There are no women in the world who can swim faster than Katie Ledecky in her freestyle events. And she proved that again at Rio's Summer Olympics, setting world records and dominating distances from 200-800 meters.

Ledecky closed out her Rio trip with a bang, shattering her own world record in the 800-meter freestyle Friday night. The win gave her four gold medals — three individual — to go along with the silver she won as part of the 4x100 freestyle relay in Brazil.

"I had a lot of fun tonight," she said afterward, according to a transcript from the Olympic News Service. "I just wanted to push myself and see what I could do."

It's been a good 24 hours for Ledecky and her roommate in Rio — she's staying with Simone Manuel, who swam to her own gold medal last night. Earlier Friday, Ledecky confessed to having a bit of a sore throat from cheering for Manuel.

It clearly wasn't a serious ailment: To say Ledecky left the competition in her wake would obscure the fact that much of her wake had settled by the time the other swimmers came along. She won by nearly 12 seconds.

Noting that this was her last race in Rio, Ledecky added, "The Olympics is the pinnacle of our sport and I have to wait four more years to have that moment again so I wanted the last one to be special."

It was special, indeed: With a time of 8:04.79, Ledecky obliterated her own Olympic record of 8:12.86 (set in a qualifying heat in Rio) and took her world record down by almost two seconds.

"It felt faster than any event I had ever done before," Ledecky said, "so I was pretty confident that I would be under that world record time."

Watching Ledecky swim, let alone race, is mesmerizing. She seems to operate on a tempo that other swimmers can't fathom. While her rivals splash around, Ledecky twists through the water as if she's being pulled by some hidden line. Often, her feet barely seem to kick; instead, they twitch in short bursts — and sometimes they're perfectly still. The impression one gets is that if Ledecky kicked harder, if she did what her competitors are doing, it would only disrupt her mystifying propulsion.

When Sarah Sjostrom — who has had a strong Olympics showing of her own — lost to Ledecky in the 200m freestyle earlier this week, she said she was content.

"It feels like gold that I'm after her," she said of Ledecky. "I couldn't have gone any faster, it's impossible."

It's fitting that Ledecky closed out these games with the 800. Back in 2012, it was her shocking win in this event (at age 15, she beat then-world record holder Rebecca Adlington) that announced Ledecky's presence as a swimmer with superstar potential.

In Friday night's race, and in many performances since the London Olympics, Ledecky has shown she's intent on fulfilling that potential. At age 19, she's both the youngest member of the U.S. swim team and its most sure-thing winner.

In 2012, Ledecky came away with just one gold — she had yet to polish her performances in the shorter distances at 200 and 400 meters. But as her sweep of individual events in Rio showed, that polish is now shining brilliantly.

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