It all started when San Francisco 49ers quarterback Colin Kaepernick took a knee during the playing of the national anthem ahead of NFL preseason football game. Since that Sept. 1 game, the gesture—one that aims to peacefully protest racial injustice—has spread to the sidelines of other NFL teams, to the soccer pitch and to high school fields. One school band even knelt during its performance of the anthem at a baseball stadium in Oakland, Calif. Variations of the knee have also taken hold, with players locking arms or raising a fist during the national anthem. Viewed by some fans—who think the gesture is an unpatriotic rejection of the nation itself—as an act of disrespect or defiance, Kaepernick has ignited a heated debate about the definition of patriotism in America.
Here, TIME has selected photographs of athletes—from the football field with Colin Kaepernick to the soccer pitch with Megan Rapinoe— as they protest racial injustice.