Among the things which increase the anxiety level of parents of children playing contact sports is the fact that many high school programs don't employ athletic trainers who have received training in recognizing the often subtle signs of a concussion. Only 42 percent of U.S. high schools, according to the National Athletic Trainers' Association, have access to an AT.* In some states, the number is much lower (Over three-quarters of Nebraska high schools, for instance, are without ATs).