconstruct something video cannot: rhythm. Ten hurdles, ten intervals. If intervals seven and eight are unusually long compared with the first six, that athlete is fading late, and the problem is fitness rather than technique. Those two diagnoses lead to entirely different training plans.

In the marathon, 5km stations generate a curve. If an athlete runs the second half faster than the first, they are pacing negatively. If they slow markedly after 30km, their endurance threshold sits somewhere near 30km. Without the stations, both pieces of information vanish, and the whole race collapses into a single number — one that cannot be used to design a single training session.

The Other Side of the Data Wall

There is a counter-argument worth considering, and I wrote it out before writing the section above.

Publishing splits creates pressure. A 17-year-old ranked second nationally for closing speed will carry that number into every training session, even though it was measured at one meet, in one set of weather conditions. Media will take the fastest figure and discard the rest. That is small-sample risk, and it is real.

It is also true that adding unstandardised variables makes a model worse. I was wrong at Cerezo Osaka precisely because I inserted a variable I could not measure. If a Vietnamese meet measures wind with an uncalibrated device, a wind column in the results file will do more harm than good.

But that argument only opposes publishing bad data, not publishing data. I collect errors, classify them, and then I know where a team is heading. The way to handle risk is not to hide the numbers, but to publish them with a measurement protocol: which device, calibrated when, and who signs off.

There is also a cost rarely discussed. A scout in Europe or Japan can read a Kenyan athlete's profile through split tables, and a Vietnamese athlete's profile through a single line. The two files are not in the same unit. When files are not in the same unit, people choose the readable one, not the better one.

That is why I believe the problem here is not technical. The timing equipment is already running. The wind gauge is already switched on. The problem is that nobody requests those columns in the official results file — and in a sporting nation, what is not requested does not exist.

Signals to Track

The annual season is in its fitness-assessment phase, and this is when small decisions about data format carry the greatest value.

I will be watching one specific thing: whether this year's national championship results file adds two columns, wind speed and splits, or keeps the same three. Every probability hides a shock — I only make sure it does not repeat. And the biggest shock in Vietnamese athletics will not be a medal. It will be the moment an athlete with the fastest closing 400m in the country becomes visible through a number, in a country half a world away.