Nguyen Huy Hoang and the Silence Between Lanes: When Vietnamese Swimming Lacks Data

There is a gap no one measures, yet every Vietnamese swimmer collides with it. I named it: the silence between lanes.

It does not live in the final number on the scoreboard. It lives in the three seconds between the starting horn and the first hand hitting the water. It lives in the brief pulse after each turn under the flag. It lives in the stretch nobody films, nobody scores, nobody records. After twelve years standing on pool decks and timing every 50-metre split, I reached a chilling conclusion: Vietnamese swimming does not lack swimmers. Vietnamese swimming lacks data readers.

On the night of the SEA Games final in Phnom Penh, I sat above lane three and split the tempo of every 50 metres in the freestyle events. Next to me, a group of young fans kept cheering whenever the leader surged in the final 100 metres. I understood the feeling. But I saw something else: the eventual winner was not the fastest over the opening stretch, nor the strongest kicker in the close. The winner was the one who kept the smallest deviation between 50-metre segments.

That is when I spotted a structural problem. Not one official ledger in Vietnam records that deviation. Most domestic meets publish no splits at all. People record results. People do not record process.

Anh Vien passed through, leaving an unanswered question

When Nguyen Thi Anh Vien retired, Vietnamese swimming lost more than a brand of medals. We lost a data landmark. During her SEA Games dominance, every time she entered the water, someone filmed, someone measured, someone compared. Through her, the Vietnamese public first grasped the idea of splits. When the hero left, the data system left with her, because what we had was never a system. It was a habit. A habit that followed a name.

This is exactly the point I stress whenever I am asked about the post-Anh Vien era. Football has Opta, Synergy, league-grade data providers, so whenever a star retires the match still leaves a readable trace. Swimming is different. No one pays for a full split dataset of the national championship, so when the best swimmer retires, we lose the measuring stick itself.

Nguyen Huy Hoang inherited no data infrastructure. He inherited a gap.

Four indicators nobody publishes

If I were given a blank sheet and a lane, I would measure four things. They are equivalents of PPDA, xG and sprint count for football: crude, limited, but far better than blindness.

First is the distribution deviation, which I call DL. It is the gap between the fastest and slowest 50-metre segment. In a top swimmer, DL stays under one second. The winner usually does not hold the fastest segment, but nearly always holds the smallest DL. Stability beats explosion.

Second is stroke rate over distance per stroke, SR/DPS. Fast rate with short stroke means burning energy like dry wood. Slow rate with long stroke means saving it. I once compared a domestic swimmer's technique between morning heats and evening final. He kept the same rate but shortened his stroke by about two centimetres per cycle. Nobody saw it. But over each 50 metres it compounded into nearly a second.

Third is underwater time after start and turn, UW. Modern swimming is won underwater more than people think. The difference between a strong dolphin-kicker and someone who surfaces too early can reach four to five tenths per turn. Domestic broadcasts rarely film underwater, so this indicator barely exists in discussion.

Fourth is closing-lane efficiency, or AI for exhaustion. It measures the drop in the final 50 metres against the prior 50. Everyday swimmers rarely fail in heart and lungs first. They fail in the arms. But we call it running out of gas and skip the mechanics.

None of these need expensive equipment.

I once thought numbers were enough. I was wrong

For years I prided myself on writing with data. I once treated a model as scripture. Now it is just a compass, but without it, we are lost.

My turning point came from a morning at a pool. In 2026 I applied a familiar formula to swimming data and got a spectacularly wrong result. The model said swimmer A would win. In reality B won, with far worse distribution numbers. I sat down and wrote a line that became my principle: xG is not wrong, football is simply irrational, and swimming is too.

From then on I learned to count even the irrational. In swimming the irrational has a very concrete shape. It is an athlete who swims badly in the morning and like a storm at night. No model catches that if you only look at the final number. You must watch the order of the numbers. And that order is exactly what almost nobody records.

Binh Duong pressing, and a new version underwater

There is a pressure nobody sees, yet every rival fears it. I named it Binh Duong pressing. In swimming, the invisible pressure takes a different shape: distance pressure. It is the sensation of the swimmer in the next lane holding a small, unclosable gap no matter how hard you pour it on. That swimmer will break their own plan in the final 50 metres.

When two swimmers are evenly matched, the one who holds a steady rhythm mid-race creates distance pressure, and the one who surges repeatedly absorbs it. Surging too early is not courage. It is a poor allocation decision disguised as drama.

The rubble and how to rebuild

When the field is empty, every model collapses. I rebuild from the burnt wreckage of data. That line was born in football during the pandemic, but it translates directly to Vietnamese swimming: when the data system is empty, every judgment collapses, and the writer must rebuild from what survives.

What survives in Vietnamese swimming? Meet records with heat and final times. Amateur footage shot by fans. The memory of coaches. Re-readings of foreign material to work backwards. It is a pile of rubble, but rubble still has architecture.

From it I rebuilt three propositions. One: Vietnamese swimmers usually do not lose on peak speed, but on sustainable average speed. Two: the biggest gap between us and strong swimming nations lies not in the sprint, but in the second to fifth 50 metres, swum in solitude, uncheered, unfilmed. Three: the largest difference is not physical capacity, but distribution discipline.

These are hypotheses, not conclusions. I need at least three cross-checked sources before turning them into fixed numbers, and the hard part is that in Vietnamese swimming those three sources often do not exist.

The contrarian angle: correlation is not causation

When I say stability beats explosion, many readers translate it as: just swim evenly and you win. Wrong. Correlation is not causation. A swimmer who holds a small deviation does not win because they swim evenly; they swim evenly because they are good at every segment. Stability is the result of ability, not the cause. Teach a weak swimmer to swim evenly and you only produce someone who finishes late with coherence.

Likewise, allocation discipline does not mean splitting time equally. Some distances are optimised by saving for the close; others by surging early to break a rival's rhythm. There is no single formula. There is a family of formulas, chosen by opponent, distance and daily state.

There is a pressure nobody sees, yet every national team fears it: your model being right on paper and wrong in water. I have tasted that.

The number does not lie, but people always find a way to lie about the number. In Vietnamese swimming we still do not have numbers to lie about. That is both bad news and an opportunity.

Blinds I publish on purpose

An honest reconstruction architect must publish the drawings not yet finished. First, sample size. Most of my observations come from a handful of meets and a handful of swimmers. Small sample. Every conclusion should be treated as a hypothesis until a full official season of split data exists.

Second, pool differences. Times depend deeply on configuration, water temperature, depth and overflow gutters. Comparing times across pools without adjustment is a mistake I have made.

Third, cross-distance translation. Good short-course form does not automatically transfer to long course. Pacing, allocation and technical demands differ too much for a single multiplier.

Fourth, irrationality. Some days swimmers break personal records on ordinary training; other days they regress despite strong indicators. I have no model that fully explains this. I only learned to count it.

The market is not in medals, but in data

In a transfer window people pour money into expectation. In swimming they pour money into medals. But the most worthwhile investment has never been funded: data infrastructure.

Imagine a domestic season where every lane has an underwater camera, every swim publishes official splits, and every swimmer has a tempo profile over time. Then scouting no longer relies on a single trial. It relies on trend.

What remains is always how you read the race. Reputation is only a name. And in Vietnamese swimming, the reading is still mostly blank.

Signals for the next round

First, watch the distribution deviation of the young cohort. If the new generation holds a smaller DL at the same distance than the previous one, that is a better signal than any medal.

Second, watch whether anyone starts publishing official splits. The day that happens is the day Vietnamese swimming becomes a different sport.

Third, look at the stretch nobody films. That is where the race is truly decided.

When the field is empty, every model collapses. But when the lane is empty, only those who stoop to read can see the order. I once treated a model as scripture. Now it is only a compass, but without it, we are lost. What I wish most for Vietnamese swimming is not a medal. It is a compass.

There is a pressure nobody sees, yet every swimmer fears it. I named it: the silence between lanes. And the open question for the next round is this: who will be the first to measure it?