Usain Bolt said he is “50-50” on competing at the 2017 World Championships in London, which he previously stated would be his final competition before retiring.

He may retire after his fourth Olympics in Rio next year instead.

“I really want to run at London, but I think the sport is not as fun as it used to be,” Bolt, 29, said on BBC radio after winning the 200m at the World Championships in Beijing on Thursday night. “It’s more taxing. I can’t enjoy it as much as I want to because I have to be sacrificing a lot more, so, uh, it’s 50-50, I’m telling you.”

Bolt said when he will retire may be influenced by and/or determined by his coach, Glen Mills.

“After Rio, as I said, my sponsors want me to go one more year, but my coach said, ‘Listen to me, if you’re not going to be serious about going to the World Championships in London,’ then I shouldn’t do it,” Bolt said in a press conference. “So it’s all about how I feel after Rio, if I feel I can really put my body through one more season. If I’m going to be focused and I’m going to be determined. That will determine if I compete after Rio. So we’ll see how it goes.”

Bolt has one more event at the World Championships in Beijing, the 4x100m relay Saturday.

VIDEO: Usain Bolt and Justin Gatlin’s first race together from 2005

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