When a foul has been committed (a rule infraction that carries a penalty) a penalty will be enforced, offset or declined. These are some of the common penalties and their respective Referee signals.
Block in the Back:
(Referee Signal: grasping one wrist, the hand open and facing forward, in front of chest)
An illegal Block in the Back involves contact against an opponent (other than the ball carrier) occurring when the force of the initial contact is from behind and above the waist. (Contrast this with Clipping which is from behind and at or below the waist). An easy way to remember this is that the Block in the Back happens in a player’s back. There are some exceptions, including when a player is attempting to tackle a runner or when a player is attempting to recover a ball. The penalty is 10 yards.
Blocking Below the Waist:
(Referee Signal Both hands brought down, wrists turned inward, in a chopping motion across the front of the thighs)
Blocking below the waist is the initial contact below the waist with any part of the blocker’s body against an opponent (other than the ball carrier). This applies to blocking an opponent who has one or both feet on the ground. A blocker who makes contact above the waist and then slides below the waist is considered to have blocked Above the Waist and not Below the Waist. Blocking Below the Waist and from behind is never permitted. Otherwise, Blocking Below the Waist from the front may be permitted depending on the rules, which are rather lengthy and can be found at Rule 9, Section 1, Article 2(e) of the Football 2009-2010 Rules and Interpretations. If it happens to be one of the blocks Below the Waist that is not permitted, this is a personal foul that includes a 15 yard penalty and an automatic first down if committed by the defense.
Chop Block:
(Referee Signal: Arms extended alongside the body, palms facing outward, then moving in to the upper thigh in a chopping motion)
A combination block by any two players against an opponent (other than the ball carrier) with or without delays between the blocks in which one player blocks low and the other blocks high. It can come in as a high then low block or a low than high block. This is a personal foul and the penalty is 15 yards plus an automatic first down if the foul was committed by the defense.
Clipping:
(Referee Signal: Chopping the back of one thigh with the hand)
A block against an opponent (other than the ball carrier) occurring when the force of the initial contact is from behind and at or below the waist. (Contrast this with a Block in the Back that is from behind but above the waist). There are some exceptions, including when a player is attempting to tackle a runner or when a player is attempting to recover a ball. This is a personal foul and the penalty is 15 yards plus an automatic first down if the foul was committed by the defense.
Encroachment:
(Referee Signal: Two arms in front of chest with closed fists rotating or “rolling” around each other)
A penalty when an offensive player other than the Center (or whoever is snapping the ball) is in or beyond the neutral zone once the snapper touches or simulates touching the ball before the snap.
False Start:
(Referee Signal: Two arms in front of chest with closed fists rotating or “rolling” around each other)
When an offensive player pretends to charge forward or shifts/moves in a way that simulates the beginning of a play. Once the snapper assumes the position for snapping the ball and touches/simulates touching it, if he moves to another position, this is considered a false start. It also includes quick movement by any of the four other Offensive Linemen other than the snapper (wearing number 50 though 79) after having placed a hand/s on or near the ground (unless the movement was a reaction to the defensive player’s movement into the neutral zone). The penalty for fouls before the ball is snapped is five yards from the succeeding spot.
Holding:
(Referee Signal: Raising one arm in front of the body and grabbing its wrist with the opposite hand)
This is one of the most popular penalties in football. It occurs when a player on offense or defense stops the movement of his opponent by holding onto his body (which includes his uniform). The penalty is 10 yards. (In the NFL it is a loss of 10 yards unless committed by the defense and then it is 5 yards and an automatic first down).
Illegal Touching:
(Referee Signal: Each hand is held up to its respective shoulder and the fingertips tap the shoulders simultaneously)
When a player who is ineligible intentionally touches a ball that has been kicked or passed before an opponent or official touches it. If this occurs on a forward pass and the player is ineligible to touch it, there is a five yard penalty from the previous spot.
Intentional Grounding:
(Referee Signal: Both arms held out straight, facing each other, moving down together diagonally from one side to the other)
A penalty when the quarterback purposely throws an incomplete pass just to avoid a sack. In college the penalty is that the ball is then marked at the spot of the foul and there’s a loss of down, which is exactly what would have happened had the play run without the penalty and the Quarterback had been sacked. So there really is no consequence for the Quarterback to attempt to get away with avoiding the Sack. However, in the NFL the rules are different. It’s a 10-yard penalty plus loss of down, unless the Quarterback is farther behind the line of scrimmage than 10 yards, then it’s at the spot of the foul. Regardless, if this play occurs in a player’s own End Zone, then the result of the play is a Safety.
Loss of a Down:
(Referee Signal: Both hands placed behind the head)
This is an abbreviation meaning “loss of the right to repeat a down.” Oftentimes after penalties, a team on offense will have the right to repeat the down, but on certain penalties they lose this right. A well-known broadcaster once had this very wrong during the broadcast and mistakenly thought after a penalty for intentional grounding that took place on 1st down that the loss of down penalty meant that rather than 2nd down, it was 3rd down. He proceeded to do an analysis on this that was completely wrong as the fact is that a team never actually loses a down, just the right to repeat it.
Offside:
(Referee Signal: Both hands placed on hips)
After the ball is ready for play, when a defensive player (a) contacts an opponent beyond the Neutral Zone before the ball is snapped, (b) contacts the ball before it is snapped, (c) threatens an Offensive Linemen such that it causes an immediate reaction before the ball is snapped or (d) is in or beyond the Neutral Zone when the ball is legally snapped. The penalty is 5 yards.
Pass Interference:
(Referee Signal: Both arms extended in front of the body, palms upright, in a pushing motion)
This can be a foul committed by either the offense or defense. The rules on this are quite complicated as written and more in-depth than I would have thought, but the general idea is that when there are two players in the vicinity of the ball, they need to be going after the ball and not the other player. The penalty for this is 15 yards plus an automatic first down if committed by the defense.
Personal Foul:
(Referee Signal: One arm extended from the body and bent at the elbow; the forearm is tilted at an angle, so the wrist is roughly in front of the collarbone but at a distance from the body. The other arm is brought down in a chopping motion, striking the first arm wrist-to-wrist)
This type of foul typically carries a 15 yard penalty plus an automatic first down if committed by the defense. It includes such penalties such as Blocking Below the Waist and Chop Block.
