The Underwater Phase: Where Swimming's Real Race Happens Out of Sight

About a meter below the surface, the light changes color. From the stands, people see arms sweeping and legs kicking up white foam. Beneath the water, it is a different sport — one where the body coils like a spring, where every vertebra has something to say, and where most of a race unfolds in silence.

I remember a morning at a training pool in southern China, before the city had shaken off its mist. A young swimmer repeated the dolphin kick after his start, over and over, until the water behind him stopped rippling. The coach said nothing. He only tapped the pool wall whenever the rhythm drifted. For the entire session, the two communicated through a single sound: water. Later I understood that I had watched a negotiation — between a body and an environment that forgives nothing.

In modern swimming, a race is divided into phases: start, dive, breakout, stroke, turn, finish. The underwater phase — the glide after the start and after each turn — accounts for a substantial share of total time, depending on the distance and the event. In butterfly and short-course freestyle, this is where records break. No spectator sees it, but the scoreboard does.

The coaching world has known this for a long time: the best swimmer is not the one with the strongest pull, but the one who holds underwater momentum longest without losing speed. Only when force-measurement systems and underwater cameras became widespread did the gap between swimming nations become clear — it lies not in arm strength but in the ability to control the body in a nearly weightless environment.

There is a detail I always watch for at major meets. Before the race, when swimmers walk out and stand behind the blocks, most spectators look at their faces. I look at their feet. A swimmer with a strong underwater phase tends to stand flat, heels down, weight evenly spread. They know the next push will come from the hips, not the toes.

At the elite level of swimming, rankings are no longer decided by the pull but by the art of turning the body into a line of wave.

The dolphin kick works on the whip principle: energy travels from the hips to the thighs, then the knees, then the ankles, each joint amplifying a little more. Clench too hard and the energy dies at the hips. Stay too loose and it dissolves in the water. Between those two extremes is where records live.

Michael Phelps was known for holding his underwater phase longer than his rivals, and frame-by-frame studies show his kick was not stronger than anyone's — it was more precise. That is the difference between power and rhythm.

I have spent many training sessions counting swimmers' kick rates. At the world level, the rhythm is almost as steady as a metronome, but there is one tiny accent on the final beat before the breakout — a harder kick, timed exactly when the body reaches optimal depth. Swimmers call it the door push. Without it, the breakout falls short, and the entire stretch that follows becomes a tiring chase to make up ground.

Kazan taught me that speed knows how to dance. I learned it watching old footage of a butterfly swimmer — how he folded at the hips rather than the back, how his feet stretched out like spearheads and retracted in a thousandth of a second. It did not look like power. It looked like dance.

And here is the interesting part: the underwater phase is where two coaching schools reveal themselves most clearly. Athletes trained in a pure-physical school often swim stronger in the back half of a race but slower in the first fifteen meters. Athletes trained in a technical school — common in Northern Europe and parts of Asia — explode off the wall faster but sometimes burn through their oxygen earlier. Neither school is absolutely right. There is only the fit between a body and the water.

What deserves suspicion is how we measure swimming. Heat maps have become the new fortune-telling of sports analysis. On a heat map, you can see which swimmer generates thrust where, on which beat. But the map cannot explain why the kick worked. It cannot describe the feeling of skin when the water cools by half a degree after the third turn. It cannot explain why a swimmer suddenly loses rhythm after the fourth wall.

In the emptiness, I hear the race's breathing more clearly. One evening at a meet with no spectators, I sat in the technical area and heard only the swimmers' heavy breathing, water slapping the overflow gutter, and the scoreboard clicking through numbers. Without the roar of the stands, you hear what cheering usually hides: one swimmer fading on the third beat, another accelerating on the fourth. The language of silence — silence lacks no language; it owns a tongue of its own.

The problem with modern swimming analysis is that we trust numbers too much and forget that numbers are born from a body. A report can tell you Swimmer X holds underwater speed 0.3 meters per second faster than Swimmer Y over the first fifteen meters. It cannot tell you the price. Not every speed is worth keeping.

Swimming is a strange sport: its most beautiful part happens where no one can see. The stands cheer when arms break the surface, but the real race was settled while the body was still submerged. I think this is why I still sit for hours beside the pools of unnamed training centers, counting the kick rates of swimmers nobody knows yet. Records are not born in finals. They are born on spectator-free mornings, when the water is still cold and a person has only their own breathing for company.