JAMIE COSTIN is worried about coffee. He's sitting in a cafe in Castleknock feeling guilty about the half-empty cappuccino in front of him when the waiter asks if he'd like another one.

He looks up anxiously and pauses. He'd love one, of course. The odd time he allows himself such treats but if he takes another that'll most certainly be it for the rest of this week. Maybe next week as well.

"I shouldn't, " he says, half hoping the waiter will hang on just another minute to tempt him.

Why not? It's only 11 o'clock in the morning and you've already walked 30 kilometres around the Phoenix Park, you haven't even put butter on your bread, what's wrong with a couple of coffees?

"My nutritionist. She's down in Limerick, she's excellent and I've a team of people who've helped get me back to where I am. She'd kill me if she found out. You won't say anything will you? It's great to have these people around you. I didn't always have that so I appreciate that and respect them and their opinions. It used to be different. . ."

It was 1998 when Jamie Costin quit his degree in economics and Irish in UCD.

There were two years left to the Sydney Olympics and he was a 20-year-old with a dream. He'd been race-walking at the athletics club back home in Waterford since he was 12, won the national championships within two months of taking up the sport and now he wanted to perform on a plateau. So off he went to New Zealand for the winter, knowing where he wanted to take his career but not knowing how. You see he was a pioneer. Nobody in Ireland had ever taken on the 50-kilometre event but all he saw was the reward and went charging towards the most gruelling of athletics events.

"I got a bank loan and off I went for four or five months training in the winter, getting out of this sort of weather, and living as a professional athlete. I knew I could always go back studying. Just because I left then didn't mean that was it. I'm actually studying massage therapy at the moment. I was meant to be doing that since January 2005 but unfortunately at that stage I was in no position to do it. So it took two years to get my life back on track. But I was very young heading off and it's a 31-mile race and we [Costin and his walking partner] were coming up with our own training plan. Without having a coach, we made many mistakes. We were asking people who did it, but it's an acquired knowledge. We were just pushing ourselves too hard because we didn't know any better. We were over-training.

We'd do a couple of hard sessions and we might have a week when we were a bit down and we didn't know that much about the physiology. We know that now, because my partner over there ended up getting very badly injured and I just about came through it and on the last day of qualification in Germany in June 2000 I qualified."

He still considers Sydney his Olympic experience, not because a shadow was cast over his time in Athens, but because he was young and didn't know how not to enjoy it. He went to the opening ceremony and spent all his time hanging around the village without realising winners don't enjoy the Olympic hype. In the end, all of it did his short-term prospects little good but there was no way he was going to be there doing anything else.

"The best experience of my life. I'm a kid looking at professionals walking around.

Michael Johnson or Haile Gebresellasie or Cathy Freeman or whoever. I met Muhammad Ali. You go from a situation where you're a kid of 22 years of age trying to qualify for an Olympic Games and then you get there and you're rubbing shoulders with that calibre of athlete. Of course you are not on a par but you're a competitor there just as they are. It was a very big step up for me. But in Sydney I didn't have a good performance in the race. That was probably due to the fact I was young, I tried to race 50k three times that year and my body just wasn't strong enough to get back together for it and I only qualified on the last day. But it was amazing. But before Athens I looked at what had happened in Sydney. I finished 38th. I said that's not going to happen again. If I spent the next four years of my life giving everything, trying to improve my level to where nothing was going to affect my performance, I wasn't going to throw all that away in the days before the event."

In the years between the two Games, he'd done everything right. He went from being an international-class competitor to a world-class contender. He befriended Robert Korzeniowski, the Polish legend only comparable to the great Czech Emil Zátopek in terms of endurance of mind and body.

Korzeniowski had won gold in the 20-kilometre walking event in Atlanta, done the unprecedented 20- and 50kilometre double in Sydney and would end up doing the same in Athens. He went unbeaten in the sport for nine years, and here was Costin learning from him.

"He was going onto the Athens games and we were looking at this situation where we'd get in with this man and he helped us with our training and he brought our knowledge of the physiology of this on an awful lot.

He was telling us everything.

We went with the best. So it gave great confidence because I knew I was doing the right thing. I'd be doing something myself and I'd say to Robert, 'What do you think of this?' and he'd say, 'Yeah, that's fine but would you not think of doing it this way?'

"Also, for my mental approach that was very important because everything goes back to the training and that's where you become confident. There's an inevitable onset of pain in the race and what you have to do is prepare yourself for that. When you get to that stage your body wants to stop. But you've trained for this and you know your body can do it so your mind has to tell your body to keep going.

It's then that your mind takes control. You have to prepare mentally for that and I've used a lot of relaxation techniques.

"When you are doing training, like if I do 30 kilometres in the Phoenix Park, it's three laps and halfway through the second lap I might be coming up to the s-bend and I'll realise I'm starting to feel tired. But you have to have a voice in your head that tells you, 'No, you're grand. You've only got five kilometres to go until the end of this lap and then you only have another lap'. So the way I approach 50k is that I compartmentalise it. If I know that I get to the end of the 35k and I hit the button on my watch and it'll say 23 minutes for the split and an average heart rate 158. That's on the button.

I know that's another section done, I've done this before and my body is working properly. It's the same with any other split, I know what the split should be, I know what my heart rate should be and suddenly my mind knows I should be able to keep going.

You break it down."

It's exactly what he did as he sat in the car wreck in Athens two days before the 50-kilometre event at the Olympics. He'd been training that morning with Korzeniowski, taken a dip in the sea and dropped the Pole back to his hotel. It wasn't far from there where a lorry came around the corner at speed on the wrong side. The road wasn't wide enough to get out of the way and he was left there to compartmentalise. He knew his toe was broken as it sat on the brake.

He thought his muscles had all been ripped from his pelvis. He also thought a cortisone injection might help him back in time.

"I had gotten a stress fracture before so I knew what bone pain felt like. That was the thought process that went through my mind.

Assess the damage and see what we can do about it. And I thought I could make it back in time. What else was I going to think? I'd just been training with the best walker in the world. I was in a great state of mind and condition for the race. Then I come around the corner and get hit by a truck.

I didn't think the worst until I got the x-rays."

What the x-rays said was that he probably should be paralysed. His back was broken in two places and part of one of his vertebrae had exploded. He didn't reach an Athens hospital for nine and a half hours, instead he was left on pain-killers in 35degree heat. But when he finally arrived, the doctors were sure of the course of action. They wanted to insert four-inch titanium rods either side of his spinal cord, up through his vertebrae. This would have fused Costin's spine and restricted his mobility. He refused and instead returned to Dublin.

The consultants were so impressed with his physical fitness and mental knowledge they didn't insert any rods. That doesn't happen.

A year later, one of those consultants in the Mater showed the before and after x-rays to a bunch of students.

They correctly diagnosed the before. The after, well, they could see little wrong or at least nothing some light work wouldn't take care of. It was a miracle. Part of the recovery involved three-and-a-half months in a body cast. Then there were the weeks of extreme treatment in Spala, Poland where he went through cryotherapy. There, a small room was cooled to minus 160 degrees by liquid nitrogen, a process that encourages deep healing.

And now he's back in training, recognising his level to be more pre-Sydney than preAthens. But he'll compete this month in the Spanish National Championships and he has Beijing as a very realistic target. "It's never been about the injury. I've moved on, I'm an athlete and I know it is part of my history but it's only part whereas most people see it as the biggest story. Like I came home a few weeks after I came out of hospital - this was about a month after the accident - and someone came over and showed me all the papers around the time and I was on the front page of all the bloody papers. I was looking at it thinking, my God, you train all your life to be on the front page having won an Olympic medal and I'm on for all the wrong reasons. But I can't help that and I want to move on and get back and be the best I can be. Sure, it's unfortunate because I was going really well. But what I'm doing now is trying to get back because I'm good enough."

It's at the borders of pain and suffering that the men are separated from the boys.