Two-time Olympic champion Caster Semenya lost her long legal battle on Tuesday against World Athletics rules that ban female runners with naturally high testosterone levels.

Switzerland's supreme court said its judges dismissed Semenya's appeal against a Court of Arbitration for Sport ruling last year that upheld the rules drafted by track's governing body affecting female runners with differences of sex development (DSD).

The ruling means Semenya cannot defend her Olympic 800-meter title at the Tokyo Games next year－or compete at any top meets in distances from 400m to the mile－unless she agrees to lower her testosterone level through medication or surgery.

The 29-year-old South African repeatedly said she will not do that and reiterated her stance in a statement through her lawyers Tuesday.