NEW YORK — More people are injured while snowboarding than in any other outdoor activity, accounting for a quarter of emergency room visits, according to the first national study to estimate recreational injuries.

Trailing snowboarding are sledding and hiking, researchers at the Centers for Disease Control and Prevention report in the journal Wilderness and Environmental Medicine.

The most common problems were broken bones and sprains, accounting for half of all cases. Seven percent of ER visits were for concussions or other brain injuries.

"We want people to participate in outdoor recreational activities. But we want people to recognize that there's cause for concern and people can and do get injured," study co-author Arlene Greenspan said Tuesday.

She said injuries can be avoided through planning and preparation: making sure your fitness level and skills match the activity and using proper equipment like helmets.

Greenspan said the study is the first to look at injuries from all activities, instead of individual sports or geographic areas.

The researchers looked at data on nonfatal injuries from outdoor activities treated at 63 hospitals in 2004 and 2005. They calculated that almost 213,000 people annually were treated for such injuries nationwide. About half of those injured are between ages 10 and 24 and half of the injuries are caused by falls.

Males are injured at twice the rate of females. "It could be that males are more risky or it could be that males just participate more than females, or a combination of both," said Greenspan.

From his experience on ski patrols, "it makes perfect sense to me that snowboard injuries rank high," said Dr. Paul Auerbach, of Stanford School of Medicine.

Auerbach, who writes a blog on outdoor medicine, said such studies allow researchers to look for patterns in injuries that can be used in prevention programs. He's one of the founders of the Wilderness Medical Society, which publishes the journal.

"Some activities have risks and you can't take all the risks out of the wilderness," said Auerbach. "But what you'd like to do is take the unnecessary risk out."

Percentage of emergency room injuries

1 Snowboarding26 percent

2 Sledding10.8 percent

3 Hiking6.3 percent

4 Personal watercraft or tubing3.7 percent

5 Mountain biking3.6 percent

6 Water skiing3.6 percent

7 Fishing3.3 percent

8 Swimming2.1 percent

9 Boating0.8 percent

10 Camping0.7 percent

Other39.7 percent*

Types of injuries

For both men and women of all ages, the most common injuries:

* Fractures27.4 percent

* Sprains 23.9 percent

* Contusions 15.9 percent

* Lacerations14.8 percent

* Other7.6 percent *

* Brain injury6.5 percent

* Dislocations3.8 percent

Safety measures

* Maintaining levels of fitness, knowing their skill levels and experience, and not exceeding their limits.

* Checking and maintaining their equipment and replacing if needed.

* Carrying a first-aid kit (and, if appropriate for the situation, a two-way communication device.)

* Alerting others about where they are going.