In football, a hit can easily jerk the head, for milliseconds, at 50g, and hits above 100g are common. One player in the study experienced 168g. It was previously suggested that a forces above 75g would likely result in a concussion, but these new results call into question that finding.
The UNC studies showed that some players suffered concussions at little more than 60g, while others sustained hits creating more than 90g and showed no signs of concussions; less than .35 percent (only one-third of one percent) of impacts greater than 80g resulted in concussions.
In one study, researchers collected data from 88 UNC players from fall 2004 through spring 2006 to determine a relationship between impact location and concussion. Eleven players sustained a concussion; one player had two concussions.
Players in the study were 6.5 times more likely to have sustained an impact greater than 80g to the top of the head rather than the sides, front or back. Six of the 13 concussions came from hits to the crown.
Another study, by graduate student Meghan McCaffrey, sought to compare differences in balance and cognition in players who did not self-report concussive symptoms within 24 hours of sustaining high-impact hits (90g) and low-impact hits (60g).
The study showed no statistically significant difference between the two groups.
"Our findings suggest that clinicians should not expect a single impact greater than 90g to necessarily result in immediate symptoms of a concussion," McCaffrey said.
Players in each of the studies represented various offensive and defensive positions, but the third study, by graduate student Jason Mihalik, looked for differences among playing positions and differences between practices and games in 72 players.
Offensive backs and wide receivers are more likely to take
|Contact: Clinton Colmenares|
University of North Carolina at Chapel Hill