Usain Bolt was ramping into warp speed when suddenly, stunningly, the sprint turned into a somersault.

Fifteen steps into the final homestretch of his final race, something gave in his left hamstring. The World's Fastest Man skittered to a stop - hopping, skipping, jumping, then finally dropping to the ground and tumbling forward before coming to a rest.

While the winning team from Britain crossed the finish line, Bolt was writhing on the track, where he eventually wound up chest down with his face pressed into Lane 5. He was certainly every bit as stunned as any of the 60,000-plus who packed the stadium Saturday, or the millions watching one of the world's most entertaining showmen make his final curtain call in the 4x100-meter relay at world championships.

There was no celebration. No gold, no silver, not even a consolation bronze, the likes of which Bolt received a week earlier in his final 100-meter race.

Jamaica closed the night with "DNF" by its name: Did Not Finish. Dead last. Bolt was helped into a wheelchair, but eventually got to his feet and, assisted by his teammates, limped gingerly across the finish line. He gave a few waves to the crowd, then left for the trainer's room, and with that, presumably left track and field forever.

"Injuries are part of our sport and, always, of course, it's sad to see," said Wallace Spearmon, the American sprinter who has been close with Bolt for years and was on hand helping the U.S. team. "So, yeah, it's tragic."

The Jamaican team doctor, Kevin Jones, diagnosed the injury that brought a strange end to Bolt's career as, simply, a cramp in the champion's left hamstring.

"But a lot of pain is from disappointment from losing the race," Jones said. "The last three weeks have been hard for him, you know. We hope for the best for him."

Watching track's No. 1 sprinter and celebrity dropping to the ground was nothing short of jaw-dropping - so much so that the fact that Britain won the race, outrunning a United States team that, somewhat amazingly, didn't drop the baton, almost seemed like an afterthought.

Nethaneel Mitchell-Blake held off U.S. anchorman Christian Coleman down the stretch and the Brits won their first-ever world title in the 4x100 in 37.47 seconds.

When Bolt took the baton from Yohan Blake for his final homestretch, he was in third place, but that was no cause for concern. In virtually each of the seven relay golds he's won at the Olympics and world championships, Bolt has reeled in the competition down the stretch and won going away, much the same as all his 100 victories have played out.

Five years and one day earlier, on the very same track, Bolt helped Jamaica set the world record. That run of 36.84 seconds earned Bolt the sixth of nine Olympic victories.

But last week in the 100, Bolt's extra gear was not enough either to catch Coleman, who finished second, or to hold off Justin Gatlin, the oft-booed American who came from behind to finish first.

Could he have caught his relay competition in this one? Nobody will ever know. Bolt was gaining no ground at the 30-meter mark, which is when he felt the pain in his leg and went tumbling.

Afterward, there was plenty of second-guessing to be done. Most of it came at the expense of the IAAF, which made the sprinters wait about 40 minutes from the time they were summoned from the warm-up room to the time the starting gun went off.

"I think this is crazy," Blake said. "Forty minutes. Waiting. Warming up. Waiting. Warming up. It just should not happen. To have your champion go out like that. It's crazy."
Said Gatlin, who remains insistent that Bolt will be back someday: "We lost all of our heat, all of our sweat, and we went out there cold."

Part of the wait was for the U.S. women's relay team to finish its victory celebration. Tori Bowie anchored the win and, with one day left in the meet, is the only athlete to win two gold medals in London. Also, a medal ceremony was held for Russian high jump champion Mariya Lasitskene, who is competing as a neutral athlete because of the doping crisis in her country and got to listen not to her own anthem, but to the IAAF's theme song, as she stood on the podium.

Other winners included Kevin Mayer of France in the decathlon and Johannes Vetter, whose victory in the javelin throw gave Germany its first gold of the championships.
In the undercard to the relays, Muktar Edris held off Mo Farah of Britain in the 5,000. With help of his Ethiopian teammates, Edris won a tactical cat-and-mouse race and denied Farah his fifth straight long-distance double, counting world championships and Olympics.

It was a fun race to watch.
But nobody steals the show the way Bolt does.
As if to prove that point one last time, he did it again - this time without even finishing the race.

AP