Concussion and college football: How many hits to the head is too much?

Many studies have already shown how the structure and function of American football players brains change throughout the course of their careers. This happens with or without them ever being diagnosed with concussion after head impacts. The findings of these studies suggest that damage to the brain following successive head impacts reaches a certain tipping point, by which an athlete's chances of suffering concussion increases.

To investigate whether repetitive head impacts play a role in the onset of concussion in college football players, Stemper and his colleagues turned to Division 1 of America's National Collegiate Athletic Association (NCAA). The researchers matched 50 athletes suffering concussion with others who did not, but who played in the same position and were on the same team.

The analysis shows that repetitive head impact exposure plays a role in the occurrence of concussive injuries in some college football athletes. Overall, compared to the players in the control group, 72 per cent of the concussed athletes in the study experienced more exposure to head impacts either on the day of suffering a concussion, or during the season leading up to the event. The link between cumulative exposure to head impacts and a subsequent onset of concussion was more pronounced among athletes taking part in more contact activities. For example, 82 per cent of athletes who participated in ten or more days of contact play had greater head impact exposure than their matched control group.

"This unique analysis provides further evidence for the role of repetitive head impact exposure as a predisposing factor for the onset of concussion among Division 1 college football athletes," says Stemper. "While these trends require further validation, the clinical implication of these findings supports the contemporary trend of limiting head impact exposure for college football athletes during practice sessions."