A new study of specialized football helmets shows that lighter blows to the head could be more serious than harder hits in some players.
Over the 2004 and 2006 seasons, football players at the University of North Carolina wore high-tech helmets that measured the amount of g-force players' heads sustained at impact.
Experts had thought forces over 75-g's would likely lead to a concussion. However, the UNC study showed some players suffered brain injury at around 60-g's, while others were bowled over with forces of over 90-g's without injury.
In fact, less than 1-percent of the hardest hits resulted in concussions. Researchers say this could lead to better guidelines for evaluating head injuries.