First Lady of the United States Jill Biden watches the swimming competition at the 2020 Summer Olympics, Saturday, July 24, 2021, in Tokyo. (AP Photo/Matthias Schrader)

Chase Kalisz, of the United States, swims during a heat for the men's 400-meter individual medley at the 2020 Summer Olympics, Saturday, July 24, 2021, in Tokyo, Japan. (AP Photo/Matthias Schrader)

Henning Bennet Muhlleitner, of Germany, reacts after his heat of the men's 400-meter freestyle at the 2020 Summer Olympics, Saturday, July 24, 2021, in Tokyo, Japan. (AP Photo/Matthias Schrader)

Elijah Winnington, of Australia, swims in the fifth heat of the men's 400-meter freestyle at the 2020 Summer Olympics, Saturday, July 24, 2021, in Tokyo, Japan. (AP Photo/Martin Meissner)

United States swimmers cheer on teammates during swimming competitions at the 2020 Summer Olympics, Saturday, July 24, 2021, in Tokyo, Japan. (AP Photo/Martin Meissner)

Lewis Clareburt, left, of New Zealand and Chase Kalisz, of the United States, shake hands following their heat in the men's 400-meter individual medleyat the 2020 Summer Olympics, Saturday, July 24, 2021, in Tokyo, Japan. (AP Photo/Martin Meissner)

Lewis Clareburt, of New Zealand, swims during a heat for the men's 400-meter individual medley at the 2020 Summer Olympics, Saturday, July 24, 2021, in Tokyo, Japan. (AP Photo/Martin Meissner)

First lady of the United States, Jill Biden waves during a swimming event at the 2020 Summer Olympics, Saturday, July 24, 2021, in Tokyo. (AP Photo/Petr David Josek)