American football in the United States and Canada is called rugby, also known as "gritty iron football" or "gritty iron" for short. The game is played on a rectangular field by two teams of 11 players, with goalposts at each end. The attacking side is the team that controls the oval football. They try to move forward by dribbling or passing the ball, while the uncontrolled team, the defending side is to stop the advance and control the ball. Own ball. The offense must advance at least ten yards in four falls or plays, or they will hand over the football to the other team; if they succeed, they will get four new defeats. Scoring is mainly achieved by pushing the ball to the end of the opponent's team for touchdown or kicking the ball past the opponent's goal post. The team with the highest score at the end of the game won.

American rugby originated from the association rugby and the development of rugby in the United States. The first game of American rugby was played between Rutgers University and Princeton University on November 6, 1869, according to the rugby rules at that time. In the second half of the 1870s, the University Football Association switched to the rugby league code, allowing the ball to be carried. Since 1880, Walter camp, the father of American football, has formulated a series of rules and established the concept of a fast-growing team composed of 11 people and a low valley. Later rule changes legalized the forward pass, created neutral zones, and specified the size and shape of the football.

In general, American football is the most popular sport in the United States. The most popular form of the game is professional football and college football, and other major levels are high school and youth football. As of 2012, nearly 1.1 million high school athletes and 70000 university athletes participated in the sport every year in the United States, with a few exceptions, almost all of them men. The National Football League is the most popular American Football League, with the highest average attendance rate in any professional sports league in the world; its championship "super bowl" is one of the most watched club sports events in the world, with an annual revenue of about 10 billion dollars.