這裏解釋了。

https://www.fox43.com/article/sports/olympics/sydney-mclaughlin-levrone-400m-final-olympics-why-she-isnt-competing/507-66d82dae-3c91-4022-b4fc-2a3e55545894#:~:text=McLaughlin%2DLevrone%20would%20have%20faced,so%20on%20until%20both%20finals.