The governing body of world athletics welcomed a landmark study showing high testosterone helped women run better, saying it justified their decision to bar Olympic champion Caster Semenya from key races.

In a study in the British Journal of Sports Medicine, Swedish researchers found women with higher testostorone could run longer and had more lean muscle mass.

The International Association of Athletics Federations (IAAF) — which governs track and field — embraced the study as proof  it had done the right thing in barring South Africa’s Semenya for high testosterone levels, a primarily male hormone.

“The IAAF introduced a testosterone limit for the female category for the sole purpose of maintaining fair and meaningful competition for women,” it said in a statement on Wednesday.

The study, it added, “reinforces our evidence-based conclusion that high testostorone levels give female athletes a significant advantage in some athletic events.”

Medical professionals had believed that testosterone-fuelled strength and endurance in men, but the benefits for female athletes were previously unclear.

No longer, according to the researchers from Karolinska Institutet in Sweden, and other institutions.

They were quoted as saying ……….”Our study supports a causal effect of testostorone on physical performance, as measured by running time to exhaustion, in young healthy women,” said the researchers, whose study was released on Tuesday.

There was no immediate reaction from Semenya, whose barring from the 800-metre race in September’s World Athletics Championship sparked controversy in and outside of sport.

Her case became a test of where sports authorities draw the line when it comes to athletes whose bodies fall outside standard ranges or who change gender then seek to compete.