Marathon Motivation: Fintan O'Tooleexplains why those who are bad at sport have an advantage when it comes to running a marathon.

Contrary to popular opinion, marathons are not for people who are good at sport. They're for wimps, nerds, cry-babies and seven-stone weaklings. There is, within every city marathon, another event altogether, a sideshow for the jocks, the competitors, the athletes. But this is a strictly minority affair, of concern to no more than 10 per cent of the runners.

The real thing is strictly for those of us who were among the last to be chosen when sides were picked in the schoolyard and were always being screamed at from the sidelines by agitated mentors; for those who snivelled at the very thought of muddy fields, January winds and Irish rains; for those who had no desire to mix it with the rough boys or girls and preferred the musty scent of the sofa to the fug of sweat, damp towels and deep heat.

The marathon is the day when the wimps, too, get to be heroes.

It is not a sport, but our revenge on sport.

The only problem is that so much of the build-up to the day and the atmospherics of the event conspire to make us forget this essential truth. We adopt training plans, just like athletes do. We read advice from the likes of Eamonn Coghlan, as if it could have any more to do with us than the ways of the gods could be those of mere mortals.

We talk about diets and supplements. We buy gadgets and gear. We work out our optimal times, and set our goals. We fall into the weird language of fartlek, pronation, glycogen, electrolytes, tapering.

We forget the point of the whole thing, until the agony takes hold after 18 miles and gives us the most painful reminder.

The point we forget is that, for us, the marathon is pointless. It is not - obviously - about winning. We're not in the business of breaking records or winning prizes. We would like to do a decent time, but that in itself is an entirely moveable feast, an essentially arbitrary goal.

A good time is simply what we think a good time is. The only objective reason for going as quickly as possible is that it's actually harder to be out there for five hours than for four.

In reality, we run the marathon for the same reason anyone climbs a mountain - because it's there. The goal is simply to get to the top. As with mountain-climbing, conditions are going to be very different as you approach the summit from what they were like at sea level.

The most important thing for the non-athlete to remember is that the marathon has two halves - the first 20 miles and the last six.

After 20 miles, the altitude is high, the air is thin, the climate is rough, the conditions are exposed. What you have to do is try to get to that point in good enough shape to endure its rigours. But if you start thinking like an athlete, you won't.

I know this because I've had two reasonably pleasant marathon experiences and two excruciating ones. The first time I ran, in 1996, I knew I was a wimp, took things easy and finished in 3:24. The next time, though, I thought it was reasonably easy, set out to match that time, kept checking my pace, and limped home in agony somewhere beyond four hours (post trauma, I didn't bother checking the exact time).

Then I tried to make up for that disaster and did even worse. By 2005, I'd got back to the proper state of wimpish carelessness and came home in 3:45, having entered only the outer circles of hell in the last few miles.

The moral of the story: if you're a wimp, run like a wimp. Accept the fact that the first three miles will be crowded and slow and don't do a Marcel Proust and try to recover lost time. Think all the time that every watt of power you expend in the first 20 miles is one you won't have when you need it in the last six. Enjoy the crowds and the banter. Stop and take a drink at a station - just because Paula Radcliffe drinks and runs at the same time, doesn't mean you have to.

Keep the Chariots of Fire music out of your head until you can actually see the finish-line - if you want to play out your Olympic fantasies, Merrion Square is a fitting arena.

None of this will make the last six miles like skipping through fields of edelweiss, but you will be boosted by the pleasure of passing out all the poor suckers who thought they were Haile Gebrselassie and are now realising they're more like Haile Selassie.

Above all, ignore all the advice about eating sensibly and avoiding alcohol after the run. Other than its glorious pointlessness, the one great purpose of the marathon is to prepare you for one of the best pints of your life. If hunger is a good sauce, the sense of smug self-righteousness that comes from finishing a marathon is a whole kitchen of celebrity chefs.

You haven't really lived until you've relished a pint of Guinness and a greasy Chinese meal with the marathon medal around your neck and the sweat slowly drying into your skin.

It may be senseless indulgence after so much hard work, but if you wanted things to be sensible, you wouldn't have run 26.2 miles in the first place.