In the early 20th century in the U.S., racial discrimination was common, with sports being segregated by race. However, in the 1936 Olympics, 18 African American athletes were able to compete, representing an opportunity for black athletes at a time when opportunities in college and professional sports were limited due to discrimination. Sports discrimination can take various forms including discrimination based on sex, religion, physical appearance, race, or political beliefs. However, rules requiring certain qualifications like age are not inherently discriminatory.