Olympic gold medalist Katie Ledecky broke multiple world swimming records before graduating high school. Now in her senior year in Bethesda, Md., she’s wrapping up her high school swimming career and looking forward to World Championships this summer. (Zoeann Murphy/The Washington Post)

There she goes, out of Lane 3, this little minnow, her now-famous face obscured by swim goggles, the low-res limitations of a 2000s-era camcorder and the passing of 11 1/2 years. She’s struggling, stopping every four or five strokes to hang on the lane rope and wipe her nose, the swimmers on either side passing her by. Finally, she sticks her face in the water and fires her motor, arms flailing. She passes the swimmer on her right, nearly catches the one on her left and touches the wall, second place in this heat of the 6-and-under 25-yard freestyle.

But something is kindled. The swimming world will see more of this 6-year-old debutante in Lane 3, this Katie Ledecky.

The footage is captured by an amateur documentarian standing on the deck beneath the lifeguard stand on a summer Saturday morning in 2003. He doesn’t realize he is filming the first career race of a kid who someday — when she’s still a kid, in fact — will win an Olympic gold medal and become known as the best female freestyler in the world. He’s just a dad, and this is what dads do. He points the camera down into his daughter’s smiling face, her goggles now pushed up atop her Palisades Porpoises swim cap, revealing a pair of big hazel eyes.

“Tell me about your first race. How was it?” he asks.

“Great,” she replies with a toothy smile. A few seconds later, she blurts: “It was soooooo hard.”

It wasn’t much, but to people who know her, the seemingly disconnected ideas conveyed on that keepsake video — it was great, and it was hard — have come to define the unrelenting brilliance of Katie Ledecky.

It is only now, looking back, that you can see the way the pieces all came together — a set of circumstances that helped the little girl become a prodigy who would stun the swimming world as a 15-year-old by winning gold in the 800-meter freestyle at the 2012 London Games. A prodigy who, in a blitz of world records that began a summer later, would set about redefining the outer limits of human possibility in women’s long-distance swimming. It’s a process that isn’t over, with Ledecky, a senior at Stone Ridge School of the Sacred Heart, turning 18 in March and, by all signs, pointed toward another record-setting summer.

The Ledeckys, David and Mary Gen and their two kids, only joined the Palisades pool in Cabin John because it had a shorter waiting list than the one near their Bethesda neighborhood. The Ledecky kids — Katie and Michael, three years older — only joined the Palisades swim team as a way to make new friends.

That’s the thing about prodigies: The talent is only half of the equation. The other half is opportunity. Somebody had to sit little Mozart down at that piano. Somebody had to put that golf club in Tiger Woods’s hands. And somebody had to wake up on a summer morning, put the Ledecky kids in the station wagon and haul them down to their new community pool. Somebody had to teach little Katie how to play sharks and minnows, how to execute a proper cannonball and, eventually, how to swim the 25 free.

And somebody had to film it.

An extraordinary gift

There she goes, back and forth, back and forth, the minutes creeping by on the clock at Georgetown Prep’s pool, the black sky outside betraying not the slightest hint of light.

For mornings such as this one, when Ledecky’s Nation’s Capital Swim Club has practice, bedtime the night before is 9:30, the alarm clock is set for 4:05 a.m. and her father drops her off by the pool entrance at 4:45 for a 5 a.m. practice. (Ledecky says she is “working on” her driver’s license but doesn’t seem to be in much of a hurry.)

Including warmups, Ledecky’s typical practice routine involves 300-plus laps of the short-course pool. At nine such practices a week, that’s around 2,700 laps a week, and at about 50 weeks of practice a year, that’s some 135,000 laps — the equivalent of 1,918 miles — a year.

“Somewhere in the mental makeup, there is something the distance swimmers have that the others don’t have,” says Bruce Gemmell , Ledecky’s coach. “Something that makes them embrace the discipline required. Katie embraced it. She likes the repetition — the borderline monotony — of distance.”

If Ledecky doesn’t stand out during these practices, it’s because her training group consists of one other girl and four high school boys — all nationally ranked, none interested in letting Ledecky beat them.

It may also be that there is nothing outwardly extraordinary — by the measures of elite swimming circles — about Ledecky physically. At 5-foot-11, she towers over most high school teammates and opponents, but put her in the middle of the medal stand at an international event and she is typically the shortest of the three.

As for her athleticism? “It’s borderline poor,” Gemmell says. “Now, lots of swimmers are like that, I think, because they spend so much time in the water. They don’t spend much time kicking a ball or throwing a ball. Some swimmers are good athletes; some are bad. She’s not on the bottom of the list. But there’s no real physical gift.

“Just the other day, we were walking up the walkway to practice, and she had her hat and her parka, and she’s kind of flopping along, and I thought, ‘Is this one of the best female athletes in the world? Really?’ ”

Just before 7 a.m., Ledecky, dressed and bundled up against the cold, flops along to her mother’s car, climbs into the passenger seat and scarfs down a breakfast of a bagel, omelet and chocolate milk on the way to school. Most weekdays, there is an afternoon practice, too, and for that one the chauffeur roles are reversed: Mom drops her off; Dad picks her up two hours later. Mom has dinner ready. Homework. Bed.

Most folks would agree: It is a cruel, spiteful fate that reaches and down and selects a husband and wife to be year-round Swim Parents. It begins innocently enough, with 6 a.m. wake-ups on summer Saturdays for four-hour summer-league meets in which your kid might be in the water a total of three minutes. Then they ask you to be a timer, so you have to get there earlier and stand the whole time.

Then the kids start wanting to swim in the winter, too.

“I’m not sure any parents would let their kids start swimming if they knew what the hours were going to be,” laughs Michael Ledecky, now a junior at Harvard. “They lure you in, and then it keeps getting earlier and earlier.”

But the Ledeckys never seemed to mind their fate. Mary Gen, a hospital administrator, had been a competitive swimmer herself, at one point nationally ranked in the 200 freestyle while at the University of New Mexico. David, an attorney, came to view his role as the one who kept the operation running, handling logistics and outside-the-pool duties — a role that grew exponentially as Katie’s swimming began to look more like a career, with a club team, year-round competition and frequent travel.

“They’re not the shrill, driven parents [who yell], ‘You’ve got to go and do this!’ ” said Washington Capitals and Wizards owner Ted Leonsis, a family friend and one-time business partner of Jon Ledecky, Katie’s uncle. “They have created an environment in the home that has promoted excellence but didn’t stringently demand it. All those stereotypes of the parents of world-class athletes have nothing to do with the Ledeckys and with how Katie was raised.”

The Ledeckys don’t recall any deep conversations about what it meant to be handed this fate — the rising awareness of Katie’s extraordinary gift and their own obligation to it. “We just did it,” Mary Gen says. “And we’ve loved it.”

“Maybe the most exceptional thing about Katie is that she’s completely normal,” Gemmell says. “She’s a completely normal 17-year-old who giggles with her friends and has her Twitter account and forgets her shoes for school sometimes.”

A love for training

There she goes, out of Lane 3, the youngest swimmer in the 800 freestyle final at the 2012 London Games, the youngest athlete, in fact, on the entire U.S. Olympic team. She bends down and grips the starting blocks several seconds before the starter’s instruction. She goes out fast — too fast, if you listen to the NBC announcers, who question whether she has enough left to bring it home, even as her lead widens.

It can be said now, with the benefit of hindsight and with the gold medal safely in her possession: The announcers were right. Though she won by more than four seconds and broke Janet Evans’s 23-year-old American record in the process, Ledecky didn’t swim a great race in London — or rather, she didn’t swim the correct race.

“The idea in London was to win, and she won, so let’s not beat her up too bad. But I think she would agree she won a gold medal without swimming the race particularly well,” says Gemmell, who took over as Ledecky’s coach when Yuri Suguiyama left to coach at California Berkeley in 2012. “Her tenacity and her competitiveness and the adrenaline let her get away with it.”

The question of what Ledecky could do when she swam her optimum race began to acquire an answer the following summer, when she destroyed the 800 and 1,500 world marks at the 2013 world championships. Last summer, during one remarkable nine-week span, she set five more world records — including lopping a full six seconds off her 1,500 mark — at the Pan Pacific Championships, where she won five golds.

It was the kind of performance that had folks within the sport talking about Ledecky revolutionizing the discipline of distance swimming.

“It was the most impressive race I’ve ever seen, and I’ve been in the sport for almost 50 years,” USA Swimming National Team Director Frank Busch said of the 1,500 final at Pan Pacs. “. . . She’s blazing a completely different trail than anyone who has come before. She’s approaching being our best 200 freestyler, as well as our best in the 1,500. That puts her in a category no one has ever been in.”

If she’s not the biggest and she’s not the most athletic and she doesn’t always swim her race the right way, what is it about Ledecky that makes her such a historic figure?

You could point to her arm stroke, which Russell Mark, a high performance consultant for USA Swimming, describes as “textbook.”

“From a technical standpoint,” Mark says, “it’s one to model yourself after.”

But that says nothing of her kick and her flip-turn, which are both works in progress. No, at the core of Ledecky’s greatness is something less tangible or explainable. It’s the invisible part, hidden below the water. It’s the competitiveness that refuses to swim in anyone’s wake. It’s the focus that makes her coaches marvel at how she never takes so much as a lap off. It’s the mind-set to swim like a sprinter even when she’s going a mile.

And it’s the capacity to love the training — legitimately love it — to the point that the water feels like her true habitat, every move a natural one, never a hint of flopping along.

“It’s hard to explain,” Ledecky says, “but when I take any time off, I start to get antsy. It kind of messes me up. I just miss swimming. . . . Sometimes when I’m out there warming down and swimming easy, I just feel like I could do that forever.”

Taking aim at history

There she goes, out of Lane 3, the Stone Ridge Gators’ co-captain, her face expressionless. Every eye at the Holton-Arms School pool is on her as the 500-yard freestyle begins. A couple lanes down, a Holton-Arms swimmer climbs the starting blocks with fake red blood dripping down her cheeks and black rings around her eyes.

Some days, Ledecky swims against the best swimmers in the world. Other days, she swims against zombies.

In mid-January, at the nationally televised Arena Pro Swim Series meet in Austin, she swept the 100, 200, 400 and 800 freestyles, nearly setting another world record in the 800. Some of her times sent a jolt through the sport: If this was how fast she’s swimming in January, what will she be doing in July and August, when swimmers are looking to peak?

“Every time she swims, people expect something great,” says freestyle sprinter Simone Manuel, Ledecky’s U.S. national team roommate. “And she always delivers.”

Less than a week later, Ledecky was back in Bethesda, leading cheers with her Stone Ridge teammates and climbing the starting blocks at the Independent School League championships. The Holton-Arms pool was festooned with signs warning of a zombie attack, and the school’s swimmers wore face-paint and tattered clothes — upholding the cherished tradition of themed home meets.

On the official starting list for the 500-yard freestyle, no competitor was within 30 seconds of Ledecky’s seed time of 4 minutes 28.71 seconds — perhaps because it is also the American record. She coasted to a 4:45.99 and won by 20 seconds, resting with her elbow on the wall, a familiar pose for Ledecky, as she waited for the other swimmers to finish.

“It’s amazing,” Gemmell says. “One day she’s standing on the starting blocks in Austin, with Universal Sports [television cameras] on her and the second-best swimmer in the world standing next to her, and she’s got eyes of steel. And a few days later, she’s standing on the blocks in Holton-Arms, next to some kid who’s 30 seconds slower than her, and she has to dive in and compete. In my point of view, she’s handled that [contrast] wonderfully.”

As her high school career comes to an end — this weekend’s Washington Metropolitan Interscholastic Swimming and Diving Championships will mark her final meet for Stone Ridge — Ledecky has tried to step back and soak in a scene that has helped keep her grounded through the years.

The dichotomy between her two worlds has worked, despite their contrasts and dueling priorities, because at Stone Ridge, she’s just Katie, a senior co-captain, and not the Great Ledecky, international destroyer of world records. And it has worked because her club team coaches and Bob Walker, Stone Ridge’s coach, have maintained an understanding that whenever schedules clash, they will do what is best for her — even when, in one particularly agonizing case, it meant skipping Metros her freshman year to swim in a crucial, pre-Olympics national meet.

“There was not even a blink of an eye, from the head of school to the athletic director to me,” Walker says. “It was: ‘Absolutely. If she needs to miss Metros, she’ll miss Metros.’ Selfishly speaking, we have to take a step back to let her succeed.”

Though she has committed to Stanford, Ledecky likely will take a gap year and remain in Bethesda to train with Gemmell through the 2016 Rio Olympics, where she will be taking aim at history. Not only is she dominating the 400 and 800 these days (the women’s 1,500 isn’t contested in the Olympics), but she is winning 200s regularly, too, and putting more emphasis on the 100, which could earn her at least a relay berth. Including relays, she could swim in five events in Rio. No U.S. woman has won five golds in a single Olympics.

“Katie Ledecky will be the face of the Summer Olympics, not only for these next Games but probably the next couple Games,” Leonsis says. “It is exactly what we would want as a country to export as an icon — a wonderfully well-adjusted, smart, well-rounded young woman who happens to be the best in the world by orders of magnitude in some of these events.”

Recent history hasn’t been so kind to American female distance swimmers who emerge as teenaged prodigies. Even Evans never matched her three-gold-medal performance as a 16-year-old in the 1988 Seoul Olympics. Life tends to get in the way.

“The challenge for someone like Katie and her coach and family is to look at what will be the arc of her career,” says Chuck Wielgus, USA Swimming’s executive director. “It requires an almost maniacal full-time commitment. While your peer group is going to grad school and getting jobs and moving on, you’re in this kind of suspended state. Trying to assess what her career path will be will be a very interesting thing to follow.”

Bring up the “arc” of her career to Ledecky herself, and she just shrugs. She can no more imagine 2024 than that 6-year-old Katie on the videotape could imagine 2012. That’s because she isn’t bound by the limits of imagination. Just when it seems that she can go no faster, that the outer boundaries of possibility have been reached, there she goes again.

Bryan Flaherty contributed to this report.