One in five teens has suffered a concussion from contact sports, a new study shows.
The research from the University of Michigan comes amid huge controversy over sport-linked brain injuries, threatening the entire culture of school and professional games.
Researchers found 5.5 percent of middle schoolers have had more than one concussion.
It comes on the heels of a major study by Boston University which showed that children who start playing football from at least age 12 will suffer emotional and behavioral damage in later life.
