American football

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This article is about the American variation of gridiron football. American football_sentence_0

For other uses, see American football (disambiguation). American football_sentence_1

American football_table_infobox_0

American footballAmerican football_table_caption_0
Highest governing bodyAmerican football_header_cell_0_0_0 International Federation of American FootballAmerican football_cell_0_0_1
NicknamesAmerican football_header_cell_0_1_0 American football_cell_0_1_1
First playedAmerican football_header_cell_0_2_0 November 6, 1869

New Brunswick, New Jersey, United States (Princeton vs. Rutgers)American football_cell_0_2_1

CharacteristicsAmerican football_header_cell_0_3_0
ContactAmerican football_header_cell_0_4_0 Full-contactAmerican football_cell_0_4_1
Team membersAmerican football_header_cell_0_5_0 11 (both teams may freely substitute players between downs)American football_cell_0_5_1
TypeAmerican football_header_cell_0_6_0 American football_cell_0_6_1
EquipmentAmerican football_header_cell_0_7_0 American football_cell_0_7_1
VenueAmerican football_header_cell_0_8_0 Football field (rectangular: 120 yards long, 53 ​⁄3 yards wide)American football_cell_0_8_1
GlossaryAmerican football_header_cell_0_9_0 Glossary of American footballAmerican football_cell_0_9_1
PresenceAmerican football_header_cell_0_10_0
Country or regionAmerican football_header_cell_0_11_0 WorldwideAmerican football_cell_0_11_1
OlympicAmerican football_header_cell_0_12_0 No (demonstrated at the 1932 Summer Olympics)American football_cell_0_12_1
World GamesAmerican football_header_cell_0_13_0 Yes (invitational sport at 2005 and 2017 Games).American football_cell_0_13_1

American football, referred to 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. American football_sentence_2

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. American football_sentence_3

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. American football_sentence_4

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. American football_sentence_5

The team with the most points at the end of a game wins. American football_sentence_6

American football evolved in the United States, originating from the sports of soccer and rugby. American football_sentence_7

The first American football match was played on November 6, 1869, between two college teams, Rutgers and Princeton, using rules based on the rules of soccer at the time. American football_sentence_8

A set of rule changes drawn up from 1880 onward by Walter Camp, the "Father of American Football", established the snap, the line of scrimmage, eleven-player teams, and the concept of downs. American football_sentence_9

Later rule changes legalized the forward pass, created the neutral zone and specified the size and shape of the football. American football_sentence_10

The sport is closely related to Canadian football, which evolved in parallel with and at the same time as the American game (although their rules were developed independently from that of Camp's). American football_sentence_11

Most of the features that distinguish American football from rugby and soccer are also present in Canadian football. American football_sentence_12

The two sports are considered the primary variants of gridiron football. American football_sentence_13

American football is the most popular sport in the United States. American football_sentence_14

The most popular forms of the game are professional and college football, with the other major levels being high school and youth football. American football_sentence_15

As of 2012, nearly 1.1 million high school athletes and 70,000 college athletes play the sport in the United States annually. American football_sentence_16

The National Football League, the most popular American football league, has the highest average attendance of any professional sports league in the world. American football_sentence_17

Its championship game, the Super Bowl, ranks among the most-watched club sporting events in the world. American football_sentence_18

The league has an annual revenue of around US$13 billion. American football_sentence_19

Other professional leagues exist worldwide, but the sport does not have the international popularity of other American sports like baseball or basketball. American football_sentence_20

Etymology and names American football_section_0

Main article: Football (word) American football_sentence_21

In the United States, American football is referred to as "football". American football_sentence_22

The term "football" was officially established in the rulebook for the 1876 college football season, when the sport first shifted from soccer-style rules to rugby-style rules. American football_sentence_23

Although it could easily have been called "rugby" at this point, Harvard, one of the primary proponents of the rugby-style game, compromised and did not request the name of the sport be changed to "rugby". American football_sentence_24

The terms "gridiron" or "American football" are favored in English-speaking countries where other types of football are popular, such as the United Kingdom, Ireland, New Zealand, and Australia. American football_sentence_25

History American football_section_1

Main articles: History of American football and American football in the United States American football_sentence_26

Early history American football_section_2

American football evolved from the sports of rugby and soccer. American football_sentence_27

Rugby like American football, is a sport where two competing teams vie for control of a ball, which can be kicked through a set of goalposts or run into the opponent's goal area to score points. American football_sentence_28

What is considered to be the first American football game was played on November 6, 1869, between Rutgers and Princeton, two college teams. American football_sentence_29

They consisted of 25 players per team and used a round ball that could not be picked up or carried. American football_sentence_30

It could, however, be kicked or batted with the feet, hands, head or sides, with the objective being to advance it into the opponent's goal. American football_sentence_31

Rutgers won the game 6–4. American football_sentence_32

Collegiate play continued for several years with matches played using the rules of the host school. American football_sentence_33

Representatives of Yale, Columbia, Princeton and Rutgers met on October 19, 1873, to create a standard set of rules for use by all schools. American football_sentence_34

Teams were set at 20 players each, and fields of 400 by 250 feet (122 m × 76 m) were specified. American football_sentence_35

Harvard abstained from the conference, as they favored a rugby-style game that allowed running with the ball. American football_sentence_36

After playing McGill University using both Canadian and American rules, the Harvard players preferred the Canadian style of having only 11 men on the field, running the ball without having to be chased by an opponent, the forward pass, tackling, and using an oblong instead of a round ball. American football_sentence_37

An 1875 Harvard–Yale game played under rugby-style rules was observed by two Princeton athletes who were impressed by it. American football_sentence_38

They introduced the sport to Princeton, a feat the Professional Football Researchers Association compared to "selling refrigerators to Eskimos". American football_sentence_39

Princeton, Harvard, Yale, and Columbia then agreed to intercollegiate play using a form of rugby union rules with a modified scoring system. American football_sentence_40

These schools formed the Intercollegiate Football Association, although Yale did not join until 1879. American football_sentence_41

Yale player Walter Camp, now regarded as the "Father of American Football", secured rule changes in 1880 that reduced the size of each team from 15 to 11 players and instituted the snap to replace the chaotic and inconsistent scrum. American football_sentence_42

Evolution of the game American football_section_3

The introduction of the snap resulted in an unexpected consequence. American football_sentence_43

Prior to the snap, the strategy had been to punt if a scrum resulted in bad field position. American football_sentence_44

However, a group of Princeton players realized that as the snap was uncontested, they could now hold the ball indefinitely to prevent their opponent from scoring. American football_sentence_45

In 1881, in a game between Yale and Princeton, both teams used this strategy to maintain their undefeated records. American football_sentence_46

Each team held the ball, gaining no ground, for an entire half, resulting in a 0–0 tie. American football_sentence_47

This "block game" proved extremely unpopular with both teams' spectators and fans. American football_sentence_48

A rule change was necessary to prevent this strategy from taking hold, and a reversion to the scrum was considered. American football_sentence_49

However, Camp successfully proposed a rule in 1882 that limited each team to three downs, or tackles, to advance the ball 5 yards (4.6 m). American football_sentence_50

Failure to advance the ball the required distance within those three downs would result in control of the ball being forfeited to the other team. American football_sentence_51

This change effectively made American football a separate sport from rugby, and the resulting five-yard lines added to the field to measure distances made it resemble a gridiron in appearance. American football_sentence_52

Other major rule changes included a reduction of the field size to 110 by 53 ⁄3 yards (100.6 m × 48.8 m) and the adoption of a scoring system that awarded four points for a touchdown, two for a safety and a goal following a touchdown, and five for a goal from the field. American football_sentence_53

Additionally, tackling below the waist was legalized, and a static line of scrimmage was instituted. American football_sentence_54

Despite these new rules, football remained a violent sport. American football_sentence_55

Dangerous mass-formations like the flying wedge resulted in serious injuries and deaths. American football_sentence_56

A 1905 peak of 19 fatalities nationwide resulted in a threat by President Theodore Roosevelt to abolish the game unless major changes were made. American football_sentence_57

In response, 62 colleges and universities met in New York City to discuss rule changes on December 28, 1905. American football_sentence_58

These proceedings resulted in the formation of the Intercollegiate Athletic Association of the United States, later renamed the National Collegiate Athletic Association (NCAA). American football_sentence_59

The legal forward pass was introduced in 1906, although its impact was initially minimal due to the restrictions placed on its use. American football_sentence_60

The idea of a 40-yard-wider field was opposed by Harvard due to the size of the new Harvard Stadium. American football_sentence_61

Other rule changes introduced that year included the reduction of playing time from 70 to 60 minutes and an increase of the distance required for a first down from 5 to 10 yards (4.6 to 9.1 m). American football_sentence_62

To reduce infighting and dirty play between teams, the neutral zone was created along the width of the football before the snap. American football_sentence_63

Scoring was also adjusted: points awarded for field goals were reduced to three in 1909 and points for touchdowns were raised to six in 1912. American football_sentence_64

Also in 1912, the field was shortened to 100 yards (91 m) long, two 10-yard-long (9.1 m) end zones were created, and teams were given four downs instead of three to advance the ball 10 yards (9.1 m). American football_sentence_65

The roughing the passer penalty was implemented in 1914, and eligible players were first allowed to catch the ball anywhere on the field in 1918. American football_sentence_66

Professional era American football_section_4

On November 12, 1892, Pudge Heffelfinger was paid $500 to play a game for the Allegheny Athletic Association in a match against the Pittsburgh Athletic Club. American football_sentence_67

This is the first recorded instance of a player being paid to participate in a game of American football, although many athletic clubs in the 1880s offered indirect benefits, such as helping players attain employment, giving out trophies or watches that players could pawn for money, or paying double in expense money. American football_sentence_68

Despite these extra benefits, the game had a strict sense of amateurism at the time, and direct payment to players was frowned upon, if not prohibited outright. American football_sentence_69

Over time, professional play became increasingly common, and with it came rising salaries and unpredictable player movement, as well as the illegal payment of college players who were still in school. American football_sentence_70

The National Football League (NFL), a group of professional teams that was originally established in 1920 as the American Professional Football Association, aimed to solve these problems. American football_sentence_71

This new league's stated goals included an end to bidding wars over players, prevention of the use of college players, and abolition of the practice of paying players to leave another team. American football_sentence_72

By 1922, the NFL had established itself as America's premier professional football league. American football_sentence_73

The dominant form of football at the time was played at the collegiate level. American football_sentence_74

The upstart NFL received a boost to its legitimacy in 1925, however, when an NFL team, the Pottsville Maroons, defeated a team of Notre Dame all-stars in an exhibition game. American football_sentence_75

A greater emphasis on the passing game helped professional football to distinguish itself further from the college game during the late 1930s. American football_sentence_76

Football, in general, became increasingly popular following the 1958 NFL Championship game, a match between the Baltimore Colts and the New York Giants that is still referred to as the "Greatest Game Ever Played". American football_sentence_77

The game, a 23–17 overtime victory by the Colts, was seen by millions of television viewers and had a major impact on the popularity of the sport. American football_sentence_78

This, along with the innovations introduced by the new American Football League (AFL) in the early 1960s, helped football to become the most popular sport in the United States by the mid-1960s. American football_sentence_79

The rival AFL arose in 1960 and challenged the NFL's dominance. American football_sentence_80

The AFL began in relative obscurity but eventually thrived, with an initial television contract with the ABC television network. American football_sentence_81

The AFL's existence forced the conservative NFL to expand to Dallas and Minnesota in an attempt to destroy the new league. American football_sentence_82

Meanwhile, the AFL introduced many new features to professional football in the United States: official time was kept on a scoreboard clock rather than on a watch in the referee's pocket, as the NFL did; optional two-point conversions by pass or run after touchdowns; names on the jerseys of players; and several others, including expansion of the role of minority players, actively recruited by the league in contrast to the NFL. American football_sentence_83

The AFL also signed several star college players who had also been drafted by NFL teams. American football_sentence_84

Competition for players heated up in 1965, when the AFL New York Jets signed rookie Joe Namath to a then-record $437,000 contract (equivalent to $2.76 million in 2019). American football_sentence_85

A five-year, $40 million NBC television contract followed, which helped to sustain the young league. American football_sentence_86

The bidding war for players ended in 1966 when NFL owners approached the AFL regarding a merger, and the two leagues agreed on one that took full effect in 1970. American football_sentence_87

This agreement provided for a common draft that would take place each year, and it instituted an annual World Championship game to be played between the champions of each league. American football_sentence_88

This championship game began play at the end of the 1966 season. American football_sentence_89

Once the merger was completed, it was no longer a championship game between two leagues and reverted to the NFL championship game, which came to be known as the Super Bowl. American football_sentence_90

College football maintained a tradition of postseason bowl games. American football_sentence_91

Each bowl game was associated with a particular conference and earning a spot in a bowl game was the reward for winning a conference. American football_sentence_92

This arrangement was profitable, but it tended to prevent the two top-ranked teams from meeting in a true national championship game, as they would normally be committed to the bowl games of their respective conferences. American football_sentence_93

Several systems have been used since 1992 to determine a national champion of college football. American football_sentence_94

The first was the Bowl Coalition, in place from 1992 to 1994. American football_sentence_95

This was replaced in 1995 by the Bowl Alliance, which gave way in 1997 to the Bowl Championship Series (BCS). American football_sentence_96

The BCS arrangement proved to be controversial, and was replaced in 2014 by the College Football Playoff (CFP). American football_sentence_97

Teams and positions American football_section_5

Main article: American football positions American football_sentence_98

A football game is played between two teams of 11 players each. American football_sentence_99

Playing with more on the field is punishable by a penalty. American football_sentence_100

Teams may substitute any number of their players between downs; this "platoon" system replaced the original system, which featured limited substitution rules, and has resulted in teams utilizing specialized offensive, defensive and special teams units. American football_sentence_101

Individual players in a football game must be designated with a uniform number between 1 and 99. American football_sentence_102

NFL teams are required to number their players by a league-approved numbering system, and any exceptions must be approved by the Commissioner. American football_sentence_103

NCAA and NFHS teams are "strongly advised" to number their offensive players according to a league-suggested numbering scheme. American football_sentence_104

Although the sport is played almost exclusively by men, women are eligible to play in high school, college, and professional football. American football_sentence_105

No woman has ever played in the NFL, but women have played in high school and college football games. American football_sentence_106

In 2018, 1,100 of the 225,000 players in Pop Warner Little Scholars youth football were girls, and around 11% of the 5.5 million Americans who report playing tackle football are female according to the Sports and Fitness Industry Association. American football_sentence_107

Women can also serve as officials; Sarah Thomas became the NFL's first female official in 2015. American football_sentence_108

Offensive unit American football_section_6

The role of the offensive unit is to advance the football down the field with the ultimate goal of scoring a touchdown. American football_sentence_109

The offensive team must line up in a legal formation before they can snap the ball. American football_sentence_110

An offensive formation is considered illegal if there are more than four players in the backfield or fewer than five players numbered 50–79 on the offensive line. American football_sentence_111

Players can line up temporarily in a position whose eligibility is different from what their number permits as long as they report the change immediately to the referee, who then informs the defensive team of the change. American football_sentence_112

Neither team's players, except the center (C), are allowed to line up in or cross the neutral zone until the ball is snapped. American football_sentence_113

Interior offensive linemen are not allowed to move until the snap of the ball. American football_sentence_114

The main backfield positions are the quarterback (QB), halfback/tailback (HB/TB) and fullback (FB). American football_sentence_115

The quarterback is the leader of the offense. American football_sentence_116

Either the quarterback or a coach calls the plays. American football_sentence_117

Quarterbacks typically inform the rest of the offense of the play in the huddle before the team lines up. American football_sentence_118

The quarterback lines up behind the center to take the snap and then hands the ball off, throws it or runs with it. American football_sentence_119

The primary role of the halfback, also known as the running back or tailback, is to carry the ball on running plays. American football_sentence_120

Halfbacks may also serve as receivers. American football_sentence_121

Fullbacks tend to be larger than halfbacks and function primarily as blockers, but they are sometimes used as runners in short-yardage situations and are seldom used in passing situations. American football_sentence_122

The offensive line (OL) consists of several players whose primary function is to block members of the defensive line from tackling the ball carrier on running plays or sacking the quarterback on passing plays. American football_sentence_123

The leader of the offensive line is the center, who is responsible for snapping the ball to the quarterback, blocking, and for making sure that the other linemen do their jobs during the play. American football_sentence_124

On either side of the center are the guards (G), while tackles (T) line up outside the guards. American football_sentence_125

The principal receivers are the wide receivers (WR) and the tight ends (TE). American football_sentence_126

Wide receivers line up on or near the line of scrimmage, split outside the line. American football_sentence_127

The main goal of the wide receiver is to catch passes thrown by the quarterback, but they may also function as decoys or as blockers during running plays. American football_sentence_128

Tight ends line up outside the tackles and function both as receivers and as blockers. American football_sentence_129

Defensive unit American football_section_7

The role of the defense is to prevent the offense from scoring by tackling the ball carrier or by forcing turnovers (interceptions or fumbles). American football_sentence_130

The defensive line (DL) consists of defensive ends (DE) and defensive tackles (DT). American football_sentence_131

Defensive ends line up on the ends of the line, while defensive tackles line up inside, between the defensive ends. American football_sentence_132

The primary responsibilities of defensive ends and defensive tackles are to stop running plays on the outside and inside, respectively, to pressure the quarterback on passing plays, and to occupy the line so that the linebackers can break through. American football_sentence_133

Linebackers line up behind the defensive line but in front of the defensive backfield. American football_sentence_134

They are divided into two types: middle linebackers (MLB) and outside linebackers (OLB). American football_sentence_135

Linebackers are the defensive leaders and call the defensive plays. American football_sentence_136

Their diverse roles include defending the run, pressuring the quarterback, and guarding backs, wide receivers and tight ends in the passing game. American football_sentence_137

The defensive backfield, often called the secondary, consists of cornerbacks (CB) and safeties (S). American football_sentence_138

Safeties are themselves divided into free safeties (FS) and strong safeties (SS). American football_sentence_139

Cornerbacks line up outside the defensive formation, typically opposite a receiver to be able to cover them. American football_sentence_140

Safeties line up between the cornerbacks but farther back in the secondary. American football_sentence_141

Safeties are the last line of defense and are responsible for stopping deep passing plays as well as running plays. American football_sentence_142

Special teams unit American football_section_8

The special teams unit is responsible for all kicking plays. American football_sentence_143

The special teams unit of the team in control of the ball tries to execute field goal (FG) attempts, punts and kickoffs, while the opposing team's unit will aim to block or return them. American football_sentence_144

Three positions are specific to the field goal and PAT (point-after-touchdown) unit: the placekicker (K or PK), holder (H) and long snapper (LS). American football_sentence_145

The long snapper's job is to snap the football to the holder, who will catch and position it for the placekicker. American football_sentence_146

There is not usually a holder on kickoffs, because the ball is kicked off a tee; however, a holder may be used in certain situations, such as if wind is preventing the ball from remaining upright on the tee. American football_sentence_147

The player on the receiving team who catches the ball is known as the kickoff returner (KR). American football_sentence_148

The positions specific to punt plays are the punter (P), long snapper, upback and gunner. American football_sentence_149

The long snapper snaps the football directly to the punter, who then drops and kicks it before it hits the ground. American football_sentence_150

Gunners line up split outside the line and race down the field, aiming to tackle the punt returner (PR)—the player who catches the punt. American football_sentence_151

Upbacks line up a short distance behind the line of scrimmage, providing additional protection to the punter. American football_sentence_152

Rules American football_section_9

Main article: American football rules American football_sentence_153

Scoring American football_section_10

In football, the winner is the team that has scored more points at the end of the game. American football_sentence_154

There are multiple ways to score in a football game. American football_sentence_155

The touchdown (TD), worth six points, is the most valuable scoring play in American football. American football_sentence_156

A touchdown is scored when a live ball is advanced into, caught in, or recovered in the opposing team's end zone. American football_sentence_157

The scoring team then attempts a try or conversion, more commonly known as the point(s)-after-touchdown (PAT), which is a single scoring opportunity. American football_sentence_158

A PAT is most commonly attempted from the two- or three-yard line, depending on the level of play. American football_sentence_159

If a PAT is scored by a placekick or dropkick through the goal posts, it is worth one point, typically called the extra point. American football_sentence_160

If it is scored by what would normally be a touchdown it is worth two points, typically called the two-point conversion. American football_sentence_161

In general, the extra point is almost always successful while the two-point conversion is a much riskier play with a higher probability of failure; accordingly, extra point attempts are far more common than two-point conversion attempts. American football_sentence_162

A field goal (FG), worth three points, is scored when the ball is placekicked or dropkicked through the uprights and over the crossbars of the defense's goalposts. American football_sentence_163

After a PAT attempt or successful field goal, the scoring team must kick the ball off to the other team. American football_sentence_164

A safety is scored when the ball carrier is tackled in their own end zone. American football_sentence_165

Safeties are worth two points, which are awarded to the defense. American football_sentence_166

In addition, the team that conceded the safety must kick the ball to the scoring team via a free kick. American football_sentence_167

Field and equipment American football_section_11

Main article: American football field American football_sentence_168

Football games are played on a rectangular field that measures 120 yards (110 m) long and 53 ⁄3 yards (48.8 m) wide. American football_sentence_169

Lines marked along the ends and sides of the field are known as the end lines and sidelines. American football_sentence_170

Goal lines are marked 10 yards (9.1 m) inward from each end line. American football_sentence_171

Weighted pylons are placed the sidelines on the inside corner of the intersections with the goal lines and end lines. American football_sentence_172

White markings on the field identify the distance from the end zone. American football_sentence_173

Inbound lines, or hash marks, are short parallel lines that mark off 1-yard (0.91 m) increments. American football_sentence_174

Yard lines, which can run the width of the field, are marked every 5 yards (4.6 m). American football_sentence_175

A one-yard-wide line is placed at each end of the field; this line is marked at the center of the two-yard line in professional play and at the three-yard line in college play. American football_sentence_176

Numerals that display the distance from the closest goal line in yards are placed on both sides of the field every ten yards. American football_sentence_177

Goalposts are located at the center of the plane of the two end lines. American football_sentence_178

The crossbar of these posts is 10 feet (3.0 m) above the ground, with vertical uprights at the end of the crossbar 18 feet 6 inches (5.64 m) apart for professional and collegiate play, and 23 feet 4 inches (7.11 m) apart for high school play. American football_sentence_179

The uprights extend vertically 35 feet (11 m) on professional fields, a minimum of 10 yards (9.1 m) on college fields, and a minimum of 10 feet (3.0 m) on high school fields. American football_sentence_180

Goal posts are padded at the base, and orange ribbons are normally placed at the tip of each upright as indicators of wind strength and direction. American football_sentence_181

The football itself is an oval ball, similar to the balls used in rugby or Australian rules football. American football_sentence_182

At all levels of play, the football is inflated to 12 ⁄2 to 13 ⁄2 pounds per square inch (86 to 93 kPa) and weighs 14 to 15 ounces (400 to 430 g); beyond that, the exact dimensions vary slightly. American football_sentence_183

In professional play the ball has a long axis of 11 to 11 ⁄4 inches (28 to 29 cm), a long circumference of 28 to 28 ⁄2 inches (71 to 72 cm), and a short circumference of 21 to 21 ⁄4 inches (53 to 54 cm). American football_sentence_184

In college and high school play the ball has a long axis of 10 ⁄8 to 11 ⁄16 inches (27.6 to 29.1 cm), a long circumference of 27 ⁄4 to 28 ⁄2 inches (70 to 72 cm), and a short circumference of 20 ⁄4 to 21 ⁄4 inches (53 to 54 cm). American football_sentence_185

Duration and time stoppages American football_section_12

Football games last for a total of 60 minutes in professional and college play and are divided into two halves of 30 minutes and four quarters of 15 minutes. American football_sentence_186

High school football games are 48 minutes in length with two halves of 24 minutes and four quarters of 12 minutes. American football_sentence_187

The two halves are separated by a halftime period, and the first and third quarters are followed by a short break. American football_sentence_188

Before the game starts, the referee and each team's captain meet at midfield for a coin toss. American football_sentence_189

The visiting team can call either "heads" or "tails"; the winner of the toss chooses whether to receive or kick off the ball or which goal they wish to defend. American football_sentence_190

They can defer their choice until the second half. American football_sentence_191

Unless the winning team decides to defer, the losing team chooses the option the winning team did not select—to receive, kick, or select a goal to defend to begin the second half. American football_sentence_192

Most teams choose to receive or defer, because choosing to kick the ball to start the game allows the other team to choose which goal to defend. American football_sentence_193

Teams switch goals following the first and third quarters. American football_sentence_194

If a down is in progress when a quarter ends, play continues until the down is completed. American football_sentence_195

Games last longer than their defined length due to play stoppages—the average NFL game lasts slightly over three hours. American football_sentence_196

Time in a football game is measured by the game clock. American football_sentence_197

An operator is responsible for starting, stopping and operating the game clock based on the direction of the appropriate official. American football_sentence_198

A separate play clock is used to determine if a delay of game infraction has been committed. American football_sentence_199

If the play clock expires before the ball has been snapped or free-kicked, a delay of game foul is called on the offense. American football_sentence_200

The play clock is set 25 seconds after certain administrative stoppages in play and to 40 seconds when play is proceeding without such stoppages. American football_sentence_201

Advancing the ball and downs American football_section_13

There are two main ways the offense can advance the ball: running and passing. American football_sentence_202

In a typical play, the center passes the ball backwards and between their legs to the quarterback in a process known as the snap. American football_sentence_203

The quarterback then either hands the ball off to a back, throws the ball, or runs with it. American football_sentence_204

The play ends when the player with the ball is tackled or goes out-of-bounds or a pass hits the ground without a player having caught it. American football_sentence_205

A forward pass can be legally attempted only if the passer is behind the line of scrimmage; only one forward pass can be attempted per down. American football_sentence_206

Like in rugby, players can also pass the ball backwards at any point during a play. American football_sentence_207

In the NFL, a down also ends immediately if the runner's helmet comes off. American football_sentence_208

The offense is given a series of four plays, known as downs. American football_sentence_209

If the offense advances ten or more yards in the four downs, they are awarded a new set of four downs. American football_sentence_210

If they fail to advance ten yards, possession of the football is turned over to the defense. American football_sentence_211

In most situations, if the offense reaches their fourth down they will punt the ball to the other team, which forces them to begin their drive from farther down the field; if they are in field goal range, they might attempt to score a field goal instead. American football_sentence_212

A group of officials, the chain crew, keeps track of both the downs and the distance measurements. American football_sentence_213

On television, a yellow line is electronically superimposed on the field to show the first down line to the viewing audience. American football_sentence_214

Kicking American football_section_14

There are two categories of kicks in football: scrimmage kicks, which can be executed by the offensive team on any down from behind or on the line of scrimmage, and free kicks. American football_sentence_215

The free kicks are the kickoff, which starts the first and third quarters and overtime and follows a try attempt or a successful field goal; the safety kick follows a safety. American football_sentence_216

On a kickoff, the ball is placed at the 35-yard line of the kicking team in professional and college play and at the 40-yard line in high school play. American football_sentence_217

The ball may be drop-kicked or place-kicked. American football_sentence_218

If a place kick is chosen, the ball can be placed on the ground or a tee; a holder may be used in either case. American football_sentence_219

On a safety kick, the kicking team kicks the ball from their own 20-yard line. American football_sentence_220

They can punt, drop-kick or place-kick the ball, but a tee may not be used in professional play. American football_sentence_221

Any member of the receiving team may catch or advance the ball. American football_sentence_222

The ball may be recovered by the kicking team once it has gone at least ten yards and has touched the ground or has been touched by any member of the receiving team. American football_sentence_223

The three types of scrimmage kicks are place kicks, drop kicks, and punts. American football_sentence_224

Only place kicks and drop kicks can score points. American football_sentence_225

The place kick is the standard method used to score points, because the pointy shape of the football makes it difficult to reliably drop kick. American football_sentence_226

Once the ball has been kicked from a scrimmage kick, it can be advanced by the kicking team only if it is caught or recovered behind the line of scrimmage. American football_sentence_227

If it is touched or recovered by the kicking team beyond this line, it becomes dead at the spot where it was touched. American football_sentence_228

The kicking team is prohibited from interfering with the receiver's opportunity to catch the ball. American football_sentence_229

The receiving team has the option of signaling for a fair catch, which prohibits the defense from blocking into or tackling the receiver. American football_sentence_230

The play ends as soon as the ball is caught and the ball may not be advanced. American football_sentence_231

Officials and fouls American football_section_15

See also: Official (American football), Chain crew, and Penalty (gridiron football) American football_sentence_232

Officials are responsible for enforcing game rules and monitoring the clock. American football_sentence_233

All officials carry a whistle and wear black-and-white striped shirts and black hats except for the referee, whose hat is white. American football_sentence_234

Each carries a weighted yellow flag that is thrown to the ground to signal that a foul has been called. American football_sentence_235

An official who spots multiple fouls will throw their hat as a secondary signal. American football_sentence_236

The seven officials (of a standard seven-man crew; lower levels of play up to the college level use fewer officials) on the field are each tasked with a different set of responsibilities: American football_sentence_237

American football_unordered_list_0

  • The referee is positioned behind and to the side of the offensive backs. The referee is charged with oversight and control of the game and is the authority on the score, the down number, and any rule interpretations in discussions among the other officials. The referee announces all penalties and discusses the infraction with the offending team's captain, monitors for illegal hits against the quarterback, makes requests for first-down measurements, and notifies the head coach whenever a player is ejected. The referee positions themselves to the passing arm side of the quarterback. In most games, the referee is responsible for spotting the football prior to a play from scrimmage.American football_item_0_0
  • The umpire is positioned in the defensive backfield, except in the NFL, where the umpire is positioned lateral to the referee on the opposite side of the formation. The umpire watches play along the line of scrimmage to make sure that no more than 11 offensive players are on the field before the snap and that no offensive linemen are illegally downfield on pass plays. The umpire monitors contact between offensive and defensive linemen and calls most of the holding penalties. The umpire records the number of timeouts taken and the winner of the coin toss and the game score, assists the referee in situations involving possession of the ball close to the line of scrimmage, determines whether player equipment is legal, and dries wet balls prior to the snap if a game is played in rain.American football_item_0_1
  • The back judge is positioned deep in the defensive backfield, behind the umpire. The back judge ensures that the defensive team has no more than 11 players on the field and determines whether catches are legal, whether field goal or extra point attempts are good, and whether a pass interference violation occurred. The back judge is also responsible for the play clock, the time between each play, when a visible play clock is not used.American football_item_0_2
  • The head linesman/down judge is positioned on one end of the line of scrimmage. The head linesman/down judge watches for any line-of-scrimmage and illegal use-of-hands violations and assists the line judge with illegal shift or illegal motion calls. The head linesman/down judge also rules on out-of-bounds calls that happen on their side of the field, oversees the chain crew and marks the forward progress of a runner when a play has been whistled dead.American football_item_0_3

American football_unordered_list_1

  • The side judge is positioned twenty yards downfield of the head linesman. The side judge mainly duplicates the functions of the field judge. On field goal and extra point attempts, the side judge is positioned lateral to the umpire.American football_item_1_4
  • The line judge is positioned on the end of the line of scrimmage, opposite the head linesman. They supervise player substitutions, the line of scrimmage during punts, and game timing. The line judge notifies the referee when time has expired at the end of a quarter and notifies the head coach of the home team when five minutes remain for halftime. In the NFL, the line judge also alerts the referee when two minutes remain in the half. If the clock malfunctions or becomes inoperable, the line judge becomes the official timekeeper.American football_item_1_5
  • The field judge is positioned twenty yards downfield from the line judge. The field judge monitors and controls the play clock, counts the number of defensive players on the field and watches for offensive pass interference and illegal use-of-hands violations by offensive players. The field judge also makes decisions regarding catches, recoveries, the ball spot when a player goes out of bounds, and illegal touching of fumbled balls that have crossed the line of scrimmage. On field goal and extra point attempts, the field judge is stationed under the upright opposite the back judge.American football_item_1_6
  • The center judge is an eighth official used only in the top level of college football. The center judge stands lateral to the referee, the same way the umpire does in the NFL. The center judge is responsible for spotting the football after each play and has many of the same responsibilities as the referee, except announcing penalties.American football_item_1_7

Another set of officials, the chain crew, are responsible for moving the chains. American football_sentence_238

The chains, consisting of two large sticks with a 10-yard-long chain between them, are used to measure for a first down. American football_sentence_239

The chain crew stays on the sidelines during the game, but if requested by the officials they will briefly bring the chains on to the field to measure. American football_sentence_240

A typical chain crew will have at least three people—two members of the chain crew will hold either of the two sticks, while a third will hold the down marker. American football_sentence_241

The down marker, a large stick with a dial on it, is flipped after each play to indicate the current down and is typically moved to the approximate spot of the ball. American football_sentence_242

The chain crew system has been used for over 100 years and is considered to be an accurate measure of distance, rarely subject to criticism from either side. American football_sentence_243

Safety and brain health American football_section_16

See also: Protective equipment in gridiron football and Health issues in American football American football_sentence_244

Football is a full-contact sport, and injuries are relatively common. American football_sentence_245

Most injuries occur during training sessions, particularly ones that involve contact between players. American football_sentence_246

To try to prevent injuries, players are required to wear a set of equipment. American football_sentence_247

At a minimum players must wear a football helmet and a set of shoulder pads, but individual leagues may require additional padding such as thigh pads and guards, knee pads, chest protectors, and mouthguards. American football_sentence_248

Most injuries occur in the lower extremities, particularly in the knee, but a significant number also affect the upper extremities. American football_sentence_249

The most common types of injuries are strains, sprains, bruises, fractures, dislocations, and concussions. American football_sentence_250

Repeated concussions (and possibly sub-concussive head impacts) can increase a person's risk in later life for CTE (chronic traumatic encephalopathy) and mental health issues such as dementia, Parkinson's disease, and depression. American football_sentence_251

Concussions are often caused by helmet-to-helmet or upper-body contact between opposing players, although helmets have prevented more serious injuries such as skull fractures. American football_sentence_252

Various programs are aiming to reduce concussions by reducing the frequency of helmet-to-helmet hits; USA Football's "Heads Up Football" program aims to reduce concussions in youth football by teaching coaches and players about the signs of a concussion, the proper way to wear football equipment and ensure it fits, and proper tackling methods that avoid helmet-to-helmet contact. American football_sentence_253

However, a study in the Orthopaedic Journal of Sports Medicine found that Heads Up Football was ineffective; the same study noted that more extensive reforms implemented by Pop Warner Little Scholars and its member teams were effective in significantly reducing concussion rates. American football_sentence_254

A 2018 study performed by the VA Boston Healthcare System and the Boston University School of Medicine found that tackle football before age 12 was correlated with earlier onset of symptoms of CTE, but not with symptom severity. American football_sentence_255

More specifically, each year a player played tackle football under age 12 predicted earlier onset of cognitive, behavioral, and mood problems by an average of two and a half years. American football_sentence_256

Leagues and tournaments American football_section_17

The National Football League (NFL) and the National Collegiate Athletic Association (NCAA) are the most popular football leagues in the United States. American football_sentence_257

The National Football League was founded in 1920 and has since become the largest and most popular sport in the United States. American football_sentence_258

The NFL has the highest average attendance of any sporting league in the world, with an average attendance of 66,960 during the 2011 NFL season. American football_sentence_259

The NFL championship game is called the Super Bowl, and is among the biggest events in club sports worldwide. American football_sentence_260

It is played between the champions of the National Football Conference (NFC) and the American Football Conference (AFC), and its winner is awarded the Vince Lombardi Trophy. American football_sentence_261

College football is the third-most popular sport in the United States, behind professional baseball and professional football. American football_sentence_262

The NCAA, the largest collegiate organization, is divided into three Divisions: Division I, Division II and Division III. American football_sentence_263

Division I football is further divided into two subdivisions: the Football Bowl Subdivision (FBS) and the Football Championship Subdivision (FCS). American football_sentence_264

The champions of each level of play are determined through NCAA-sanctioned playoff systems; while the champion of Division I-FBS was historically determined by various polls and ranking systems, the subdivision adopted a four-team playoff system in 2014. American football_sentence_265

High school football is the most popular sport in the United States played by boys; over 1.1 million boys participated in the sport from 2007 to 2008 according to a survey by the National Federation of State High School Associations (NFHS). American football_sentence_266

The NFHS is the largest organization for high school football, with member associations in all 50 states as well as the District of Columbia. American football_sentence_267

USA Football is the governing body for youth and amateur football, and Pop Warner Little Scholars is the largest organization for youth football. American football_sentence_268

Other professional leagues American football_section_18

Several professional football leagues have been formed outside the auspices of the NFL. American football_sentence_269

One such league, the XFL, is currently operating as of 2020. American football_sentence_270

Rival leagues American football_section_19

The most successful league to directly compete with the NFL was the American Football League (AFL), which existed from 1960 to 1969. American football_sentence_271

The AFL became a significant rival in 1964 before signing a five-year, US$36 million television deal with NBC. American football_sentence_272

AFL teams began signing NFL players to contracts, and the league's popularity grew to challenge that of the NFL. American football_sentence_273

The two leagues merged in the 1970 season, and all the AFL teams joined the NFL. American football_sentence_274

An earlier league, the All-America Football Conference (AAFC), was in play from 1946 to 1949. American football_sentence_275

After it had dissolved, two AAFC teams, the Cleveland Browns and the San Francisco 49ers, became members of the NFL; another member, the Baltimore Colts joined the league, but folded after just a year in the NFL. American football_sentence_276

Other attempts to start rival leagues since the AFL merged with the NFL in 1970 have been far less successful, as professional football salaries and the NFL's television contracts began to escalate out of the reach of competitors and the NFL covered more of the larger cities. American football_sentence_277

The World Football League (WFL) played for two seasons, in 1974 and 1975, but faced such severe monetary issues it could not pay its players. American football_sentence_278

In its second and final season the WFL attempted to establish a stable credit rating, but the league disbanded before the season could be completed. American football_sentence_279

The United States Football League (USFL) operated for three seasons from 1983 to 1985. American football_sentence_280

Originally not intended as a rival league, the entry of owners who sought marquee talent and to challenge the NFL led to an escalation in salaries and ensuing financial losses. American football_sentence_281

A subsequent US$1.5 billion antitrust lawsuit against the NFL was successful in court, but the league was awarded only $1 in damages, which was automatically tripled to $3 under antitrust law. American football_sentence_282

Complementary national leagues American football_section_20

The original XFL was created in 2001 by Vince McMahon and lasted for only one season. American football_sentence_283

Despite television contracts with NBC and UPN, and high expectations, the XFL suffered from low quality of play and poor reception for its use of tawdry professional wrestling gimmicks, which caused initially high ratings and attendance to collapse. American football_sentence_284

(The current XFL, also owned by McMahon, does not include those gimmicks.) American football_sentence_285

The United Football League (UFL) began in 2009 but folded after suspending its 2012 season amid declining interest and lack of major television coverage. American football_sentence_286

The Alliance of American Football lasted less than one season, unable to keep investors. American football_sentence_287

International play American football_section_21

American football leagues exist throughout the world, but the game has yet to achieve the international success and popularity of baseball and basketball. American football_sentence_288

It is not an Olympic sport, but it was a demonstration sport at the 1932 Summer Olympics. American football_sentence_289

At the international level, Canada, Mexico, and Japan are considered to be second-tier, while Austria, Germany, and France would rank among a third tier. American football_sentence_290

These countries rank far below the United States, which is dominant at the international level. American football_sentence_291

NFL Europa, the developmental league of the NFL, operated from 1991 to 1992 and then from 1995 to 2007. American football_sentence_292

At the time of its closure, NFL Europa had five teams based in Germany and one in the Netherlands. American football_sentence_293

In Germany, the German Football League (GFL) has 16 teams and has operated for over 40 seasons, with the league's championship game, the German Bowl, closing out each season. American football_sentence_294

The league operates in a promotion and relegation structure with German Football League 2 (GFL2), which also has 16 teams. American football_sentence_295

The BIG6 European Football League functions as a continental championship for Europe. American football_sentence_296

The competition is contested between the top six European teams. American football_sentence_297

American football federations are present in Africa, the Americas, Asia, Europe and Oceania; a total of 64 national football federations exist as of July 2012. American football_sentence_298

The International Federation of American Football (IFAF), an international governing body composed of continental federations, runs tournaments such as the IFAF World Championship, the IFAF Women's World Championship, the IFAF U-19 World Championship and the Flag Football World Championship. American football_sentence_299

The IFAF also organizes the annual International Bowl game. American football_sentence_300

The IFAF has received provisional recognition from the International Olympic Committee (IOC). American football_sentence_301

Several major obstacles hinder the IFAF goal of achieving status as an Olympic sport. American football_sentence_302

These include the predominant participation of men in international play and the short three-week Olympic schedule. American football_sentence_303

Large team sizes are an additional difficulty, due to the Olympics' set limit of 10,500 athletes and coaches. American football_sentence_304

American football also has an issue with a lack of global visibility. American football_sentence_305

Nigel Melville, the CEO of USA Rugby, noted that "American football is recognized globally as a sport, but it's not played globally." American football_sentence_306

To solve these concerns, major effort has been put into promoting flag football, a modified version of American football, at the international level. American football_sentence_307

Popularity and cultural impact American football_section_22

United States American football_section_23

Main article: American football in the United States American football_sentence_308

"Baseball is still called the national pastime, but football is by far the more popular sport in American society", according to ESPN.com's Sean McAdam. American football_sentence_309

In a 2014 poll conducted by Harris Interactive, professional football ranked as the most popular sport, and college football ranked third behind only professional football and baseball; 46% of participants ranked some form of the game as their favorite sport. American football_sentence_310

Professional football has ranked as the most popular sport in the poll since 1985, when it surpassed baseball for the first time. American football_sentence_311

Professional football is most popular among those who live in the eastern United States and rural areas, while college football is most popular in the southern United States and among people with graduate and post-graduate degrees. American football_sentence_312

Football is also the most-played sport by high school and college athletes in the United States. American football_sentence_313

In a 2012 study, the NCAA estimated there were around 1.1 million high school football players and nearly 70,000 college football players in the United States; in comparison, the second-most played sport, basketball, had around 1 million participants in high school and 34,000 in college. American football_sentence_314

The Super Bowl is the most popular single-day sporting event in the United States, and is among the biggest club sporting events in the world in terms of TV viewership. American football_sentence_315

The NFL makes approximately $10 billion annually. American football_sentence_316

Super Bowl games account for seven of the top eight most-watched broadcasts in American history; Super Bowl XLIX, played on February 1, 2015, was watched by a record 114.4 million Americans. American football_sentence_317

American football also plays a significant role in American culture. American football_sentence_318

The day on which the Super Bowl is held is considered a de facto national holiday, and in parts of the country like Texas, the sport has been compared to a religion. American football_sentence_319

Football is also linked to other holidays; New Year's Day is traditionally the date for several college football bowl games, including the Rose Bowl. American football_sentence_320

However, if New Year's Day is on a Sunday, the bowl games are moved to another date so as not to conflict with the typical NFL Sunday schedule. American football_sentence_321

Thanksgiving football is an American tradition, hosting many high school, college, and professional games. American football_sentence_322

Steve Deace of USA Today wrote that Americans are passionate about football "because it embodies everything we love about American exceptionalism. American football_sentence_323

Merit is rewarded, not punished. American football_sentence_324

Masculinity is celebrated, not feminized. American football_sentence_325

People of various beliefs and backgrounds – a melting pot, if you will – must unify for a common goal for the team to be successful". American football_sentence_326

Implicit rules such as playing through pain and sacrificing for the better of the team are promoted in football culture. American football_sentence_327

The safety of the sport has also sparked national controversy in American popular culture. American football_sentence_328

It is often received as "overly aggressive", and defamiliarized in popular culture. American football_sentence_329

The 2015 film Concussion aimed to shed light on the sport's safety, specifically in the NFL by having Will Smith portray Dr. American football_sentence_330 Bennet Omalu, a neuropathologist who was the first to discover and publish findings of chronic traumatic encephalopathy or CTE. American football_sentence_331

Other countries American football_section_24

In Canada, the game has a significant following. American football_sentence_332

According to a 2013 poll, 21% of respondents said they followed the NFL "very closely" or "fairly closely", making it the third-most followed league behind the National Hockey League (NHL) and Canadian Football League (CFL). American football_sentence_333

American football also has a long history in Mexico, which was introduced to the sport in 1896. American football_sentence_334

It was the second-most popular sport in Mexico in the 1950s, with the game being particularly popular in colleges. American football_sentence_335

The Los Angeles Times notes the NFL claims over 16 million fans in Mexico, which places the country third behind the US and Canada. American football_sentence_336

American football is played in Mexico both professionally and as part of the college sports system. American football_sentence_337

A professional league, the Liga de Fútbol Americano Profesional (LFA), was founded in 2016. American football_sentence_338

Japan was introduced to the sport in 1934 by Paul Rusch, a teacher and Christian missionary who helped to establish football teams at three universities in Tokyo. American football_sentence_339

Play was halted during World War II, but the sport began growing in popularity again after the war. American football_sentence_340

As of 2010, there are more than 400 high school football teams in Japan, with over 15,000 participants, and over 100 teams play in the Kantoh Collegiate Football Association (KCFA). American football_sentence_341

The college champion plays the champion of the X-League (a semi-professional league where teams are financed by corporations) in the Rice Bowl to determine Japan's national champion. American football_sentence_342

Europe is a major target for the expansion of the game by football organizers. American football_sentence_343

In the United Kingdom in the 1980s, the sport was popular, with the 1986 Super Bowl being watched by over four million people (about 1 out of every 14 Britons). American football_sentence_344

Its popularity faded during the 1990s, coinciding with the establishment of the Premier League—top level of the English football league system. American football_sentence_345

According to BBC America, there is a "social stigma" surrounding American football in the UK, with many Brits feeling the sport has no right to call itself "football" due to the lack of emphasis on kicking. American football_sentence_346

Nonetheless, the sport has retained a following in the United Kingdom; the NFL operates a media network in the country, and since 2007 has hosted the NFL International Series in London. American football_sentence_347

Super Bowl viewership has also rebounded, with over 4.4 million Britons watching Super Bowl XLVI. American football_sentence_348

The sport is played in European countries like Switzerland, which has American football clubs in every major city, and Germany, where the sport has around 45,000 registered amateur players. American football_sentence_349

In Brazil, football is a growing sport. American football_sentence_350

It was generally unknown there until the 1980s when a small group of players began playing on Copacabana Beach in Rio de Janeiro. American football_sentence_351

The sport grew gradually with 700 amateur players registering within 20 years. American football_sentence_352

Games were played on the beach with modified rules and without the traditional football equipment due to its lack of availability in Brazil. American football_sentence_353

Eventually, a tournament, the Carioca championship, was founded, with the championship Carioca Bowl played to determine a league champion. American football_sentence_354

The country saw its first full-pad game of football in October 2008. American football_sentence_355

According to The Rio Times, the sport is one of the fastest-growing sports in Brazil and is almost as commonly played as soccer on the beaches of Copacabana and Botafogo. American football_sentence_356

Football in Brazil is governed by the Confederação Brasileira de Futebol Americano (CBFA), which had over 5,000 registered players as of November 2013. American football_sentence_357

The sport's increase in popularity has been attributed to games aired on ESPN, which began airing in Brazil in 1992 with Portuguese commentary. American football_sentence_358

The popularity and "easy accessibility" of non-contact versions of the sport in Brazil has led to a rise in participation by female players. American football_sentence_359

According to ESPN, the American football audience in Brazil increased 800% between 2013 and 2016. American football_sentence_360

The network, along with Esporte Interativo, airs games there on cable television. American football_sentence_361

Football is often associated in Brazil as being the sport of supermodel Gisele Bündchen's husband Tom Brady. American football_sentence_362

The NFL has expressed interest in having games in the country, and the Super Bowl has become a widely watched event in Brazil at bars and movie theaters. American football_sentence_363

Variations and related sports American football_section_25

See also: Canadian football, Arena football, and Flag football American football_sentence_364

Canadian football, the predominant form of football in Canada, is closely related to American football—both sports developed from rugby and are considered to be the chief variants of gridiron football. American football_sentence_365

Although both games share a similar set of rules, there are several key rule differences: for example, in Canadian football the field measures 150 by 65 yards (137 by 59 m), including two 20-yard end zones (for a distance between goal lines of 110 yards), teams have three downs instead of four, there are twelve players on each side instead of eleven, fair catches are not allowed, and a rouge, worth a single point is scored if the offensive team kicks the ball out of the defense's end zone. American football_sentence_366

The Canadian Football League (CFL) is the major Canadian league and is the second-most popular sporting league in Canada, behind the National Hockey League. American football_sentence_367

The NFL and CFL had a formal working relationship from 1997 to 2006. American football_sentence_368

The CFL has a strategic partnership with two American football leagues, the German Football League (GFL) and the Liga de Futbol Americano Profesional (LFA). American football_sentence_369

The Canadian rules were developed separately from the American game. American football_sentence_370

Indoor football leagues constitute what The New York Times writer Mike Tanier described as the "most minor of minor leagues." American football_sentence_371

Leagues are unstable, with franchises regularly moving from one league to another or merging with other teams, and teams or entire leagues dissolving completely; games are only attended by a small number of fans, and most players are semi-professional athletes. American football_sentence_372

The Indoor Football League is an example of a prominent indoor league. American football_sentence_373

The Arena Football League, which was founded in 1987 and ceased operations in 2019, was one of the longest-lived indoor football leagues. American football_sentence_374

In 2004, the league was called "America's fifth major sport" by ESPN The Magazine. American football_sentence_375

There are several non-contact variants of football like flag football. American football_sentence_376

In flag football the ballcarrier is not tackled; instead, defenders aim to pull a flag tied around their waist. American football_sentence_377

Another variant, touch football, simply requires the ballcarrier to be touched to be considered downed. American football_sentence_378

Depending on the rules used, a game of touch football may require the player be touched with either one or two hands to be considered down. American football_sentence_379

See also American football_section_26

Credits to the contents of this page go to the authors of the corresponding Wikipedia page: en.wikipedia.org/wiki/American football.