Lock your feet onto a snowboard, and you can expect to fall. But whether or not a fall results in a broken wrist or separated shoulder depends on a lot of factors -- including just how you go down.

Based on information from nearly 2,000 upper extremity fractures and dislocations, researchers in Japan found that snowboarders lacking licensed instruction accounted for 9 out of every 10 injuries -- the largest portion of which were to the wrist from a backward fall.

"Many snowboarders think that because the surface is made of snow, it will always be soft," Gregg Davis, a snowboarding instructor at Breckenridge Ski and Ride School in Colorado, noted in an email to Reuters Health. "Most of the time the surface is quite hard and can lead to a strong impact on the extremities," added Davis, who was not involved in the study.

Previous studies have shown that about half of all snowboarding injuries occur to the upper extremities. However, no one ever teased apart the influences of snowboarding stances and fall directions.

Dr. Kei Miyamoto of Gifu University in Japan and colleagues looked for such details in the records of snowboarders treated for injuries at a Japanese hospital between 2000 and 2008 -- shortly after the sport's 1998 Olympic debut in Nagano, Japan, and subsequent rise in popularity.

After excluding injuries from jumps, half-pipe and collisions, they identified 1,918 fractures and dislocations of the wrist, arm, elbow or shoulder. According to the investigators, about 1 out of every 50,000 snowboarder visits to their local Okumino ski area resulted in one of these injuries. Statistics show that U.S. ski mountains welcome approximately 60 million snowboarder visits each year, with 4 to 7 of every 1,000 visits resulting in some type of injury.

"Most of the injuries occur when new snowboarders try to teach themselves or have friends show them how to do it instead of an instructor," noted Davis. "Just a single day's lesson makes all the difference."

Miyamoto's team reports that most of the injured snowboarders (88 percent) had not taken snowboarding lessons from a licensed instructor. Only about 12 percent did. Most of the injured snowboarders were beginners.

The researchers found that shoulder and upper arm injuries typically resulted from the front edge of the snowboard catching the snow and the rider falling forward, while wrist and elbows were more likely hurt with a backward fall. Both fall directions were nearly equally likely, report the researchers in the American Journal of Sports Medicine.

They also found that it did not matter whether the snowboarder slid down the mountain with their left or right foot forward; the latter technique is dubbed "goofy" and is more likely used by a left-handed rider.

"Most of the wrist fractures occurred on the side opposite to the sliding direction, while most of the shoulder dislocations, upper arm fractures, and elbow fractures and dislocations occurred on the same side as the sliding direction," Miyamoto told Reuters Health.

Snowboarders' wrists sustained half of all injuries. The finding jives well with Davis' 18 years of experience as an instructor at Breckenridge: The few injuries he has seen were "almost entirely" to the wrist due to falling back and bracing with the hands on the snow, he said.

One of the first things Davis teaches his students is to curl their fingers into their hands. "This helps to keep new riders from using the palms to contact the snow," he said. "Instead it spreads potential impacts to the forearms and the entire body when falling."

If a snowboarder falls forward, a headfirst baseball slide works well, adds Miyamoto. For a graceful and injury-free backward fall, Miyamoto suggests taking a cue from the martial art, judo: hit the snow with your back side, arms at your sides, and with a slight jump into the fall at the moment your body loses its balance.

SOURCE: http://link.reuters.com/quh82m

American Journal of Sports Medicine, online June 3, 2010.