In football, a sport that demands military-style discipline and singular focus, there's ample precedent for speaking out against the status quo.
What happened at the University of Missouri in recent days, with African-American football players calling for a boycott with the support of coaches, is dramatic, but it's the kind of action that was quite common around 50 years ago, according to historian Lane Demas, a professor at Central Michigan University.
"There's a three-year period of roughly 1967 to 1970 when there really was a wave of black football protest that coincided with kind of th