Football is a dynamic sport that demands peak physical performance and exceptional mental acuity on the part of its players. It is a game that is simple in essence but complex in application. At a fundamental level, football is basically a version of Capture the Flag; get to the opponent’s end of the field to win the drive and collect points. However, the game provides multiple layers of subtle complexity that contains both a strategic and a tactical dimension.
Football is played on a rectangular field that is 120 yards in length and 53.3 yards in width. The area of the field designated for play where the ball may be spotted is 100 yards in length. There is a scoring end zone on each end of the field that is 10 yards long. Eleven players for each team take the field on any given play. The field also includes a set of upright goalposts at the ends of the field for scoring points after touchdown and field goals. The dimensions of the goalposts vary by league, but for college and professional football, the bottom crossbar must be 10 feet above the ground, the upright posts must extend 30 feet above the crossbar, and the two posts must be 18 1/2 feet apart. The game itself is most easily categorized into three sections – the offense, defense and kicking segments.
Make It Official
The game is overseen by a crew of seven on-field officials. These officials include the head linesman, a line judge, a back judge, a side judge, a field judge, a referee and an umpire. These officials are responsible for determining the spot of the ball after each play, calling penalties for infraction of the rules and monitoring the events of the game overall.
Line of Scrimmage
The line of scrimmage is the dividing line between the two teams on the field. It marks where the ball is on the field at any given time. This determines how far away the offense is from scoring and how much of the field the defense has to protect. From a given line of scrimmage, the offense has four attempts – called “downs” -- to advance the ball 10 yards. If the offense is successful, it gets a new set of four downs to advance the ball another 10 yards. It continues in this fashion until it reaches the opponent’s end zone, with the line of scrimmage moving with each play. Generally, a team will only use three downs to attempt to advance the ball; if they fail to do so, they will usually use the fourth down to punt the ball as deep into the opponent’s territory as possible.
On the Clock
Time is an important element of football. The game is strictly managed by both a game clock and a play clock. At the college and professional level, the game is 60 minutes long, and it's divided into four 15-minute quarters. Halftime takes place between the second and third quarter, and it lasts for 12 minutes in the NFL and 20 minutes at the college level. The game clock doesn't run continuously; it only runs during game play, specifically during each series of downs. The clock stops on incomplete passes, change of possession, called timeout by either team and for official review of a play. For timeouts, each team gets three during each half of the game. There is also a play clock. The play clock counts down a specific number of seconds between each play. This span of time is how long the offense has to snap the ball and conduct a play. If the clock runs to zero before the ball is snapped, the offense receives a delay-of-game penalty, and the line of scrimmage is moved back 5 yards.
The offensive portion of the game focuses around one of the two teams who has possession of the ball, and must incrementally carry that ball either to the opponent’s end zone for a touchdown worth six points or a field goal kicked through the opponent’s goal posts for three points. A team that scores a touchdown will make a Point After Touchdown attempt either by kicking it through the goal posts for one point, or through making a second end zone play for two points. The offense includes four distinct positions – quarterback, running back, wide receiver and offensive line. The dynamics of each offensive play determine how many players of each position are on the field at any one time and where they are arranged on the field.
The defense has one primary goal – to stop the progress of the offense as quickly as possible, with as little advancement as possible. The four main positions for the defense are defensive line, linebacker, cornerback and safety. The arrangement of those positions depends on the in-game dynamics of any given play, such as how far the offense has to get a new set of downs or score, what personnel the offense has on the field, and the physical talents of the defensive players themselves.
Special teams units handle all kicking plays, such as kickoffs and punts. There is an offensive and defensive special teams unit. The kicking team attempts to drive the ball as far from its own end zone as possible; the return team attempts to catch the kicked or punted ball and run it back toward the kicking team as far as possible. The rest of the players on each team attempt to block or clear a path for the returner.