David Rudisha ,Kenyan Runner Breaks World record to win 800m race in Olympics 2012..Usain Bolt retained his title and won 200m race this time too.Rudisha won the 800m race in 1minute 40.91seconds thus setting a new world record which is very tough to break. Bolt won the race in 19.32 seconds and was the 4th fastest run in the world. And the coincidence is that it matched the Gold medal record of 1996 Atlanta olympics. Bolt tightened up his back during the race otherwise he would have broken his own record of 19.19 seconds. 4 out of 6 fastest run in the world are All By Usain Bolt.