MOAB, Utah -- Mike Gostlin hikes up his baggy shorts to reveal tight, shiny patches of skin along both knees, souvenirs from his mountain bike rides along the red sandstone mesas here.

"This isn't Disneyland," he warns the biking daredevils who come from around the world to careen down this region's famed "slickrock" trails.

Some make it out of the expert trails unscathed, but most do not, and that has given the town another, albeit more obscure, national reputation: its hospital's emergency room knows everything there is to know about putting together ripped and shredded skin.

Tim McGinty, an emergency room nurse, said he'd put their ER doctors up against any cosmetic surgeon because they're so used to dealing with facial lacerations. "These guys can sew," he said.

As specialties go, it's not the stuff of medical journals.

"I can't say it's a source of great pride, but we do see so much of it, we're pretty efficient," said Dr. Bobby Hudgins, director of emergency medicine at Allen Memorial Hospital. "During the busy seasons -- spring and fall -- there are times when mountain bikers will be lined up out the door, holding body parts and dripping all over our floors."

During those seasons, as much as 90 percent of the ER's cases come from bikers -- so many that its treatment statistics are being studied by a Utah group that tracks wilderness injuries.

For most riders in town, the terrain of their lower extremities tells the painful tale. Andy Adams, who has been riding here all his life, says he's known on a first-name basis at the hospital.

What makes Moab such a unique place to ride is also what creates skin-peeling crashes. Bikers race high up on mesas across broad, flat sandstone slabs, called slickrock. Even fat mountain bike tires find little purchase on the smooth paths. Then, on the way down, sand coats the trails, which are wall-to-wall rock.

There are few easy trails here and there are no soft landings. Even the most leisurely rides can end up with a face planted into local red rock.

Around Moab's busy bike shops, locals say they can easily tell which customers are accidents waiting to happen: Lycra-clad "experts" who don't sufficiently respect the terrain.

"The big shots are the No. 1 most-injured group," said Gostlin, a native who works at the rental desk at Poison Spider Bicycles. "They act like they know it all and they will be the ones in the next day with their arm in a sling."

Moab's low-slung hospital is snuggled against the red rock mesas that are so popular with bikers. Georgia Russell is the emergency room coordinator and has been an ER nurse for 25 years. Her staff is the first line of treatment for biking injuries. Invariably, the injuries require staff time that's all out of proportion to their severity.

"We try to triage within five minutes of arrival," Russell said. "These bikers, with an extreme full-body abrasion -- it can take 45 minutes to clean them up. We've got patients backing up, and we're still digging the dirt and grit out of their wounds.

"Still, we have a reputation for getting them in and out. It's a routine. We're used to it."