Pole vaulter, nuclear astrophysicist, stuntman, skeleton racer: Iain Roberts' employment history, if not his insurance premiums, could make even the most content covetous. But it is easy to be envious when you are not standing at the summit of an skeleton run, sheathed in lycra, preparing to hurl yourself head first down an ice track at 80mph on what is, essentially, a tea tray.

Skeleton is tobogganing for the twisted.

"I had a conversation with someone recently who insisted I must go down feet first, like the luge, because not only was going head-first illegal but impossible, too," explains Roberts of a sport that requires huge subtlety, as well as strength and speed, to guide the sled round the 15 breathtaking bends most tracks boast. "But it's more forgiving than people think. Sure, if you come off you're going at 80mph, but that's on ice, not concrete, so it's not like coming off a bike at 80mph. Still, it's not a position you want to be in.

"I always thought nothing disastrous would happen because these runs had been designed by extremely clever men who made sure you just glided down . . . until I saw my first crash. I've lost the sled three times, which is the worst thing that can happen. If you flip on to your front, the chances are you can right yourself in the next corner but if you lose the sled you can hit it and that's when it gets nasty."

That is a fate Roberts has, so far, avoided since his first involvement in skeleton five years ago. Born and raised in England, he was a pole vaulter of decent standard by the time he moved to Edinburgh in 1997 to begin a university degree in mathematical physics and improved his personal best to four metres before realising that he would never attain his childhood goal of reaching the Olympics.

Amid the depression that followed, he began training to become a stuntman - a video on his website shows the 29-year-old being tossed into the air by a speeding car - before a chance meeting with a German bobsleigher introduced him to skeleton. Within months, he was offered a place on a British military training camp in Norway.

"I was standing at the top of the run for the first time wondering what the hell I was doing," he admits, remembering a twisting tunnel of ice and fear. "As soon as I realised I couldn't get off the sled I wanted to stop, but by the time I got to the bottom I was like a five-year-old who wanted to race back up again and have another go."

His journey from there was almost as rapid. Within three months, Roberts had been contacted by the New Zealand sporting authorities, asking if he would be interested in representing the country of his father's birth. "I always remember something he said to me when I was doing athletics - If you get good enough, I'd like to see you wear black' - and that swung it," he confesses, committing himself to a schedule that parts him from disgruntled fiancee Jill for six months of the year.

"I was lucky in that I had no strong commitments at the time . . . actually, that's not entirely true, I was doing a PhD in nuclear astrophysics but it wasn't going so well. The point came where I had to decide and I knew I was not for the astrophysics world."

The scientific background persists, though. As well as embarking on a new PhD at Edinburgh University on the mechanics of a sled with a view to one day building his own, Roberts uses physics as a reassurance when the terrifying nature of skeleton penetrates his consciousness. "I put my faith in what I consider to be very solid principles, but that may be false logic because I've still got to control it on the way down," he says, explaining that the biomechanical quirks that hindered him as a vaulter actually help in his new pursuit.

Perhaps the most vital skeleton skill, though, is experience. As one of the most callow competitors, he is often at a significant disadvantage over those who have amassed hundreds of runs on the various tracks on the circuit. Still, Roberts has scraped into this weekend's world championships at Lake Placid with a ranking of around 25th despite struggling with a g-force-induced neck injury and will be disappointed if he finishes outside the top 20. That's not to say he isn't aiming higher, though.

"The first time I got to an international event that was my life goal achieved," he admits. "It felt amazing, but then I looked around at these guys I was competing against who had world and Olympics medals and I realised that could be me in a few years. That is some inspiration. Realistically, I'm looking at the Sochi Olympics in 2014. I felt past it in the pole vault when I was 24 but all three medal winners in Turin four years ago were over 35 and that's the age I'll be when we go to Russia - prime medal-winning age."

If all goes to plan, then, Roberts will have yet another achievement of note to add to his cv.