SOCHI, Russia Norway snowboarding medal hope Torstein Horgmo broke his collarbone in a practice run at Sochi on Monday and is out of the Olympics.
Horgmo's injury comes amid mounting safety concerns over the Winter Games course.
"It was on the first rail element it happened," team coach Per-Iver Grimsrud said. "He was doing a switch hardway, backside 270. He landed wrong on the rail, and then he fell into the stairs to the side."
"It was the worst fall I've seen," Austrian snowboarder Anna Gasser told Norway's TV2.
"He landed with his back straight on the rail, and they had to put in rods to stabilize his back before he was brought down on a stretcher."
Horgmo was taken by ambulance to a local hospital, where the broken collarbone was confirmed.
"It is of course very sad that this happened. Falling is part of our sport, but the timing is terribly bad," Horgmo said in a statement.
"Now I just want to recover quickly, get back on the board and have fun again."
A winner of the X Games in Big Air in 2013, 26-year-old Horgmo was one of Norway's big medal hopes for the Sochi Games before his fall, and his accident further raises concerns over the course at the Rosa Khutor Extreme Park.
Irish snowboarder Seamus O'Connor had earlier in the day described the course as "pretty dangerous" and urged his fellow competitors to speak up about it.
"They overbuilt the jumps because they were anticipating that the snow would melt. At the moment the riders are not happy. The rails up top are too close," he told reporters after his training runs.
"It's pretty dangerous at the moment. I think it's definitely going to be a problem for the women, it's pretty gnarly for them.
"The riders need to speak up about the conditions," he added. "The rails can't be fixed but they can fix the jumps."
Australian Chef de Mission Ian Chesterman said that with minor adjustments the course would be in good shape for the competition.
"We are dealing with an extreme sport and that's pretty much part and parcel of any day out on the hill and in slopestyle," he said.
"The guys working with this are the experts and the experts will make sure the course is safe. The experts are the international federation which is running the sport and they work hand in glove with the coaches who are responsible for the athletes.
"So I'm sure come competition day there will be just a great course for a great show."
(Editing by Peter Rutherford/Rex Gowar)