Are you risking your spine riding a mountain bike?

NEW YORK (Reuters Health) - High speeds, extreme terrain and long vertical drops might be making the increasingly popular sport of mountain biking as risky as football, diving and cheerleading, suggests a new study.

Great Britain's Thomas Braithwaite jumps as he cycles during the men's UCI Mountain Bike World Cup downhill competition at Mount Ste-Anne in Beaupre, July 25, 2009. REUTERS/Mathieu Belanger

The findings warn that taking two wheels to the trails invites the danger of a spinal injury. One of every six cases reviewed was severe enough to result in complete paralysis.

“People need to know that the activities they choose to engage in may carry with them unique and specific risks,” Dr. Marcel Dvorak, of the University of British Columbia in Canada, told Reuters Health by email. “Helmets will not protect you from these injuries, nor will wearing Ninja Turtle-like body armor.”

Previous studies had described both the range of injuries sustained by mountain bikers and the spinal injuries suffered across a variety of sports. But no one had yet evaluated the specific risks of spinal injury among mountain bikers.

Dvorak and his colleagues identified 102 men and 5 women who were seen at British Columbia’s primary spine center between 1995 and 2007 after mountain biking accidents. The average patient was 33 years old and all but two were recreational riders, they report in The American Journal of Sports Medicine.

The team couldn’t calculate the risk of a spine injury among those who mountain biked, but they figured that over the 13-year study period, the annual rate was one in 500,000 British Columbia residents. The riders accounted for 4 percent of all spine trauma admissions to the center.

Surgery was required for about two-thirds of the mountain bikers. But the most devastating injuries were the 40 percent that involved the spinal cord. Of these, more than 40 percent led to complete paralysis.

“Wrist fractures and facial fractures are common” among mountain bikers, said Dvorak. “But spine injuries are the most severe with the most profound long-term consequences.”

The majority of riders, he explained, were injured as a result of either being propelled over the handlebars (going “endo”) or falling from great heights (“hucking”). In both scenarios, the result was often a severe impact to the head that triggered trauma down the neck and spine. “The higher the jump or fall,” added Dvorak, “the higher the risk.”

Perhaps surprisingly, the researchers found no relationship between helmet wearing and the overall severity of a rider’s injuries. “Helmets are good in preventing head injuries, but they do not in any way protect your neck,” noted Dvorak.

Also of unique concern to the sport is its “playing field”: remote forested and mountainous areas. Some of Dvorak’s patients had fallen while riding alone or at the back of a group. As a result, they were not found for an hour or more, and even then it was difficult for ambulances or helicopters to access the site.

His advice to mountain bikers: Be cautious about any tricks or jumps, know your terrain, and always ride in a group and stay together.

SOURCE: here 532.abstract The American Journal of Sports Medicine, online May 20, 2010.