Caster Semenya has responded to losing her legal challenge against new gender rules by entering the 800 metres in Doha Diamond League meeting, while she hinted at ending her career in several cryptic tweets.

Semenya, the double Olympic champion at the distance, was added to the 800m start list yesterday morning, a day after her appeal against a new rule regulating testosterone levels for women athletes was rejected by the Court for Arbitration of Sport (CAS).