GARDINER, N.Y. — In the run-up to the 2016 Olympics, Vinny Marciano was one of America’s best young swimmers and a contender for future Games.

During one meet, Marciano shattered five records for boys ages 11 to 12. As a high school freshman, he won New Jersey’s 100-yard freestyle championship and missed the U.S. Olympic trials by just 0.27 seconds in the 100-meter backstroke. He was a prodigy, mentioned in the same breath as Michael Phelps and Ryan Murphy.

Then, as quietly as mist rising from a pool, he disappeared. He entered no races after December 2017, made no college commitment, quit updating his swim-saturated Facebook and Twitter accounts.

Where did he go?

For all the rewards of winning, each medal and milestone can became an anchor around the necks of elite athletes. Their identity can become indistinguishable from their accomplishments, and they may feel burdened by the expectation that they will always do more, more, more.

But what if they harbored a secret desire to stop, and wanted to start anew — to hit Ctrl-Alt-Delete, essentially?

Marciano reset his life when he abandoned the down-to-the-millisecond world of swimming to pursue something anonymous and ethereal: bouldering with friends in the Shawangunk Ridge here or other climbing meccas in the Northeast.

Marciano, now 20, trains up to four hours a day, five days a week, either at a climbing gym in Poughkeepsie, where he is a junior at Marist College, or at his parents’ house in Randolph, N.J. He has installed a climbing wall in his family’s garage angled at 55 degrees, and a fingerboard in the basement similar to the one Alex Honnold used in “Free Solo.”

“When you’re 15 feet off the ground, you forget about everything else,” he said. “You’re not thinking about hitting all that traffic on the way there. You’re not thinking about the extra homework assignment. It’s like nothing else matters.”

As a swimmer, Marciano was obsessed with the clock, always calculating what splits he needed on every lap in order to break a certain record. After he missed the Olympic trials in 2016, he tried to gain an edge by joining a more competitive club, Eastern Express, an hour and a half away.

It turned out to be the beginning of his journey from amphibian to terrestrial.

On Monday afternoons, he would go straight from school to a three-hour evening practice. He would stay overnight with a teammate, motor through a two-hour workout, then return to school, late but excused. His coach would give him sets to do alone on Tuesdays at a local Y.M.C.A.

Repeat on Wednesdays and Fridays.

Marciano bonded with his new team, and he was swimming well. College powerhouses like Michigan and Arizona State contacted him. But his grades cratered. He barely saw his friends. Swimming became a job.

“I loved competing, but it got to the point where I hated going to practice,” he said.

It took about six months for him to work up the nerve to tell his parents that he was thinking of taking a break. They were supportive, but also told him: “You shouldn’t make this decision in haste.”

Marciano knew his motivation had evaporated, however, when he went to Ithaca, N.Y., for a meet with his club team and didn’t look up any times beforehand. So when he was told that he got a best time in the 50 freestyle, he didn’t feel much joy. After that, he only competed in high school meets, mostly to be around friends.

“I saw a never-ending ladder — no matter what I did, there was always going to be something I was expected to achieve,” he said.

The next year, Marciano visited Zion National Park with his father. He was mesmerized by people climbing walls and buttresses. So he headed for the rocks.

Ever since his first outdoor climb in the summer of 2019, Marciano has devoured climbing articles, videos and podcasts. He posts photos and videos on Instagram and YouTube.

“It’s a liberating sport,” he said. “It’s collaborative.”

Marciano is not disconnected from swimming. He occasionally teaches lessons, and he has attended the Big East championships to support a former club teammate.

“I’m not like, oh, I wasted 10, 11 years of my life,” said Marciano, an aspiring psychologist, during a recent workout in Randolph. “A lot of the techniques — training and competition — I can apply to whatever I do.”

Marciano’s parents are a little more circumspect. In an upstairs office, they keep a shadow box filled with ribbons and articles, highlighted by a July 2012 Swimming World Magazine profile with a smiling Marciano, braces and all. A 45-gallon plastic bin overflows with trophies and national age-group certificates.

“He was once the fastest in the world, at 10 and under, in the 50-meter backstroke,” his mom, Patricia, wistfully recalled.

On a recent damp day in the Shawangunks, Marciano joined two climbing friends, Will Stollsteimer, 23, and Mike Stollsteimer, 17, brothers from Newtown, Pa.

The trio applied chalk to the crevices, for better friction, and dissected the degree of difficulty of their favorite boulders (a V4 here, a V9 there). Marciano was excited for the physical test and the spiritual release that would come with it. At Gill Egg, he used his maize and blue Michigan sweatpants, and every inch of his 6-foot-3 frame, to dry the damp spots on the rocks.

“I thought it’d be less wet,” he said.