SALT LAKE CITY — American snowboarder Kevin Pearce was in critical condition at a Utah hospital today after suffering a head injury while training in Park City, his publicist said.

Pearce's condition at University of Utah hospital in Salt Lake City hasn't changed since undergoing surgery Thursday, Danielle Burch said.

Pearce, a top-ranked halfpipe rider with a good chance of making the U.S. Olympic team, was knocked unconscious when he hit his head during a training run on Thursday.

Hospital officials on Friday weren't releasing information on Pearce's condition and were forwarding inquiries to his publicist. Family and friends set up a Facebook page for well-wishers and to offer updates on Pearce's condition.

The 22-year-old from Norwich, Vt., was preparing for next week's Olympic qualifying events in Mammoth Mountain, Calif. He is considered, along with Shaun White, to be one of America's top athletes in a sport dominated by the United States.

Olympic halfpipes are essentially hollowed out ice shells, the sides of which rise up to 22 feet in the air. Riders gain speed as they go from one side to another and fly several feet over the edges, where they flip and spin, often rotating 720 or 1080 degrees on a single jump.

Three weeks ago, Pearce fell during a preliminary run at an Olympic qualifying event in Copper Mountain, Colo., and sustained a concussion.