Olympic champ Sun Yang failed doping test in May

Gold medallist Sun Yang of China reacts after winning the men's 400m freestyle final swimming competition at the Munhak Park Tae-hwan Aquatics Center during the 17th Asian Games in Incheon September 23, 2014. [Photo/Agencies]

Swimmers receive an automatic disqualification for false starts, but Sun was allowed to retain his spot because the official starter had told the swimmers to stand up from their crouching position because of the crowd noise.

Sun's nerves were frayed but he responded by slashing more than three seconds off his own world record to easily win gold.

With his victory came money - and plenty of it. He was showered with sponsorships and endorsements, but the flood of cash came at a price.

In early 2013 he was suspended from engaging in commercial activities after missing training and breaching team rules, but he seemed unfazed about it.

Later that year he was ordered to spend a week in detention after crashing a car he had driven without a licence.

China's swimming authorities slapped a blanket suspension on him, banning him from all training and competition, before he made his return at this year's Chinese National Championships, which doubled as the trials for the Asian Games.

Despite being below his best, he still managed to win the 200, 400 and 1,500m titles and remains as confident and rebellious as ever.

Sun Yang beat Japanese Kosuke Hagino to claim the men's 400m freestyle gold medal at the Munhak Park Tae-hwan Aquatics Center during the 17th Asian Games in Incheon September 23, saying his victory killed Japanese morale in the Asian Games swim competition.