Heading a soccer ball causes at least short-term cognitive dysfunction, according to a new study by researchers at the University of Texas in Houston.
High school soccer players who had just completed a practice session that included heading the ball performed worse on an iPad cognitive test that measured reaction times when compared to non-soccer players.
Previous studies have found brain abnormalities in lifelong soccer players compared with the general population. The most recent study, published in the open access science journal PLOS ONE, shows that "soccer playing with ball-heading [results] in cognitive changes," but the study was unable to determine whether the effects were long-lasting. Previous studies have found that aerobic exercise (without head trauma) increases cognitive performance for a short period of time, so the study's authors suggest that the "disruption of cognitive performance in soccer players in [the] study was not likely due to aerobic activities immediately preceding the testing session."
"The most conservative interpretation of our findings is that these changes are transient and the result of the immediately preceding soccer session," the researchers write. "We are unable in our study to tease apart immediate transient effects from longer lasting effects due to the study design."
The authors suggest that further research is necessary to determine whether or not significant brain damage is possible from merely heading a ball.
"Though the [cognitive] changes we report were robust, they do not necessarily imply sustained changes or brain injury," they write.
Head injuries in sports, especially American football, has been a controversial topic of late. Before its 2012 season, the NFL announced it would donate $30 million to the National Institutes of Health for brain injury research, the single largest donation the organization has ever made.