A false start in football occurs when an offensive player who is set for the play moves in a way that simulates that the play is starting prior to the ball being snapped.
The official NFL rule on false starts in football is as follows:
It is a False Start if the ball has been placed ready for play, and, prior to the snap, an
offensive player who has assumed a set position charges or moves in such a way as to simulate the start of a play, or if an offensive player who is in motion makes a sudden movement toward the line of scrimmage.
Any quick abrupt movement by a single offensive player, or by several offensive players in unison, which simulates the start of the snap, is a false start– NFL Rulebook
As you can see from the definition above the general idea behind false start penalties is that they will be called when a player moves in a way that would make his opponents think the play is starting.
The penalty for a false start is five yards. A false start penalty is a dead ball foul meaning that it takes place before the play starts. This means that if this penalty is called the play will immediately be blown dead.
For football fans it can be tough to determine what movement is going to cause their team to be given a false start penalty.
Unfortunately for players set in their positions on the line of scrimmage a small flinch is enough to cause this penalty. If an offensive lineman flinches or even raises a foot this is enough to have this penalty called.
Exceptions – QBs Under Center Can Look Around
Though false start penalties can be called based off almost any movement there are a few exceptions built into the rule that will not be called.
If a quarterback is under center he is able to turn his head in shoulders in order to scan the field. Under center would mean that a player, usually the quarterback is crouched right behind the center ready to snap the ball.
In this position the quarterback is still allowed to look around to read the defense before the snap. This exception is put into place because otherwise quarterbacks would not be able to get a pre snap read while under center.
If a guard or tackle attempted to turn their head or shoulders after getting set in position they would earn themselves a false start penalty.
What About Players In Motion?
One aspect of the false start penalty that can be confusing is the players moving in the backfield. If you’ve watched football before you have likely noticed that some plays feature players running before the play even starts.
There are two reasons that a player in motion in the backfield does not get this penalty. First the offense is allowed to have a single player in motion as a play starts. Second that player must not be travelling towards the line of scrimmage.
In other words one player can move in the backfield but he must be moving laterally or backwards.
Since this player is not moving towards the line of scrimmage he is not simulating that the ball is being snapped. A player in motion will almost never cause a defensive player to jump across the line of scrimmage because he believes the play has started.
If a player in motion starts to travel towards the line of scrimmage he will earn himself a false start or an illegal motion penalty.
How Does A Quarterback Get A False Start?
Though not always the case quarterbacks tend to get false start penalties when trying to get the defense to jump offside.
Quarterbacks are able to use a hardcount to trick their opponents but if the QB resorts to bobbing his head or moving around too much he is going to earn himself a flase start penalty.
On the odd occassion a quarterback may earn a false start penalty if they are moving around to exuberantly while trying to get their offensive lineman to snap the ball in a hurry.
Though in most cases this would be let go as it is not influencing the opponents into thinking the play has started. Instead the quarterback is simply trying to get his linemans attention so he will snap the ball.