With the U.S. women’s soccer team winning the World Cup and coming home to a ticker tape parade in New York City — the first for female athletes in 50 years — parents may be eager to enroll their youngsters, and especially their daughters, in the increasingly popular sport.

While there are many things to recommend soccer as a sport, it can also cause injury, including concussions, in young people.

The victory of the Women’s National Team has created an aura of girl power for soccer, but it turns out high school girls suffer more concussions per capita than their male peers, according to a new study published today in the journal JAMA Pediatrics.  

Soccer Concussions

Researchers led by R. Dawn Comstock, Ph.D., of the Colorado School of Public Health at the Colorado University Anschutz Medical campus, found that for every 10,000 high school soccer games and practices, girls sustained 4.5 concussions while boy soccer players sustained just 2.8.

The risk of concussion is evident even on the triumphant Women’s National Team. Starting defender Ali Krieger wears a headband aimed at preventing concussions. (According to the Institute of Medicine, there’s no evidence that such headgear works.)

Second-string defender Lori Chalupny was initially turned away from this year’s national team because coaches were concerned about her history of concussions.

Even so, injury rates remain significantly lower in soccer than they are in American football and other full-contact sports, Comstock said.

Learn More About Concussions »

Gender Trouble

In sports like soccer and basketball where boys and girls play with the same rules and equipment, girls consistently have higher rates of concussion. It’s not clear why.

A 2013 Institute of Medicine study points to boys’ stronger necks. Comstock’s previous research found that on both boys and girls teams, players with stronger necks were less likely to get a concussion.

But there’s another possibility: Maybe girls’ injuries are simply more likely to be reported than boys’.

“Maybe girls are more informed, or maybe the adults around girls sports are more protective than the adults around boys sports,” Comstock said.

Teaching Athletes About the Dangers of Concussions »

Wrapping Your Head Around Heading

As soccer has become more popular among boys and girls and concussions more common, some have called for youth leagues to ban heading — the act of using of one’s head to direct a fast-traveling ball.

Heading may be hard to watch, but does it actually cause the concussions that happen on the soccer field?

“I’m not for banning heading and I’m not against it,” Comstock said. “But I’m an injury epidemiologist, so I like data-driven decisions.”

The researchers looked at data from more than 300 representative high schools in the United States to see whether heading was in fact the riskiest part of soccer. They found that player-to-player contact was the most common cause of concussion in both sexes, accounting for more than 7 in 10 concussions in boys and half of concussions in girls.

Girls were somewhat more likely to suffer a concussion while heading the ball. Just under 10 percent of concussions in girls soccer occurred while heading and were not attributable to player-to-player contact. In boys soccer, that figure was 7 percent.

Although heading was the single most common activity during which head injuries took place, it accounted for less than a third of all soccer-related concussions.

“You could reduce concussions by, at most, 30 if you ban heading, but you could prevent many, many more if you simply better enforce the existing rules of the game,” Comstock said.

Cracking Down on Rough Play

The findings suggest that the best way to reduce injuries in soccer is to crack down on the athlete-to-athlete contact that referees tolerate in the game.

One study footnoted in Comstock’s analysis concluded, based on hundreds of hours of videotape, that referees have, over time, allowed more rough play.

For instance, if one player is positioned to make contact with the ball as he or she jumps up to head it and another comes leaping in from the side, that second player is technically violating the rules of the game. This kind of violation is increasingly tolerated.

Comstock also pointed to several incidents during the third-place game in the Women’s World Cup when players body-checked one another. No fouls were called, despite written rules that prohibit such moves.

“Kids watch what their heroes do on live TV and they emulate them on the field,” Comstock said.

A concerted effort to reduce rough play could bring changes to the game, Comstock said, if history is a guide.

Soccer groups and officials previously set out to reduce the number of injuries caused by cleats during slide tackles. With consistent foul calls, officials forced players to be more careful and reduced the number of injuries.

“Soccer has been allowed to become a more and more aggressive sport. We don’t have to let it become football,” Comstock said.

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