Semenya due to run in Doha amid uncertainty over her future

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Caster Semenya is due to compete in the Diamond League on Friday despite hinting at retirement after losing her case against the IAAF.

The Court of Arbitration for Sport (CAS) on Wednesday dismissed the two-time 800 metre Olympic champion's appeal against the IAAF's testosterone regulations in a landmark legal case.

Semenya challenged a new ruling which will require her to reduce her testosterone levels by taking medication in order to compete in distances up to a mile.

The regulations will come into force next Wednesday, so South African Semenya is still able to run in Doha two days after a verdict which put her career in doubt.

Semenya vowed that the CAS decision will not hold her back and she will "rise above and continue to inspire young women and athletes in South Africa and around the world".

Yet the 28-year-old prompted speculation over her future with a social media post on Thursday.

She tweeted: "Knowing when to walk away is wisdom. Being able to is courage. Walking away with your head held high is dignity."