Frontline has produced a brilliant documentary on the effects and prevalence of concussions amongst football players. It's not limited to professionals as many belief. It happens to college players, and to teenagers.
Players of all ages have died from CTE, or Chronic traumatic encephalopathy. More than fifty brains of deceased NFL players have been examined, and well over forty were proven to have had CTE. Many living former players are suffering from its effects: memory loss, mood swings, the inability to concentrate. Many have turned to drug use, violence or suicide (e.g. Junior Seau).
The NFL owners knew about it all along. And they chose to pretend it didn't exist.
Neuropathologist Dr. Bennet Omalu was the first to uncover and track the effects and number of players with CTE. The NFL labelled Dr. Omalu's work as "voodoo". In other words, the league that said for fifty years, "Black men can't play quarterback," has said "Black men can't be good doctors."
In the film, some equate the NFL's denial of the link between concussions and CTE as being akin to the tobacco industry's denial of the link between tobacco and cancer. A truer comparison would be hard to make.
Watch the documentary. Stop watching football.
Five more still living players have been diagnosed with CTE, including wide receiver Mark "Super" Duper, and "hall of fame" running back Tony Dorsett.