Caster Semenya has lodged an appeal with the Court of Arbitration for Sport to challenge the IAAF's ruling on hyperandrogenism.

In April, Athletics' governing body announced new regulations affecting women with higher than normal levels of testosterone who compete in track events ranging from the 400 metres up to a mile.

Two-time Olympic gold medallist Semenya is among the athletes who will still be eligible to compete, but only provided testosterone levels are within set limits for a continuous period of at least six months.

The rule will come into force on November 1, but CAS confirmed on Tuesday that Semenya has registered a request to "declare such regulations unlawful" and stop its introduction.