Concussions are the leading cause of brain damage in sports, especially in football. But they're not the only type of head injury that's problematic: smaller hits, over the course of a season or career, can also add up.
Damir Janigro is the director of cerebrovascular research at the Cleveland Clinic and led the study published today in the journal PLOS ONE.
JANIGRO: Everybody knows that concussions are bad for you but one thing that people have frequently overlooked is the sub-concussive episode.
He's talking about those hits that are jarring but not full blown concussions. His study found over time these hits were linked to whiplash-like brain damage in some football players.
JANIGRO: Our fear is that these episodes may accelerate brain aging.
Janigro's research adds to the growing body of evidence on this topic.