South African middle distance star Caster Semenya has hinted at retirement a day after losing her case against track and field’s governing body the I-Double A-F.

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

Semenya who will compete in the Doha Diamond League tomorrow, 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 28-year-old prompted speculation over her future with a social media post this morning when she tweeted ……….quote “knowing when to walk away is wisdom. Being able to is courage. Walking away with your head held high is dignity….end of quote”