High-tech helmets reveal new information about the impact of hard hits t...( CHAPEL HILL -- In a game that spawne...)

CHAPEL HILL -- In a game that spawned the term "slobber knocker," is there a limit to the amount of impact a football player's head can handle before the player suffers a concussion"

The answer is yes ... and no, say researchers at the University of North Carolina at Chapel Hill. High-tech helmets worn by some University of North Carolina football players over the 2004 to 2006 seasons yielded new data that challenges conventional theories about these mild traumatic brain injuries.

The UNC study, in the December issue of Neurosurgery, shows that hits, and heads, are as individual as the players themselves, and researchers advise against establishing a one-size-fits-all rule for evaluating concussions.

"People see massive hits and think, 'that's the one!' and ignore more trivial blows," said Kevin Guskiewicz, Ph.D., senior author on the papers and chair of the department of exercise and sport science in UNC's College of Arts & Sciences. "Now we know that these trivial hits may be just as serious as the harder ones."

This new information could lead to better guidelines for evaluating head injuries and deciding a player's playing status, Guskiewicz said. It might also lead to a better understanding of brain injuries from other trauma, or perhaps of diseases such as mild cognitive impairment and Alzheimer's which have been linked to recurrent concussion in professional players.

Using special accelerometers embedded in helmets, researchers were able to measure in real time the amount of g-force players' heads experienced at impact, where on the head the players were hit and the directional force of the hits -- linear (straight) or rotational (twisted). The system is called HITS, or Head Impact Telemetry System.

G-force, a measure of acceleration against the earth's gravitational pull, is most often associated with fighter jets or roller coasters. In those scenarios, the body takes a maximum of about 4.5g, or four
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