大象传媒

Earlier in the Games, gymnast Simone Biles dropped out of the all-around, floor exercise, vault and asymmetric bars finals, citing how the 'twisties' had impacted on her mental health and skills, and made it unsafe for her to perform. The 'twisties' is thought to be when an athlete loses their spatial awareness - a loss of orientation that could lead to serious injury.

But what is actually happening to cause these? Graham Easton, a UK family doctor, explains how they can also affect golfers' performance (where spasms are known as the 'yips'). He says that there is no definitive answer to what causes the condition, but a disconnect between mind and body, and stress, may play a part.

'It seems an athlete's mind and body lose connection and their muscle memory fails. It's incredibly dangerous if your position in the air is something you can't rely on.'

Photo: Simone Biles in the Women's Balance Beam Final at the Tokyo Olympics Credit: Mike Egerton/PA Wire