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|A trainer attends to Kevin Everett after he showed no signs of consciousness following a helmet-to-helmet hit on Denver's Domenik Hixon at the start of the second half.|
Buffalo Bills reserve tight end Kevin Everett likely experienced about two-thirds of a ton of compressive force on his spine in a hit Sunday that left him with a serious spinal injury, according to a professor who has studied the physics of football.
Dr. Timothy Gay, professor of physics at the University of Nebraska-Lincoln, said kickoffs produce more violent collisions than almost any other play in football because players have more of a chance to get up to full speed.
Gay, who was not at the game but saw video slow-motion replays, said it appears Everett's head was down when he made the tackle. That means the force of the collision was applied to his spine.
"That's why you don't go flying at a guy without your head up," said Gay, who played football at Caltech."The problem is ultimately it's a dangerous sport. You have 250-pound guys running 10 feet per second into each other. You're putting yourself in a dangerous position."
There were physics and physiology at play in Everett's case, said Gay, author of "Football Physics: The Science of the Game." The physics at play mostly involved Newton's 2nd Law of Motion: F = ma (force equals mass times acceleration). When a player undergoes extreme deceleration -- as Everett did when he hit Denver's Domenik Hixon during the second-half opening kickoff -- there will be a big force required to cause that deceleration. If Everett's head was up so his neck was not compressed, then the same force would not have done the same physiological damage.
Gay said, in his opinion, more protective head restraints or different equipment likely wouldn't have made a difference in Everett's case because the issue was the angle of his head at the moment of impact.
-- Jena Janovy, ESPN.com