Double Olympic champion Caster Semenya has hinted she could walk away from athletics.
The South African runner lost an appeal yesterday against new rules on testosterone levels in female athletes.
Semenya will now have to take medication to reduce her naturally high levels of testosterone.
She posted on Twitter saying, "knowing when to walk away is wisdom.. be able to is courage."
Meanwhile, the International Association of Athletics Federation's president, Lord Sebastian Coe, stands by the ruling.