Wednesday night is the start of the 80th Sisters Rodeo with the opening performance promoted as Xtreme Bulls.

Saddle Bronc Riding is generally thought of as rodeo’s classic event — requiring strength certainly, but also a large serving of style and precision. It’s a lot more technical than it looks. If saddling up on a 1,200- or 1,300-pound wild horse isn’t enough adrenaline, getting on the back of 2,000 pounds of angry, contorting, pure muscle should do the job.

Bull riding is called “the most dangerous eight seconds in sports.”

Climbing on the back of a frothing one-ton bull evolved from the fearless and occasionally fool-hardy nature of the American cowboy. The risk of serious or permanent injury cannot be overstated especially considering the bull has horns. Nonetheless cowboys do it and fans love it making bull riding one of rodeo’s most popular events. Some would argue the absolute top draw.

Bull riding, apart from being dangerous and crowd pleasing, is demanding, necessitating extreme physical prowess, enormous concentration and raw grit. As with bareback and saddle bronc riders, bull riders may use only one hand to stay aboard during the eight-second ride. Touching the bull or himself with his free hand results in no score.

The artistry of staying on a bull

The rider clenches a flat braided rope that is wrapped around the bull’s chest just behind the front legs and over its withers. The end of the bull rope, called the tail, is threaded through a loop on the other end and tightened around the bull. The rider then wraps the tail around his hand, sometimes weaving it through his fingers to secure a better grip.

With a nod of the cowboy’s head, the chute gate opens, and he and the bull explode into the arena sometime as if shot by a cannon. No two bulls buck the same. A bull might swerve to the left, then to the right, then rear back. Some spin or circle continuously in one spot in the arena. Others add jumps or kicks to their spins, while others might jump and kick in a straight line or move side to side while bucking.

It’s billed as Xtreme because the stock provider enters their best, i.e. wildest, most menacing bulls for an eight-second challenge as bull riders hang on for a high score and an even bigger payday. Judges aren’t just looking for them to “make the 8.” Scoring is complex, measuring the rider and the bull.

There’s a big difference between “scoring” and “winning.” It’s not simply holding on.

There are two judges watching each ride, scoring both the rider and the bull 0-25. The four scores are added up with a total maximum score of 100 points. Wade Leslie is the only bull rider in history to score a perfect 100 when he rode Wolfman back in 1991.

The cowboy’s points are awarded based on how well he covers the bull. Judges are looking for riders that are balanced and in control of the ride. Extra points will be awarded if the rider spurs the bull to encourage bigger bucks.

The stock points come from the ferocity of the bull. Bulls, for example, that run and kick in a straight line won’t score the number of points of bulls that spin and buck close to the chute gates. Judges look for a bull’s style of movement, overall agility, and speed of its moves.

In general, bulls have a raw power that can buck cowboys off instantly with quick spins and vertical bucks, making it crucial for cowboys to be balanced and in sync with the bull during their rides. Judges look for constant control and rhythm in the rider as he tries to match his movements with the bull.

Forty riders have entered for tonight’s bulls including Mason Clint Cooley from nearby Powell Butte and Greg Shannon from Prineville. In all, riders will hail from eight states and the province of Saskatchewan. Cullen Teffler from Thonotosassa, Florida, will have traveled the farthest. He and the other cowboys will be squaring off for a slice of the $10,000 Xtreme Bulls pie.

Bull riding is considered to be the most dangerous of any organized sport, and rodeo athletes get injured and die at a rate higher than any other professional sport according to the National Library of Medicine. Concussions account for 11 percent of the injuries, and a combination of neck, face and head represent 30 percent of the injuries.

Look for most riders to wear specifically designed helmets and protective vests. It’s not all brawn. The top two Xtreme Bulls riders as of last week’s national standings, each stood at 5-feet-9-inches tall, one at 140 pounds and the other at 155.