Tim Benjamin, at 26, is a powerful reminder that a professional sports career is a life within a life, with a separate chronology and its own condensed processes of growth and decline.

In 2005 he was widely regarded to be among the world's best 400m runners. That summer he was the only British man to reach an individual track final at the World Championships in Helsinki, where he finished fifth, and in a season that seemed to promise so much, Benjamin twice claimed the scalp of Jeremy Wariner, the defending Olympic and world champion.

Three years on, Benjamin now knows his remaining seasons as an world-class athlete must be counted one at a time - the calendar, like the incessant wear and tear on his body, will refuse to be ignored indefinitely.

His withdrawal from the Olympic Games, because of the chronic sinusitis problem that has dogged him throughout the year, is a crushing blow to the Welshman, who was desperate to salvage something from the wreckage of a season where he attempted to overcome serious illness, injury and lack of form. Ultimately, he realised that was far from an ideal cocktail for Olympic success.

Despite operations to correct the problem with his sinuses, which took place in February, the former British champion has been forced to concede defeat.

"It’s been a bit of a nightmare really," he said. "I had an operation on it but I haven’t been able to train, because one of the side-effects is fatigue, which I know has really held me back over the last 18 months.

"It's got to the point where I actually think I’m the kind of guy that if I got through a full year’s training I might not run well.

"Because I have never ever, ever had a season where I have not been out for a length of time. This has been one of the hardest to deal with because I have never had an illness to overcome before."

Beijing may no longer be on Benjamin's radar, but he remains determined to fulfill his Olympic ambitions in London in 2012, a target he says has kept him going even in the darkest days.

"Thinking about 2012 is what keeps me going," he said. "During the worst times of this operation I actually started to think seriously about whether I had a future in the sport.

"I have just had setback after setback after setback and it gets to you. But 2012, like a little bell at the back of my head rang, and I told myself 'you just can’t think like that'. Because it’s the Olympics, and I want to have a big crack at it. It's what keeps me motivated, I am determined to get to 2012 - it would be very special."

The warning signs were clear to see for Benjamin, who finished last at the Golden Spike in the Czech Republic, in a time of 47.94, some three and a half seconds outside his personal best. He then withdrew from the Olympic trials in Birmingham before finally admitting defeat in his bid to reach Beijing.

"If you had spoken to Nicola Sanders in June last year, she would have said her world was crashing down," she said. "Then a month and a half later, she's knocked two seconds off her personal best and ended up with a World Championship silver medal.

"So it’s about getting healthy and staying healthy and I won’t look too far beyond that."

Whether Benjamin eventually becomes known as one of life’s nearly men and continues to be hampered by the physical fragility that has dogged his career so far, remains to be see. But he is clearly an athlete with the will to emerge from this latest setback a stronger man. Whether his body allows him to fufill his Olympic dreams is an entirely different matter.