Berlin (Germany), Aug. 22 : Jamaican sprinter Usain Bolt has again stressed he is not on drugs after another astonishing world-record performance.

The fastest man on the planet said he hoped people would one day stop asking if he was on performance-enhancing drugs.

"I keep telling people I''m clean, but I can''t make anyone believe it," The Telegraph quoted Bolt, as saying after he smashed his own 200m record, running an amazing 19.19sec in the world championships final.

"I''ve just got to keep running and training. I get tested all the time. I''m not going to worry about it, because I work hard and get tested a lot. I know it''s going to be always in the sport; I''ve just got to counter it by being clean and running fast," Bolt added.

Bolt has been linked by association to drugs after five of his fellow Jamaican sprinters tested positive recently for an obscure stimulant, methylhexaneamine. Two of the five were in Bolt''s training group.

There is a history of sprint stars falling to the curse of drugs, with Ben Johnson, Justin Gatlin, Linford Christie, Tim Montgomery, Dwain Chambers and Marion Jones all having their sporting legacy destroyed because of cheating.

But Bolt continues to prove he is simply a freak of nature, and the way he attacked the line in his latest record-breaking performance has most convinced he isn''t finished yet. (ANI)