Usain Bolt's balky hamstring is healed. So, too, are any other nagging injuries that have been holding him back in recent months.

The fastest man on the planet feels completely healthy heading into the world championships in Moscow next week.

His sport can't say the same thing.

Track has a dark cloud hanging over it after some of the best sprinters recently tested positive for banned substances, a list that includes Tyson Gay, Asafa Powell, Veronica Campbell-Brown and Sherone Simpson.

These days, Bolt's task may not be to just win titles, but to win in spectacular fashion, which could be one way to change the conversation his sport is currently mired in.

The Jamaican sensation insists there's no added pressure and that once he coils his 6-foot-5 frame into the starting blocks, his focus is only on one thing — the finish line.

"I can't let those scandals cloud my job," Bolt wrote in an email to The Associated Press. "I see running as a gift given to me to inspire people."

He certainly puts on an entertaining show, preening and prancing before a race and then dominating once the gun goes off. As is often the case, Bolt will be the star attraction in Moscow even in a depleted field.

"I'd be lying if I said we have the normal anticipation and hype going into the worlds," said Ato Boldon, a four-time Olympic medallist and NBC sprint analyst. "The fans, on social media, they're like, 'I'll watch, but it's not like I can see Gay vs. Bolt. It's not what it could've been."'

Maybe not. But there's always the prospect of what numbers Bolt can put on the board, because a world record is always possible when he steps on the track.

Bolt's proud sprinting country has fallen under scrutiny after Powell and Simpson tested positive for a banned stimulant at their national championships in June. Before that, Campbell-Brown had a positive test for a banned diuretic at a meet on the island in May.

Obviously, that doesn't reflect well on his nation.

"Of course there is an impact, but I have to remain focused on making my country proud," said Bolt, who will be featured as a character in the video game "Temple Run 2" from Imangi Studios and given special abilities that will make him run — as if he needs it — even faster. "Right now, my only focus is winning three gold medals at worlds."

Bolt has been virtually unbeatable since his rise to prominence leading up to the 2008 Beijing Olympics. He's won six Olympic titles and shattered world records in the 100 (his current mark is 9.58 seconds) and the 200 (19.19).

Both the current records were set in 2009, the year after Beijing, which kept track in the headlines for the right reasons.

In 2013, the year after the London Olympics, Bolt is essentially racing against the clock again. His main competition is gone. Yohan Blake, who famously beat him in the 100 and 200 at Olympic trials last year and who won worlds in 2011 when Bolt false-started, is out with a hamstring injury. Gay will be a no-show after relinquishing his spots when he failed drug tests this summer.

Not that Bolt is too concerned with whomever is stepping into the blocks next to him — never has been, really.

"Having the best athletes in the world in the finals is always good for the sport," Bolt said. "However, I have to focus on what I have to do and that's winning three gold medals at worlds."

The main person in his way figures to be Justin Gatlin, the American who edged him at a meet in Rome nearly two months ago. Asked if Gatlin is on his mind, Bolt responded: "I never focus on any single athlete."

Gatlin certainly is concentrating on Bolt, though. Gatlin is eager for a rematch on an even grander stage and with even more fans watching, just to validate his success that day in Rome against a sprinter who rarely gets beat.

"I have mutual respect for him," said Gatlin, who added a bronze medal in London to the gold he captured at the 2004 Athens Games. "I'm not scared of anything. I have to (compete) anyway, so why do it with fear in my heart?

"He knows that I'm going to come with my 'A' and he's going to come with his 'A' game, because we're both the kind of people that turn it on when the lights come on in a competition."