PLEASANTON -- It's a clear and cold winter night, and the Alameda County Fairgrounds are silent and dark -- except for Building D, which is lit up and seems to vibrate with an rumbling, low-level roar.
Inside, skaters speed around a banked wooden track, trying to stay upright as they jostle and cut each other off. They aren't here for recreation. They're here to learn how to skate in a pack, leap over fallen competitors and muscle their way past blockers intent on body-slamming them. They're here to learn roller derby -- San Francisco Bay Bomber-style.
"My family thinks I'm crazy," said Bill Navarro, a soft-spoken and powerful 230-pound member of the Bombers who lives in Mountain House and spends his off-trackhours in the office of Shames Construction in Livermore.
"They don't want to see me injured or hurt," he said." I'm constantly praying before and while on the track. I don't mind being knocked down and roughed up; just so I'm not really hurt."
The half-dozen-or-so daredevils on the track this night are part of the current training camp put on by the American Roller Skating Derby league, known as ARSD.
The league, one of many in the U.S. and throughout the world, was established about 16 years ago, and includes six teams: the Bombers, the Brooklyn Red Devils, the Orlando Thunder, the Midwest Pioneers, the L.A. Firebirds and the New York Chiefs.
"This is a very simple game," said Bomber Pam Schwab, a veteran skater,
The trick is that "you only have a 12-foot (wide) surface to work on, and you're up against gravity since the track is banked," Schwab said. "The bigger you are and the better you are, you'll rule out there."
Many leagues are women-only and feature flat-track competition, but ARSD teams are coed, although men and women skate in separate, alternating 10-minute periods.
The sport's popularity is fueled by a diverse audience and no shortage of skaters willing to risk injury for competitive glory.
Ex-trucker and longtime skater Guy Navarette, 43, of San Jose, has been a Bomber for about a year.
"It's not for wimps, mentally or physically," he said with a smile. "In my first game last year, I got yelled at worse than ever in my life. It was something I had to learn. I learned to be more humble."
Bomber Makani of Danville, who goes by a single name only, balances his track time with his other job -- as a flight attendant for American Airlines. It's not uncommon for a group of airline co-workers to attend his games, he said.
"I love the fast-paced sport," he said. "It's very physical and exciting. It's extremely rough, almost like hockey with a blend of wrestling. It's a fusion sport on wheels."
On this night, Jessica Hong of San Francisco is the most tentative skater, and for good reason. The 26-year-old accountant only recently learned to skate.
"I work in a safe environment where I sit for eight hours a day," she said. "I didn't know roller derby existed, but I thought it was very cool. I like a challenge, and this is really different from anything I've ever done. It tests my courage."
Her resolve is on trial later, when Hong grabs hold of 15-year Bomber veteran "Maverick" -- another one-name skater -- for a "whip," a pull by a teammate to accelerate past blockers. She loses her balance and sprawls on the track, quickly assisted by Maverick, who advises her on technique.
The size of a linebacker, Maverick has come late to practice from San Leandro, where he's had a rehearsal as church organist.
"This is where I come and let my aggression out from the week," he said. "But the thing I love most is signing autographs for the kids and seeing their faces."
On the track, the skaters cheer as rookie Bomber Crista Chua, a pharmaceutical company employee from San Jose, hunkers down and slips past a wall of blockers.
"Skating on the track is a different world than skating in a rink," said Navarro. "It's a great sport and a great pastime and there are a lot of good people here.
"But you have to be a forgiving person because you do get hit a lot."
The San Francisco Bay Bombers will compete in a three-way event against the Los Angeles Firebirds and the Brooklyn Red Devils at 8 p.m. Saturday at the Alameda County Fairgrounds, 4501 Pleasanton Ave., Pleasanton. Tickets are $20-$30, or $10-$20 in advance. Tickets for children 12 and under are $10, $5 in advance. Advance tickets may be purchased at www.arsdbombers.com.
For a slide show of more photos and a video on the revival of roller derby, visit www.contracostatimes.com