On Athletics:Last Saturday evening I got to attend the Irish premiere of There Will Be Blood, which included a post-screening interview with the film's star, Daniel Day-Lewis. When asked what it was that drew him to his character, the uncompromising Daniel Plainview, he put his hand across his mouth and paused, ran his fingers through his hair, then eventually answered.

"There was this realisation that my life was receding behind me."

To me this suggested his awareness that time and opportunity don't run parallel forever, and that some day this kind of demanding characterisation may be beyond him. As he expanded on this thought, it seemed clear that Day-Lewis would have regretted turning down the role.

The idea of walking away from your chosen career with no regrets is almost as old as individual existence, and a large part of any sporting life. Those two words "no regrets" are so often used and abused that it's difficult to know when they're real and when they're not. But is there a difference? There's one for Jean-Paul Sartre.

Several years ago I shared a beer with Mark Carroll at the Ri Ra Irish bar in Providence, Rhode Island. A few weeks earlier, Carroll had failed to make the final of the 5,000 metres at the Sydney Olympics, and to me this was a huge disappointment, another example of Carroll's great potential going unfulfilled.

Earlier that year, Carroll won the European Indoor 3,000 metres in brilliant style, yet I wondered if he'd have swapped that gold medal for a more satisfying run at the Olympics.

"No regrets, no regrets," Carroll repeated several times over, with a strong hint towards that old Frank Sinatra tune I Did It My Way.

I still wonder if Carroll meant those words. His talent, application and enormous capacity for hard training were exceptional, and to me he'll always be one of Ireland's greatest distance runners. To this day only one other European has bettered his 7:30.36 for 3,000 metres. Yet Carroll never got the credit he deserved, partly because he never won a medal at Olympics or world championships.

At age 36 he's still running, and just last Thursday he finished second in the Armagh International road race in preparation for tomorrow's Rás na hÉireann in Louth. Carroll still hasn't given up hope of competing in the Beijing Olympics - but if he is true to his word then I'm sure he won't regret not being there.

One athlete who would heavily regret not being in Beijing is Derval O'Rourke, and this may help explain the "will-she-won't-she" lark that carried on this week surrounding her participation in the World Indoor championships, set for Valencia in a fortnight's time.

O'Rourke, lest anyone needs reminding, is defending champion in the 60-metre hurdles.

On Tuesday, I wrote that O'Rourke wouldn't be defending that title because of a combination of factors, namely a foot injury (which forced a three-week lay-off), a couple of disappointing races (her 8.09 well down her best of 7.84) and most recently a head cold ("swollen glands, lumpy neck", et cetera).

Within hours of that appearing in print a statement was issued by O'Rourke's agent, who described this as both "unfounded" and "groundless" - which was hardly fair given two sources very close to O'Rourke had provided whatever is the opposite to "unfounded" and "groundless".

So to confirm this I contacted O'Rourke (by accident, believe it or not) and ended up draining the battery on my mobile phone, such was the warmth and openness of our conversation. I didn't actually ask her straight up if she was going to run in Valencia, as it soon became fairly obvious she wouldn't.

Sure, she desperately wants to defend her title, but what really concerns O'Rourke is Beijing. After the dizzy heights of 2006 (World Indoor gold, European outdoor silver) last year had been disappointing, particularly her semi-final exit at the World Championships in Osaka. She needed to make some changes, shake things up, and make sure she got to Beijing with no regrets.

So after seven years O'Rourke left her coach in Dublin, though not without careful consideration. Part of the problem was that she no longer had quality athletes to train with. On good advice, she linked up with Britain's top hurdling coach, but because of his ties with UK Athletics, this had to be kept relatively quiet. Since October, she has been based in Bath for three weeks of every month, and at no stage has she regretted that move.

The foot injury could have happened anywhere, and the head cold was almost inevitable given she'd so far survived the whole winter without one. Such are the breaks in sport. So she's had to sit back a little and watch while Susanna Kallur of Sweden, who took the bronze medal behind O'Rourke at the World Indoors two years ago, recently lowered the world record to 7.68 seconds.

Kallur, by the way, has a twin sister, Jenny, who shares not only the identical genetic make-up, but also a devotion to sprint hurdles. Jenny Kallur, however, has only run 8.27 this year, and just like O'Rourke, she's had some hard luck with injury and illness. Such are the breaks in sport.

It hurts O'Rourke to think she'll miss the World Indoors, and that's understandable. There was no need to muddy the situation with the heavy counter-claim by her agent. Athletes in all sports are often prone to paranoia when it comes to media coverage, believing we're somehow out to get them, when in fact no one wants O'Rourke to run in Valencia more than we (Dos grandes cervezas, por favor). The Olympics, however, are once every four years. O'Rourke wants to walk off the track in Beijing next August with her head held high, knowing she's given it her all - no regrets. At least she's being honest about that.