Last year a 600 kilogramme (1,300 pound) bull jammed a horn as thick as a man's arm through Bill Hillmann's thigh twice, narrowly missing his femoral artery.

It was his first goring in 10 years of running with the bulls at Spain's famous San Fermin festival, but not the first time he got injured.

A bull trampled the 33-year-old Chicago native two years ago, kicking him in the head and giving him concussion, while in 2006 his knee became infected after he bruised it in a fall.

The injuries did not discourage him from returning this year to the week-long festival, which began in the northern city of Pamplona on Monday, to defy death yet again by running ahead of a thundering pack of fighting bulls.

"I have never had a more peaceful and beautiful experience with an animal in my life than the times when I have been able to lead a bull up the street. It is absolute peace," said Hillmann, a journalist, author and former boxer who has written a book about his experiences at San Fermin.
For most daredevils, risking your life once at the festival is enough. But a small group of veteran runners like Hillman return year after year, despite having suffered serious injuries.

"Someone who starts running regularly gets this poison in them which leads them to say: 'I'm going to keep running, I like it'," said Koldo Larrea, a Pamplona journalist who has written several books about the bull-running festival.

- 'Value each day' -

Each morning of the fiesta, six half-tonne fighting bulls are freed from a corral at 8:00am to rumble after hundreds of runners down a winding, 846.6-metre (925-yard) course through cobbled streets to a bull ring where the animals are killed in an afternoon bullfight.

Last year just over 17,000 people took part in the festival's eight daily bull runs, two-thirds of them for the first time, according to Pamplona city hall.
"First you run out of tradition, then it becomes a hobby and finally it becomes an addiction and all you think about is running," said Juan Pedro Lecuona, a 42-year-old Pamplona native who has taken part in over 200 San Fermin bull runs since he first started running in 1989.

Lecuona, a married father of four, has suffered broken ribs, bruises and stitches. His most serious injury happened in 2010 when a 650-kilogramme bull gored him in his leg, leaving him bedridden for two months.

He said taking part in bull runs makes him more appreciative of his life's blessings.

"I risk my life to reflect on it," said Lecuona, decked out in traditional white clothing with a red neckerchief as he gathered with other revellers in a packed square outside of Pamplona's Baroque town hall after running with the bulls on Wednesday.

"What I gain from the bull runs are not images and videos to put on social networking sites. It is the realisation that what is most important is hugging my wife, my sons, being with them, of valuing how wonderful it is to be alive.

"It makes you learn to value each day," he added.

- 'Sense of relief' -

Fifteen people have been killed in the bull runs since modern-day records started in 1911, most recently in 2009 when a 27-year-old Spaniard was gored.
Veteran runners say they prepare throughout the year by observing bulls at ranches to get a sense of their instincts, jogging on pavement and doing contact sports.

Peter Milligan, a 44-year-old lawyer from New Jersey who has taken part in San Fermin each year since 2004 with his younger brother Aryeh, said playing basketball was the best way to prepare for "the other runners bumping into you and shoving".

He broke his ankle during a run in 2013, a year after a bull gored Aryeh, 41, in his calf.

But they were back again this year and Milligan said he plans to take part in San Fermin "as long as I can walk".

"I find it to be one of the most joyous things that I do. I just love running as fast as I can, then that sense of relief when it is over," he said.