Marathon Countdown:The training may be over, but the last 48 hours before the race are crucial to your performance, writes Ian O'Riordan.

'Men, today we die a little." So said Emil Zatopek at the start of the 1956 Olympic marathon, and he knew what he was talking about. The great Czech runner had won the gold medal four years previously, only this time, after hitting the marathon's infamous "wall", he ended up sixth - finishing in a trance-like state of exhaustion.

Naturally, Zatopek was exaggerating a little, but not entirely. Running 26.2 miles will, sooner or later, feel something like a near-death experience, largely depending on the amount of training put in.

At this stage it's too late to do any further training. All the hard work, presumably, has been done over the past number of weeks and months, though that's not to say the final 48 hours before race-time won't influence how you feel on Monday morning.

There are several important elements to the final countdown of running a marathon, most of which involve common sense. Some of these are based on personal situations (marathon experience, travel requirements, race targets, etc) but there are universal dos and don'ts that can significantly add or subtract from the marathon performance.

Having run three marathons in very different circumstances, starting with Dublin, then Athens, and more recently Honolulu, I would say the final countdown is partly about careful planning and partly about compromise.

For Dublin, the start was within walking distance, which meant a good night's sleep, a light breakfast at home, and no last-minute panic of any sort. Athens involved practically all the runners taking the hour-long bus trip to the historical town of Marathon, exactly 26 miles north of the city, in time for the 8am start, and that felt like organised chaos.

Honolulu started at 5am, obviously to avoid the Hawaiian sunshine, and that meant practically no sleep the night before and a constant battle against dehydration. No prizes for guessing which race went the best.

But even the vastly differing experiences of those three marathons confirmed that it's two days before the race, more so than the day before, that most influences the marathon performance. In other words, it's what you do today, and not tomorrow, that will have the greater bearing on how you feel on Monday morning.

Some people prefer to do no running whatsoever on the weekend before a marathon, and that's understandable. Clearly freshness and rest are paramount. However, there's probably as much to be gained from a 10- or 15-minute jog on both mornings - painfully slow, remember - to help keep the muscles loose and relaxed. Either way, the amount of time spent on your feet should be reduced to a minimum, so forget about shopping or sightseeing trips.

The Irish record-holder Catherina McKiernan, winner of the London, Berlin and Amsterdam marathons, talked about this tapering process in her autobiography, Running For My Life. Used to running around 100 miles a week, McKiernan found the days before the marathon particularly boring, as she was effectively tying to do as little exercise as possible. It's a good idea to take in a trip to the cinema or theatre, or anything similarly relaxing, to help kill the time.

There is also the more extreme example of the Limerick-born Jim Hogan, who before running the European marathon in Budapest in 1966 hardly left his hotel room for a full three days, spending most of that time lying in bed with his legs up.

That served its purpose, however, as Hogan won the gold medal.

Given this reduction in exertion, not to mention nerves, sleep may become more difficult than in the weeks of tiring training beforehand. That's normal, but as most people know, it's better to get a good sleep two nights before an important event than the night before - so it's tonight's sleep that matters most. Inevitably, the night before the race will be an anxious one, with possibly little sleep, though this shouldn't have any undue effect on Monday's performance.

Even the most novice marathon runner will have heard something about "carbo-loading" - the practice of increasing high-carbohydrate foods such as pasta, rice and potatoes in the days leading up to the marathon in order to produce maximum energy on race day. And this is generally sound practice. Carbo-loading became popular during the marathon boom of the early 1980s, particularly in the US, and practically every major marathon - Dublin included - now hosts a pre-race "pasta party".

Runners of all levels appreciate the benefits of pasta - it's quick and simple to cook; it tastes good; and best of all it's an easily digested form of concentrated carbohydrate.

As important as the carbo-loading is, it's just as important not to overdo it - and the marathon doesn't necessarily come with a ticket to any all-you-can-eat restaurant.

Again, two days before, more than the day before, is more critical, and it's better to have three or four well-balanced meals over the day than one giant splurge at the local Italian.

Definitely out is a big heavy meal on the Sunday evening, which may well come back to haunt you in the early miles of Monday's race.

Getting through the final miles of a marathon is where carbo-loading really comes into play. The dreaded wall that practically all marathon runners experience after 19 or 20 miles is actually the leg muscles draining of their energy stores, or glycogen.

This can be partly offset by ensuring those stores are full going into the race, hence the pasta meals, washed down with any sweet-tasting drink.

It's also possible to top up these stores during the race by consuming the energy drinks laid on at intervals, though this is best practised in advance. Anyone not used to consuming these drinks en route may well find them hard to digest, with some unpleasant consequences.

So to Monday morning. It's crucial to have the final hours before the race worked out well in advance. You'll want to be around the start area an hour beforehand, ready for a gentle jog or walkabout, and a little stretching. There is no perfect pre-marathon breakfast, but make sure it's something light and familiar, and eaten at least two hours before the start. This is not the time to try something different, and it's better to start the race slightly hungry than slightly full.

It's often said that caffeine is the ally of the marathon runner, and while I would not go so far as to advocate a double espresso on the morning of the race, it certainly worked for me.