League of Denial: The NFL's Concussion Crisis
The National Football League presides over America's indisputable national pastime, but the league is under assault: Thousands of former players have claimed it tried to cover up how football inflicted their long-term brain injuries. What did the NFL know, and when did it know it? In a special two-hour investigation, FRONTLINE reveals the hidden story of the NFL and brain injuries.
Aired: 10/07/13Video has closed captioning.