Climbing: When the rock is a hard place: Upwardly mobile climbers are being kept in the dark. But all in all it's just another trick in the wall. Patrick Miles reports

THERE are certain mystical qualities to indoor climbing, a sport that has grown in leaps and bounds since men raced to be the first to the summit of Napes Needle in the Lake District in 1886 - the event regarded as the birth of competitive mountaineering.

About 150 climbers from around 20 countries have come to the mountain in Birmingham this weekend for the final round of the World Cup of indoor climbing. The mountain in this case is a kind of Arc de Triomphe structure made of resin and sand, about 50 feet high, with the top overhanging the bottom by about 20 feet, and a series of barely visible handholds, known as karabiners, set in the surface.

It is the wall of which competitors speak in reverential tones as they wonder what route they will be facing during the competition today and tomorrow. The climbers are not permitted to see the wall, and the strategically placed karabiners which will determine their path to the summit, until a few minutes before their turn. They are 'in isolation' - not a dark chamber full of salt water, but a room backstage at the National Indoor Arena.

Isolation is taken very seriously, as is the sport itself. Any competitor caught taking an illegal glance at the wall faces disqualification. When their moment arrives, the climbers are allowed six minutes to see the wall before they begin their ascent. They have about 10 minutes to get to the top but such is the degree of difficulty, the time limit is rarely breached before they either reach the top - which is the object of the exercise - or lose their grip and be left swinging on the end of a rope.

The men's and women's quarter-finals, plus the semi-finals for the women, are being held today and the men's semi-finals and both finals tomorrow, when British hopes will be held in the strong and supple fingers and toes of Tony Ryan and Felicity Butler. Butler, 34, from Beeley near Matlock, is the 10th-ranked women's climber in the world while Ryan, 30, from Manchester, is 34th among the men.

Like most of the climbers they began purely as enthusiasts with a love of adrenalin in the great outdoors. 'For me,' Ryan said, 'climbing is not a hobby, it's not really a sport - it's a lifestyle.

'I come from a climbing family. My father is a climber and my first experience came when I was seven years old. I didn't really enjoy it. I used to be very scared when I started, but with more experience, I lost my fears.' Ryan said he had never imagined climbing as a competitive sport but now he is committed to the circuit - for at least another year.

The season runs mostly during the winter months and starts to get serious in about September. Both Ryan and Butler work part- time during the summer to cover their climbing costs, although grants from the Sports Council to the British Mountaineering Club help to pay for expenses.

This year, World Cup competitions have been held in Britain, France, Switzerland, Japan, Germany and Austria, and next year, Bulgaria and Norway are expected to be added to the itinerary.

'For the past eight to 10 weeks, I have been in a different country every weekend, either for training or climbing competitions,' Butler said. 'In the three years I have been on the circuit, I have seen the sport change dramatically, mostly to accommodate the interest from the media. It has become far more professional.'

The telegenic nature of indoor climbing, the fact that the weather is not an issue and the combination of strength and grace have all served to give the sport a tremendous lift. It still sounds slightly off-the-wall when intelligent young athletes talk about going into 'isolation' before they tackle 'the wall' for the first time. But season after season, as new walls are built, its popularity and intensity are increasing.

(Photograph omitted)