When it comes to the actual gameplay, the object of American football is to score the highest amount of points possible against the opposing team. In order to do this, the team is divided into three different units, or groups, that include the offensive, the defensive, and the special teams unit. The offensive works on getting the ball to the proper end zone while the defense works to block the opposing team from scoring any type of goal. The final unit is used for the purpose of kicking plays, such as the first kickoff and field goal attempts. With each of these teams, the team wants to score points through a combination of touchdowns, conversions (also known as points after touchdown, or PAT), field goals, and safety points.
Both teams play on a field that is 120 yards by 53.33 yards with lines that surround the rectangular field for the side lines and the end lines. There are also other markings to differentiate other aspects of the field with white lines to show the distance from both end zones and the center of the field. These include hash marks to show each yard with lines that travel the width every five yards and numbers that mark every ten yards. Within the end zones, there are the goal posts that are centered and have crossbars that are ten feet from the ground. The uprights of the goal posts are positioned 18.5 feet apart on the crossbar and have a total height of 35 feet. For each game, the football is an oval one similar to those found in rugby with an inflation of 13 psi and a weight of 14.5 ounces. They are typically eleven inches in length when measured on its longest axis. These standards must be met in order to have a fair game between the two teams.
Most football games have a duration of 60 minutes that is divided equally into two halves and four quarters though high school games are divided by the same divisional lines except with only 48 minutes of playing time. With a small break between periods and a longer one between the halves, the game can actually last closer to 180 minutes and the additional stoppages that occur at the professional level. The game is typically begun with the teams meeting together in the midfield with a referee and a coin toss. The teams do switch sides a couple times throughout the game to keep the game interesting.
The main goal of the game for the offensive side of the team is to keep the ball in play and advance it down the field towards the proper end zone through a series of passes and runs. The play is decided and called by the quarterback, who receives the snap from the center lineman and decides based on the play to pass the ball or run the ball himself. Tackling of the player with the possession of the football will end the play and result in a down. Each play is given four downs to reach a total of ten yards down the field. If successful, these downs are renewed, but failure means the ball is sacrificed to the other team’s offensive line. To keep track of the ten yards needed for a successful down, there is a chain crew that measures the distance and shows the number of downs the team has received.
Kicking plays an important role in the game as it can be used in two main instances: the scrimmage kick and the free kick. With the free kick, one team is usually starting off the first or third quarter, the kick after a successful score from a conversion or field goal, and the safety kick. The scrimmage kicks are made through a place kick, a drop kick, or a punt. The first two can score points for the team while a punt can’t. These are made from the line of scrimmage or behind that line from the offensive team. With each type of kick, there are limitations as well as advantages in utilizing them at the appropriate times.
With any sport, there need to be officials in place to administer the rules and call out any fouls that take place by either team. With the officials of American football, they all wear the uniform of a black-and-white striped shirt with black hats so they can stand out among the many on the field and on the sidelines. There are a total of seven officials that are on the field at any given time to watch for fouls to take place and call them as they are seen. They are the referee, the umpire, the back judge, the head linesman, the side judge, the line judge, and the field judge. Along with these judges are the chain crew, who are responsible for the measurement of distances and the number of downs as mentioned earlier. These officials have standardized their methods and have found relative acceptance on both sides in their accuracy.