London: Usain Bolt suffered a injury midway into his anchor leg of the men's 4x100 metres relay and pulled out of the last race of career at the World Athletics Championships here on Saturday. Bolt, who suffered his first 100 metre defeat in nine years on August 5, apparently had a pulled leg only 30 metres into the race. He limped to the finish line in agony. Britain won the gold in 37.47 seconds, the US won silver in 37.52 and Japan was third in 38.04, Xinhua reported. China, silver medalist two years ago, was fourth in 38.34.