Professional Bull Riders Built Ford Tough Series. 7:50 p.m. Jan. 18 and 2 p.m. Jan. 19. $15-$100. Gwinnett Arena, 6400 Sugarloaf Parkway, Duluth. 770-813-7600, www.gwinnettcenter.com. Caution: Bull riding is a violent sport in which riders and assistants are easily injured. Families should consider this as they make plans to attend.

Bulls will burst out of chutes at Gwinnett Arena this weekend, leaping, twisting and throwing their 2,000 pounds of weight around in efforts to dislodge the human pests on their backs.

Fans will watch breathlessly as cowboys struggle to hang on, withstanding the spine-jarring jolts and swiveling action.

Riders will go flying to the ground as spectators gasp to see whether they’ll get trampled or manage to scramble to safety.

Welcome to the Professional Bull Riders tour.

It’s about man vs. beast and the intoxication of danger. It’s also about being a tough guy. (No women ride in this event.)

“That’s the cowboy way. You’ve got to be tough,” said J.B. Mauney, 27, from Mooresville, N.C. He’s one of the top-ranked riders on the PBR circuit.

Thirty-five professional riders will compete in the Gwinnett event. They’re fresh from shows in Chicago and Madison Square Garden in New York. They’ll end the tour in Las Vegas, where a world champion will emerge and the winner will take home $1 million.

Along the way, their competitions will draw lots of families with children.

“I think it’s a great sport for kids to watch,” said rider Matt Triplett, 22, from Columbia Falls, Mont. He began bull riding when he was a child. “I got on a junior bull when I was 8 years old.”

It’s exciting for youngsters, he said. “It gets them out of their seats.”

The injuries sustained in the sport might give older people pause.

For example, Pistol Robinson, a 30-year-old rider from Bureleson, Texas, broke both his legs at Madison Square Garden two years ago when the bull Carrillo Cartel bucked him off and stomped on him. He was bedridden for two months. It took six months to recover, but Robinson returned to the sport last year.

In an era of increasing concern about concussions in football games, bull riding is gaining spectators by leaps and bounds. Professional Bull Riders began in 1992 when 20 riders split from the professional rodeo circuit to focus on bull riding events. They each chipped in $1,000. The organization says it’s grown from an audience of 310,000 in 1995 to a yearly average of 1.5 million today, with national TV coverage and major advertisers.

Riders come from the United States, Canada, Mexico, Brazil and Australia.

Another organization, Championship Bull Riding, also holds events around the country and on TV. In addition, the Professional Rodeo and Cowboys Association sponsors the Xtreme Bulls competition.

Animal rights activists oppose the sport. They say the flank rope that encircles the bull’s abdomen and causes him to buck is cruel to the animal. The Humane Society of the United States, in fact, opposes all rodeo sports.

And families going to a show ought to consider whether younger members are ready for the realities of the sport, in which riders are easily injured.

In bull riding, there are two athletes, the man and the bull.

“We cheer not only for the rider to stay on, but for the bull,” said Nancy Thompson, who works for Championship Bull Riding.

Bulls with names like Preacher Man, Sorry Charlie and A Bull Named Sue are among the 80 to 90 that may be part of the competition this weekend.

The action is quick. The clock starts when the bull and rider come gyrating out of the gate. The rider hangs on tight, gripping a rope. The animal kicks his hind legs out and bucks in an effort to dislodge the flank rope. Riders also spur the bull.

The rider must stay on the animal for eight seconds: The clock stops when his hand comes off the rope, he hits the ground, or his free arm touches the bull.

Assistants known as bullfighters also are involved. As soon as the bucking bull leaves the chute, three bullfighters are in the ring, staying in a triangle around the bull. The moment the rider hits the dirt, they jump into the sightline of the bull to distract its attention from the rider so that he can safely get away.

Both the rider and the bull are rated by four judges. The bull’s score is based on its degree of difficulty to ride, including how low it drops, how high it kicks, and its spins and direction changes.

Riders are scored on control — how well they counter the bull’s moves.

In the two-day event in Gwinnett, the top 15 riders will advance from Round 2 Sunday to compete in the championship round atop another bull.

To whip up the drama, the show starts with pyrotechnics, explosions and flames. The riders stride out amid a circle of fire.

Ryan Seddon of PBR described the spectacle: “It mixes the Western lifestyle and rodeo heritage with a rock ’n’ roll atmosphere.”

Championship Bull Riding’s Thompson admitted the show has another appeal to her: the cowboys. “There’s nothing wrong with some of those fit bull riders,” she allowed.