Usain Bolt will be "101%" fit when the 100 metres heats start in 11 days, Jamaican team officials insisted.

The world's fastest man was conspicuous by his absence from the team's open training session at the University of Birmingham. Doubts over the defending champion's fitness have intensified since he was beaten by training partner Yohan Blake over 100 and 200m at the Jamaican trials at the end of June, while he withdrew from last Friday's Diamond League meeting in Monaco with a minor hamstring problem. Fellow sprinter Asafa Powell was also not at yesterday's training session, leaving some of the team's less heralded names to entertain the crowd of schoolchildren and students.

Ludlow Watts, Jamaica's team manager, said: "By the time he gets to the Olympics Bolt will be competition fit. Some times in your preparations there may be certain disruptions, but I believe that he's adequately prepared. He's training very well and by August 3 we will see the real Usain Bolt. I am not aware of any niggles at the moment. I believe he's okay."

Don Quarrie, the technical athletics manager, added: "He's 101% fit, he's ready. He has been working on the track here. His performances have been close to what he was doing in 2008 before the Olympics. That tells me he'll be ready to run in London."

A repeat of the sensation Bolt caused in Beijing, when he broke the 100 and 200m world records in taking double gold, is what organisers and spectators alike are hoping for, but, despite Quarrie's assurances, his performances so far this summer have suggested it is far from guaranteed. He is ranked second in the world behind Blake in both events, with season's bests of 9.76 seconds and 19.83secs. Four years ago he went into the Games with runs of 9.72 and 19.67.

His showdown with his training partner, good friend and fierce rival Blake is perhaps the most eagerly anticipated encounter of the Games, but Jamaica's men's team captain Michael Frater still fancies the main man to come out on top when it matters.

Asked who he thought would win the 100m, Frater, a member of the sprint relay team which will be red-hot favourites for gold, said: "That's a difficult one to say. Usain Bolt is something phenomenal. I wouldn't bet against him."