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American football, known in the United States and Canada simply as football, is a competitive team sport. The object of the game is to score points by advancing the football into the opposing team's end zone. The ball can be advanced by carrying the ball, or by throwing or handing it from one teammate to the other. Points can be scored in a variety of ways, including carrying the ball over the goal line, throwing the ball to another player past the goal line or kicking it through the goal posts on the opposing side. The winner is the team with the most points when the time expires and the last play ends. However, tied games can occur. Outside of the United States and Canada, the sport is usually referred to as American football (or sometimes as gridiron or gridiron football) to differentiate it from other football games. Popularity
Rules The object of American football is to score more points than the opposing team within a set time limit. Field and players American football is played on a rectangular field 120 yards (110 meters) long by 53 1/3 yards (49 meters) wide. The longer boundary lines are sidelines, while the shorter boundary lines are end lines. Near each end of the field is a goal line; they are 100 yards apart. A scoring area called an end zone extends 10 yards beyond each goal line to each end line. Yard lines cross the field every 5 yards, and are numbered from each goal line to the 50-yard line, or midfield (similar to a typical rugby league field). Two rows of lines, known as inbounds lines or hash marks, parallel the side lines near the middle of the field. All plays start with the ball on or between the hash marks. At the back of each end zone are two goal posts (also called uprights) that are 18.5 feet (5.6 m) apart (24 feet (7.3 m) in high school). The posts are connected by a crossbar 10 feet (3 m) from the ground. Each team has 11 players on the field at a time. However, teams may substitute for any or all of their players, if time allows, during the break between plays. As a result, players have very specialized roles, and almost all of the 46 active players on an NFL team will play in any given game. Thus, teams are divided into three separate units: the offense, the defense and the special teams. Game duration A standard football game consists of four 15-minute (typically 12 minutes in high school football) quarters, with a half-time intermission after the second quarter. The clock stops after certain plays; therefore, a game can last considerably longer (often more than three hours in real time). If an NFL game is tied after four quarters, the teams play an additional period lasting up to 15 minutes. In an NFL overtime game, the first team that scores wins, even if the other team does not get a possession—this is referred to as sudden death. 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. College overtime rules are more complicated and are described in Overtime (sport). Advancing the ball Advancing the ball in American football resembles the six-tackle rule and the play-the-ball in rugby league football. The team that takes possession of the ball (the offense) has four attempts, called downs, to advance the ball 10 yards towards their opponent's (the defense Except at the beginning of halves and after scores, the ball is always put into play by a snap. All players line up facing each other at the line of scrimmage (the position on the field where the play begins). One offensive player, the center, then passes (or "snaps") the ball between his legs to a teammate, usually the quarterback. Players can then advance the ball in two ways: A down ends, and the ball becomes dead, after any of the following: Officials blow a whistle to notify all players that the down is over. Before each down, each team chooses a play, or coordinated movements and actions, that the players should follow on a down. Sometimes, downs themselves are referred to as "plays." Change of possession The offense maintains possession of the ball unless one of the following things happens: Scoring A team scores points by the following plays: Kickoffs and free kicks
Penalties Rule violations are punished with penalties. Most penalties result in moving the football either towards the defense's endzone in the case of a defensive penalty, or away from the defense's endzone in the case of an offensive penalty. Some defensive penalties give the offense an automatic first down. In addition, if a penalty gives the offensive team enough yardage to gain a first down, they get a first down as usual. If a penalty occurs during a play, an official throws a yellow flag near the spot of the foul. When the play is over, the team that did not commit the penalty has the option of taking either the penalty and replaying the down, or the result of the play and advancing to the next down. A few of the most-common penalties include: Players Most football players have highly specialized roles. At the college and NFL levels, most play only offense or only defense. Offense Not all of these types of players will be in on every offensive play. Teams can vary the number of wide receivers, tight ends and running backs on the field at one time. Defense Special teams The units of players who handle kicking plays are known as special teams. Two important special-teams players are the punter, who handles punts, and the placekicker or kicker, who kicks off and attempts field goals and extra points. Basic strategy To some fans, the chief draw of football is the strategy that goes on between the two coaching staffs. Each team has a playbook of dozens to hundreds of plays. Ideally, each play is a scripted, strategically sound team-coordinated endeavour. Some plays are very safe; they are likely to get only a few yards. Other plays have the potential for long gains but at a greater risk of a loss of yardage or a turnover. Generally speaking, rushing plays are less risky than passing plays. However, there are relatively safe passing plays and risky running plays. To deceive the other team, some passing plays are designed to resemble running plays and vice versa. There are many trick or gadget plays, such as when a team lines up as if it intends to punt and then tries to run or pass for a first down. Such high-risk plays are a great thrill to the fans when they work. However, they can spell disaster if the opposing team realizes the deception and acts accordingly. Many hours of preparation and strategizing, including film reviews by both players and coaches, go into the days between football games. This, along with the demanding physicality (see below) of football, is why teams play at most one game per week. Physicality American football is a collision sport. To stop the offense from advancing the ball, the defense must tackle the player with the ball by knocking him down. As such, defensive players must use some form of physical contact to bring the ball-carrier to the ground, within certain rules and guidelines. Tacklers cannot kick, punch or trip the runner. They also cannot grab the face mask of the runner's helmet or lead into a tackle with their own helmet. Despite these and other rules regarding unnecessary roughness, most other forms of tackling are legal. Blockers and defenders trying to evade them also have wide leeway in trying to force their opponents out of the way. Quarterbacks are regularly hit by defenders coming on full speed from outside the quarterback's field of vision. To compensate for this, players must wear special protective equipment, such as a padded plastic helmet, shoulder pads, hip pads and knee pads. These protective pads were introduced decades ago and have improved ever since to help minimize lasting injury to players. Despite protective equipment and rule changes to emphasize safety, injuries remain very common in football. Twenty-eight football players, mostly high schoolers, died from injuries directly related to football from 2000-05, according to the National Center for Catastrophic Sport Injury Research. Concussions are common, with about 41,000 suffered every year among high school players according to the Brain Injury Association of Arizona. The danger of football and the equipment required to reduce it make regulation football impractical for casual play. Flag football and touch football are less-violent variants of the game popular among recreational players. History Both American football and soccer have their origins in varieties of football played in the United Kingdom in the mid-19th century, and American football is directly descended from rugby football. McGill University athletes, who had learned rugby from the local British Army garrison, introduced the sport to the U.S. with a game against Harvard University in 1874. The game quickly spread to other Ivy League colleges. Encouraged by Yale University's Walter Camp, the schools began to adopt rules that would differentiate American football from rugby in the 1880s. The scrimmage was introduced in 1880 and the system of downs in 1882. By the turn of the 20th century, football had become notoriously dangerous; 18 college players died in 1905 alone. Colleges responded with a series of rule changes to open up the game, most importantly the forward pass. The game had achieved its modern form by 1912, when the field was changed to its current size, the value of a touchdown increased to 6 points, and a fourth down added to each possession. Originally dominated by the Ivy League, football soon captured the interest of colleges nationwide. By 1916, when the Rose Bowl game matching eastern and western teams became an annual event, football had developed a national following second only to baseball among team sports. Professional football developed in the mill towns of Pennsylvania and the American Midwest in the early years of the 20th century. The NFL was founded in 1920 in Canton, Ohio. Professional football remained a largely regional sport of secondary importance until after World War II. Television broadcasts greatly enhanced NFL football's national appeal, and the pro game surpassed both college football and baseball in popularity in the 1960s. The first Super Bowl—between the champions of the NFL and the rival American Football League—was played in 1967, and the two leagues merged in 1970. See also Notes | |||||||||||
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