If he wasn’t the man we know him to be, one might assume that Lance Armstrong was having some sort of midlife crisis. Divorcee from Texas, runs a support charity for cancer sufferers, delivers a great motivational speech, travels the world in a private jet, keeps fit by running marathons, dates a pop star, an actress and a fashion designer (not concurrently – even with his stamina that’s some ask) and spends time with his three kids.

A lifestyle most of us would trade up to in the blink of an eye. He’s 36, he has won the Tour de France seven times, after beating testicular cancer, he’s been retired for three years and now it’s time to make the comeback of all comebacks for Lance “sick of twiddling my thumbs” Armstrong. Most men are already placing the order for the Harley-Davidson at this point.

Lance hasn’t mentioned twiddling thumbs; he hasn’t got time to twiddle. He declares that his main motivation for getting back on the bike is to raise the global awareness of cancer and then to prove, contrary to allegations unfounded, that he wasn’t doping in the seven years he won the Tour de France. He doesn’t say it so bluntly, but it’s a huge factor. He wants to nail that myth, squash that lie once and for all that he was “just a bit more clever with his doping” or that he benefited from his cancer drugs.

But the only way that he will do that is to win the thing, not just turn up and hang out with the peloton. In 1922, Firmin Lambot won the Tour de France at 36 and nobody over the age of 34 has done it since. As admirable as his aim for cancer awareness is, I am sure that Lance can continue such campaigns without the great physical pain he will put himself through between now and next summer, when he will be 37. When the pain of training was constant, he didn’t notice it, because that was his norm.

Hurting like hell, feeling sick because his lungs felt as though they were about to burst, eating a restricted and monitored diet, getting up to ten hours’ sleep a night, being selfish because all of that took enormous effort; well, that was what it took to win seven Tour de France titles.

When he was trapped inside that bubble - yes, trapped, because he couldn’t get off the ride until he’d obliterated the record books – he must have peeked outside at the world and fancied a nibble of normality. All highly tuned athletes do.

Every medal-winner whom I interviewed in Beijing fantasised about having a few weeks off, or eating a steak, or having a beer or going to Great Yarmouth (Louis Smith, gymnast). Nobody wanted a Ferrari for their efforts, they just wanted to say “yes” to an impromptu night out or experience a lie-in on a Sunday morning. Once those simple desires have been satisfied, they’ll be desperate to get back into the training zone and how much easier it is to do that when you’ve been away from it for only a few weeks. How much harder when you’ve had three years to party, live, learn and love whenever you wanted to; which all make Lance’s comeback even more spectacular.

He’s not an old boxer whose money has been squandered on women, wine and song, and those are surely the saddest comebacks of all, motivated purely for the cash.

Sporting comebacks are understandable, encouraged even, when the athlete has more to prove, when they left the field of play too early; Sharron Davies, Martina Hingis or Jennifer Capriati were all girls when they left their sport and women when they returned. They were competing in sports that require enormous sacrifice as children. The pressure can lead to them resenting the whole experience and it’s only after some time out that they understand their talent and recapture the love they once innocently had for their sport. Lance didn’t leave the field of play too early, he wasn’t forced out with injury, he didn’t fall out of love with his bike, he left on his own terms.

Two years ago my husband, Kenny, was playing in the Dubai sevens rugby tournament. He’d been retired for a year and he was rooming with Bobby Skinstad. Once the blue-eyed boy of South African rugby, the No 8 had been retired even longer than Kenny; Bobby was happily ensconced in working life in London, entertaining clients and doing some media work.

One night when they were sat in their hotel room, Bobby told Kenny a secret, that he was thinking of coming out of retirement. He’d go back to South Africa to train with Natal Sharks and he aimed to be in the South Africa rugby union World Cup squad in 2007, just 12 months later. Bobby didn’t just make the squad, his side won the World Cup. Bobby’s motivation was a classic case of unfinished business; a broken arm had forced him to miss the World Cup four years earlier. It’s rare that the fairytale has such a happy ending.

We are fascinated by our heroes returning. Hollywood cottoned on to this a long time ago, they didn’t make Superman and walk away, did they? Rocky could have quit when he beat Apollo Creed.

If he was poor, if he was lonely, if he was without purpose, we could all understand a little bit more about why Lance Armstrong is preparing to ride 21 stages of pain.

The first part of his battle to raise awareness of cancer is already on its way, look how many times I have mentioned the c-word in this column alone, and if he wins the 2009 Tour then he will have shut up the drug cynics for ever; and still those reasons don’t feel like his real motivation. But with Lance it never “was” about the bike, was it? And who are we to try to fathom this colossus of the roads.