More than 500 gymnasts descend on Qatar this week for the Artistic Gymnastics World Championships, but most eyes will be on the sport's biggest star, the USA's Simone Biles.

The quadruple Olympic gold medallist will make her return to frontline international competition after taking a year off following her triumphant showing in Rio in 2016.

Her self-enforced absence from the sport — she returned to competition in July — has only served to increase expectation for the 10-day championships, the first ever to be held in the Middle East.

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Biles, 21, will become the first woman in history to win four world all-around titles if she takes gold in that discipline in Doha. Her main competition is likely to come from teenage compatriot Morgan Hurd, the 2017 champion.

Biles could also take gold in the vault, floor exercise and beam competitions. She is a member of an exceptionally strong US team looking for its fourth consecutive straight world title, but its preparations have been anything, but smooth.

Since Biles performed in the 2016 Olympics, it has been a tumultuous time for US gymnastics. In July 2017, former team doctor Larry Nassar was sentenced to up to 175 years in prison on charges of sexual assault.

In January this year, Biles revealed herself to be one of his victims. In the fallout, US gymnastics chief executive Kerry Perry resigned because of her handling of the scandal.

And, just this month, interim CEO Mary Bono resigned after just five error-strewn days in charge after posting a critical tweet alluding to Nike and its support for NFL star Colin Kaepernick, who triggered a political firestorm after kneeling during the US national anthem to protest racial injustice.

Biles was hugely critical of Bono, taking to Twitter to say “it's not like we needed a smarter USA gymnastics president or any sponsors or anything”.

Doha presents the US with a chance to draw a line under the chaos, which has engulfed the team in recent years.


Doubts as Uchimura returns

Another notable return is that of Japan's Kohei Uchimura, a six-time all-around world champion. The 29-year-old came back to competition earlier this year after suffering an injury at last year's championships in Montreal.

His preparations though were put in doubt after it was announced earlier this week he had pulled out of the individual all-around competition because of ongoing problems with his right ankle. His injury in Canada last year, led to China's Xiao Ruoteng taking the title.

Another returnee is Russia's Aliya Mustafina, a double Olympic champion on the uneven bars, who missed the 2017 season after giving birth to a daughter.

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Another mother, Uzbekistan's Oksana Chusovitana, will compete at her 16th world championships. The 43-year-old has the chance of a medal on the vault, the apparatus on which she won a silver medal back in 1991.

Others who are likely to be competing for medals include Sanne Wevers of the Netherlands and Japan's Mai Murakami in the women's events.

Gold medal winners at the Rio Olympics, Kenzo Shirai of Japan and Britain's Max Whitlock are also expected to feature prominently in the men's disciplines. As well as medals, Doha will be the first opportunity for competitors to qualify for the 2020 Olympics.

The event, which takes place at the Aspire Dome, next door to the Khalifa Stadium, which will host the 2019 World Athletics Championships, begins on October 25.