Usain Bolt fails to finish final race of his career, crumpling to track during 400 relay
Usain Bolt ended his stellar career in excruciating pain.
The Jamaican great crumpled to the track with a left-leg injury as he was chasing a final gold medal for the Jamaican 400-meter relay team on Saturday at the world championships.
Having to make up lots of ground on the anchor leg, Bolt...