President Barack Obama today honoured the two African-American sprinters who protested against racial inequality with a gloved fist salute at the 1968 Olympics in Mexico.
Their defiance cost them their careers in sport, but similar protests are now being seen at stadiums across the US.
Tommie Smith and John Carlos became an iconic image of the Civil Rights movement and President Obama says America is "proud of them".
"Their powerful silent protest of the 1968 games was controversial, but it woke folks up, and it created a greater opportunity for those that followed," he said.
Their protest has been remembered in the context of recent actions by NFL players and other athletes who refuse to stand during the national anthem as a protest over police shootings of minorities.
During a town-hall meeting with US soldiers and their families, President Obama defended the protests conducted by football players such as Colin Kaepernick.
"I want Mr Kaepernick and others who are on a knee to listen to the pain that that may cause somebody who, for example, had a spouse or a child who was killed in combat and why it hurts them to see somebody not standing," he said.
"I also want people to think about the pain he may be expressing about somebody who's lost a loved one that they think was unfairly shot. One of thing I saw about American democracy is that it can be frustrating, but it’s the best system we've got."