After learning that she might lose the bronze medal she won in the floor exercise at the Paris Olympics — the only individual medal she won at these Summer Games — the American gymnast Jordan Chiles took to social media on Saturday and posted four broken heart emojis on a black background.

That’s four broken hearts for the four seconds that cost her a bronze medal. Four seconds over which she had no control.

The International Olympic Committee confirmed on Sunday that it would strip Chiles of her bronze medal and give it to Romania’s Ana Barbosu. The decision came after the Court of Arbitration for Sport ruled on Saturday that Chiles’s coach had filed a scoring inquiry four seconds too late, according to gymnastics rules.

The United States Olympic & Paralympic Committee said Sunday it would appeal the reallocation of Chiles’s medal. “We firmly believe that Jordan rightfully earned the bronze medal,” it said in a statement.

Chiles, who had helped the United States win the gold medal in the team event in Paris, and whose bronze in the floor completed the first all-Black podium in Olympic women’s gymnastics history, was subjected to racist abuse online after the judges’ initial decision to raise her score. That abuse and the stripping of her medal cast a shadow on the closing day of what had otherwise been a highly regarded Games.

Barbosu was in third place in the floor exercise on Monday when Chiles, the final competitor, began her routine. Chiles was given a score of 13.666 points, which put her in fifth place. Barbosu began celebrating her bronze medal.