Caster Semenya trains for the World Championships in Daegu, Soth Korea, on Tuesday. Since being cleared to compete as a woman following a dispute over her gender, questions have arisen over whether she is in shape. Max Rossi / Reuters

Caster Semenya sprinted to the women's world 800m crown two years ago and quickly found herself entangled in a maelstrom of seedy allegations that saw her cast into limbo because of doubts over her true gender.

But the South African returns to action at the World Athletics Championships in Daegu, South Korea, cleared to run by the sport's world governing body, the IAAF, and largely accepted by her peers.

The 20-year-old Semenya, who clocked a jaw-dropping personal best of 1:55.45 in storming to victory at the 2009 Berlin worlds, was stood down soon after and remained on the sidelines until July 2010.

The Pretoria University student was revealed to be a hermaphrodite after the leaking of test results following her 800m win in Berlin.

The incident generated anger from the South African public and government, who rallied behind the athlete, and sparked a major gender review by the IAAF, which in April introduced new eligibility rules for women athletes with excessive male hormones, a medical condition known as hyperandrogenism.

Semenya was cleared to compete as a woman in July 2010, nearly a year after she shot to prominence.

"It wasn't easy to come back after the IAAF ban, but this was the goal," Semenya admitted.

She will face a tough outing at Daegu, up against the likes of former world champion and Olympic silver medallist Janeth Jepkosgei of Kenya, world indoor and European outdoor champion Mariya Savinova of Russia and Britain's Jenny Meadows, who won world championship bronze behind Semenya and Jepkosgei in 2009.

"Defending a world title is not easy," she said last month. "The 800m is a bit tricky. It can be a fast race or a slow one, and it depends on how strong you are mentally.

"Personally, I think I have a chance to defend my title but somebody else will want to win. Everybody in the final can get first place.

"I'll be happy if I get back on the podium, it doesn't matter if it's silver or bronze, as long as I'm back there."

However, doubts persist over Semenya's fitness after manging sub-2min times just twice in 13 outings this season and also having pulled out of the recent World University Games in China with a back injury.

With the sometimes physical nature of the 800m, Semenya will have to be on the ball to safely negotiate what will likely be three races in four days, culminating in the final on September 4, the last day of competition.

"Semenya remains disciplined, focused and excited about representing South Africa at the world championships in South Korea," her management spokesman said in a bid to dispel local media doubts of her participation.

"In true championship style, she has embarked upon a stringent training programme in preparation for the world event.

"Currently she is doing light, final training at the home base in Pretoria, South Africa. We wish to dismiss any rumours that there is trouble in her camp.

"These rumours are seen as attempts to discourage and distract her from her glorious quest for gold."