Athletes will face the most gruelling of all Irish races this weekend when they tackle the Beast of Ballyhoura, writes Laurence Mackin

"It started off with a 42km trek through the desert with a horse carrying our backpacks, then we ran another desert marathon without the horse, and then we did a 164km mountain hike. Then we did some white-water swimming and then we slept for two hours. And that was day two [of a nine-day race]."

Welcome to the gruelling world of adventure racing (AR). Vanessa Lawrenson is an Irish athlete who regularly competes in this growing extreme sport that puts marathons, triathlons and many other endurance events in the shade.

"There are different types of adventure races. They range in duration from between three hours to up to nine days. People normally start out with the three-hour ones . . . and it goes all the way to something like Primal Quest [ the race mentioned above]," says Lawrenson.

She was also part of an Irish AR team that came 16th in a world championship event in Fort William, Scotland, at the end of May. This was the first time a totally Irish team had competed in a world series event and received a ranking, from a formidable field of 50 teams. "We had a cracking race and at one stage we were in 10th place, but then the team picked up some injuries," she says.

Adventure racing might be in its infancy here, but the calibre of the athletes involved is formidable. "A lot of athletes when they are finished their professional racing go to AR. The top team in the world is Nike, whose captain is Mike Kloser, a nine-time mountain bike racing champion. And now for the last few years he has been an AR champion."

There is a lot of debate on the AR circuit about whether it could become an Olympic sport but Lawrenson says this is a remote possibility. "Olympic sport by its nature is very prescriptive.

In AR the whole point is that the athletes don't know the course until just before the race, they don't know the distances, they get a kit list and just before the race you are given a map and you have to navigate with your team through wild places. [AR] enjoys its appeal to the adventurist."

Lawrenson has spent the past few months organising an adventure race, the Beast of Ballyhoura, which will unleash some of Ireland's toughest athletes on to the Galtee Mountains this weekend and will cover counties Tipperary, Limerick and Cork. The event will have two competitions, a 22- to 28-hour hour main team race and an intense three-hour Ballyhoura Blitz.

"The Beast of Ballyhoura is the only 24-hour race in Ireland this year," says Lawrenson. "This weekend people are going to run along the lines of a mini international expedition race. We are getting all these people, including rookies, who really don't know what they are getting themselves into" - at this point she flashes a grin that is positively unsettling, and is made all the worse by the fact that one of the rookie teams on the race is made up of several of Lawrenson's close friends, together with singer songwriter Juliet Turner.

"They are been given a map at 7am, with points marked on it just like grid references. Then they are being taken somewhere else on a bus where we are going to release them like a herd of cats into the wild and hopefully we'll see them at the finish line 24 hours later."

That 24 hours will see the teams scramble over a mountain or two, and run, kayak, mountain bike, abseil and shoot their way through the unforgiving mountain terrain of Ballyhoura. Just reading about it makes the muscles ache.

The Beast is not the only AR monster to be roaming the Irish countryside at the moment, and Lawrenson and a team of organisers are hoping to have a world-series race in Ireland next year. At the moment, they are trying to secure funding so they can put on a top-class event. The director of the international adventure racing world championship has given his backing to the plan, which would see a three- or four-day race, featuring the world's best adventure racers, competing over the Kerry landscape.

But for now, the Beast is the most immediate challenge. Whether Lawrenson will have any friends left on Juliet Turner's team come Sunday evening, only the Galtee Mountains can tell.

The Beast of Ballyhoura starts next Sat at 7am and continues into Sun. See www.ballyhourabeast.com