Florida's Caeleb Dressel reacts with a gator chomp after winning the 50-yard freestyle and setting an NCAA record of 18.20 seconds during the men's college swimming and diving championships in March. (John Amis/AP)

When he was 8 years old and still learning what it meant to be a competitive swimmer, little Caeleb Dressel was a formidable adversary for the volunteer wranglers — those poor, harried swim moms and swim dads charged with herding the slippery 8-and-under swimmers to the starting blocks for their heats. Caeleb might be anywhere — on the playground, the basketball court or in the parking lot tossing a football — except where he was supposed to be.

“It’d be like, ‘Caeleb, you’re fixing to be up!’ ” his mother, Christina, recalled. “We’d finally find him, all sweaty. But that’s what makes him tick. He’s never been one of those kids sitting in the stands, eating his Power Bar.”

Now 19 and the best young sprinter in the United States, Dressel no longer has to be wrangled to the starting block. On Saturday and Sunday, in two of the most highly anticipated races of the Atlanta Classic Swim Meet — one of the last major tuneups before next month’s U.S. Olympic trials — Dressel will square off against four-time Olympic medalist Nathan Adrian in the 50- and 100-meter freestyles. In each, the victor could be considered the favorite at the trials in Omaha, and it is possible both will compete at the Rio de Janeiro Olympics in August.

They will make quite a pair on the starting blocks: Adrian, 27, the defending Olympic champion in the 100 and the American-record holder in the 50, clean-cut and built like a power forward — a sculpted 6-foot-5, 227 pounds. And Dressel, a slender 6-1, 185, sporting tattoos of an eagle and the American flag on his shoulder and back.

In the hyper-competitive, all-immersive world of elite swimming, Dressel has always been different, with a deep, internal need to disconnect himself from the swimming life. As a pre-teen, he informed his family — including three siblings, all of whom are competitive swimmers — that he did not want to talk about swimming when he was away from the pool. A moratorium began then and there.

Even now, as a sophomore at the University of Florida, Dressel’s coaches know he needs to take a weekend every now and then to drive from Gainesville to his family’s 60-acre spread in tiny Green Cove Springs, south of Jacksonville, to ride horses, shoot guns, watch movies or play epic games of table tennis with his brother. And they know not to call him while he’s there.

When Dressel is at the pool, said Gregg Troy, Florida’s coach, “his focus is amazing. If we have a team meeting, it’s like you’re just talking to him. [But] he has a lot of interests, and that’s good — because then [swimming] doesn’t become stale.”

When it’s time to return to Gainesville, he shows up on time, trains like a maniac and transforms back into the relentless champion who has laid waste to the NCAA and American short-course record books over the past few months.

“As soon as the whistle blows,” Dressel said, “something triggers me.”

Though he has long been seen as a star in the making — having broken numerous age-group records as a boy, including some once held by Michael Phelps, and qualified for the Olympic trials as a 15-year-old in 2012 — what Dressel did in March at the NCAA championships made him something approaching a legend. There, he set NCAA and American records in both the 50-yard (18.20 seconds) and 100-yard (40.46) freestyles. He now owns the six fastest times in history in the former, with four of them coming on a single day at NCAAs.

But Dressel’s ascent has been far from a steady, unbroken rise. Two years ago, as his dazzling high school career was coming to a close — and after he had committed to Florida — Dressel suddenly decided he needed a break from swimming, and he wasn’t sure he was ever coming back.

“He had just had four meets in a row, back-to-back-to-back-to-back,” Christina recalled. “And in his last [high school] state meet, he had just became the youngest ever to go under 19 seconds [in the 50-yard freestyle]. And for the finals, when he didn’t get another best time, the whole crowd went, ‘Awwwwww.’ He never forgot that. He said, ‘You know what? If this is what happens, I have to take some time to figure this out.’ ”

Increasingly, Dressel had begun to feel as if he were swimming for others — the people in the stands, the ones chirping at him on social media — and not himself. So he shut it all down. Like the 8-year-old Caeleb who disappeared to the playground during meets, the 17-year-old Caeleb needed some space. His downtime lasted six months, during which he never dipped so much as a single toe in a swimming pool. In the past, he has referred to these months as a “dark period.”

“To me, this was part of his maturing,” Christina said. “His counselor told him, ‘Don’t let swimming define you. You are Caeleb. Swim for you because you’ll never please the crowd.’ ”

Finally, when he felt the time was right, Dressel sent his coaches a text message with a picture of a swimming pool — a signal that he was ready to swim again. He arrived in Gainesville to begin his collegiate career feeling refreshed and recharged — but out of shape.

“My passion came back. I fell in love with the sport again, so that wasn’t a problem,” Dressel said. “But getting back in shape was kind of a big thing because when you take that much time off, that’s a necessity. So last year was a lot of getting in shape and getting used to racing again.”

For the past year or so, Dressel has been advancing on parallel tracks — one, measured in short-course yards, leading him in March to the pinnacle of collegiate swimming and into the NCAA record book, and the second, in long-course meters, pointed toward Omaha and Rio de Janeiro.

By the end of this weekend, after successive showdowns with Adrian in the sprint events, Dressel should have a pretty good idea where he stands. And between now and June 26, when the Olympic trials start, if he isn’t in the pool, there is a good chance you can find him at home in Green Cove Springs — on a horse or absorbed in a movie.

And it would be best if you didn’t to try talk to him about swimming.

Notes: Bethesda’s Katie Ledecky, the gold medal favorite in the 200-, 400- and 800-meter freestyles in Rio, swam a sizzling 1 minute 54.82 seconds to win the 200 on Friday night, the second-fastest time in the world this year. She also set a personal best with a 4:37.93 in the 400-meter individual medley but finished third behind 2012 London silver medalist Elizabeth Beisel (4:33.55) and 2015 world championships silver medalist Maya DiRado (4:36.98).

Still to come this weekend for Ledecky are the 100, 400 and 800 frees and the 200 IM. Ledecky and her coach, Bruce Gemmell, are undecided as to whether she will swim the IMs in Omaha.