RIO DE JANEIRO • She has cast herself as the "Iron Lady," so she should be able to absorb blows from all sides.

The way the Olympic swim meet is developing, after just the first day, Katinka Hosszu of Hungary will have to take that steely approach, because the following elements of her existence are being examined, and closely: Her relationships, her training methods, her performances, her words.

"I'm already thinking how I can get faster," she said on Sunday, after she had obliterated the world record in the 400m individual medley. "I definitely want to and I think I can. So that's just something that definitely excites me."

So bring your scrutiny, world. The Iron Lady is ready.

Michael Phelps is due to add to his medal count, which means history every time. Katie Ledecky is a threat to beat her own world records, and the Australians already had one good day.

But there is an argument that Hosszu, a 27-year-old from the mountain city of Pecs who is swimming at her fourth Olympics, is the most compelling character in the pool at this Rio Games.

Start with the evidence from the clock: the old 400m IM record, set by China's Ye Shiwen at the 2012 London Games, was 4min 28.32sec.

On Saturday night, Hosszu was under that pace after 50m, 100m, 150m... after every length of the pool. Her final time was 4:26.36, nearly two seconds lower than the fastest time ever recorded.

"I think my jaw was just..." and Kirsty Coventry of Zimbabwe opened her mouth wide, mimicking her astonishment. "At one point, when she was five seconds under world-record pace, I was like, 'That's just insane.' "

One swimming journalist tweeted: "Something smells in the women's 400 medley." It would not mean much, but then Todd Schmitz, who serves as the coach of American five-time medallist Missy Franklin, retweeted it.

Hosszu has never tested positive for performance-enhancing drugs, yet there are whispers that she is not clean.

"I think, unfortunately, with the McLaren report and the Russians, most Eastern European countries are being looked at the same way regardless of the doping controls in their own country," Coventry said.

"That's unfortunately just where we are: Everyone's a little sceptical of everything and everybody."

Add to this a husband-and-wife dynamic that would be compelling regardless of Hosszu's performances in Rio, regardless of whether people held suspicions that they did not keep under their breath.

Hosszu is coached by Shane Tusup, 28, whom she met when both were swimming at the University of Southern California. During any of her races, her husband is unmissable on the pool deck - exhorting, berating and contorting, unable to contain his emotion.

At London 2012, she failed to win a medal. After she married Tusup in 2013, she now has six world championship medals, including four golds, and two female Swimmer of the Year awards. She also became the first athlete to surpass US$1 million (S$1.34 million) in World Cup series prize money.

That she has accomplished all of this with her temperamental husband overseeing all aspects of her preparation, has led to unease in some members of the tight-knit swimming community.

Tusup's eruptions, such as berating Hosszu publicly on her rare off days, have elicited stares, complaints and calls for his removal, reported the New York Times.

Jessica Hardy, an Olympic medallist who used to train with Hosszu, wrote about being subjected to verbal and emotional abuse as a child, and said: "I've seen a lot of inappropriate and not-okay behaviour in Shane. I've seen coaches exhibit that kind of behaviour in training, but this is another level. It's scary."

Hosszu and Tusup acknowledge that their relationship is complicated, but insist it is not unhealthy. She credits his tutelage, under which she has become, in her words, "a 24-hour athlete".

"He's pretty hard as a coach," she said, "but at home he's super sweet and loving and really funny. So we can laugh a lot."

WASHINGTON POST