When the national anthem plays before the start of a U.S. sporting event, fans and players are expected to salute the flag by placing a hand over their hearts, often singing along. While not doing so is considered unpatriotic by some, athletes have at times abstained as a form of protest.
At the 1968 Olympics in Mexico City, U.S. athletes Tommie Smith and John Carlos each wore a black glove and raised a fist in the air during the medal ceremony as a sign of solidarity with those fighting for greater equality, which some dubbed as radical and an endorsement of the black power movement.
Former Denver Nuggets point guard Mahmoud Abdul-Rauf was suspended by the NBA after refusing to stand during the national anthem in 1996 because of what he called conflicts with his political and religious beliefs.
In 2003, Toni Smith, a basketball player from Manhattanville College in upstate New York, turned her back on the flag while the anthem played to protest America's involvement in Iraq.
San Francisco 49ers quarterback Colin Kaepernick recently refused to stand when the anthem was played during NFL games, citing police brutality against black people and other forms of racial injustice.