Semenya charges to fastest 800m ever run in U.S.

STANFORD, California (Reuters) – Caster Semenya charged to the fastest 800 meters ever run in the United States at the Prefontaine Classic on Sunday as the South African continued to challenge new IAAF testosterone rules that could affect her career.

The double Olympic champion triumphantly finished the two-lap race in one minute, 55.70 seconds on a sunny afternoon at Stanford University. She held the previous U.S. best of 1:55.92, set last year in Eugene, Oregon.

American record holder Ajee Wilson came second in 1:58.36 as Semenya won her 31st consecutive final at the distance. She last lost an 800 meters final in Berlin on Sept. 6, 2015.

The competition was the South African’s first at her favorite distance since the Swiss Federal Tribunal ruled she did not have to adhere to the IAAF regulations until her appeal against a Court of Arbitration for Sport (CAS) ruling in favor of the new rules is decided.

Under the regulations, XY chromosome athletes with differences in sexual development (DSDs), like Semenya, must take medication to lower their natural testosterone levels if they are to compete at distances from 400m to a mile.

Semenya, 28, has refused to take the medication, saying: “I am a woman and I am a world-class athlete. The IAAF (International Association of Athletics Federations) will not drug me or stop me from being who I am,.”

The IAAF has said the regulations are necessary to preserve the integrity of female athletics in the restricted events.

Testosterone is a hormone that increases muscle mass, strength and hemoglobin and the IAAF said its own research showed it gave a significant endurance advantage to athletes in the 400 meters to mile range.

Earlier, Kenya’s world record holder Beatrice Chepkoech cruised to the fifth fastest time in the women’s 3,000 meters steeplechase, 8:55.58.

American Rai Benjamin showed he was ready to challenge for his first world 400 meter hurdles title when he ran 47.16 seconds – the ninth fastest of all time.