No athlete is more closely associated with extreme sports than Shaun White, who has parlayed his snowboarding daring and artistry into two Olympic gold medals, 13 Winter X Games titles and a multimillion dollar franchise.

So when White abruptly withdrew from the inaugural Olympic slopestyle competition at the Sochi Games on Wednesday — citing the risk of injury and his preference, on balance, to focus on winning a third gold in the halfpipe — it had seismic effects.

White’s decision to bow out of the slopestyle event on the eve of qualifying not only robbed Sochi of yet another big name in a much ballyhooed event. It also added to the mounting evidence that Olympic organizers, in their zeal to jazz up the Winter Games in order to connect with a younger audience, may be carrying the “no-limits” ethos of extreme sports one step too far.

At issue is the safety of Sochi’s slopestyle course, which earlier this week ended the pursuit of gold medal favorite Torstein Horgmo of Norway. The first snowboarder to land a triple cork (three off-axis flips and four full rotations), Horgmo crashed while attempting a difficult trick on the rails near the top of the course in Monday’s opening training session and broke his collarbone.

From figure skating teams to female ski jumpers - a dozen new events will debut at the Winter Olympics in Sochi. (Associated Press)

On Tuesday, Finland’s Merike Enne injured her left ankle in a crash, and White, 27, jammed his left wrist in an accident.

A slopestyle course is akin to an ice-covered, downhill obstacle course littered with jumps, rails and boxes. Riders are free to negotiate them any way they choose, rewarded for the daring and creativity of the jumps, flips and spins they pull off on their descent.

Last weekend’s rain scuttled the customary pre-event tests of the Olympic slopestyle course at Rosa Khutor Extreme Park. So the first time riders tried it was Monday. The height of the jumps came as a jolt to many riders who boast of knowing no boundaries.

“Yikes!” U.S. hopeful Keri Herman said, asked her initial impression. “But that’s the same as X Games every year. You show up; it’s scary. You hit it a couple of times and you are like, ‘All right, I can deal with this.’ ”

White called it “intimidating.”

And Sebastien Toutant of Canada told the Olympic News Service, “It’s like jumping out of a building.”

After several snowboarders appealed for changes Monday night, the course was modified, with the tops and bottoms of some of the jumps smoothed out.

Switzerland’s Jan Scherrer told reporters Tuesday the modifications had helped.

“It makes it more safe, but you can still go as big as before,” Scherrer said. “The rails are much better so that you can see more tricks, rather than just trying to survive.”

After market research in the mid-1990s showed that the Winter Games were losing younger audiences, the International Olympic Committee turned to extreme sports to stem the decline, adding two snowboarding events (halfpipe and giant slalom) for the 1998 Nagano Games.

In Sochi, a record 10 snowboarding events will be contested. Combined with a record 10 freestyle events, that means extreme sports will account for 20 of Sochi’s 98 events.

As the first medal event contested, slopestyle snowboarding, in which riders flip down the course like high-flying pinballs in a pinball machine, is expected to set an eye-popping tone for the Games.

Venue map of 2014 Olympic games in Sochi Russia

Although both snowboarders and freestyle skiers wear helmets, the risk of injury remains high.

White gave no indication of his plans to withdraw during a news conference Wednesday afternoon, fielding questions from reporters in Sochi about the challenge of juggling both the Olympic halfpipe and slopestyle competitions and saying that his wrist injury had been “blown out of proportion.” But within an hour, he told NBC he was pulling out, saying that “the potential risk of injury is a bit too much for me to gamble my other Olympic goals on.”

Moments later, he issued the following statement through the U.S. Ski and Snowboard Association: “After much deliberation with my team, I have made the decision to focus solely on trying to bring home the third straight gold medal in halfpipe for Team USA. The difficult decision to forego slopestyle is not one I take lightly as I know how much effort everyone has put into holding the slopestyle event for the first time in Olympic history, a history I had planned on being part of.”

Roberto Moresi, assistant snowboard race director for the International Ski Federation, defended the course, telling the Olympic News Service: “It’s only him that’s pulled out, but people had already started to get into the course and like it a lot.”

Freestyle skiing’s slopestylers will compete on the same course in Sochi.

Charlottesville’s Sara Greenfield, a former freestyle instructor and competitor who started the National Ski and Board Safety Association after her son’s best friend was killed at a local resort, applauded White’s decision to withdraw.

“Injury prevention is easier to provide when athletes stand up for their beliefs,” Greenfield wrote in an e-mail exchange. “I have seen many a jump redesigned to make it safer. Death and serious injury is simply put unacceptable, and it is occurring at alarming rates in these two sports. If there is a call for rail or jump safety, the builders of these obstacles should make them safer, or shut them down, take them out.”

Even though stars like Lindsey Vonn will not be competing in this year's Olympics, here are seven other U.S. athletes who may step into the Sochi spotlight. (Kate M. Tobey, Jonathan Elker and Davin Coburn/The Washington Post)