As a soccer coach, I’ve often yelled at my players to head the ball before it reaches the ground.

And anyone who has watched the World Cup this year knows what a beautiful role heading plays in the game, with Robin van Persie’s goal in the Netherlands vs. Spain game a prime example.

But given the latest medical reports, I’m beginning to wonder how much I should push my team of 16-year-olds to hit the ball with their heads. Today, former U.S. women’s team star Brandi Chastain joined a couple of nonprofit advocacy groups in calling on new rules to restrict the use of heading among young players.

“I believe that the benefits of developing heading skills as children are not worth the thousands of additional concussions that youth soccer players will suffer,” said Chastain in a press release.

Specifically the Sports Legacy Institute (SLI) and the Institute of Sports Law and Ethics (ISLE) want to restrict heading to players of high school age or older. The idea is that younger children’s brains are still developing. Also their necks are not as strong as those of adults. Concussions happen when a sudden motion of the head causes the brain to slosh around in the skull.

SLI Founding Executive Director Chris Nowinski planned to push for these changes in a hearing today before the U.S. Senate Special Committee on Aging.

Here’s what the research shows about heading, concussions and soccer:

• About two-thirds of college soccer players experience a concussion during a season
• Most concussions occur when players hit each other, rather than the ball. But these collisions often happen in “heading duels” where two players are competing to head a ball.
• Various studies of the brains of players who report lots of heading show that they are different from the brains of other players.
• These players also perform worse on memory tests.
• Overall soccer players perform as well on memory tests as non-soccer players.
• There is mixed evidence about whether headgear reduces the risk of concussions in soccer. (Helmets are not all that effective against concussions in American football either, because they don’t stop the sloshing.)
• Researchers have identified one case of chronic traumatic encephalopathy (CTE) in an athlete who played soccer. Patrick Grange died of brain damage at age 29.

The evidence may not be enough to support particular guidelines yet:
Here’s what the American Pediatric Association says on the topic:

The risk of a head injury is comparable to other contact/collision sports, though evidence does not support repeated heading as a risk for short- or long-term cognitive issues. However, to reduce the risk of injury from heading the soccer ball, players should be taught proper heading technique at the appropriate age and with an appropriate-sized ball.

Excessive heading drills should be discouraged until more is known about the effects on the brain. Also, no recommendations regarding the use of helmets or cushioned pads to reduce head injury in soccer can be made at this time. More research and established safety standards and regulations are needed.

Given these findings, I’ll probably keep heading the ball myself. I’ll teach players how to do it, as well, with an emphasis on proper technique. I will consider neck strengthening exercises, which are already recommended for American football players to prevent concussion.

And I’ll keep an eye on the research as it develops.