Gold medalist Usain Bolt of Jamaica celebrates after competing in men's 100m final contest, at London 2012 Olympic Games in London, Britain, on August 5, 2012. Usain Bolt of Jamaica won gold medal with a new Olympic record of 9.63. (Xinhua/Li Ga)

Usain Bolt of Jamaica takes part in men’s 100m final contest, at London 2012 Olympic Games in London, Britain, on August 5, 2012. Usain Bolt of Jamaica won gold medal. (Xinhua/Li Gang)

Gold medalist Usain Bolt of Jamaica celebrates after competing in men's 100m final contest, at London 2012 Olympic Games in London, Britain, on August 5, 2012. Usain Bolt of Jamaica won gold medal with a new Olympic record of 9.63. (Xinhua/Li Ga)

Usain Bolt of Jamaica takes part in men’s 100m final contest, at London 2012 Olympic Games in London, Britain, on August 5, 2012. Usain Bolt of Jamaica won gold medal with a new Olympic record of 9.63. (Xinhua/Yang lei)

Gold medalist Usain Bolt of Jamaica celebrates after competing in men's 100m final contest, at London 2012 Olympic Games in London, Britain, on August 5, 2012. Usain Bolt of Jamaica won gold medal with a new Olympic record of 9.63. (Xinhua/Guo Yong)

Gold medalist Usain Bolt of Jamaica celebrates after competing in men's 100m final contest, at London 2012 Olympic Games in London, Britain, on August 5, 2012. Usain Bolt of Jamaica won gold medal with a new Olympic record of 9.63. (Xinhua/Liao Yujie)