Concerns over police brutality against African-Americans have led to a wave of athlete protests in recent weeks. Players across the country, from pee-wee sports to the pros, have followed the lead of the San Francisco 49ers quarterback Colin Kaepernick, whose kneeling during the national anthem has spurred a national debate. So far, only a handful of college athletes have participated in the demonstrations. Athletics leaders say that many players have shown support for Mr. Kaepernick, with some expressing a desire to take a knee themselves.