Usain Bolt
Bolt is still expected to compete in Rio after applying for a medical exemption.Getty Images

Usain Bolt, the six-time Olympic sprint champion, has suffered a hamstring tear to throw into doubt his participation at Rio 2016 just six weeks before the Games. The 29-year-old picked up the blow during Jamaica's Olympic trials in Kingston and has been diagnosed with a grade one tear.

Bolt was initially hurt during round one of the 100m, before withdrawing after winning the resulting semi-final. Though he was unable to competing in the final - won by London 2012 silver medalist Yohan Blake - Jamaica's selection policy allows for a medical exemption which should allow Bolt to compete.

However, Bolt faces a race against time to be fit in time to prove his fitness ahead of the start of the athletics competition in Rio, which starts on 12 August. The Games themselves begin on 5 August. The two-time 100m, 200m and 4x100m Olympic champion aims to compete in London, scene of his triple triumph four years ago, at the annual Anniversary Games in July before travelling to Brazil.

"After feeling discomfort in my hamstring after the first round last night and then again in the semi-final tonight I was examined by the chief doctor of the national championships and diagnosed with a grade one tear," the world record holder said on Twitter. "I have submitted a medical exemption to be excused from the remainder of the National Championships. I will seek treatment immediately and hope to show fitness at the London Anniversary Games on 22 July to earn selection for the Olympic Games in Rio."