Advancing the ball in American football resembles the six-tackle rule and the play-the-ball in rugby league. The team that takes possession of nfl throwback jerseys
the ball (the offense) has four attempts, called downs, in which to advance the ball at least 10 yards (9.1 m) toward their opponent's (the defense's) end zone. When the offense succeeds in gaining at least 10 yards, it gets a first down, meaning the team starts a new set of four downs to gain yet another 10 yards or to score. If the offense fails to gain a first down (10 yards) after 4 downs, the other team gets possession of the ball at the point where the fourth down ended, beginning with their first down to advance the ball in the opposite direction.
Except at the beginning of halves and after scores, the ball is always put into play by a snap. Offensive players line up facing defensive players at the line of scrimmage (the position on the field where the play begins). One offensive player, the center, then passes (or "snaps") the ball backwards between his legs to a teammate behind him, usually the quarterback.
Players can then advance the ball in two ways:
  1. By running with the ball, also known asnfl jerseys
rushing.
  2. By throwing the ball to a teammate, known as a pass or as passing the football. If the pass is thrown down-field, it is known as a forward pass. The forward pass is a key factor distinguishing American and Canadian football from other football sports. The offense can throw the ball forward only once during a down and only from behind the line of scrimmage. However, the ball can be handed-off to another player or thrown, pitched, or tossed sideways or backwards (a lateral pass) at any time.
A down ends, and the ball becomes dead, after any of the following:
   * The player with the ball is forced to the ground (a tackle) or has his forward progress halted by members of the other team (as determined by an official).
   * A forward pass flies beyond the dimensions of the field (out of bounds) or touches the ground before it is caught. This is known as an incomplete pass. The ball is returned to the most recent line of cheap nfl jerseys
scrimmage for the next down.
   * The ball or the player with the ball goes out of bounds.
   * A team scores.
Officials blow a whistle to notify players that the down is over.
Before each down, each team chooses a play, or coordinated movements and actions, that the players should follow on a down. Sometimes, downs themselves are referred to as "plays."
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