Tackle Football is another name for American football.

American football is a game played by two teams of players, eleven on both offense and defense, on a filed measuring a hundred yards long. The offensive team has four downs to either advance the ball ten yards to gain a new set of downs, or score by advancing the ball into the opposing team's endzone. The defensive team attempts to stop the offensive team from scoring, or gaining a new set of downs in order to get possession of the ball.

The goal of football is to score more points than the opposing team at the end of regulation, and if necessary, overtime.

Each team has 11 players on the field at a time. However, teams may substitute for any or all of their players, if time allows, during the break between plays. The game begins with a coin toss to determine who will kick off to begin the games and which goal each team will defend. A standard football game consists of four 15-minute quarters (12-minute quarters in high-school football and often shorter at lower levels), with a half-time intermission after the second quarter. Once a team gains possession of the ball, that team becomes the offensive team and must advance the ball. Players can then advance the ball in two ways: by running with the ball, also known as rushing, or by throwing the ball to a teammate. The offense can throw the ball forward only once during a down and only from behind the line of scrimmage. The ball can be thrown, pitched, handed-off, or tossed sideways or backwards at any time. A team scores by advancing the ball into the opposing team's endzone. Change of possession can occur on a turnover, a loss of down when the offense fails to gain a new set of down, a punt, or by scoring. There are a number of other rules governing the game, some differing between the various levels of play.

Tackle, or American, football is a sport with roots in rugby and soccer. Football diverged from rugby through the rule changes initiated by Walter Camp, considered as the "Father of American Football." Among these important rule changes were the introduction of the line of scrimmage and of down-and-distance. In the late 19th and early 20th centuries, gameplay developments by Knute Rockne, and Glenn "Pop" Warner helped take advantage of the newly introduced forward pass. The popularity of collegiate football grew as it became the dominant version of the sport for the first half of the twentieth century. Bowl games, a college football tradition, attracted a national audience for collegiate teams. The origin of professional football can be traced back to 1892, with William "Pudge" Heffelfinger's $500 contract to play in a game for the Allegheny Athletic Association against the Pittsburgh Athletic Club. In 1920 the American Professional Football Association was formed. This league changed its name to the National Football League (NFL) two years later, and eventually became the major league of American football.

Football
Helmet
Protective pads

Football is a heavy contact sport where injuries can occur often. To lessen the likelihood of injuries, protective padding and helmets should always be worn properly. Certain rules have been enacted to protect player safety such as rules protecting the quarterback and the illegal chop block.

Football training begins with general strength and conditioning designed to get players physically ready to handle the demanding nature of the sport. From there, training breaks down into position specific drills designed to enhance a player's ability to play certain positions. For example, a quarterback will undergo passing drills to improve accuracy and timing, as well as instruction to work on throwing mechanics. From there, training progresses to full on scrimmages between the offense and defensive players. Scrimmages often mirror real game situations and is a way for teams to practice plays.

Blitz - when a defensive player other than a defensive linemen rushes across the line of scrimmage immediately after the snap

Carry - a statistical term equal to a single rushing play

Dead Ball - occurs between plays after the player with the ball has run out of bounds, or is down by contact

Dime Package - a defense using six defensive backs

Down - a period in which the play happens; teams have four down attempts to advance the ball ten yards to gain a new set of downs

End Zone - area between the end line and goal line where teams must advance the ball in to score a touchdown

Extra Point - an attempt at a one-point field goal try after a touchdown is scored

Field Goal - a placekick worth three points

Fumble - occurs when a player in possession of the ball, loses possession of the ball before running out of bounds, or being ruled down by contact

Interception - occurs when a pass attempt by the offensive team is caught by the defense

Kick Off - occurs at the beginning of each half or after a team scores; a team kicks the ball down field at the opposing team who catches it and gains possession

Line of Scrimmage - imaginary line stretching across the field where a defensive team cannot cross before the snap of the ball

Reception - when a pass is caught by the offensive team

Safety - occurs when an offensive player in possession of the ball is tackled in their own end zone; this results in two points being awarded to the defensive team

Touchdown - worth six points and happens when a player with possession of the ball crosses the goal line

http://en.wikipedia.org/wiki/American_football