I have been "taking a knee" since I started kindergarten. Born and raised Catholic part of our religion dictates that to show respect and honor to the church altar before mass that we "genuflect" which is defined as placing one or both knees on the ground. Catholics also Genuflect when during mass they receive the communion, the Holy body of Christ.  Other common "take a knee folks" are those who do so to respect and honor royalty and knights who are being knighted by a King or Queen. The more common use of Genuflection today is by a man who "takes a knee" as a sign of his love and dedication to the woman he is now asking to marry him. So Genuflection, or now with a new nickname of "taking a knee"  has a long history of an act that is done only to clearly demonstrate respect, honor and dedication from the person who is "taking the knee".