Interviews

The head athletic trainer at Stephenville High School in Stephenville, Texas, he warns that relying on coaches to assess a player's health is a dangerous conflict of interest. "The athletic trainer at the secondary-school level is really the most important person to have to care for the kids," he tells FRONTLINE. "I just don't think a coach can do that."

A leading expert on heatstroke, he is a researcher at the University of Connecticut and chief operating officer at the school's Korey Stringer Institute, named for the Minnesota Vikings' offensive lineman who died of heatstroke in 2001. "There should never, ever be a person who dies from exertional heatstroke, because it's 100 percent survivable," he says.

A writer and columnist for ESPN, Easterbrook used to play high school football himself and now attends his son's games. "If you want to know where the scandals are in football, they are not in the NFL," he tells FRONTLINE. "They are in high school."

A co-director of the Purdue MRI Facility, Talavage authored a study that found cognitive damage in high school football players who had not been diagnosed with a concussion. "Nobody really expected to see this at the high school level ... and we certainly didn't expect to see it throughout the season in such a large percentage of the players."