American football is a game in which two opposing teams are engaged and prevent each other from scoring touchdowns or reaching the opposing teams territory. In football there are 2 different units for each team. One unit plays defense and the second plays offense.
The ultimate makeup of the offense and how it operates is governed by the head coach or offensive coordinator's offensive philosophy.
Center (C)—the center performs the normal blocking functions of all linemen and is the player who puts the ball in play by means of the snap.
Offensive guard (OG)—the two guards are the offensive linemen directly on either side of the center and inside the tackles. Like all interior linemen, their function is to block on both running and passing plays. On some plays, rather than blocking straight ahead, a guard will "pull" - moving around behind the other offensive linemen upon the start of the play - in order to block a player on either side of the center, in an inside running play called a "trap" or an outside running play called a "sweep".
Offensive tackle (OT)—the offensive tackles play on either side of the guards. Their role is primarily to block on both running and passing plays. The area from one tackle to the other is an area of "close line play" in which some blocks from behind, which are prohibited elsewhere on the field, are allowed. For a right-handed quarterback, the left tackle is charged with protecting the blindside, and is often faster than the other offensive linemen to stop 'speed rushers' at the Defensive End position. Like a guard, the tackle may have to "pull", on a running play, when there is a tight end on his side.
The description above of the guard and tackle positions apply only to a line that is balanced (has equal numbers of players on both sides of the player who is to snap the ball). In an unbalanced line, there may be players designated "guard" or "tackle" next to each other.
Offensive linemen can catch or run the ball if they want but in most circumstances. Except for the snap by the offensive center as each play from scrimmage starts, ordinarily the only way an offensive lineman can get the ball during a play is by picking up a fumble. On rare occasions offensive linemen legally catch passes; they can do so either by reporting as an eligible receiver to the referee prior to the snap or by catching a pass which has first been deflected or otherwise touched by an eligible receiver or a defensive player. Any other touching of the ball by an offensive lineman will result in a penalty.
Tight end (TE) — Tight ends play on either side of, and roughly next to, the tackles. They are a mix between a blocker and a pass receiver. If an end moves away from the tackle, he is called a split end. Modern formations typically have one end tight and one end split. Many modern formations also forego tight ends and replace them with wide receivers. Sometimes a formation is referred to as having "three tight ends." This means in reality that an additional blocker (a wingback or an eighth lineman) has been substituted for a wide receiver. This would be done as in short-yardage situations where receivers are not needed.
Wide receiver (WR) — The wide receivers are speedy pass-catching specialists. Their main job is to run pass routes and get open for a pass, although they are occasionally called on to block. A wide receiver may line up on the line of scrimmage and be counted as one of the necessary 7 players on the line in a legal formation (a split end), or he may line up at least one step behind the line of scrimmage and be counted as being in the backfield (a flanker if he is on the outside, a slot if he is not). There are generally two types of wide receivers, "speed" and "possession". A speed receiver's primary function is to stretch the field, to be a deep threat, and to pull away an eighth defensive man near the line of scrimmage from moves against the quarterback. A possession receiver is generally the more sure-handed of the two types and is used to keep possession of the ball by making catches that gain first down yardage, but he usually lacks the speed to attack a defensive backfield.
Fullback (FB) — Positioned behind the middle of the line, a fullback may do some running, some blocking, and some short receiving. A classic fullback is more of a power runner than a running back. Many modern formations do not use a fullback. Most plays utilizing the fullback call for him to block, generally by running up the middle of the line, clearing a path for a running back to use.
Penn State Nittany Lions quarterback #14 Anthony Morelli hands the ball off to his tailback #33 Austin Scott in their 2007 season opener.Running back (RB) — The modern term for the position formerly called "halfback". The running back carries the ball on most running plays and is also frequently used as a short-yardage receiver. Running backs, along with the wide receivers, are generally the fastest players on the offensive team. Most of them tend not to run straight ahead, preferring to make quick cutbacks to try to find holes in the defense. This, however, is a generalization, since some running backs are more power-oriented. "Fullback" is now regarded as a separate position from running back, with a substantially different role (especially in the NFL).
Tailback (TB) — A running back that is positioned behind the middle of the line and deepest of all backs.
H-back — A position that was popularized by Joe Gibbs during his first tenure with the Washington Redskins, the H-back is a hybrid position that combines the skill sets of fullback, tight end, and even wide receiver. An H-back lines up similarly to a slotback—but deeper and not as wide—and frequently serves as a blocker for a more deeply positioned back.
Wingback — A player positioned just outside the outermost tight end, the wingback is slightly offset from the line of scrimmage which designates the position as wingback rather than tight end. The wingback is typically used in extreme blocking situations or unbalanced offensive formations.
Slotback — A player positioned just outside the outermost offensive lineman, the slotback is slightly offset from the line of scrimmage which designates the position as a slotback rather than a tight end. The slotback is a typical position in flexbone formations and other Triple Option formations.
Quarterback (QB) — Typically the quarterback is positioned to take a snap handed between the center's legs. However, recent usage refers imprecisely to a player who is positioned behind the center at any distance, calls signals, is not the usual punter or place kick holder, and usually takes the snap as "quarterback" regardless of exact position, because those functions have typically been performed by quarterbacks. Typical play from formations where the quarterback takes the snap proceeds by the quarterback either handing the ball off to a running back to run, throwing the ball downfield, or running personally.
Teams can vary the number of wide receivers, tight ends and running backs on the field at one time. Football rules limit the flexibility of offensive formations. Seven players must line up on the line of scrimmage, and only the two at the end are eligible to catch passes. Sometimes, offensive lineman can declare eligibility and become "tackle eligible." Jumbo Elliott and Dan Klecko are two tackles who have caught touchdowns while being tackle eligible. Typical formations include:
One running back, two tight ends and two wide receivers.
Two running backs, one tight end and two wide receivers.
One running back, one tight end and three wide receivers.
One running back, no tight end and four wide receivers.
No running backs, no tight end and five wide receivers.
[edit] Defense
The defensive team or defense is the team that begins a play from scrimmage not in possession of the ball. The object of the defensive team is to prevent the other team from scoring. The sign that the defensive goal has been accomplished is a fourth down, which usually involves punting the ball.
Unlike the offensive team, there are no formally defined defensive positions. A defensive player may line up anywhere on his side of the line of scrimmage and perform any legal action. However, most sets used in American football include a line composed of defensive ends and defensive tackles and (behind the line) linebackers, cornerbacks, and safeties.
Defensive ends and tackles are collectively called defensive line, while the cornerbacks and safeties are collectively called the secondary, or defensive backs.
Defensive end (DE) — The two defensive ends play on opposite outside edges of the defensive line. Their function is to attack the passer or stop offensive runs to the outer edges of the line of scrimmage (most often referred to as "containment"). The faster of the two is usually placed on the right side of the defensive line (quarterback's left) because that is a right-handed quarterback's blind side.
Defensive tackle (DT) — Sometimes called a defensive guard, defensive tackles are side-by-side linemen who are between the defensive ends. Their function is to rush the passer (if they can get past the offensive linemen blocking them), and stop running plays directed at the middle of the line of scrimmage. A defensive tackle that lines up directly across from the ball (and therefore, is almost nose-to-nose with the offense's center) is often called a nose tackle or nose guard. The nose tackle is most common in the 3-4 defense and the quarter defense. Most defensive sets have from one to two defensive tackles. Sometimes, but not often, a team will employ three defensive tackles.
Linebacker (LB) — Linebackers play behind the defensive line and perform various duties depending on the situation, including rushing the passer, covering receivers, and defending against the run. Most defensive sets have between two and three linebackers. Linebackers are usually divided into three types: strongside (left or right outside linebacker: LOLB or ROLB); middle (MLB); and weakside (LOLB or ROLB). The strongside linebacker usually lines up across from the offense's tight end; he is usually the strongest LB because he must be able to shed lead blockers quickly enough to tackle the running back. The middle linebacker must correctly identify the offense's formations and what adjustments the entire defense must make. Because of this, the middle linebacker is nicknamed the "quarterback of the defense". The weakside linebacker is usually the most athletic or fastest linebacker because he usually must defend an open field.
Cornerback (CB) — Typically two players that primarily cover the wide receivers. Cornerbacks attempt to prevent successful quarterback passes by either swatting the airborne ball away from the receiver or by catching the pass themselves. In rushing situations, their job is to contain the rusher.
Safety (FS or SS) — The safeties are the last line of defense (farthest from the line of scrimmage) and usually help the corners with deep-pass coverage. The strong safety (SS) is usually the larger and stronger of the two, providing extra protection against run plays by standing somewhere between the free safety and the line of scrimmage. The free safety (FS) is usually the smaller and faster of the two, providing variable and extra pass coverage.
Typically, a team will have a safety who also has a reputation of being a hard hitter, as evidenced by Troy Polamalu, Mark Carrier, Rodney Harrison and Bob Sanders, John Lynch, and Sean Taylor to name a slim few. More recently, teams are looking for hybrid safeties who can do both jobs, as in a cover 2 defense, the strong safety has a greater role to play in coverage. Safeties are also used in a variety of blitzes.
Defensive back — It is not a specific position, however, it is any position besides the line, including cornerbacks, safeties, etc., that is behind the line of scrimmage.
Nickelback and Dimeback — In certain formations one extra (a fifth) defensive back (called a nickel defense), two extra (a sixth) DB (called a Dime package), or even three extra (a seventh) DB called a Quarter may be used to augment the backfield or defensive line. Nickelbacks, dimebacks, and Defensive Quarterbacks are usually used to defend pass plays with extra receivers, but they can also be used to rush quarterbacks or running backs more quickly than linemen or most linebackers can. A starting cornerback who is good at blitzing and tackling will sometimes be referred to as a nickelback to distinguish them from cornerbacks.
Typical defensive formations include:
Six defensive linemen, two linebackers and three defensive backs (the 6-2 formation)
Five defensive linemen, three linebackers and three defensive backs (the 5-3 formation)
Four defensive linemen, three linebackers and four defensive backs (the 4-3 formation)
Four defensive linemen, four linebackers and three defensive backs (the 4-4 formation)
Three defensive linemen, four linebackers and four defensive backs (the 3-4 formation)
Four defensive linemen, two linebackers and five defensive backs (the Nickel formation)
Four defensive linemen, one linebacker and six defensive backs.(the Dime formation)
One defensive linebacker, three linemen and seven defensive backs (the Quarter defense)
2007-12-29 19:01:51
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answer #1
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answered by Anonymous
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