Then she saw her family, and the tears started flowing as she ran into their arms — mom Debbie, sister Whitney and brother Michael.
"I've never done anything this impressive," she remembers Michael saying.
"Are you kidding me?" Hilary responded.
It was July 25, 2010, not even two years after Michael Phelps had won eight gold medals at the Beijing Games, smashing previous records and taking a pretty good shot at the title of greatest swimmer ever.
But Michael's admiration after her triathlon, says Hilary, is part of what it means to be a Phelps, a family comprising not so much one star orbited by lesser planets as a tightly bound and interconnected constellation.
"We're all impressed by each other's feats," she says.
With Michael headed to his fourth and final Summer Games later this month, the mutual support society that is his family is London-bound as well. They are both cheering squad and reality check, a home base for him as his travels have taken him around the world and his celebrity has soared.
"He needs to connect. 'I just need to see my family,' he'll say. It grounds you; it's safety," Hilary Phelps says. "It's why we go to so many meets. He can see us in the stands."
Family comes up often with Michael, particularly when he is talking to children in his charitable foundation's wellness and water safety programs. He points to his parents' divorce when he was 9 as one of the challenges of his childhood, but credits his mother, and Hilary and Whitney, who are seven and five years older, respectively, with setting him on the path to success.
"Being able to watch my sisters and mom do what they did … it made me a stronger person," the 27-year-old swimmer told a group of kids at a Boys & Girls Club in Indianapolis this spring. "That was super cool for me, having three women in the household showing me everything. I was the baby. Being the youngest is the best — you get away with everything."
His mother, Debbie, the principal of Windsor Mill Middle School in Baltimore County, has become the go-to reaction shot for the TV cameras after his races and a familiar figure in his commercials and anecdotes. He joked in Indianapolis that she loves the city not just for the personal memories — he qualified for his first Olympics, in 2000, there — but because there's a restaurant there that she likes.
"'We'll have to go to P.F. Chang's,'" he cooed, mimicking her voice.
That may be an old joke that needs retiring, since Debbie moved two years ago from the family's longtime home in Rodgers Forge to the Ritz-Carlton Residences just across the Inner Harbor from the Chang's on Pratt Street.
Whitney Flickinger, who works as a recruiter, has since moved to Olney, and Hilary Phelps, who operates her own website, to the Washington area, but they frequently reunite at their mother's condo or wherever Michael is swimming.
"I get energy from downtown," Debbie Phelps says. "And now that Michael's billboard is up, I get to see my son every night."
As do all drivers approaching downtown on Interstate 95, where an Under Armour billboard features Michael with his arms fully extended to the 6-foot, 7-inch span that has helped propel his remarkable swimming career. Debbie has probably seen more of the sign than of her son lately, with his intensive pre-Olympic training taking him out of town for much of the year.
But through texting and Skype, his family has stayed in touch — and provided a necessary break from his sport.
"I don't talk swimming with him," Whitney said. "It's just, 'Love you, thinking of you.'"
Swimming, though, is one of the ties that bind the siblings, and something that has brought the family much joy but also produced a measure of sadness.
Hilary began swimming as a young girl, and soon Whitney followed. It started casually enough, but in true Phelps fashion, soon turned into overachieving.
"We lived in the middle of all this acreage in Harford County," Debbie said of the early years of her marriage to Fred Phelps, her high school sweetheart and now a retired Maryland state trooper. "You had to get in the car to be with other kids. We joined a swim club because I wanted socialization for the kids, I wanted water safety for them and, three, I wanted to hang out with other moms."
Hilary remembers coming in third in one race as a 7-year-old and telling her mom she wanted one of the bigger trophies. "I wanted to swim where the fast girls swam," she said.
Soon she would. At a meet against North Baltimore Aquatic Club swimmers, a coach approached Debbie and said they had room for Hilary on the team. And, the coach said, Whitney too.
While Hilary continued to swim competitively, breaking school records as a swimmer at the University of Richmond, she also made sure not to miss out on beach trips and other teen distractions. Whitney, though, was driven and rose to the top of national and international rankings.
But she developed neck and back pains and, at 14, was diagnosed with stress fractures and bulging and herniated disks. She swam through it, not wanting to be "a wimp," Whitney said, but her own Olympic dreams would be dashed.
Entering the 1996 Olympic trials top-ranked in the 200-meter butterfly race, which has become one of her brother's signature events, Whitney says she "bombed." In the stands, her mother and siblings were devastated.
"I had Hilary on one side and Michael on the other, and we were all crying," Debbie told The Baltimore Sun in an earlier article.
Swimming off and on after that, Whitney made the cut for the trials for the 2000 Olympics, but the pain was too much and she scratched. Instead, it was 15-year-old Michael who qualified, becoming the youngest male to represent the U.S. in the Olympics in decades.
The family headed to Sydney for his first Games, but Whitney stayed home.
"I regret that," she says now. "But I didn't know what to do with myself. It was hard. It had been my life for so many years. It was kind of a mourning period. It took a while before I could go watch and enjoy it again."
It's a bit faded now, but there's a tattoo of a butterfly on the top of her right foot that recalls when the Phelps known for that swim stroke was Whitney, not Michael. But if she's left her competitive swimming days behind, she hasn't given up the kind of discipline that defined it.
She'll get up at 3 in the morning to run, a time she carves out from a busy schedule: She works as a recruiter for the Henry M. Johnson Foundation for the Advancement of Military Medicine, putting together teams of researchers.
After having a little too much fun as a college student at the University of Nevada Las Vegas and leaving without a degree, she is now taking management classes at the University of Maryland University College.
And then there are her kids, 6-year-old Taylor, whom Whitney calls her little intellectual, always buried in a book and curious about the world, and 4-year-old Connor, currently obsessed with superheroes because, in his young mind, obviously he is one himself.
Taylor will join the family entourage in London to watch Uncle Michael, with Connor staying home with dad, Bob Flickinger, a federal employee.
"The kids adore him," Whitney says of her brother. "He's a big kid himself. For Christmas he got Connor this Lego set that was for 8- to 12-year-olds, with a million pieces. He sat down on the floor and helped him put it together."
To the kids, Hilary is He-He, what Whitney called her sister before she could say her full name. Debbie is G, shortened from the G-Unit nickname the hip-hop-loving Michael had given his own grandmother.
On a recent night, Phelps mere et filles gathered at the Royal Sonesta Harbor Court Hotel for a photo shoot for the Sun Magazine.
Debbie arrived in one of her trademark Chico's outfits, a flowing zebra-patterned jacket, which prompts a memory — one of her "DP moments," as she hashtags them on her Twitter account.
"The last time I had this on was in Rome. It was the 100 fly," she says, recalling the 2009 world championships and another of Michael's dramatic victories. He beat a rival, Milorad Cavic, despite wearing a regular Speedo rather than the controversial rubberized suits that, serving as something of personal flotation devices, helped many swimmers break world records before they were banned.
As a principal, she doesn't get summers off — she'll rush back after the Olympic swimming events to continue interviews for new staff at Windsor Mill and reopen the school for another year. At Michael's meets, she is something of an Everymom, pulling swimmers close, her hands on their cheeks for some quiet, eye-to-eye contact before enveloping them in a warm hug.
She and Michael have always been close, although after two daughters, she had some adjusting to make.
"I had two girls who colored, who played with paper dolls. When I was having girls, my friends seemed to be having boys" who seemed to be all over the furniture, racing toy cars and breaking lamps, she said. "I would think, 'What's wrong, can't you parent?' Then I had Michael."
Now, as then, Hilary seems like an island of calm in any Michael-induced frenzy. Maybe it's the yoga she avidly practices, having lived for a time in an ashram in Florida. Or her healthful eating — she's been a vegan, although she resumed eating meat when training for the Ironman, and she's now considering a raw-food diet.
Her website, Genuine Joy, reflects her many interests, from food to fashion to fitness, and began as a blog in which she explored them.
"Why can't you be a runner who also likes to wear high heels?" Hilary says.
In London, she'll do some television pieces on the Games, an outgrowth of the writing and photography that she has done on her website.
She is the protective big sister, quick to defend Michael against critics and wary of the hangers-on drawn to his stardom. There have been times when she would be on a date, and the man would learn who her brother is.
"'Oh, when do I get to meet him?'" she says, echoing the faux casualness of the question, the asking of which ensured her answer: "Never."
It's starting to sink in for all of them that London marks the endpoint of this particular part of their family's life. All the traveling. All the trying to distribute Debbie's shoes and jewelry to avoid overweight-bag fees. All the shifting around of mealtimes and holiday celebrations to work around one Phelps or another's training schedule and swim meets.
Hilary and her boyfriend, Doug Eldridge, a sports and entertainment agent, were recently talking about a trip he had coming up in December — always reserved on the Phelps family calendar for the NBAC Christmas meet.
"That's when it hit me," Hilary says. "You know, I don't have the Christmas meet."
Her favorite memories of Michael's swimming career are the quiet ones — how after winning his first medal in the 2004 Games he found a way to meet his mother and sisters on the other side of a fence to show them his ribboned medallion. How he once fulfilled a paralyzed boy's dream through the Make-a-Wish Foundation, putting him on his back and swimming that way for an hour.
"That is the happiest I've seen him," Hilary says. "That is what makes me proudest to be his sister."
Michael plans to remain involved in the sport — through his foundation, his chain of swim schools and his ownership, with his longtime coach Bob Bowman, of Meadowbrook Aquatic Center in Mount Washington and NBAC. But the end of his competitive career has made the run-up to London something of a sentimental journey.
Debbie has made sure swimmer and coach take a picture at each of the pools where they traveled over the years, ever since Bowman told his parents that the 11-year-old Michael could be an Olympic swimmer. Michael himself has been keeping a journal to make sure he remembers everything from this final lap.
Meanwhile, there's the next generation to consider, and to raise in the Phelps family way.
As her mother was being made up and styled for the magazine shoot, Taylor played with He-He's iPhone, trying unsuccessfully to call up some photos. "I can't," she said.
"Don't say 'can't,'" G called out. "You can do anything."