On swimming’s last night, a thrilling wait: Will a world record happen again?

The buzzer sounds. An Omega clock starts to tick.

It’s 8.04pm on the final day of the World Aquatics Championships and Leon Marchand, son of Olympians and cousin of Aquaman, is trying, in a manner of speaking, to defeat eight things in the 400m individual medley (IM). Seven other men and that clock. He wants a 1 by his name and perhaps also a WR. One is the greatest number, the other is the finest acronym.

World Record.

It’s what I’ve come to see on this night.

The WR is somewhat rare – the men’s 400m IM record has been broken only thrice in the past 20 years – which is why they are unforgettable. People say this is a “fast” pool but what is more readily verifiable is that Marchand, a Frenchman, is a fast fellow. Days earlier Chad le Clos, four-medal Olympian, pays him an Everest of a compliment. “He’s like a young Michael (Phelps). He’s got everything. Speed, endurance, nerve under pressure.”

Records are usually snipped, sliced and shaved. They’re set by a fingernail and broken by an eyelash. The faster humans go, the tighter the margins logically become.

Yet in the 200m IM on July 30,

Marchand lops over a second off the world record. He doesn’t break it, he mutilates it. Human potential, he reminds us, is a well whose depth we cannot comprehend.

If he doesn’t break one on Aug 3, then maybe Summer McIntosh will in her 400m IM. At 8.19pm she dives in, a young woman whose age is only 18 yet her ambition is transparent. In the 200m butterfly, she won but marginally failed to break the WR and swore in annoyance. History had slipped away.

Days later after coming third in the 800m, you could see defeat had stung. “I hate losing more than I like winning,” she said. “Moments like these are what I think about in training when I’m dying in a hard set and have to keep pushing.” Maybe this fury would push her to a WR. After all, this year she has already set three.

The WR is proof of a species’ advance. Through time humans in multiple nations are simply bigger, they eat smarter, train harder, study technique on computers and soothe bodies in ice baths. And so records tumble under the assault of science and ambition. In 1959, the men’s 400m IM WR was 5min 8.80sec, now it is 4:02.50.

The WR requires bravery, belief, temerity. “I don’t think limits,” Usain Bolt once tweeted. Phelps made the same point in the title of his autobiography which was No Limits. It’s a language understood by only a few. Perhaps by the man who climbed 914m of sheer rock without a rope and the woman who descended over 120m into the ocean on a single breath. Will is their superpower, hard labour their preferred morning routine.

Marchand leads from the first 50m and so does McIntosh in her race. In truth, they are chasing only themselves. The 400m IM records they pursue are ones which they own. As the race progresses, the blue line which marks the WR on television is ahead of them, the rest of the pack is way behind. Both these swimmers are flying yet how do they feel?

Sometimes accelerating athletes can feel like a gale force, sometimes they can’t tell a record is imminent. Regan Smith, the current 100m backstroke world-record holder, told The Straits Times days ago, “I feel like I’ve had world-record swims where I feel lights-out incredible and I’ve had world-record swims where I feel like I’m crawling to the finish”.

But once a WR is set, how must it feel? When Italy’s Thomas Ceccon, the reigning 100m backstroke world-record holder was asked, he sighed. “Everyone can win, right? But the world record is different because you are the fastest man alive. Ever. That’s me, that’s my name, and, yeah, it’s very cool.”

No athlete forgets their tilt at history. The day I interview Smith is, she says, exactly six years since the day she broke her first world record. “I’ll never forget the way that it felt because at that point I didn’t think that I was that type of athlete who was capable of doing something like that.”

Marchand and McIntosh are capable of anything on any day, but their first job on Aug 3 is to win and they leave with gold. Neither breaks a world record and yet they are out of this world. The Frenchman wins by 3.59 seconds, the Canadian by 7.48sec. He leaves with two individual golds, she with four.

This last night of a long aquatic championships which began with a water polo game on July 11 ends with the 4x100m women’s medley relay. The swimmers have to be tired, it’s been hot, the tension thick, the days long with racing and yet the beauty of elite athletes is their commitment to striving.

The US win in 3:49.34.

The scoreboard says WR.