WHAT is it that attracts hundreds of Americans back to Pamplona year after year to risk their lives running with the bulls through the Spanish town's narrow streets?

　　Is it the need for the adrenaline rush that comes from dodging the horns of a half-ton bull, the camaraderie shared by veterans of the bull run or nostalgia for the old-fashioned romance conjured up by Ernest Hemingway's 1920s novel, "The Sun also Rises", set against the backdrop of the Pamplona festival?

　　Possibly a combination of all three. But, whatever the reason, many Americans repeatedly make the pilgrimage to the quaint northern Spanish town each July to join thousands of local residents and foreigners for the San Fermin festival, a week-long binge of drinking, music, fireworks and most importantly, bull-fighting and bull-running.

　　Leon Friedrichsen, one of a group of mainly middle-aged Americans relaxing outside a Pamplona cafe after taking part in the first run of this year's festival, first ran with the bulls in 1969 and has done so around 70 times since.

　　He says he keeps coming back "out of honour and respect. I love the bulls, I love this festival, I love the people and I want to be part of it. It's an honour to run with such magnificent animals."

　　Every morning at 8:00am from July 7 to 14 each year, six bulls are released onto an 825-metre (900 yard) course leading through Pamplona's winding streets to the bullring, where they will be killed in an afternoon bullfight.

　　Old tradition

　　Continuing a centuries-old custom, thousands of people, dressed in the festival's traditional red and white, dash along in front of them, running the risk of being gored or trampled.

　　Thirteen people have been killed since 1900, the last American Matthew Tassio, who was caught by a bull on July 13, 1995.

　　Two Americans and an Australian were gored and seriously injured during last week's bull run. Hundreds more have been injured in the runs which last only a few minutes.

　　"The first time I ran was July 10, 1969. It took me four days to get up the courage to do it, but on the 10th of July I just found myself in the street. Some other emotion that I never use seemed to have brought me out there," Friedrichsen, a 54-year-old interior decorator from Bishop, California, said.

　　"It's the same now. After all this time I'm still scared to death, my adrenaline is pumped up. It never loses its velocity at all. Never."

　　The running of the bulls dates back to the 16th century when it was the most practical way to get them from the outskirts to the bullring. As time went by, daredevils began to jump on to the course to run before the bulls. Local authorities tried for years to stamp out the practice before officially endorsing it in 1876.

　　San Fermin devotees often book rooms at the same hotel every year with the most sought-after being rooms at the elegant La Perla, where Hemingway's tale of deep passions and marathon drinking sessions was supposedly set.

　　American aficionados return year after year even though some have suffered injuries in the mad stampede.

　　Their enthusiasm for the bull runs is not shared by everybody. Scores of animal rights activists, including about 20 of them parading naked, held a noisy protest last Saturday to call for the abolition of an event they say is cruel to animals.

　　Friedrichsen says he has never been injured by a bull, but once dislocated his shoulder when he hit a drain pipe and once hurt his knee when he dived for cover through the barricades lining the course.

　　Lucky escape

　　John Parrish, 44, from Atlanta, Georgia, notching up his 10th year in Pamplona, had a nasty experience in 1993 when a bull ran into him, although luckily it did not gore him.

　　"I had finished my run, the pack had gone by and a loose bull came around the corner and caught me, hit me square (with) the head, right between the horns. I was real lucky, and then he was just dragging me against the fence," he said.

　　A policeman caught hold of him and dragged him over the fence to safety, leaving him with nothing more serious than bruises.

　　What brings him back year after year? "It gets in your blood, the excitement of it. It's a lot of fun," he said.

　　Parrish became interested in the bull run when he saw it on television in the early 1980s, but his older brother Paul made it to Pamplona before him and has been a regular visitor since 1986.

　　"The first time I came was the 'Hemingway thing' - prove your manhood," said Paul Parrish, a 46-year-old attorney and writer from Tampa, Florida.

　　Even after so long, it always gives him a thrill to run with the bulls, he said. "The first day I go out there and I'm not nervous, I'm going to just climb right over (the fence) and leave, because something bad is going to happen."