Concussions account for as many as 8.6 percent of injuries in soccer, according to a study by Dr. Tom Schweizer, director of the neuroscience research program at St. Michael's Hospital in Toronto, Newsmax Health reports. Some of these concussions are caused by collisions, while others come from heading -- deliberately using your head to control the ball.
Not enough attention is paid to the consequences of this particular tactic, which can have lasting effects on thinking and memory even when the blows to the head aren't severe enough to cause a concussion, Schweizer said.
In a review of existing studies published online recently in the journal Brain Injury, Schweizer examined how often concussions occur in soccer.
One study revealed that nearly 63 percent of varsity soccer players had symptoms of a concussion at some point, but only about 19 percent knew it.
The research found that those who suffered one concussion had a 3.15 times greater chance of having another one than players who never had this type of injury.
One study noted that professional soccer players who engaged in the most heading performed the worst on verbal and visual memory tests as well as tests of their attention span.
The studies that involved brain imaging found players who suffered concussions had physical changes to their brain.