It may not seem surprising that a sport that involves gigantic men slamming into one another goes hand-in-hand with head injury. But in American football, the severity of the life-long consequences has gone under appreciated until recently. And there are other sports that should be concerned. Soccer players who head the ball could be injuring their brains, as well, according to a recent paper in PLoS ONE.
The authors explain that it’s still unclear whether soccer balls can cause serious damage:
However, whether less violent head impacts such as heading a soccer ball could lead to subconcussive brain injury is unclear. A recent imaging study showed detectable structural differences in brain areas, consistent with traumatic brain injury (TBI), between amateur adult (mean age of 31 yrs, played soccer since childhood) soccer players with self-reported high and low heading frequencies. Similar findings were also obtained in another recent imaging study which found differences in white matter integrity in a small sample of professional male soccer players (mean age of 20 yrs, who played soccer since childhood) compared with a control group of swimmers (mean age of 21 yrs). Previous imaging studies have failed to find structural brain differences directly related to heading balls. Previous studies using formal cognitive testing have also failed to detect changes with ball heading in young adults or in 13- to 16-year-old soccer players.
In their study, the researchers had 24 high school soccer players, half men and half women, head the balls during a practice. They were then provided with a tablet and asked to perform a simple task—touch wherever the little white box was on the screen. What they found was that heading the ball made it harder for the athletes to complete the task. The PLoS press release explains:
According to the study, tasks that involve pointing away from a target require specific voluntary responses, whereas moving toward a target is a more reflexive response. Based on their observations, the authors conclude that sub-concussive blows to the head may cause changes specifically linked to certain cognitive functions.
Last year, another team of researchers took a different approach. They scanned the brains of professional soccer players in Germany, to look for the patterns that indicate brain injury common in boxers and football players. The Los Angeles Times writes:
Using a high-resolution MRI technique called diffusion tensor imaging, the researchers observed microscopic changes in the frontal, temporal and occipital lobes — regions that control attention, visual processing, higher thinking and memory.
What these studies actually mean…well, that’s unclear. It’s possible that these effects are so small that they don’t matter much. It’s also possible that they do matter a lot, and we just don’t know yet. And, for soccer players, it’s hard to imagine a way around heading. The American Youth Soccer Organization tested out helmets for kids, but it seems as though they don’t make much of a difference. Karen Mihara, the director of the AYSO, told the Los Angeles Times “they feel they’re protected and play with reckless abandon more than they might if they didn’t have it.”
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