They burst onto the sports scene together, seven summers ago.

In their own ways, the Bird’s Nest and Usain Bolt redefined what was possible at the Olympics.

A stadium could be a star. The $450 million, 91,000-seat Bird’s Nest, latticed with steel beams, was the centerpiece of the Beijing Games, and it shined in a spectacular opening ceremony that featured a skywalking gymnast, fireworks and a cast and crew of more than 15,000.

Then came Bolt.

The 6-foot-5 Jamaican raced in three events. Won gold medals and set world records in all. He returns to the Bird’s Nest next Saturday for the start of world championships — helping the largely underused stadium brush off some cobwebs while possibly shedding some positive light on a sport that has been dogged, yet again, by ugly news on the doping front.

Since departing the Bird’s Nest the night of Aug. 22, 2008, Bolt has improved on his records, which stand at 9.58 seconds for the 100, 19.19 for the 200 and 36.84 for the 4×100 relay. He has won three more Olympic golds, and dealt, on and off, with a variety of injuries, new challengers and even a couple of car accidents.

Through it all, he has remained the man to beat with the next Olympics less than a year away. But he will turn 30 on day of the closing ceremony in Rio de Janeiro. It doesn’t all come so easily anymore.

Fewer parties. More vegetables.

“I have to be real careful, have to be aware of everything around me to make sure I’m on point,” said Bolt, who made Chicken McNuggets his dinner, and lunch, of choice at the 2008 Olympics.

He will use his next appearance at the stadium where he became a true, bona fide superstar as something between a tune-up for next year and the real thing. This is, after all, the biggest event he’ll race in until he gets to Brazil.

But this summer, Bolt has been beset by leg injuries, not running his best, rounding into form. He ran his top time of the season, 9.87 seconds, July 24 at a meet in London — at the other Olympic stadium where he has ruled. He called it an appearance that was “all about getting race ready.”

How ready he is in Beijing this time around is almost beside the point. He will be the headliner, and will provide a respite for his sport when he appears at the nine-day meet, where he’s scheduled to run in the 100, 200 and 4×100 relay — the usual. The integrity of track which has been battered this year under a doping cloud as thick and persistent as the haze that hovers over China’s capital.

In June, The Associated Press learned the U.S. Anti-Doping Agency launched an investigation into allegations that famed track coach Alberto Salazar encouraged Olympic silver medalist Galen Rupp and others in his stable of elite runners to skirt anti-doping rules.

More recently, reports from German broadcaster ARD and The Sunday Times newspaper in Britain examined results of 12,000 blood tests involving 5,000 athletes from 2001 to 2012. The reports concluded that 146 Olympic and world-championship medals in middle- and long-distance races — including 55 gold — were won by athletes who have recorded suspicious tests.

The IAAF has responded with a detailed denunciation of the reports and an equally robust defense of its own anti-doping measures, backed by none other than Sebastian Coe, the middle-distance great who is running against pole vaulting icon Sergei Bubka for president of the IAAF before the start of world championships.

The winner will oversee a sport with only one true, worldwide star. It’s Bolt, who has steered clear of all the doping troubles, even as sanctions have been leveled against luminaries in his own track-crazy country, including former world record holder Asafa Powell and Olympic relay gold medalist Sherone Simpson.

“It definitely does upset me,” Bolt said of the steady stream of doping stories that tarnish his sport. “Because then it starts with pointing fingers again and speculating. It doesn’t help the sport in any way, so at times, I do get frustrated and angry.”

At the last pre-Olympic world championships, in South Korea, Bolt jumped the gun in the final of the 100 meters, setting the stage for his own training partner and countryman, Yohan Blake, to win the title and set himself up as Bolt’s main challenger heading into the London Games.

Blake beat Bolt at their Olympic trials, but the Olympics themselves were no contest. Bolt won every race handily. This year, American Justin Gatlin is getting most of the pub as Bolt’s main rival, in part because he’s been on a steady competition schedule, while Bolt has spent most of his time training. Gatlin has the four best 100 times this year, topped by a 9.74 in May.

Both men have been asked if Gatlin should be considered the favorite in the final, set for next Sunday.

Gatlin: “I don’t look at myself as being the favorite. I look at myself as one of the pieces to make the race very exciting.”

Bolt: “I know he has been doing good this season. But I am not worried. When the championship comes, if anyone knows anything about me, I will show up.”