Many claim it is the ultimate sporting challenge a test of physical and mental endurance like no other, WRITES EMMA-KATE LIDBURY.

First comes a 2.4-mile sea swim, then a tortuous 112-mile cycle, which is followed by a marathon.

Welcome to the world of Ironman triathlon a world seven men from the Oxford Triathlon Club will be diving into next weekend when they take part in Ironman Lanzarote, one of the toughest long-distance triathlons there is.

Many of them have dedicated at least 15 hours a week to training over the past six months ahead of Lanzarote, which is a qualifying event for the World Ironman Championships, held in Hawaii each year.

Some are hopeful their reward for training through the cold, dark, wintry months will be a place on the Great Britain team, but others are just looking forward to the huge buzz of completing one of the world's most challenging events.

The Oxford triathletes taking part are Hanno Nickau, Simon Johnson, James McLaughlin, John Maxted, Dominic Rorke, Ian Osborne and Pete Dowling.

Rorke, the youngest of the group at 29, did Ironman Austria last year and now has the bug.

He said: "There's no doubt it's the greatest challenge of my life. It's going to be awesome.

"I've done a ridiculous amount of training. Once you do one, you find yourself entering one more, then another."

Nickau and Johnson have made no secret of the fact they are hoping to qualify for the Worlds.

"Having finished the London Marathon three weeks ago in under three hours I'm confident of my chances," said Nickau, an Oxford University lecturer.

Johnson, 36, who runs his own painting and decorating business, said: "A few years ago I was a 17-stone beer monster.

"Now, after four years of Ironman, I'm serious contemplating taking on the best in the world. It just shows anything is possible."

For McLaughlin, a GP from Kirtlington, it will be his seventh Ironman race.

"The combination of heat, wind and the hilly course at Lanzarote make it a painful but exciting day," he said.

"It is good to challenge yourself like this and I aim to beat last year's time."

It is not just a question of lasting the distance the conditions will be tough, with the bike course taking the triathletes 2250m above sea level and the heat being a seriously debilitating factor throughout the marathon.

But Maxted, 50, who will also be racing in Lanzarote for the seventh time this year, looks at it philosophically.

"Why run a mile when you can run a marathon?" he asks.

"I love the entire race the swim start is always a little wild but the water is clear and beautiful.

"The bike course is tough, but the whole island gets out behind the race.

"The run is hard, but by the time I hit the streets most of the British holidaymakers are well on their way to being drunk so I always get a good shout wearing a Union Jack. It's superb."

For information about Oxford Triathlon Club, visit www.oxfordtri.co.uk