In gridiron football, a line of scrimmage is an imaginary transverse line (across the width of the field) beyond which a team cannot cross until the next play has begun. Its location is based on the spot where the ball is placed after the end of the most recent play and following the assessment of any penalty yards.
The line of scrimmage first came into use in 1880. Developed by Walter Camp (who introduced many innovations that are part of the modern game of American football), it replaced a contested scrimmage that had descended from the game's rugby roots. This uncontested line of scrimmage would set into motion many more rules that led to the formation of the modern form of gridiron football (although the Canadian rules were developed independently of the American game, despite their similarities).
A line of scrimmage is parallel to the goal lines and touches one edge of the ball where it sits on the ground prior to the snap. In American football, the set distance of the line of scrimmage between the offense and defense is 11 inches (28 cm), the length of the ball. In Canadian football, the set distance of the line of scrimmage is 1 yard (91 cm), more than three times as long as the American line.
Under NCAA, and NFHS rules, there are two lines of scrimmage at the outset of each play: one that restricts the offense and one that restricts the defense.The area between the two lines (representing the length of the ball as extended to both sidelines) is called the neutral zone .
Modern video techniquesenable broadcasts of American football to display a visible line on the screen representing the line of scrimmage. The line is tapered according to the camera angle and gets occluded by players and other objects as if the line were painted on the field. The line may represent the line of scrimmage or the minimum distance that the ball must be moved for the offensive team to achieve a first down.
Many fans and commentators refer colloquially to the entire neutral zone as the "line of scrimmage," although this is technically incorrect. In the NFL rulebook, only the defensive-side restraining line is officially considered a line of scrimmage.Referees, when explaining a penalty, will refer to "the previous spot" instead of the "line of scrimmage" to avoid confusion.
Canadian football is a sport played in Canada in which two teams of 12 players each compete for territorial control of a field of play 110 yards (101 m) long and 65 yards (59 m) wide attempting to advance a pointed oval-shaped ball into the opposing team's scoring area.
In gridiron football, not all players on offense are entitled to receive a forward pass: only an eligible pass receiver may legally catch a forward pass, and only an eligible receiver may advance beyond the neutral zone if a forward pass crosses into the neutral zone. If the pass is received by a non-eligible receiver, it is "illegal touching". If an ineligible receiver is beyond the neutral zone when a forward pass crossing the neutral zone is thrown, a foul of "ineligible receiver downfield" is called. Each league has slightly different rules regarding who is considered an eligible receiver.
A snap is the backward passing of the ball in gridiron football at the start of play from scrimmage.
The quarterback, colloquially known as the "signal caller", is a position in gridiron football. Quarterbacks are members of the offensive platoon and mostly line up directly behind the offensive line. In modern American football, the quarterback is usually considered the leader of the offense, and is often responsible for calling the play in the huddle. The quarterback also touches the ball on almost every offensive play, and is the offensive player that almost always throws forward passes. When the QB is tackled behind the line of scrimmage, it is called a sack.
Gridiron football, also known as North American football or, in North America, simply football, is a family of football team sports primarily played in the United States and Canada. American football, which uses 11-player teams, is the form played in the United States and the best known form of gridiron football worldwide, while Canadian football, featuring 12-player teams, predominates in Canada. Other derivative varieties include arena football, football for smaller teams, flag football and amateur games such as touch and street football. Football is played at professional, collegiate, high school, semi-professional, and amateur levels.
A down is a period in which a play transpires in gridiron football. The down is a distinguishing characteristic of the game compared to other codes of football, but is synonymous with a "tackle" in rugby league. The team in possession of the football has a limited number of downs to advance ten yards or more towards their opponent's goal line. If they fail to advance that far, possession of the ball is turned over to the other team. In most situations, if a team reaches their final down they will punt to their opponent, which forces their opponent to begin their drive from further down the field; if they are in range, they might instead attempt to score a field goal.
American and Canadian football are gridiron codes of football that are very similar; both have their origins in rugby football, but some key differences exist.
Strategy forms a major part of American football. Both teams plan many aspects of their plays (offense) and response to plays (defense), such as what formations they take, who they put on the field, and the roles and instructions each player are given. Throughout a game, each team adapts to the other's apparent strengths and weaknesses, trying various approaches to outmaneuver or overpower their opponent in order to win the game.
Gameplay in American football consists of a series of downs, individual plays of short duration, outside of which the ball is dead or not in play. These can be plays from scrimmage – passes, runs, punts, or field goal attempts – or free kicks such as kickoffs and fair catch kicks. Substitutions can be made between downs, which allows for a great deal of specialization as coaches choose the players best suited for each particular situation. During a play, each team should have no more than 11 players on the field, and each of them has specific tasks assigned for that specific play.
A formation in football refers to the position players line up in before the start of a down. There are both offensive and defensive formations and there are many formations in both categories. Sometimes, formations are referred to as packages.
In gridiron football, the neutral zone is an area in which no member of either team may be, other than the person holding the ball. The neutral zone only exists in dead ball situations.
In American football, the specific role that a player takes on the field is referred to as their "position". Under the modern rules of American football, both teams are allowed 11 players on the field at one time and have "unlimited free substitutions", meaning that they may change any number of players during any "dead ball" situation. This has resulted in the development of three task-specific "platoons" of players within any single team: the offense, the defense, and the so-called 'special teams'. Within these three separate "platoons", various positions exist depending on the jobs that the players are doing.
A comparison of American football and rugby union is possible because of the games' shared origins, despite their dissimilarities.
In gridiron football, motion refers to the movement of an offensive player at the time of the snap.
The following terms are used in American football, both conventional and indoor. Some of these terms are also in use in Canadian football; for a list of terms unique to that code, see Glossary of Canadian football.
American football, referred to simply as football in the United States and Canada, and also known as gridiron, is a team sport played by two teams of eleven players on a rectangular field with goalposts at each end. The offense, the team with possession of the oval-shaped football, attempts to advance down the field by running with the ball or passing it, while the defense, the team without possession of the ball, aims to stop the offense's advance and to take control of the ball for themselves. The offense must advance at least ten yards in four downs or plays; if they fail, they turn over the football to the defense, but if they succeed, they are given a new set of four downs to continue the drive. Points are scored primarily by advancing the ball into the opposing team's end zone for a touchdown or kicking the ball through the opponent's goalposts for a field goal. The team with the most points at the end of a game wins.
In gridiron football, a penalty is a sanction called against a team for a violation of the rules, called a foul. Officials initially signal penalties by tossing a bright yellow or orange colored penalty flag onto the field toward or at the spot of a foul.
Offside is a minor foul in gridiron football caused when a defender crosses the line of scrimmage ahead of the snap of the ball. The penalty associated with the infraction is the advancing of the ball five yards and a replay of the down.
In gridiron football, a punt is a kick performed by dropping the ball from the hands and then kicking the ball before it hits the ground. The most common use of this tactic is to punt the ball downfield to the opposing team, usually on the final down, with the hope of giving the receiving team a field position that is more advantageous to the kicking team when possession changes. The result of a typical punt, barring any penalties or extraordinary circumstances, is a first down for the receiving team. A punt is not to be confused with a drop kick, a kick after the ball hits the ground, now rare in both American and Canadian football.