Nine Data Layers of a Swimming Lane: The Lesson from an Empty Spreadsheet

Three in the morning in Saigon, and my spreadsheet was empty. Not a single time column, not a line of splits, no swimmer's name, no meet name — just white cells stretching out like an abandoned lane in a still pool. I sat in front of the screen, hands resting on the keyboard, and realized that the hardest moment in my job is not when I have to make a prediction, but when I have to admit I have nothing to say. People assume an analyst exists to conclude. But on some nights, the most honest conclusion is silence.

I work as a sports betting analyst, specializing in swimming, with sixteen years of observing the industry, and I live in Saigon. Those years taught me one thing: swimming is a sport where data surfaces slowly, yet says a great deal. A 100m freestyle lane lasts under a minute, but behind it lie thousands of data points — reaction time off the blocks, number of underwater kicks, body rotation angle at the wall, stroke rate, distance per stroke, breathing rhythm. Miss one layer and you misread the whole race.

For years I have worked with a nine-tier framework applied to every lane. Not for show, but so I never fool myself. Those nine tiers are: technique; performance and data; competition system; world landscape; rules and anti-doping governance; athlete career; risk profile; media and expectations; and industry ripple. On that empty-spreadsheet night, all nine tiers stood before one word: insufficient information.

I am writing this to show you what a professional swimming analyst actually looks at when looking at a lane — and why empty data is more dangerous than a wrong result.

Tier one — technique, where everything begins

Swimming is a sport where technique cannot be faked. In short events, a lane is divided into four segments: the start and underwater phase, the middle swim, the turn, and the finish. Each segment has its own data.

The start is measured by reaction time — the gap between the starting signal and the moment the toes leave the block. For Olympic-level competitors this usually falls between 0.6 and 0.7 seconds. A 0.05-second difference sounds small, but in a 50m freestyle final it can be the gap between a medal and a place off the podium. I once watched a final where a swimmer lost by exactly 0.01 seconds — and the cause lay in reaction time, not in swimming strength.

After the start comes the underwater kick phase. In freestyle, butterfly and backstroke, the rules allow a swimmer to stay under the surface for a maximum of 15m. This is where lanes are decided in silence. The best at this segment turn the dive into a spear: body straight, legs whipping like a rope, not surfacing too early. An efficient underwater kick can save several tenths of a second — a huge margin at this level.

The turn is the most underrated segment. A proper flip turn consists of wall contact, rotation, push-off and glide. In distance events like the 800m or 1500m, mastering the turn means shortening every meter. In breaststroke and butterfly, a simultaneous two-hand touch is mandatory, and in breaststroke there is the one-dolphin-kick allowance before the standard breaststroke cycle. One wrong movement here and the entire result can be voided.

Swim efficiency is measured by two opposing indicators: stroke rate and distance per stroke. When tired, most swimmers increase stroke rate but reduce distance per stroke — a sign of a breaking lane. A good swimmer, by contrast, holds distance per stroke into the final meters. A line I often use: numbers do not lie, but they know how to hide something. Distance per stroke is the most carefully hidden number in swimming.

Tier two — performance and data

A result only means something when placed on the right coordinates. The three benchmarks I always build: world record, all-time list, and current-season ranking. Without those three, a number is just a number.

Swimming has a historical lesson any analyst must remember: in 2026-2026, when high-tech swimsuits appeared, a wave of world records fell in a short time. In 2026, World Aquatics banned those suits, and many records from the textile-suit era still stand today. Anyone comparing performances across those two eras directly is misreading history. This is the kind of error I see often in newcomers.

Split data reveals pacing structure. A distance swimmer whose second half is faster than the first — a negative split — usually has a strong base of fitness and tactics. Conversely, someone losing speed in the final 50m has a distribution problem. In the 1500m freestyle, the gap between someone pacing correctly and someone pacing wrong can reach tens of seconds, despite identical training volume.

Tier three — competition system

Not all meets carry the same value. The Olympics, the World Championships, the World Cup and domestic meets sit on different tiers. What matters is identifying the year within the four-year cycle: Olympic year, adjustment year, build year, or sprint year. A performance in an adjustment year, when an athlete has just returned from an off-cycle, means something completely different from the same number in an Olympic year.

For meets with A and B cuts, participation depends both on personal performance and on each nation's quota rules. This is a layer the media audience rarely sees, yet it decides which athletes actually appear on the blocks.

Tier four — the world landscape

When looking at a lane, I always place it on the power map of the swimming world. Some nations dominate by distance, others by stroke.

In women's distance freestyle, the name on top for years has been Katie Ledecky. In men's breaststroke, Adam Peaty was the first to break the 57-second barrier with a 56.88 at the 2026 World Championships. In butterfly and medley, Léon Marchand rose strongly at Paris 2026. In women's breaststroke, Tatjana Schoenmaker set a 200m world record at Tokyo 2026. Each event has a ruler and a group of challengers behind, and that group changes every cycle.

This map also includes the talent supply chain: each nation's youth development system, squad depth, and the flow of athletes switching sporting nationality. Ignore this part and you will be surprised by names rising from unexpected places. When assessing squad depth, I usually cross-check against composite indices, because a single star does not speak for an entire swimming nation.

Tier five — rules and anti-doping governance

Swimming has a rulebook detailed down to individual movements. The 15m underwater rule, the one-dolphin-kick allowance in breaststroke, the use of the backstroke start device — all can create advantage or risk.

On anti-doping, the governance framework involves World Aquatics working with national anti-doping agencies and WADA. A doping complaint must be separated: what is a confirmed violation, what is a contamination dispute, what is a procedural issue, and what is merely a media allegation. I never conclude on a doping case before an official decision. An analyst loses credibility fastest by repeating unproven rumor.

Tier six — athlete career

Every athlete has a career curve. Swimming has a particular phenomenon: the puberty barrier, especially for women. Many young talents explode then stall as their bodies change, and only those with a technical foundation and good support systems push through. This is why I am very cautious when assessing a young swimmer who has just shone.

Physically, two haunting injuries are swimmer's shoulder and breaststroker's knee. Mentally, pressure at major meets can turn a good trainer into an underperforming racer. Multi-event load is another variable. Ignore these and you are reading an athlete with half the information.

Tier seven — risk profile

Risk in swimming is not only about winning and losing. It includes competitive risk, when rivals improve faster; career risk, from injury or stagnation; doping risk; rules risk; psychological and public-opinion risk; and systemic risk, when coaching staff changes or budgets are cut.

With an empty spreadsheet, the only identifiable risk lies not in the lane but in the process itself: the input data source is broken. That is a systemic risk, not a sporting one. And it reminds me that sometimes the biggest problem is not a swimmer performing badly, but an analyst holding nothing in hand.

Tier eight — media and expectations

Every lane carries a story. There are prodigies, record nights, comebacks, scandals. Media creates expectations, while technique creates results. The gap between the two is where an analyst works.

When a swimmer is hyped by the media, I always check three things: is the underlying performance truly solid, is the sample size large enough, and does the story hold over several meets. Emotion-driven expectations can dissolve fast. Emotion is the most expensive thing — not only in the transfer market, but also on the starting blocks. A swimmer valued a few percent above true ability is, over time, a mispricing.

Tier nine — industry ripple

Finally, I look outside the lane. What does a peak performance pull along for the training market, the equipment industry, event business, the agency ecosystem, facility investment, and derivative markets?

In Vietnam, the name Nguyễn Thị Ánh Viên once created a new wave of interest in swimming. Such waves usually come with investment in pools, training centers, and children's swim classes. A peak lane is not just a medal; it is an economic signal. And that signal must be read with data, not with inspiration.

To analyze swimming properly, you must walk all nine tiers. But to walk all nine, you need one minimum condition: data to start with. And here I return to the empty-spreadsheet night.

The most dangerous thing in my job is not analyzing a swimmer wrongly. The most dangerous thing is being forced to analyze when you have nothing in hand. An empty spreadsheet is not a topic; it is an alarm bell. And the right reflex is not to invent a pretty conclusion, but to say plainly: no information yet, no conclusion possible.

In an industry where everyone wants speed, the answer "I do not know yet" is a professional answer. It is like a distance swimmer knowing when to stop rather than fading in the final 100m. That Saigon summer, I learned that data also needs watering — and a barren spreadsheet should not be forced to bloom.

Looking ahead, I believe Vietnamese swimming will need serious data people more than enthusiastic commentators. Every lane is a data point, but not every data point is a lane worth analyzing. The question I leave for myself, and for anyone reading: when your source is empty, do you invent a number, or do you stay silent and go find real data?