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.


Jamaica's Usain Bolt falls to the track in the men's 4x100-metre relay final. (Matthias/Getty Images)

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-metre relay at world championships.

Usain Bolt bids farewell to track career in worst way possible1:00

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-metre 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.

Great Britain inches out victory on home soil in men's 4x100m relay8:05

"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."

Canada finishes 6th

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.

IAAF World Championships Day 9: Evening Session1:59:59

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.

Canada finished sixth without its top sprinter Andre De Grasse, who missed worlds with a hamstring injury. Gavin Smellie, Aaron Brown, Brendon Rodney and Mobolade Ajomale finished in 38.59. 

Canadian men's relay team on 6th place finish: 'We just gotta make the best of it and learn from every experience'0:47

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-metre mark, which is when he felt the pain in his leg and went tumbling.

'I think this is crazy'

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.

Yohan Blake: 'I'm distraught, to see a true legend go out like that'1:12

"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.

Americans sprint to gold in women's 4x100m relay4:46

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.

Farah falls in final race

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.

Muktar Edris takes men's 5000m gold11:18

Canada's Mohammed Ahmed stuck with a lead group for all but the final lap. The 26-year-old from St. Catharines Ont., who was fourth in the event in Rio, finished in 13 minutes 35.43 seconds.

"I felt pretty good, I was gathering myself for that last 400 metres, I was in position with 400 metres to go, and I just didn't have enough," Ahmed said. "They just hit another top gear that I didn't have, and I couldn't hang."

Ahmed, who was born in Mogadishu, Somalia, had raced to eighth in the 10,000 metres last week. Both finishes are Canadian bests. But not good enough for Ahmed.

"I have aspirations to be on the podium, winning it," he said. "That's the frustrating part, is not being close enough."

Toronto's Justyn Knight finished in 13:39.15, and the young runner was one of the few Canadians actually smiling on Saturday, calling the race a "huge learning experience."

Knight appreciated the historical significance of being in Farah's last world race.

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.

With files from CBC Sports