the positioning of a center in an offensive formation.

Center (C) is a position in American football and Canadian football. The center is the innermost lineman of the offensive line on a football team's offense. The center is also the player who passes (or "snaps") the ball between his legs to the quarterback at the start of each play.

In recent years, the importance of centers for a football team has increased, due to the re-emergence of 3-4 defenses. According to Baltimore Ravens general manager Ozzie Newsome, "you need to have somebody who can neutralize that nose tackle. If you don't, everything can get screwed up. Your running game won't be effective and you'll also have somebody in your quarterback's face on every play."^[1]

Roles[link]

The center's first and primary role is to pass the football to the quarterback. This exchange is called a snap. Most offensive schemes make adjustments based on how the defensive line and linebackers align itself to the offensive line, and what gaps they line up in. Because the center has an ideal view of the defensive formation before the snap, he typically makes the first line call. This call is typically based on the position of the defensive linemen or linebackers in his gaps (0i-1i), most subsequent adjustments are dependent on this call. In some cases the center may call an adjustment for the entire offensive line. For these reasons, the center is usually the most intelligent player on the offensive line and this attribute is a critical component to a center's success.

After the snap, the center performs blocking assignments. The blocking assignments vary by offense but typically consist of the following:

Run blocking[link]

Run blocking assignments will vary based on the current play and the defensive formation when the ball is snapped. Typically, these assignments consist of the following:

• Blocking middle or backside linebackers in certain formations, then moving up to secondary levels if no linebacker is present.
• Assisting guards in their blocking assignments. This may be a center/guard double-team where the center and guard are assigned to the same target (usually a defensive tackle) to get extra push or drive. Assistance may also be just a quick hit or "chip" to throw the defensive player off balance and help the guard to execute his block, while the center moves up to higher level targets.
• Backside blocking of defensive tackles for pulling guards. In some offensive schemes, certain plays will involve "pulling" an offensive lineman to block for the ball carrier. If a guard needs to pull for a block, the center will typically block the defensive tackle in order to fill the guard's void.

Pass Blocking[link]

• Pass blocking for a center is very similar to the above Run Blocking section. The center will initially help guards based on the position of the defensive linemen. In the case of a blitz, the center may need to pick up a rushing linebacker, safety or corner. A good center also needs to stay vigilant during pass blocking to protect against defensive stunts and twists.

During the play[link]

On most plays, the center will snap the ball directly into the quarterback's hands. In a shotgun formation, the center snaps the ball to the quarterback lined up several yards behind him. In punt and field goal formations, the center also snaps the ball several yards behind him to the punter or holder on the field goal unit. Because bad snaps can ruin special teams plays and cause turnovers, some teams have a center who is specifically trained for snapping the ball in punt and field goal formations. This player is often referred to as the team's long snapper. Also, the center does not have to snap the ball to the quarterback, holder, or punter. He is allowed to snap the ball to anyone behind him. Because of this, some plays involve snaps directly to running backs instead of the player generally expected to receive the snap, hoping to fool the defense.

In slang, the player receiving the snap is said to be "under center" if he receives the ball directly from the center (not in shotgun). This phrase is typically applied to quarterbacks, but has been used in reference to other positions as well.

Special teams[link]

In special teams situations, the center is a long snapper, who snaps the ball to a punter standing approximately 12-14 yards behind him, or to the holder for the place-kicker, kneeling approximately 7 yards (6.4 m) behind him. These long snappers are players particularly talented at performing these snaps, and are sometimes a different player from the regular center.

Drawing penalties[link]

Although the quarterback commands the ball, it is the center's snap that renders the ball in play; the defensive line may not cross the line of scrimmage until the center snaps the football. An astute center can help draw an opposing team offside prior to the snap or potentially trick the other team into a penalty by quickly snapping the ball while the opposing team attempts to substitute players.

In college football, the Dave Rimington Trophy is awarded annually to the nation's most outstanding center.

References[link]

American football

The U.S. Naval Academy Midshipmen (left) face off against the Colorado State Rams.
Nickname(s)	Gridiron
First played	November 6, 1869, Rutgers vs. Princeton
Characteristics
Contact	Full contact
Team members	11 at a time
Categorization	Outdoor
Equipment	Football
Olympic	No Was demonstrated in the 1932 Summer Olympics Not recognized as an Olympic sport

American football is a sport played between two teams of eleven with the objective of scoring points by advancing the ball into the opposing team's end zone. Known in the United States simply as football, it may also be referred to informally as gridiron football,^[1][2] and even more rare, the "pigskin".^[3] The ball can be advanced by running with it or throwing it to a teammate. Points can be scored by carrying the ball over the opponent's goal line, catching a pass thrown over that goal line, kicking the ball through the opponent's goal posts or tackling an opposing ball carrier in his own end zone.

In the United States, the major forms are high school football, college football and professional football. Each of these are played under slightly different rules.^[4] High school football is governed by the National Federation of State High School Associations and college football by the National Collegiate Athletic Association and National Association of Intercollegiate Athletics. The major league for professional football is the National Football League.

American football is closely related to Canadian football but with some differences in rules and the field.^[5] Both sports can be traced to early versions of association football and rugby football.

History[link]

An American football team at the turn of the 20th century. Note the continued use of a rugby-type ball (front row, right).

The history of American football can be traced to early versions of rugby football and association football. Both games have their origins in varieties of football played in the United Kingdom in the mid-19th century, in which a ball is kicked at a goal and/or run over a line. Many games known as "football" were being played at colleges and universities in the United States in the first half of the 19th century.^[6][7]

Rutgers University and its neighbor, Princeton University, played the first game of intercollegiate football on 6 November 1869 on a plot of ground where the present-day Rutgers gymnasium now stands in New Brunswick, New Jersey. Rutgers won that first game, 6-4.^[8]

Walter Camp

American football resulted from several major divergences from rugby football, most notably the rule changes instituted by Walter Camp, considered the "Father of American Football." Among these important changes were the introduction of the line of scrimmage and of down-and-distance rules. In the late 19th and early 20th centuries, game play developments by college coaches such as Eddie Cochems, Amos Alonzo Stagg, Knute Rockne, and Glenn "Pop" Warner helped take advantage of the newly introduced forward pass.

The popularity of collegiate football grew as it became the dominant version of the sport for the first half of the twentieth century. Bowl games, a college football tradition, attracted a national audience for collegiate teams. Bolstered by fierce rivalries, college football still holds widespread appeal in the US.^[6][9][10]

The origin of professional football can be traced back to 1892, with William "Pudge" Heffelfinger's $500 contract to play in a game for the Allegheny Athletic Association against the Pittsburgh Athletic Club. The first Professional "league" was the Ohio League, formed in 1903, and the first Professional Football championship game was between the Buffalo Prospects and the Canton Bulldogs in 1919. In 1920, the American Professional Football Association was formed. The first game was played in Dayton, Ohio on October 3, 1920 with the host Triangles defeating the Columbus Panhandles 14–0. The league changed its name to the National Football League (NFL) two years later, and eventually became the major league of American football. Initially a sport of Midwestern industrial towns in the United States, professional football eventually became a national phenomenon. Football's increasing popularity is usually traced to the 1958 NFL Championship Game, a contest that has been dubbed the "Greatest Game Ever Played". A rival league to the NFL, the American Football League (AFL), began play in 1960; the pressure it put on the senior league led to a merger between the two leagues and the creation of the Super Bowl, which has become the most watched television event in the United States on an annual basis.^[11]

High school football dates to the 1880s and enjoys regional popularity.

Rules[link]

Field and players[link]

The numbers on the field indicate the number of yards to the nearest goal line.

Football is played on a field 360 by 160 feet (120.0 by 53.3 yards; 109.7 by 48.8 meters).^[12] The longer boundary lines are sidelines, while the shorter boundary lines are end lines. Sidelines and end lines are out of bounds. Near each end of the field is a goal line; they are 100 yards (91.4 m) apart. A scoring area called an end zone extends 10 yards (9.1 m) beyond each goal line to each end line. The end zone includes the goal line but not the end line.^[12] While the playing field is effectively flat, it is common for a field to be built with a slight crown—with the middle of the field higher than the sides—to allow water to drain from the field.

Yard lines cross the field every 5 yards (4.6 m), and are numbered every 10 yards from each goal line to the 50-yard line, or midfield. Two rows of short lines, known as inbounds lines or hash marks, run at 1-yard (91.4 cm) intervals perpendicular to the sidelines near the middle of the field. All plays start with the ball on or between the hash marks. Because of the arrangement of the lines, the field is occasionally referred to as a gridiron in a reference to the cooking grill with a similar pattern of lines.

At the back of each end zone are two goalposts (also called uprights) connected by a crossbar 10 feet (3.05 m) from the ground. For high skill levels, the posts are 18 feet 6 inches (5.64 m) apart. For lower skill levels, these are widened to 23 feet 4 inches (7.11 m).

Each team has 11 players on the field at a time. Usually there are many more players off the field (an NFL team has a limit of 53 players on its roster, 46 of whom can be dressed for a game). However, teams may substitute for any or all of their players during the breaks between plays. As a result, players have very specialized roles and are divided into three separate units: the offense, the defense and the special teams. It is rare for all team members to participate in a given game, as some roles have little utility beyond that of an injury substitute.

Start of halves[link]

The game begins with a coin toss to determine which team will kick off to begin the game and which goal each team will defend.^[13] The options are presented again to start the second half; the choices for the first half do not automatically determine the start of the second half. The referee conducts the coin toss with the captains (or sometimes coaches) of the opposing teams. The team that wins the coin toss has three options:^[13]

1. They may choose whether to kick or receive the opening kickoff.
2. They may choose which goal to defend.
3. They may choose to defer the first choice to the other team and have first choice to start the second half.^[14]

Whatever the first team chooses, the second team has the option on the other choice (for example, if the first team elects to receive at the start of the game, the second team can decide which goal to defend).

At the start of the second half, the options to kick, receive, or choose a goal to defend are presented to the captains again. The team which did not choose first to start the first half (or which deferred its privilege to choose first) now gets first choice of options.^[13][15]

Game duration[link]

A standard football game consists of four 15-minute quarters (12-minute quarters in high-school football and often shorter at lower levels),^[16] with a half-time intermission after the second quarter.^[17] Depending upon the level of competition, the duration of the half-time ranges from 10 to 20 minutes. At all levels, a down (play) that begins before time expires is allowed to continue until its completion, even after the clock reaches zero. The clock is also stopped after certain plays, therefore, a game can last considerably longer (often more than three hours in real time), and if a game is broadcast on television, TV timeouts are taken at certain intervals of the game to broadcast commercials outside of game action. If an NFL game is tied after four quarters, the teams play an additional period lasting up to 15 minutes. As of the 2012 season, if the first team with possession does not score a touchdown on the initial possession, the other team is given a possession. If the score is still tied after both teams have had a possession, then the old sudden death rules go into effect. In a regular-season NFL game, if neither team scores in overtime, the game is a tie. In an NFL playoff game, additional overtime periods are played, as needed, to determine a winner.^[18] College overtime rules are more complicated.

A line of scrimmage on the 48-yard line. The offense is on the left.

A quarterback searching for an opportunity to throw a pass.

A running back being tackled when he tries to run with the ball.

Air Force Academy quarterback Shea Smith prepares to throw a pass.

Forward pass in progress, during practice.

A kicker attempts an extra point.

Advancing the ball[link]