Rules of the Game of Football

American football has been played largely in the United States since the 19th century. The sport combines qualities of both rugby and soccer. Standardization of rules began in 1873 through the Intercollegiate Football Association and evolved in subsequent years, including changes to the number of players on the field, the size of the field and the number of downs that a team was allowed to move the ball a sufficient distance forward. Variations such as Canadian football and arena football have similar rules to American football with some modifications.

  1. Setup

    • A football field is 100 yards long with yard markers every 10 yards

      American football is played on a field that is 100 yards long with end zones on either side of the field that are 10 yards long. The field is 53 yards wide. Each team has 11 players on the field at a time. The center of everyone's attention is the football, a spherical ball that has a circumference of between 28 and 28.5 inches, according to EquipmentforFootball.com. The game begins when one team kicks the ball to the other team, who then has possession of the ball.

    Movement

    • The team in possession of the ball attempts to move it down the field toward an end zone. The team can move the ball either by passes that travel through the air and are caught before touching the ground or by runs by a player holding the ball. When a player with the ball is tackled to the ground or knocked out of bounds or a passed ball is not completed, the ball is set down by a referee and a new play is run by the team with the ball. The possessing team must either reach the end zone or advance 10 yards within four plays or it will forfeit the ball to the other team. If it does advance 10 yards, it earns four more plays to score or move 10 more yards. Penalties called on either team move the ball either forward or backward.

    Scoreboard

    • The time periods of a football game vary by the level of competition. However, in the National Football League, the highest level of the sport, teams play four 15-minute quarters with an extended break (halftime) between the second and third quarters. Teams that reach an opponent's end zone in possession of the ball receive six points for what is called a touchdown. Following a touchdown, the ball is placed at the two-yard line and teams can choose to either attempt to kick the ball through the goalposts that stand behind the end zone (one point) or take one play to attempt to reach the end zone again (two points). Teams also are allowed to attempt to kick the ball between the goalposts before scoring a touchdown, which if successful means three points.

    Defense

    • The team playing defense attempts to stop the team in possession of the ball in a myriad of ways. The most prominent way is by tackling to the ground the opposing player who has the ball. However, the defensive team can also gain possession of the ball by stealing it from the opposing team or by catching an airborne pass before it touches the ground. A defense can score either by returning the ball to its opponent's end zone or by tackling an opposing player with the ball in that end zone.