A trips formation is an offensive football formation, initially used by Joe Gibbs and the Washington Redskins, in which three receivers line up on the same side of the field. The side is usually specified by the quarterback calling "Trips right" or "Trips left" when he calls the play in the huddle.
There are multiple variables of the trips formation, and it may be combined with other types of formations. For example, the call "Shotgun, trips right, slot left" formation would indicate that the tight end and two wide receivers would line up on the right side of the field, while two receivers would line up on the left side of the field (one "wide", the other slightly off the line of scrimmage in the "slot"). The quarterback would line up at least five yards behind the center.
The objective of a trips formation is to flood the defense on one side of the field in order to create and exploit holes in zone pass coverage.
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 cornerback (CB) is a member of the defensive backfield or secondary in gridiron football. Cornerbacks cover receivers most of the time, but also blitz and defend against such offensive running plays as sweeps and reverses. They create turnovers through hard tackles, interceptions, and deflecting forward passes.
A wide receiver (WR), also referred to as a wideout, historically known as a split end, is an eligible receiver in gridiron football. A key skill position of the offense, WR gets its name from the player being split out "wide", farthest away from the rest of the offensive formation.
A screen pass is a play in gridiron football consisting of a short pass to a receiver who is protected by a screen of blockers. During a screen pass, a number of things happen concurrently in order to fool the defense into thinking a long pass is being thrown, when in fact the pass is merely a short one, just beyond the defensive linemen. Screens are usually deployed against aggressive defenses that rush the passer. Because screens invite the defense to rush the quarterback, they are designed to leave fewer defensemen behind the rushers to stop the play.
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.
American football positions have slowly evolved over the history of the sport. From its origins in early rugby football to the modern game, the names and roles of various positions have changed greatly, some positions no longer exist, and others have been created to fill new roles.
In American football, the pro set or split backs formation is a formation that has been commonly used as a "base" set by professional and amateur teams. The "pro set" formation features an offensive backfield that deploys two running backs aligned side-by-side instead of one in front of the other as in traditional I-formation sets. It was an outgrowth of the three-running-back T-formation, with the third running back in the T becoming a permanent flanker, now referred to as a wide receiver.
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 sports, a starting lineup is an official list of the set of players who will participate in the event when the game begins. The players in the starting lineup are commonly referred to as starters, whereas the others are substitutes or bench players.
The I formation is one of the most common offensive formations in American football. The I formation draws its name from the vertical alignment of quarterback, fullback, and running back, particularly when contrasted with the same players' alignments in the T formation.
Single set back is an offensive base formation in American Football which requires only one running back lined up about five yards behind the quarterback. There are many variations on single back formations including two tight ends and two wide receivers, one tight end/three wide receivers, etc. The running back can line up directly behind the quarterback or offset either the weak side or the strong side.
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.
Slotback, sometimes referred to as an A-back or "slot receiver," is a position in gridiron football. The "slot" is the area between the last offensive lineman on either side of the center and the wide receiver on that side. A player who lines up between those two players and behind the line of scrimmage fills that "slot." The slotback position is a fixture of Canadian football and indoor football where they act as extra receivers. It is also used in American football where the position requires a versatile player, who must combine the receiving skills of a wide receiver, the ball-carrying skills of a running back, and the blocking skills of a tight end.
Safety is a position in gridiron football on the defense. The safeties are defensive backs who line up ten to fifteen yards from the line of scrimmage. There are two variations of the position: the free safety (FS) and the strong safety (SS). Their duties depend on the defensive scheme. The defensive responsibilities of the safety and cornerback usually involve pass coverage towards the middle and sidelines of the field. While American (11-player) formations generally use two safeties, Canadian (12-player) formations generally have one safety and two defensive halfbacks, a position not used in the American game. As professional and college football have become more focused on the passing game, safeties have become more involved in covering the eligible pass receivers.
In American football, a play is a close-to-the-ground plan of action or strategy used to move the ball down the field. A play begins at either the snap from the center or at kickoff. Most commonly, plays occur at the snap during a down. These plays range from basic to very intricate. Football players keep a record of these plays in a playbook.
Zone coverage is a defense scheme in gridiron football used to protect against the pass.
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.
The run and shoot offense is an offensive system for American football which emphasizes receiver motion and on-the-fly adjustments of receivers' routes in response to different defenses. It was conceived by former high school coach Glenn "Tiger" Ellison and refined and popularized by former Portland State offensive coordinator Mouse Davis.
A play calling system in American football is the specific language and methods used to call offensive plays.