Biles was suffering from a gymnastics phenomenon known as “the twisties.”

Team USA Olympic gymnast Simone Biles’ withdrawal from both the team and individual women’s gymnastics event sparked a bit of confusion from onlookers at the time. Biles didn’t appear to be visibly injured, so it wasn’t immediately apparent why she wasn’t able to compete. After the fact, though, she made a confession: during one of the vaults she performed during the finals, Biles suddenly lost track of where she was in the air. This is a dangerous phenomenon known to professional gymnasts as “the twisties.”

In the Olympic team final, Simone Biles planned to perform a 2½-twisting vault, but her mind stalled after just 1½ twists: “I had no idea where I was in the air. I could have hurt myself.”

This is what “the twisties” are and why they're so dangerous: https://t.co/lhG0jzuftE

— The Washington Post (@washingtonpost) July 28, 2021

“I know that feeling so deeply in my body,” former competitive gymnast Catherine Burns told NPR, “of being, like, I’m lost, I came out [of the move] too early, where am I? And all of that is happening in the course of split seconds, that recognition of something’s not right and I need to be able to complete the trick without injuring myself.”

“Hated it, so much,” 2016 Olympic gymnast Laurie Hernandez said, adding, “it actively makes you feel like you’re not the caliber of athlete that you are.”

I wrote about the twisties — kind of like the yips but upside-down and in mid-air — and what they feel like, why they’re dangerous and how gymnasts try to make them disappearhttps://t.co/Xk41bwRpIg

— Emily Giambalvo (@EmilyGiam) July 28, 2021

The understanding of her condition from both her fellow athletes and fans means a lot to Biles, who said on her Twitter that “the outpouring [of] love and support I’ve received has made me realize I’m more than my accomplishments and gymnastics which I never truly believed before.”