American Football

There are a number of sports played across the world under the name football, with most of the world reserving that name for association football or soccer. Soccer is discussed in Chapter 5 of this volume, this chapter considers American football, the basic structure of which is described in the next paragraph. Most of the material in this chapter is discussed in terms of the National Football League, the professional football league in the United States. Other versions of the game include college football in the United States and professional football in Canada. There can be substantial differences between different versions of American football, e.g., the Canadian and United States games differ with respect to the length of the field and the number of players among other things. Despite these differences, the methodology and ideas discussed in this chapter should apply equally well to all versions of American football. American football, which we shall call football from this point on, is played by two teams on a field 100 yards long with each team defending one of the two ends of the field (called goal lines). Games are 60 minutes long, and are broken into four 15-minute quarters. The two teams alternate possession of the ball and score points by advancing the ball (by running or throwing/catching) to the other team’s goal line (a touchdown worth 6 points with the additional opportunity to attempt a one-point or two-point conversion play), or