Caster Semenya wins the 800m womens final during Day 2 of the 2016 ASA SA Senior Championships at Coetzenburg Stadium, Stellenbosch on 16 April 2016 ©Chris Ricco/BackpagePix

Star athlete Caster Semenya could be heading for another storm as she chases a possible double gold at the Rio Olympics in August, and it seems there is little anyone can do to prevent the controversy, least of all the athlete.

This week at the African Athletics Championships in Durban, Semenya has shown she has returned to world-beating form with an easy victory in the 1 500m on Friday, with a personal best of 4.01.99. On Saturday she followed that with a win in the 800m heats and will run that final on Sunday.

Read: Brilliant Caster just misses Zola’s record

But while Cape Town’s Ross Tucker, an internationally respected sports scientist, is confident Semenya will cruise to gold in the women’s 800m in Rio, possibly with a world record time, he also predicts she could face “a few probing questions”.

There are already people hinting Semenya is not competing on a level playing field.

It seems a recent Court of Arbitration for Sport (CAS) ruling could have given her a loophole that is allowing her to once again dominate the middle distance events. It is no secret Semenya has been through this before, in the years building up to London 2012. That was after she burst on to the athletics scene with some phenomenal times as a junior.

That unseemly and well-publicised controversy seemed to have been quelled thanks to a ruling by the IAAF that prevented women from competing if their testosterone levels were above 10nmol/l (nanomoles per litre).

That upper limit “was set up based on a study done on all the women competing in the World Championships in 2011 and 2013”, Tucker wrote on his website The Science of Sport.

Semenya’s performances, under this policy of reducing testosterone, dropped off in a predictable manner. Having run the 800m in 1:55.45 at 18, she never got close again.

She did however win Olympic silver in London, behind Mariya Savinova, who was one of the Russian athletes caught in the doping scandal which has led to that country’s athletics team being excluded from Rio. Semenya also won a World Championship silver in 2011.

“Last year, she failed to advance beyond the semi-finals in Beijing, and hadn’t even made the qualification mark for the preceding year’s Commonwealth Games. Two minutes had become a significant barrier, when the world record had been plausible at 18.

“Now, she is untouchable. People will (and have) said it’s down to her focused training, recovery from injury and so forth, but I’m not buying that,” Tucker said.

Instead, he believed the change was more likely the result of the restoration of Semenya’s natural testosterone levels. And that was thanks to the CAS ruling last year that the IAAF could no longer enforce the upper limit of testosterone.

Tucker labelled the CAS ruling the “stupidest, most bemusing legal/scientific decision ever made”. But he conceded the issue was complex.

Just over a month ago Semenya won the 800m and the 1 500m, as well as the 400m, on the same day at the South African Championships in Stellenbosch. In 2016 she has now run the best 800m time for the year and four of the top 10 times.

These championship runs point to potential gold for Semenya when she gets to Rio, and there is strong talk of a rare 1 500m/800m double.

Weekend Argus