Johannesburg - The difference between a Caster Semenya whose testosterone levels are suppressed with medication and a Caster Semenya who runs with what mother nature gave her is between six and seven seconds over in an 800m race.

It follows that if the International Association of Athletics Federations (IAAF) succeeds in November in again instituting a restriction on the testosterone levels of female athletes, it would cast a dark cloud over the South African star’s career, said sports psychologist Ross Tucker.

Last month, the IAAF’s council decided to again institute a limit on the testosterone levels of women who run in certain events. The limit applied between 2011 and 2015.

Only four items were singled out – the 400m, the 400m hurdles, the 800m and the 1 500m races.

Despite the fact that the greatest difference in performance was measured in the hammer throw and the pole vault, these events were not included on the list of those the IAAF wants maximum testosterone level limits for. The 1 500m, for which no advantage could be found in athletes with higher testosterone levels, is, however, on the list.

This week, Semenya won gold at the Commonwealth Games in the 800m and the 1 500m, breaking Commonwealth records in both races.

Tucker said the new policy could well be specifically targeting Semenya.

“The IAAF did something strange. They drop the hammer and pole vault and add in the 1 500m. Why? There’s no reason to do that. If the premise driving the policy is that high testosterone gives an advantage, and your policy is aimed at ensuring fairness, then you can apply it where you have evidence,” he said.

“They don’t have evidence in the 1 500m. They do have evidence in the hammer and pole vault.”

Tucker said this made the policy look at least partly arbitrary.

“And an arbitrary rule is a poor rule. Perhaps they will explain their reasoning for this, or maybe it will come out if it is discussed as part of a future arbitration proceeding. But, for now, it looks very arbitrary and this is the reason people are saying that this rule is targeted specifically at Semenya, because she, coincidentally or not, runs in those events.”

Tucker is not convinced that the IAAF’s new policy will get the green light from the Court of Arbitration for Sport (CAS).

The new IAAF policy follows studies, which it funded, showing that female athletes with higher testosterone levels enjoy an advantage in five events – the 400m, the 400m hurdles, the 800m, hammer throw and the pole vault.

“There are two major problems with the new policy. Firstly, you must remember that the CAS, when it overturned the previous policy on hyperandrogenism [a high level of male sex hormones in women] in 2015, told the IAAF to come back with evidence that shows a significant difference between the performance of women with high testosterone levels and those with lower levels.

“What the IAAF study found was a difference of between 2% and 5%. If you take into account that the physiological difference between men and women is accepted to be about 10%, it’s likely that the CAS will say that differences recorded in the IAAF study are not high enough,” Tucker said.

“Secondly, there is the fact that the study found differences in five events, but the IAAF only wants to institute restrictions in four. Of those, one – the 1 500m – is not among the original five, while there won’t be new rules in two of the five. Why are the hammer throw and pole vault excluded from the new policy? It just doesn’t look right.”

Tucker said the study, according to which the new regulations were determined, was less than clear. Female athletes’ testosterone levels were measured at the IAAF World Championships in 2011 and 2013, and they were divided into three groups – high, middle and low testosterone levels. After that, the results of the athletes in these groups were compared to determine the differences.

“We can talk about the science of the study for hours, but, in my opinion, it’s impossible to do an entirely accurate study because it can never be 100% ethical,” said Tucker.

“The best method would involve measuring the testosterone levels of some women without telling them it is being done. And that is not ethical.”

The IAAF’s findings have been handed to the CAS for a decision. In the meantime, Semenya this week went on doing what she does best – winning medals.

“If the new policy is instituted, Caster will not be banned from athletics, she will only be forced to lower her testosterone levels. But that will have an impact on her,” said Tucker. – Additional reporting by Silver Sibiya