Tom Humphries finds Sonia O'Sullivan at home in New York and taking preparations in her stride as she takes a significant diversion on the road to AthensThe runs which Radcliffe has done in London and in Chicagohave energised the marathon business. There is a competitive grain inO'Sullivan which refuses to allow anyone else's achievement to be seenas something other than a gauntlet offered.

In the distance, the mustard- yellow cabs ply the canyons of the epicly-disfigured New York skyline and, right behind her, doughty tugboats, with funnels painted candy-apple red, haul long, flat dredges along the broad brown Hudson. Sonia O'Sullivan stretches an elegant limb towards the sweep of the Brooklyn Bridge and thinks that right now, right here, is where she wants to be. Forget the past. Forget the future. This is the spot. This is the town.

If you could choose once in your life to be a star, just once, for one week only, well, New York is the city you'd choose to be a star in. You'd take it for its energy, its pace, its sheer ability to pump up the volume and maximise the hype. Being used up and spat out by New York is better than a lifetime of caresses from the bespoke praise of the west coast, it's more thrilling than an eternity of qualified hosannas in Europe.

New York. If you can make it here, you can . . .

Later this month, Sonia O'Sullivan will be 33. Running is no longer an adventure to be had while yomping around the European grand prix circuit with a small knapsack on her back. Running is about a finite number of choices, a limited number of things which are left to be done. Thirty-three and the second half of a career of waning velocity has been filled with other things. The clutter of grown-up life. Love. Death. And babies.

Thirty-three-years old. and beyond the brow of the hill that is the Athens Olympic Games another life awaits. Thirty-three. If she wanted to sit down and do the maths she could probably count the months and count the races and count the very yards which will flesh out her career. Why bother, though? Instead, she's stepped onto the rollercoaster, into the great joyride of the unknown again. The boroughs. The bridges. The winds. The raucous, cheering millions. The New York marathon.

Yup, if you are going to be star, you'd come here.

Take Thursday morning at the Tavern on the Green in Central Park, an upscale eatery where ladies who lunch do so, with chutzpah, for charity. Outside there is a panhandler who jabs a curled hand your way and says "gimme 50 bucks man, I need to get me some lobster".

Inside, there is a New York marathon press conference. A couple of tables full of runners: each say a few words and then disperse to different tables for individual press conferences.

Auxiliary chairs are brought to O'Sullivan's table. Soon it's standing room only behind the extra chairs. Soon the cameramen are standing on freshly-fetched chairs behind the rows of standing hacks. Every other table in the place looks like it is hosting a quiet romantic meal.

"That's Sonia," says Eamonn Coghlan, surveying the scene, "that's the power she still has."

She loved this town the first time she saw it. It was 1987 and she'd never been to America before in her life. Cobh was her oyster. Running was a career option. The first time she was ever in America she came here and got seduced, though. So much fell into place.

Easter 1987. A recruiting trip to Villanova University. They fly you out and hope to entice you. They like your times and your potential, they hope you'll like their college and their tradition. Two girls from Villanova came to pick up this kid from Cobh at JFK. She came through customs waif-thin and saucer-eyed.

Villanova had chosen their chaperones well. Cassie and Colleen, who looked so like Sonia that people had trouble telling them apart. The idea was to whisk the recruit straight to Philadelphia and out to the rural verdancy of Villanova, where she would feel re-assured and at home.

But Cassie and Colleen saw the flash of mischief in the new kid's eye and they came through Queens, hit the mid-town tunnel and into Manhattan for the evening.

"Get out and look up there, girl."

Cassie would improvise a parking spot in some hectic chasm and Sonia would step out into the evening air and gaze up at the walls of concrete around her.

Up Fifth Avenue. Down Broadway, through Times Square. Wrong way on another avenue and a crazy U-turn hung in the middle of a New York street, every horn chastising and three girls in a car giggling their heads off.

They had pizza, and when the hot peppers came Sonia poured them on top like salt and pepper.

"Hey girl you don't know what you're doing with those peppers."

But she ate them anyway without blinking. Course, she knew what she was doing.

Forty-eight hours, and that rush of adrenalin didn't subside till a week after she was back home in Cobh. Providence, Rhode Island, had been in with a shout when it came to recruitment. After that, it was gone. A no-brainer, the Americans said.

This year, she knew before the European Championships that she'd be coming here for the marathon, but she didn't want to talk about it. Not even to Alan Storey, her coach. It was a little promise to herself stowed away.

"I knew I would run it. I started thinking about it during the mini-marathon here in June. There were a few lunches and a few dinners out with the organisers and a few comments were passed about the marathon.

"So I had a little taste of it. There was no strategic plan, no feeling that it was time. Just a feeling that I'd like to do it."

STRATEGIC plans were hard to come by at the time. After the death last year of Kim McDonald, who at various stages had been mentor, coach, boyfriend, agent, adviser, there was a void. It was as if the people who worked in the office of McDonald's company had inherited a thoroughbred racehorse without knowing the first thing about maintaining such a creature. There was no advice, no strategy forthcoming. Just encouragement and admiration.

So many pats on the nose.

"So in June this year Nic (Bideau, her partner) became more involved in organising my races. I was still with Kim (McDonald's agency), but not getting any advice really, and what they would do I couldn't see the sense in really. I still wanted to work with them for all the logistical things they do, from airports down to my accounts, but the advice didn't exist, they were just booking me into races.

"Eventually people like Rickey and Duncan, who work in the office, said to me that they hadn't the confidence to tell me what to do and what not to do. That was reasonable, they couldn't be expected to know. But I needed somebody."

So when New York began dropping hints, she and Nic began looking at the calendar and this year of all years made sense in terms of a marathon. She spoke to Storey, a man who knows marathons like few other people. He had one question. Why a huge, high-profile marathon for the first serious attempt? Why go so public?

She thought about it and decided she liked the high-wire effect. The adrenalin. The fear of failure. She needed those things. A big event.

Energy and excitement everywhere. Here she is.

"New York has the things I wanted. I never wanted to do a marathon just for a fast time. There's more to the race here. It's a great thing to do."

The side benefits are considerable. Her sponsors, Nike, love it. These big city marathons are meat and drink to the sports leisure industry and most of the week since she got here has been spent in Nike fleet cars, being whisked from event to event.

Then there is the six-figure appearance fee. The promise of a cheque for $80,000 and a Pontiac car if she is first woman home tomorrow and a complicated series of bonuses, depending on what time she submits. A run under two hours 22 minutes tomorrow would yield a bonus of $65,000.

She concedes that a big city marathon can earn as much as a decent season on the track, but argues that the risk is greater, the road to the starting line is longer and more fraught with dangers. And anyway, who knows how many big marathons a body has in it?

And of course there is another factor which is skirted about and talked around. Her friend and rival, Paula Radcliffe. The runs which Radcliffe has done in London and in Chicago have energised the marathon business. There is a competitive grain in O'Sullivan which refuses to allow anyone else's achievement to be seen as something other than a gauntlet offered. She knows that a good run tomorrow will set tongues wagging. She likes the tease.

"I don't know what I'll do next year until after this year. I want to run the Worlds on the track next year, I know that. Everyone talks about Paula, but I don't know about doing another one of these (marathons) until after I do this one."

Paula. Paula. Paula. The speculation is there already. The comparisons. The talk of head-to-head races. In a quiet way, O'Sullivan is bemused by it.

"At the moment, Paula approaches things a little differently. At the moment, every time she runs she has to go as fast as she can go. That's the form she's in. For me right now, it's not the be all and end all. If I run 2:20 or 2:30 here, it doesn't make too much difference to me. If I win, it doesn't make any difference at all what time I do.

"It's funny. I suppose back in 1998 and stuff, it was never any big deal. When I beat Paula regularly nobody talked about her racing me. We've raced many times and I've won many times. It's not that big a thing between us. If I was to race against her, I'd like it if we could both go against each other at our best. Lots of times those things can be mismatches.

"So I don't see it happening in a marathon. It's a bit far. A shorter race maybe. It would be more interesting for everyone if it was a shorter race. As I say, I don't know yet if I'll run another one of these. This is a diversion on the road to Athens. No thoughts of running the marathon in Athens. It's a big city, fun-run thing."

Diversion or not, her competitive juices are flowing. A few weeks ago she was heading to Loughrea for a road race and it occurred to her that she hadn't seen Gerard Hartmann, her physio, since before the European Championships in Munich. She was planning to see him before she came to New York, so she decided to kill two birds with the one stone while in Ireland.

Hartmann, though, was gone to Chicago with Paula Radcliffe.

"He travels a lot with Paula. He'd told me in June that he had blocked off his schedule for Chicago. I wasn't totally dependent on him. If he was there, he was there. I saw his assistant, Alison Rose, and had four days of treatment as good as Gerard's."

During the summer she'd had a physio from Australia working with her and when he went home she'd found another guy who's surname was sufficiently unpronounceable for her to enter him in her phonebook as X. Merely Richard X.

If Hartmann's professional involvement with the legs of another athlete is understandable, so too are the new legions of aches and pains which come with age and turning up the distances.

She finds herself doing a large volume of stretching and back work and has been seeing on osteopath, Barry Savory (a former 800metre runner), over the summer.

Recovery is slower. After anything tough, she needs to immerse in an ice bath for a minimum of 12 minutes. She has discovered that the way to pass the chattering time in the tub is to text message people on the phone. That makes the minutes go by.

Still. On Saturdays she's been doing hard sessions in the mornings and the evenings. Into the ice bath twice. Sunday's a long session. In to Alaska again.

In summer-time, the living was easy. An ice bath had a certain allure. Then they switched seasons and she'd come in on Tuesday nights from the dark and the cold of the track and tell herself she could have no dinner until the ice bath, and dinner-time would get later and later as she'd look at the tub of water and ice and coax herself to get in.

That's the life, though. That's the choices. In the afternoons she doesn't get the sleep that other serious marathoners take. Ciara is at the door like a dog with a lead in her mouth and younger daughter Sophie is standing, already bursting with the same twitchy energy that all the O'Sullivan women appear to have.

LUCKILY, she's mellowed. She doesn't sweat the small stuff any more. Doesn't get strung up on the details. She tells a story of the summer and her preparations for New York. They make a co-incidental counterpoint to the anecdotes concerning Paula Radcliffe's astonishingly scientific preparations for Chicago.

Sonia would go running with a group of Australian runners and Nic would pace them. For pacing purposes, he purchased a mountain bike to which he had attached a speedometer. All summer, the times weren't just good, they were astonishing. Finally Sonia decided there was something wrong with the speedometer on the bike. If there was, though, it was too late to do anything about it.

September rolled around and the days drew cooler and Ciara went back to nursery school. Nic decided it would be a nice idea if he had a baby seat welded to the back of the bike and baby Sophie could come along for the rides through the park. So the mountain bike went in to have a seat attached and when it came back all Sonia's times were slow to the point of being treacly.

Yikes! She called the bike shop.

"Did you do anything to the speedometer?"

"Nope." And she shrugs and laughs.

"So I don't know. It was measuring too short? It was measuring too long?"

You look at her in astonishment.

"I just decided I didn't care."

And still stretching her legs on the esplanade at Brooklyn Heights, she looks across the river again at the great city beyond and begins talking about what she likes about this challenge. Subtract the hoopla, which she likes, and it's the same old thing.

"I think about each mile. Getting to each one at a certain split time. I just work at that in my head until it gets into a rhythm. It all adds up .

"Click. Click. Click. An hour at fast pace goes by so quick. You get in this rhythm and stick there. Just say nothing and click them off, all wrapped in your own thoughts. Working away. You're not thinking of anything really, just the rhythm. It's just a zone. One gone. One gone. One gone. Like striking days off a calendar. It's sore afterwards. It's a long way, but you don't think how long at the start. It's one mile at a time. One landmark at a time."

Thirty-three-years old. And that's how it's always been. One mile. One landmark. One race at a time.

She talks, and you can see she has mellowed, but something else too. She wants to devour this race. Big city. Same girl. Still ready for it.