Activities Sports & Athletics Clipping in Football Definition and Explanation Share PINTEREST Email Print Referee Bob McElwee #95 calls a clipping penalty on Fullback Obafemi Ayanbadejo #30 of the Baltimore Ravens for hitting the ball carrier of the Cincinnati Bengals in the back during an NFL football game at PSINet Stadium on September 24, 2000. Michael J. Minardi/Getty Images Sport/Getty Images Sports & Athletics Football Basics Playing & Coaching Best of Football Plays & Formations College Football Baseball Basketball Bicycling Billiards Bodybuilding Bowling Boxing Car Racing Cheerleading Cricket Extreme Sports Golf Gymnastics Ice Hockey Martial Arts Professional Wrestling Skateboarding Skating Paintball Soccer Swimming & Diving Table Tennis Tennis Track & Field Volleyball Other Activities Learn More By James Alder James Alder is an expert on the game of American football, blogs for The New York Times, and appears on radio shows. our editorial process James Alder Updated August 06, 2018 Clipping is an illegal block in which a player hits an opponent from behind, typically at waist level or below. The National Football League defines clipping as “the act of throwing the body across the back of the leg of an eligible receiver or charging or falling into the back of an opponent below the waist after approaching him from behind, provided that the opponent is not a runner.” Rolling up on the legs of an opponent after a block is also considered clipping. Clipping was initially banned in college football in 1916 due to the potential severity of injuries, and other leagues followed suit in the years that followed. A Dangerous Penalty Clipping is one of the most dangerous, and potentially injurious penalties in football. Clipping has the potential to cause a wide variety of injuries to the player that is clipped. Some such injuries can be career-ending, and in some severe cases life-altering, as the player that is clipped is unaware of the incoming hit and thus has no time to physically prepare for the hit. Close Line Play Although in all other cases it is illegal, clipping is allowed in what is referred to as “close line play.” The close line is the area between the positions traditionally occupied by the offensive tackles. It extends out three yards on each separate side of the line of scrimmage. In this area it is legal to clip above the knee. In close line play, clipping is permitted because players on both sides of the ball are fighting for position against each other simultaneously, so the ability to perform the act is equal. Clipping is allowed in close line play because it serves as a useful tactic in pass-blocking. Clipping can be committed by any position on the field: offense, defense, or special teams. The result is a 15-yard penalty, and an automatic first down for the offense if committed by the defense. Block in the Back Similar to clipping, but slightly less severe is the block in the back penalty. A block in the back is when a blocker contacts a non-ball-carrying member of the opposition from behind and specifically above the waist. This act poses a similar danger to clipping, as the player being blocked in the back is still unaware of the incoming hit. Block in the back violations often occur during special teams play when blockers in the open field fail to get a proper angle to block an opponent trying to tackle the ball-carrier. A block in the back results in a 10-yard penalty. Blocking an opponent above the waist level from behind is less dangerous than clipping him from below the waist, so the penalty is less severe. Chop Block Also in the same vein as clipping is a chop block. A chop block is an attempt by an offensive player to block at the lower leg level a defensive player who is already being blocked above the waist by another offensive player. Like clipping, a chop block results in a 15-yard penalty.