Simone Biles withdrew from the team final at the Tokyo Olympics after one vault, and subsequently from four individual finals. The explanation she gave was specific rather than general: she had the twisties, a loss of air awareness in which a gymnast cannot reliably tell where they are during a rotation.
Why that is a safety issue, not a nerves issue
A twisting double somersault is performed blind. The gymnast relies on proprioception to know when to open out for the landing. A gymnast who loses it mid-air on a vault is descending head-first from about three metres with no reliable way to correct.
Several gymnasts have ended careers with spinal injuries in precisely that situation. Biles competed in the beam final, having removed the twisting element, and won bronze.
What changed
Every major federation has since written air-awareness protocols into its medical guidance, and the language around athlete withdrawal has shifted noticeably.
Biles returned to competition in 2023 and won three gold medals at the Paris Olympics the following year. Both halves of that sequence matter. The first made the second possible.
