Katie Ledecky is the kind of person who races the 400-meter individual medley—one of swimming's most grueling events — just for fun. But the freestyle is her specialty, and she proved her dominance again Friday by winning the 400-meter free at the Arena Pro Swim Series at the Jean K. Freeman Aquatic Center.

Ledecky, 18, made waves at last summer's world championships by becoming the first swimmer to sweep the women's 200, 400, 800 and 1,500 freestyle. She set three world records in the process, stamping her as a potential superstar for the upcoming Rio Olympics. After breaking the pool record with a victory in Thursday's 200 free, she followed up with another pool record in the 400 with a time of 4 minutes, 2.67 seconds—two seconds faster than runner-up Leah Smith.

Four years ago, Ledecky said, she had never competed at a star-laden meet like this week's event in Minneapolis. She turned heads by winning gold in the 800 free at the 2012 Olympics as a 14-year-old, and her success at the world meet means people now ask her for photos and autographs.

"I have a lot more experience (than in 2011), and I know what to expect when I come to meets like this,'' said Ledecky, of Bethesda, Md. "That just gives me a new level of confidence.

"But I still have the same mentality I had in 2011 and 2012. There are still a lot of things that motivate me, and I have really big goals for this year.''

Other champions Friday included former Gopher David Plummer, who won the men's 100 backstroke in 52.85. Plummer lives in Minneapolis and trains at the U pool. Conor Dwyer and Chase Kalisz each earned his second victory at the meet, with Dwyer taking the men's 400 freestyle in 3:48.11 and Kalisz catching Michael Phelps to win the men's 200 butterfly in 1:58.07.

Missy Franklin earned her first title of the meet, winning the women's 100 backstroke in 1:00.18.

The meet concludes Saturday with eight races.

Rachel Blount