American football is a remarkable combination of planned and highly organized team play, conducted through the physical, often brutally violent, encounters between offensive and defensive players. Football is the preeminent spectator sport in the United States. Football is played at the highest professional level in the 30—team National Football League (NFL). Hundreds of U.S. colleges and universities at various levels of competition as sanctioned by the National Collegiate Athletic Association (NCAA) also participate. There are also thousands of very active high school and community football programs.
American football is derived from the English game of rugby, itself a reworking of the much older sport of soccer. There is considerable historical debate as to when the first version of an American football game was actually played; in 1869, the universities of Rutgers and Princeton of the eastern United States played a game that had a number of the elements later identified as those of football, including the tackling of an opponent. The more direct connection between rugby, a 15-man contact sport whose rules were first codified in England in 1845, and American football occurred by way of Montreal, Canada. The British garrison stationed there in the 1860s had taken up rugby and that game had achieved some local popularity, with the first formal match taking place in 1865. In 1874, McGill University of Montreal played Harvard in a rugby game that included some modifications of the rules concerning the number of players and the tactics that could be employed. The potential for both speedy play and rough, emphatic tackling made this variation of rugby an almost instant success. The initial McGill v. Harvard contest spawned further competitions between a number of American university teams in the years that followed.
Various attempts to standardize the rules of what was the new American football first occurred in the late 1870s, continuing through the early 1900s. In an initiative spearheaded by the coach of Yale University, Walter Camp (1859–1925), widely recognized as "the father of American Football," the rules of the game became consistent across the United States. It was during this period that American football became less of a rugby variant and far more of a distinct sport.
The foundation rules that led to this distinction included:
American football is a battle for territorial supremacy, where control of the field, through the control of the ball, is ultimately rewarded by a greater opportunity to score. The basic offensive object of the game remained similar to that of rugby: to advance the ball across the opposing team's goal for a touchdown (similar to the rugby "try," or alternatively, to kick the ball through the opponent's goal posts for a field goal (similar to the rugby "drop goal"). The value given to these different scoring options has been varied by rule as the game has evolved; the modern football scoring standards are six points for a touchdown, three points for a field goal, one point for a kicked convert after a touchdown was made, two points for a convert scored by the ball being taken across the goal line (as an alternative to the kicked convert), and a two-point safety, awarded to a defensive team that tackles an offensive ball carrier in the offensive team end zone.
The primary defensive object of the game has remained constant through the history of American football: to prevent the progress of the offensive team, primarily through the tackling to the ground of the ball carrier. Where the offensive team is required to come to a set position prior to any attempt to move the ball forward against the defensive team, the defensive players are permitted freedom of movement behind the line of scrimmage.
The growth of football in the universities of the eastern United States in the late nineteenth century was mirrored by the growth of local clubs and leagues that were the forerunners to modern professional football. Loose associations of clubs in the states of Ohio and Pennsylvania spurred the creation of intense local rivalries, which became an environment for the first professional players. In 1892, former Yale star William (Pudge) Heffelfinger (1867–1954) became the first known footballer to be paid for his athletic services when he took to the field for the Allegheny Athletic Association against their rivals from Pittsburgh. Professional players became a common but not universal feature of these club contests. The most famous of the early professional players was the noted 1912 Olympic decathlon gold medalist Jim Thorpe, who was a star performer for a number of Midwestern U.S. teams in the period prior to 1929.
In the early days of American football, the college and university competitions were by far the most glamorous and the most popular with the sporting public; the phrase "college football" includes both four year-degree granting colleges as well as universities, and the terms college and university are used interchangeably. The college game structure was formalized through the creation of the Intercollegiate Athletic Association (IAAUS) in 1906, in part to limit the rising injury rate in this violent, hard-hitting sport for which protective equipment was both primitive and optional. The IAAUS was a forerunner of the modern National Collegiate Athletic Association (NCAA), the governing body for most aspects of American intercollegiate athletics since 1939. Walter Camp was one of the developers of the first All American collegiate team selections, which made household names of himself, coach Knute Rockne of Notre Dame, and his quarterback George Gipp, and the various rivals of the Ivy League schools such as Princeton, Yale, and Harvard. The Rose Bowl, first contested between two selected top university teams in 1902 in California, was followed by the creation of the Sugar, Cotton, and Orange Bowl games, each involving elite college teams and played on New Year's Day. College football became cemented into the sport hierarchy of America: the bowl games remain a prominent fixture today, as a part of the American college football championship process known as the Bowl Champion Series, whereby a national champion is selected.
From the formation of the IAAUS in 1906, there followed the formation of regional collegiate conferences, which themselves engendered often intense inter-school rivalry. The football team became a symbol of the identity of a university, which fostered alumni interest in the games.
The concept of the athletic scholarship was also a significant factor in the growth of the extent and the quality of the play in intercollegiate football. Athletic scholarships were ostensibly a device by which universities could now recruit players to their teams who otherwise may never have been in a financial position to attend a university. With the scholarship came the inevitable abuses of college admission; as scholarship practices became refined, a clear division arose in American intercollegiate athletics between those schools that would not alter their academic admissions practices to improve their football or other sports teams, and those institutions that would.
In the period between the formation of the NFL in 1920 and the end of World War II, the professional game grew while remaining in a subordinate position to the college game. Unlike modern football, in which the best college players inevitably move to a lucrative professional contract, in the 1920s not every college star moved on to compete at a professional level. The first great college player to move into the professional ranks in this era was the legendary Harold (Red) Grange (1903–1991), who upon graduation from the University of Illinois signed a contract with the Chicago Bears of the NFL. Grange played for Chicago for nine seasons, and his presence in the league went a considerable distance to legitimizing an organization seen as distinctly second rate when compared to the college game.
Professional football burst into a preeminent position on the American sports landscape at the end of World War II. The return of service personnel, many who had played for talented American armed services teams, presented a great availability of football talent.
The greatest stimulus to the advancement of professional football was the advent of television. The pro game was now available to a very wide audience, and teams such as the New York Giants, the Baltimore Colts, the Green Bay Packers, and the Cleveland Browns, and their star players, became household names. Television had another remarkable benefit for the NFL franchises, as television rights were sold by the league at ever-increasing rates. The NFL and its member clubs divided all television revenues equally. This device permitted the so-called "small market teams," based in smaller population centers such as Green Bay, Wisconsin, to compete on a more equal footing with those teams headquartered in a metropolis such as New York or Chicago.
The NFL also shrewdly positioned itself regarding competition from rival leagues. With respect to both the All America Football Conference (1946–1950) and the American Football League (1960–1967), the NFL ultimately absorbed the strongest of the rival league franchises, making itself stronger in the process. By the late 1970s, football at all of its levels combined had become the most popular spectator sport in the United States. The interest in football is based in part on the nature of the game and on the wide attraction that football holds, given its status as a high school and college sport. Football also generates huge revenues for the gaming industry; the "Las Vegas line," representing the wagering odds determined for a particular game, is a part of the American football lexicon.
As with the National Basketball Association (NBA) and the training of its future players, the NFL enjoys what is in effect a no-cost development program provided by the NCAA. In contrast to American baseball and North American ice hockey, each of which maintains expensive developmental leagues known as the "farm system," prospective NFL players are groomed in the intense NCAA systems at no cost to the NFL; NCAA football is itself a significant source of revenue to its member schools. NCAA institutions in turn obtain their players from the thousands of high school programs operating in the United States.
Football excellence is defined by the modern Super Bowl, the championship awarded at the conclusion of each NFL season. The Super Bowl is an event marketed worldwide, attracting in excess of one billion television viewers. The Super Bowl has become a spectacle that transcends the athletic competition. In recognition of the international interest generated by the Super Bowl, the NFL has established a developmental league known as NFL Europe, with teams in a number of European cities, manned almost exclusively by American players. In recent years the NFL also entered into a development agreement with the Canadian Football League to secure easier access to trained players from that organization.
American football has an extremely high injury rate among its players. In the NFL, most teams experience an effective rate approaching 100%; the average career of an NFL player is less than four years, due primarily to the effect of injury. Many collisions in American football are extremely violent and unpredictable, given the nature of the game. In the period since 1980, the size of a typical offensive lineman has increased to more than 300 lb (135 kg). Knee injuries, particularly cartilage and ligament tears, are relatively common among all players.