The Scoreboard Flashes Once: Vietnam's Missing Split Data in Swimming

The starter sounds, eight lanes dive in, and when a hand touches the wall the scoreboard flashes exactly once. One line of numbers. A name. A lane. Then the screen goes dark, the stands applaud, and reporters like me bend over our notebooks to copy that number down.

For years I carried a squared notebook to pools. At every meet I logged final times across almost every event: 50 freestyle, 100 butterfly, 200 individual medley, 1,500 freestyle. After a few seasons I had thousands of lines of times. Then one afternoon, flipping back through them, I realised the notebook was missing nearly everything that matters: 50-metre splits, reaction time, stroke rate, distance per stroke, the depth of the underwater phase.

That was not my fault. The scoreboard does not print them. Organisers do not hand them out. Nobody asks. And because nobody asks, the gap became the default.

Swimming is a sport measured to the hundredth of a second. No other discipline packs an entire race into data so completely: from the instant the hand leaves the block to the instant it touches the wall, everything is a number. At international meets, results come with 50-metre splits, reaction time, sometimes stroke rate and distance per stroke. A coach in Europe opens a laptop and sees exactly where a swimmer lost four tenths of a second.

Here, what gets published is the final time, plus the placing. Two pieces of information. Nothing else.

The result is a paradox sitting at the heart of the most transparent sport we have: we know who won, not why. When Nguyễn Thị Ánh Viên closed her career with 25 SEA Games gold medals, the number repeated everywhere was 25. Nobody discussed how she distributed her pacing in the 200m individual medley, or how much time she spent in the turn that was her signature. When Nguyễn Huy Hoàng won bronze in the 1,500m freestyle at the 2026 Asian Games, the public remembered the medal. Few knew that in a 1,500m the decisive stretch usually sits between 800m and 1,100m, where the pace sags out of sight of any scoreboard.

That is the analyst's job, and it is why I keep a separate file on my machine, named "Pool Rhythm".

In a 25-metre short-course pool, a 200m freestyle race contains seven turns. If one swimmer loses an extra 0.2 seconds at each turn against an opponent of the same level, he loses 1.4 seconds — more than the gap between gold and bronze at the SEA Games in that event.

That figure explains why strong swimming nations invest in starting blocks, turns and underwater technique before they ever think about adding volume to a training programme. For us, that 1.4 seconds exists in no report, because nobody measures it. It dissolves into the sentence "the kid ran out of gas today".

My "Pool Rhythm" file grew out of an old habit. In 2026, as a fresh staffer at a sports analysis outlet in Saigon, I lost money trusting a purely emotional tip, then built a manual xG tracker for a V-League club. I found the team was outscoring its xG by 40 per cent and wrote a warning piece; by round 16 they had stopped scoring. Since then, every judgement I make has to carry a number. For swimming, that file holds splits I timed by hand from international broadcasts, along with reaction times and pacing distributions of several Southeast Asian swimmers.

It showed me three recurring patterns.

The first is the overly fast opening. Many young Vietnamese swimmers cover the first 50m between 1 and 1.5 seconds quicker than their own standard, then pay for it in the third 50. Without splits, coaches blame fitness or mentality. With splits, the problem turns out to be pacing strategy — something fixable in a few weeks.

The second is the turn. Between the ages of 14 and 16, the technical gap in turning between a properly coached swimmer and the rest can exceed half a second per length, while the fitness gap is only a few per cent.

The third is consistency. A swimmer whose times swing 2 per cent between races is normal; a 6 per cent swing usually reflects technique that has not yet stabilised, not a dip in form.

None of these patterns appear in any press release, because they only surface when you have splits.

The rest is a market story. Swimming is a thin-liquidity sport: low betting limits, few events, and bookmakers price mainly on recent results plus reputation. A medal at a junior meet can inflate expectations fast, while a swimmer's real improvement curve — measurable across 18 months of splits — gets ignored. That gap between the two is where both bookmakers and the public go wrong.

This is where I have to be careful with my own method. Missing data is not a conspiracy; it is a resourcing problem. A domestic meet organiser does not have the money to install intermediate touch pads, and a short-staffed newsroom does not have a reporter sitting there timing every split by hand. Blaming someone is easy; fixing it costs money.

More dangerous is reading the absence of data as the absence of a problem. We have grown used to a swimmer finishing with a personal best and treating everything as fine. Yet splits can show that he just produced an explosive final 50m to cover for a botched turn and a sagging middle stretch. Next time, there is no guarantee that explosion repeats.

Splits lie in their own way too. A swimmer deliberately swimming positive splits — slowing towards the end — has not made a mistake; it can be a strategy to save energy for a morning heat or a later event the same day. I once watched a stroke-technique change produce visibly better splits over three months while final times got worse, because the new rhythm broke the familiar acceleration over the last 15 metres. Better splits and medals are correlated, not caused.

PPDA is not a number, it is a confession. Splits in swimming work the same way. They confess how a swimmer distributed his effort, how a coach taught the turn, and how far the whole system has invested. Numbers do not lie, but they know how to hide something — and we have let them hide it for far too long.

What I am waiting for in the next cycle is not a medal. I am waiting to see whether a national championship publishes 50-metre splits after every final, and whether a training centre installs touch pads at both ends of the pool. The day a young coach opens a laptop and can point to the exact stretch where his swimmer lost 0.4 seconds, Vietnamese swimming will finally start counting. That Saigon summer, I learned that data needs watering too. The pool already has water; the data still needs someone willing to scoop it.