BRISTOL, Connecticut: Triple Olympic and world sprint champion Usain Bolt of Jamaica said on Monday he expects years of fast feats to ease doping doubts in athletics and has no plans to play American football.

Appearing on ESPN programs and in light-hearted races outside the television sport network's studios, Bolt said he feels he must prove himself to a skeptical sports world in the wake of past doping scandals.

"I have to prove myself to the world that you can run fast without it," Bolt said.