The offense must advance at least ten yards on four downs or plays; if unsuccessful, they deliver the ball to the defense, but if successful, they are given another set of four tries to continue training.
Points are scored primarily by advancing the ball into the opponent’s end zone for a touchdown or by hitting the ball through the opponent’s goalposts for a field goal.
The team with the most points at the end of a match wins.
Evolved in the United States, originating from the sports of soccer and rugby. The first game of American football was played on November 6, 1869, between two college teams, Rutgers and Princeton, using rules based on football rules of the day.
A series of rule changes developed beginning in 1880 by Walter Camp, the “father of American football”, established the snap, line of scrimmage, eleven-man teams, and the concept of downs.
Later rule changes legalized the forward pass, created the neutral zone, and specified the size and shape of the stock.
The sport is closely tied to Canadian football, which evolved alongside and concurrently with the American game, although its rules were developed independently of those of the Camp.
Many of the characteristics that distinguish American football from rugby and soccer are also present in Canadian football. Both sports are considered the main variants of grid football.
American football is the most popular sport in the United States. The most popular forms of the game are professional and college football, while the other major levels are high school and youth football.
As of 2012, nearly 1.1 million high school athletes and 70,000 college athletes play the sport in the United States each year.
The National Football League, America’s most popular professional football league, has the highest average attendance of any professional sports league in the world. Its championship game, the Super Bowl, is one of the most-watched club sporting events in the world.
The league has an annual revenue of approximately $15 billion, making it the most valuable sports league in the world. There are other professional leagues around the world, but the sport lacks the international popularity of other American sports like baseball or basketball.