Kaitlyn Gerber, Carleton College
For years, parental concerns regarding the dangers of heading the ball, or deliberately taking the ball out of the air with the player's head, have been brushed off by players, coaches, and even FIFA, the international soccer federation. In 2001, a study conducted by the U.S. Soccer Federation and the UNC Orthopedic Clinic found that that intentionally heading the ball spreads out the impact over the entire body, minimizing risk of a concussion. When presenting the study, Dan Flynn, USSF Secretary General, concluded that "diminution of cognitive function comes from head injury, not simply heading the ball."
But what if they were wrong?
Through advanced MRI-based tests on 38 amateur soccer players, researchers at the Albert Einstein College of Medicine determined that players who headed the ball frequently showed symptoms similar to those seen in patients who have sustained concussions, also known as mild traumatic brain injuries (TBI). In a press release and a presentation at the Radiological Society of North America (RSNA) in Chicago, the researchers explained that there appeared to be a threshold of how many balls a player can head before sustaining brain damage -- in this case, 1,100 to 1,500 times per year, depending on which part of the head comes into contact with the ball.
“While heading a ball 1,000 or 1,500 times a year may seem high to those who don’t participate in the sport, it only amounts to a few times a day for a regular player,” said lead author Michael Lipton, MD, PhD. “Heading a soccer ball is not an impact of a magnitude that will lacerate nerve fibers in the brain,” said Dr. Lipton. “But repetitive heading may set off a cascade of responses that can lead to degeneration of brain cells.”
The players who participated in the study were volunteers who had played competitive soccer since childhood, though none had played at a professional level. Participants completed a detailed questionnaire developed especially for the study so that the researchers could determine approximately how many times they had headed the ball in the previous year, and whether or not they had previously experienced concussions. These surveys were also intended to rule out any additional variables that may have caused brain damage in certain players, so that heading the ball could be isolated as the specific cause for brain damage.
The results indicated that heading did, in fact, produce some brain damage, but only if the player exceed the 1,000 to 1,500 limit. Using an advanced MRI-based technique called diffusion tensor imaging (DTI), the researchers were able to isolate five areas in the brain's frontal lobe and temporal-occipital lobe that showed significant loss of white matter compared with peers who did not head the ball frequently enough to reach the threshold. These areas are normally responsible for attention, memory, executive functioning and higher-order visual functions.
In a subsequent study conducted with Lipton's colleague Molly Zimmerman, the same 38 players were tested on their verbal memory and psychomotor speed relative to their peers. The results showed that players who headed the ball frequently performed substantially worse than their peers -- even though most of them were not aware of any mental deficits.
Dr. Lipton explained: “These two studies present compelling evidence that brain injury and cognitive impairment can result from heading a soccer ball with high frequency.”
Admittedly, there have been several previous indications that heading the ball may have physiological and psychological consequences. A 1991 study conducted by the National Hospital in Oslo, Norway found that retired professional players showed significant deficits in memory, judgment, and concentration as compared to their peers. They also experienced dizziness and headaches more often than normal. However, studies such as this one failed to account for possible alcohol use or histories of concussions, so the results were generally overlooked. Still, the connection between soccer and concussions has never been clearer. Concussions occur when the brain slams into the skull, causing internal bleeding on the brain and mild to severe symptoms such as dizziness, nausea, headaches, and memory problems.
A soccer player myself, I became aware of these statistics the hard way when, during my senior year of high school, I sustained a moderate concussion when I collided in mid-air with another player's elbow and was knocked temporarily unconscious. I don't remember much about the actual accident, but I do remember the confusion and headaches that followed me throughout the next few days. In the month that followed, I learned how common concussions are in soccer, particularly in the women's game; one 2007 study led by Dawn Comstock found that among high school sports, girls and boys soccer rank second and third, respectively, for concussion rates, behind only football. I returned to playing after about three weeks of rest and recovery. Other players aren't so lucky.
Most concussions, however, are the result of colliding with objects -- players' elbows, players' heads, the goalposts, or ground. Rarely are actual concussions caused by heading the ball itself. But this new study shows that this point may not matter -- in the end, frequent heading of the ball causes very similar damage to a concussion -- even if it is not a concussion in itself. In the two years since my own concussion, I've always attributed frequent headaches to that particular incident, and nothing more. Now I wonder whether the real culprit is simply that I love heading the ball.
Soccer is the most popular sport in the world, and heading the ball is an integral part of the game. While I agree that these results should not be taken lightly, I'm not sure that the solution is as simple as encouraging kids to head the ball less frequently, especially since learning to head the ball safely -- that is, with proper neck support rather than on the top of your head -- is a key part of preventing injury later on. However, as it stands, something has to change. I'm not sure whether that would be developing protective gear or simply encouraging children to trap the ball on the ground more frequently. I do know, though, that as wonderful as the game of soccer is, it isn't worth a lifetime of brain damage in my future.
Kaitlyn Gerber is a sophomore at Carleton College, where she plans to major in biology. Originally from Ridgefield, CT, she is an active soccer player and science fan, especially of ecology and astronomy.