Maya DiRado practices during a training session at the swimming venue in Rio De Janeiro. (Jonathan Newton/The Washington Post)

Decades ago, before there was such a thing as an Olympic swimming veteran, Maya DiRado would not have been a story for the same reason she is a story today. For instance, back then, Summer Sanders grew up in northern California, swam at Stanford, put her eyes on the 1992 Olympics in Barcelona, won four medals there, and retired a legend. That’s how it was done.

Now here is DiRado. She grew up in northern California, swam at Stanford, and at some point over the past couple of years put her eyes on the Rio Olympics. Saturday, she’ll swim for a medal in the 400-meter individual medley. Regardless of what she does in that event, and the 200 individual medley and the 200 backstroke, she will retire, legend or not. She is 23.

She is swimming better than she ever has. After this meet ends, she will stop. She thinks those two facts are related.

“I think the reason that I’ve had this success this year is because I know that swimming is wrapping up for me,” DiRado said. “It’s so much easier to work hard every day and push myself and be excited about all the little things that make swimming great but are kind of hard to get excited about when you’re looking at this like, ‘Oh, I have so many more years ahead of me doing this.’”

Since the turn of the century, swimming has changed perhaps as much as any Olympic sport. Spurred in part by the mainstream stardom of Michael Phelps and his 22 Olympic medals, successful American swimmers now can find sponsors that allow them to train and compete professionally through several Olympic cycles. Phelps is here, in his fifth Olympics, at 31. Ryan Lochte is here, in his fourth Games, at 32. Dana Vollmer is swimming as a mom. Missy Franklin turned professional two years into her college career and, at 21, has a reasonable expectation to be back for two Olympics beyond Rio.

So DiRado’s decision, once the norm, now is considered extraordinary.

“As I got to know Maya better, one thing that surprised me was what motivates her,” said Greg Meehan, her coach at Stanford. “It was never about being competitive or trying to win. It was always about being the best she could be, to find her own version of perfection. She’s also the smartest person I’ve ever coached.”

This decision is rooted solidly in who DiRado is. Training for an Olympics, for the first finisher or the 50th, is almost by definition consuming. DiRado never allowed it to consume her. As she became a teenager, and began turning in times that showed she would likely be able to continue her career, people would ask whether she was looking forward to swimming in college.

“And she said, ‘I really like swimming now, but I’ve been doing it for half my life,’” said her father, Ruben. “She said, ‘Maybe by the time I get to college, I’ll want to do something else.’ And I thought to myself: What a perfect answer. ‘I like it now. I’m enjoying it. But there’s no reason I have to keep doing this.’”

DiRado grew up as a voracious reader, and at a young age, she gave clues as to how her mind would work. In, say, third grade she would read about World War II and ask her father questions such as, “What do you think of Stalin?” Her father called her a “symbolic thinker,” because she easily identified patterns and assigned them meaning. It’s the kind of thinking that leads to a perfect score on the math section of the SAT, which DiRado attained. It’s also the kind of thinking that can be applied to swimming.

“It gives you a language and tools by which to analyze,” Ruben DiRado said. “Analysis is a big part of what her strengths are. She has the ability to do a swim, kind of get feedback on it, look at the splits or look at the video, and she kind of can make an assessment. She can say, ‘If that’s what I did, how would I need to change that?’”

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That played into how she approached this run to the Olympics. On one side of DiRado’s life, she was completely grown up. She became engaged to her college boyfriend, former Spanish swimmer Rob Andrews, and accepted a job with McKinsey and Co., an elite global management firm. They planned to move to Atlanta and start their lives — until swimming interrupted. She was getting faster, across the board. McKinsey allowed her to delay the start of her job if she wanted to train through the 2015 world championships and, potentially, through Rio. Sponsorship surfaced. She could make a living.

Yet a long career in swimming is not for everyone. Even as DiRado won a silver at worlds in the 400 IM — cementing the idea that the Olympics were not just attainable, but that she could excel in them — her decision to leave swimming after this year seemed even better. The reason: She grew bored.

“That was honestly one of the hardest parts of this,” DiRado said. “Especially summers, over swimming, you just veg out, go to practice, come back, watch TV, nap — and that’s fine. But after a couple of months of that you’re like, ‘Oh my gosh, I can feel my brain atrophying.’ . . . At one point I was like, ‘Well, if I keep swimming, was Stanford the most stressed my brain was ever going to get?’ And that totally freaked me out.”

What she wants: a successful week to come, for sure. But after that: a life.

“Part of the reason why I am swimming so well is knowing that I have a hard stop date, and so it’s so much easier to be excited about all of this and give it everything I have when I know that this is my last go-through,” she said. “I don’t think that’s a sign that I need to keep swimming. I think it’s a sign that my preparation this year has been really good – and that I’m ready to move on to something new.”