The Data Gap in Vietnamese Swimming

At a national swimming championship I followed in Nha Trang, organisers handed reporters a results sheet with exactly three columns: name, year of birth, final time. No 50m splits. No reaction time. No 15m underwater time. No turn times at each wall. A swimmer racing the 200m individual medley goes through four different strokes, and the sheet said only that she finished in 2 minutes 19 seconds.

I stayed behind after the session and looked up international results in the same event on my phone. There, every swim is a string of numbers: 27.8 for the opening 50m butterfly, 32.1 for the second 50m breaststroke, then losing ground on the backstroke leg and clawing it back on freestyle. A swimmer's whole story fits into four lines of numbers. The sheet in my hand had one.

That was when I understood the problem was not the swimmer.

Swimming is arguably the Olympic sport with the most complete data system. World Aquatics publishes every official race with 50m splits, reaction times, and at many meets, 15m underwater times as well. Long course, 50 metres, and short course, 25 metres, are recorded separately and never converted into each other, because the number of turns and the turn technique differ completely.

Olympic qualifying standards also rest on data. The A-cut earns a direct entry; the B-cut puts a swimmer into a waiting pool. Athletes know exactly what they must swim, in which pool type, inside which qualifying window. Coaches, sports scientists and media all operate on that data layer.

Vietnam sits inside that system on paper. But following domestic meets over many years, what I usually receive is only the final result. Nguyen Thi Anh Vien has been the most frequently mentioned name in Vietnamese swimming for more than a decade, and every time her name appears, the accompanying question is still about results, rarely about technique. A swimming nation that cannot measure detail cannot fix detail. That is what I want to say plainly here.

Splits: four lines of numbers tell a story

Katie Ledecky set the women's 800m freestyle world record of 8:04.79 at the Rio 2026 Olympic Games, according to the World Aquatics record list. What makes that swim a teaching document is not the final figure. It is the splits: she swam negative splits, each 50m faster than the one before, for most of the race, something that almost never happens over 800m.

Without splits, you cannot tell where your swimmer wins or loses. A swimmer finishing the 200m freestyle in 2:05 may be pacing entirely wrong: fast on the first 50m, collapsing on the third. Looking only at the final time, a coach concludes she needs endurance work. The real problem may be breathing technique, stroke rate under fatigue, or going out too hard. Three causes, three different fixes, and a results sheet that cannot tell them apart.

Worse, the same final time can be produced by two opposite ways of swimming. One athlete starts slowly and finishes strongly. Another explodes early and dies on the last 50m. On the scoreboard they look identical. On the splits they are two different problems requiring two different training plans.

The 15m underwater: the most neglected segment

In modern swimming, the underwater phase after the start and after each turn is where the biggest differences are created in short events. The rules allow up to 15m underwater. In butterfly and freestyle, elite swimmers use nearly all of it with dolphin kicks, because underwater kicking is faster than surface stroking.

At many domestic meets, nobody measures the 15m. Nobody counts kicks. Nobody knows what share of the race a swimmer spends underwater. Yet this is the most improvable segment of all: it needs no extra strength, only a corrected body angle and more kicks. A technique that can improve in weeks is being ignored because nobody measures it.

Turns: where time evaporates

A 200m swim in a long course pool has three turns. Each turn costs a good swimmer roughly 0.6 to 0.9 seconds from hand contact with the wall to the head leaving the wall in the other direction. A weak turner loses more than 1.2 seconds. Times three, that is more than a second and a half, enough to change placings in a final.

I have re-watched hours of domestic meet footage, timing each wall by hand. That is not a professional method. But it showed me what the scoreboard does not say: some young swimmers lose nearly two seconds per turn because they hit the wall at the wrong angle, fail to tuck, or push off late. Fix that and the time drops immediately, without adding a single training session.

Long course and short course: two worlds that do not compare

This is where domestic media often slips. A time swum in a 25m pool cannot be compared directly with a 50m pool. There are twice as many turns in short course, so the advantage goes to the swimmer with better turns and a stronger underwater kick. An athlete can win a national title in short course and still miss the standard in long course.

If pool type is not stated in every results list, we create a data system that cannot be compared. And when data cannot be compared, every conclusion about a nation improving or regressing is guesswork.

The talent supply chain: puberty is the missing variable

Swimming is a sport where girls often peak very early. Many female swimmers reach Olympic finals at 16 or 17. But it is precisely at that age that physical change can stall or reverse performance for one or two years.

Understanding that requires longitudinal data: the same swimmer, measured continuously across years, in the same event. We do not have that data. We have results from individual meets, disconnected, impossible to link. The result is that when a young swimmer plateaus, the default reaction is that she has run out of potential, when the far more likely explanation is that she is passing through a phase every developed swimming system has a specific plan to manage.

In the United States, the NCAA college system creates a parallel lane: athletes study and compete, gaining four more years of development with continuous training and competition data. In several countries, centralised development systems record biological and technical data month by month. We do not need to copy any model. But we do need to know what we are missing.

Injury and load management: the romanticised part

The story I hear most often from female swimmers is about shoulders and backs. A swimmer's shoulder takes thousands of repeated loads each week. A breaststroker's knee absorbs continuous rotational force. These are accumulated injuries, not accidents.

What matters is how we tell those stories. A swimmer who competes through shoulder pain is usually described with the word brave. I have written that way myself. A week later I re-read it and saw I had been wrong. Because behind the word brave sits a decision about competition scheduling, about training volume, about who gets rest and who does not.

Load management sounds scientific. But without training-load data, without pain measurement, without a mandatory rest threshold, load management is just a prettier name for scheduling by competition demand. Behind the dressing-room door, there are stories that have never been told. Most of them are about bodies pushed past their limits, in silence.

The interview series I ran while competitions were suspended during the pandemic was called Voices from the Dressing Room. Its only rule was to let the athlete speak for most of the time. I asked open questions, such as what is the biggest thing you have lost, and then stayed quiet. Those silences brought back more information than any press conference.

The contrarian angle: smaller physiques is a substitute for analysis

This is where I want to push back hardest.

Every time Vietnamese swimming falls short at continental level, the explanation arrives almost automatically: Vietnamese bodies are smaller, arm spans shorter, we cannot compete in short events. It sounds reasonable. And it is suspiciously convenient, because it ends every discussion.

But if physique were the deciding variable, every athlete in distance events would lose from the start, while in reality the 800m and 1500m are where technique, pacing and psychology carry the greatest weight. And if physique were the deciding variable, we would have to prove it with numbers: height, arm span, stroke rate, distance per stroke. We do not have those numbers.

What I see in the little data I collect myself is not that Vietnamese swimmers are weak. It is that they lose time in places that can be fixed: turns, underwater segments, breathing rhythm on the final 50m. Add those three together and you get two to three seconds over 200m. Two to three seconds is not the gap of genes. It is the gap of technique, and of nobody measuring.

I went to Russia to find answers and found only more questions. The question was: where are the women? In technical analyses, in coaching seminars, in published datasets. The answer I have found over the years is that they are in the water, on the track, in the dressing room, just not in the data.

What is changing

What I believe is changing is not the physique of Vietnamese swimmers. It is the tools. A young coach with a tablet, a camera at the pool wall, a spreadsheet logging splits after every session: that is the entire distance between a swimming nation that guesses and one that knows.

The stands are empty, but the voices from the dressing room have never stopped. When the crowd is gone, we finally listen to the athlete. And when we start measuring, we finally understand them. The question is no longer what Vietnamese swimmers lack. The question is: what are we refusing to measure?