Caster Semenya has posted two cryptic tweets on her Twitter account that appear to hint at retirement from athletics, following the Court of Arbitration for Sport’s ruling in favour of the IAAF’s testosterone restrictions in female runners.

Cas ruled in favour of the governing body on Wednesday that will result in Semenya being required to take testosterone-lowering medication in order to compete in the future.

The two-time 800m Olympic champion fought against the IAAF’s ruling on the basis that it discriminates against athletes with Differences in Sexual Development (DSD) such as herself, but saw the appeal rejected even though Cas accepted it will discriminate against them because “such discrimination is a necessary, reasonable and proportionate means of achieving the IAAF’s aim of preserving the integrity of female athletics in the restricted events”.

The South African has now put out two cryptic Twitter messages ahead of her scheduled appearance in Doha on Friday, where she is due to run in the 800m at the Diamond League meet – the last race in which she will be allowed to compete without taking medication.

The first, which featured a shrugging emoji, added: “Knowing when to walk away is wisdom. Being able to is courage. Walking away with your head held high is dignity.”

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After receiving a stream of messages pleading for her not to retire, Semenya then posted a second tweet which read: “That’s me and will always be. I’m finished.”

Semenya was added to the 800m start list in Doha on Thursday, having initially been left off while awaiting her appeal decision.

Following the announcement, Athletics South Africa issued a statement to say the governing body was “reeling in shock”, and added that the ruling “goes to lengths to justify (discrimination)”.

Semenya also received support from Indian sprinter Dutee Chand, who won a legal battle over her own elevated levels of male sex hormones.

“I feel sad for her – she has been made to suffer like me,” said Chand, who was cleared to compete last year after winning a court appeal against IAAF regulations.