As reported in the March 11, 2013 issue of American Journal of Sports Medicine, researchers reviewed:
... the 243 football fatalities reported to the National Center for Catastrophic Sports Injury Research from July 1990 through June 2010 ... Football fatalities averaged 12.2 per year, or 1 per 100,000 participants.
Most indirect events occurred in practice sessions; preseason practices and intense conditioning sessions were vulnerable periods for athletes to develop heat illness or SCT fatalities, respectively. In contrast, most brain fatalities occurred during games.
High school and college football have approximately 12 fatalities annually with indirect systemic causes being twice as common as direct blunt trauma. The most common causes are cardiac failure, brain injury, and heat illness. The incidence of fatalities is much higher at the college level for most injuries other than brain injuries, which were only slightly more common at the college level. The risk of SCT, heat-related, and cardiac deaths increased during the second decade of the study, indicating these conditions require a greater emphasis on diagnosis, treatment, and prevention.