By Katie Kerwin McCrimmon

Lacrosse is the fastest-growing high school sport in the country with 170,000 athletes now playing, and a new study shows girls could benefit from wearing helmets like boys do.

Boys’ lacrosse is a full-contact sport and athletes wears pads and helmets to protect them as they check each other with their bodies and sticks.

In girls’ lacrosse, athletes are not supposed to hit each other directly. So girls wear protective goggles and mouth guards, but not helmets or pads. The new study published Tuesday in the The American Journal of Sports Medicine shows that helmets could prevent a significant percentage of concussions.

“In girls’ lacrosse, nearly 70 percent of concussions were caused by the ball actually striking the girl’s head or the stick striking her head,” said Dawn Comstock, one of the study’s lead authors and an associate professor of epidemiology at the Colorado School of Public Health.

In boys’ lacrosse by comparison, athlete-to-athlete contact caused 74 percent of concussions.

“That’s an important difference,” Comstock said. “Our data seem to support the call for putting girls’ lacrosse players in helmets.”

She compared the injuries in girls’ lacrosse to accidents on construction sites. Construction workers wear helmets to protect themselves from objects that could strike their heads, like falling hammers. That’s similar to a ball or stick landing on a player’s head, and helmets do a good job of protecting from injuries like that, Comstock said.

Helmets can’t offer as much protection when two players crash into each other and the force of their collision snaps their heads back and forth on the neck, shaking the brain.

Overall, Comstock said injury rates in youth athletics are relatively low and the benefits of playing sports far outweigh any injury risks.

“We want kids to be more physically active more often,” Comstock said. “My job is to keep them as safe as possible while they’re playing sports.”

The study found that between 2008 and 2012, the injury rate in both boys’ and girls’ playing high school lacrosse was 20 per 10,000 competitions and practices.

Despite those relatively low injury rates, Comstock said there’s a vigorous debate across the country about whether girls should wear helmets in lacrosse. Florida is the first state so far to require helmets. But the mandate is new for this fall and may not go into effect, she said.

Pioneered by Native Americans, lacrosse is booming in Colorado and the western U.S. after long being popular in the Northeast. About 6,000 athletes now play high school lacrosse in Colorado. Across the country, Comstock’s study showed boys get injured more often than girls, sustaining 67 percent of the total injuries. Among boys, about 36 percent of injuries were sprains and strains, and about 22 percent were concussions. Of those head injuries, player to player contact caused 74 percent of the concussions and 41 percent of injuries overall.

Among girls, 44 percent of injuries stemmed from sprains and strains. Like the boys, about one in four injuries among girls stemmed from concussions. The causes of those concussions were different, and that was unexpected for Comstock and her fellow researchers.

“The biggest surprise was how glaring the difference was in the mechanism of the concussion between girls and boys. That’s very striking. We don’t see that kind of difference in other sports played by both boys and girls,” she said.

Unlike soccer, lacrosse has different rules by gender, but the injury patterns reveal new information, she said.

Full contact sports — including football, hockey and boys’ lacrosse — lead to the highest number of injuries for high school athletes, Comstock said. In those sports, athlete-to-athlete contact is the main cause for all injuries.

In sports like soccer, basketball and girls’ lacrosse, athletes are not supposed to have full contact, but sometimes run into each other. Injuries rarely occur in other sports, including swimming, diving, track and field, volleyball and cross-country running.

Comstock created and runs the National High School Sports-Related Injury Surveillance System, also known as High School RIO. It’s an online data collection tool that tracks injuries in 22 sports. Last year, athletic trainers at 280 high schools across the U.S. participated, providing detailed injury reports for the survey that began in the 2005-06 academic year.

Comstock initially tracked nine sports and in 2007-08, expanded to monitor injuries in 22 sports ranging from football to diving to track and field.

“In the first nine years, we’ve captured over 60,000 individual injury case reports in over 30 million athletic exposures. This is a really large data set, which gives us the power to look at very interesting patterns.”

The lacrosse study harnesses that data and is the first to compare injuries in the sport among high school athletes by type of incident and gender.

If Florida proceeds with the requirement for girls to wear helmets, Comstock will be able to track injuries and see if they go down based on the rule change.

In general, when officials ponder adding protective equipment, Comstock said the arguments against it are always the same. First, there’s what she calls the “gladiator effect.”

“If we put protective equipment on athletes, they will feel invincible, will play harder and injuries will increase instead of decreasing.”

Comstock said she’s never seen a study showing that the gladiator effect really exists.

Athletes and coaches also worry that if the athletes wear helmets or goggles, their vision will suffer and they’ll run into each other more.

“I haven’t see that yet,” said Comstock, who is monitoring changes in field hockey rules that help her gauge the impacts of requirements for protective eye wear in some regions.

And third is a fear that helmets increase the mass of the head and therefore could make some types of concussions more severe.

The debate around the country and evolving rules about protective gear will allow her to continue to make conclusions over time.

“It’s very, very remarkable that Florida has taken the first steps toward adding helmets for girls,” she said. “Now we can follow it over time and see.”