Ledecky wins 400m free with room to improve at World Championships
She set a world record of 3:56.46 in winning gold at the Rio Olympics in 2016.
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Katie Ledecky. AFP PHOTO
By NewVision Reporter
Journalists @NewVision
Katie Ledecky easily won the 400m freestyle at the US swimming championships on Friday, but the US great knows she'll need to do more to challenge for the title at