According to a new study, sledding is the most dangerous winter activity, causing more injuries than hockey, snowboarding, snowmobiling and skiing.

Researchers found that more than 700,000 injuries are caused in the United States each year due to sledding. And, more than 30 percent are head injuries caused by collisions.

While the numbers might be surprising at first, they make sense when you consider that sleds can often reach speeds in excess of 25 miles per hour. Here's a rundown of some sledding safety tips to consider:

Have parental supervision at all sledding outings.

Make sure children wear helmets.

Choose a site without trees, fences or buildings.

Check for holes, ditches, roots or other possible hazards under the snow.

Avoid collisions by allowing only one sled on a hill at a time.

Do not use cardboard boxes, cafeteria trays or other sled substitutes.