According to the National Federation of State High School Associations, some 1.14 million students annually participated in high school football. Approximately 9%, or at least 140,000 of these young athletes, suffered a concussion each year (Koester 2010). Training programs for high-school football coaches were increasingly focused on concussion recognition. But identification of a player at risk was not an easy matter. According to the Centers for Disease Control (CDC), the symptoms of a concussion were sometimes subtle and athletes often experienced or reported symptoms hours or even days after the concussive event (HHS). Coaches felt pressure to keep talented players on the field, and players often hid their symptoms in order to keep playing. Some high school players took their cues in this regard from professional players: