gridiron football Gridiron football ( ),"Gridiron football"
''Encyclopædia Britannica'' ...

, clipping is the act of a "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 the opponent is not a runner."This is the NFL's definition
Rule 3, Section 5
/ref> It is also clipping to roll up on the legs of an opponent after a block. It is usually illegal, but in the

National Football League The National Football League (NFL) is a Professional gridiron football, professional American football league in the United States. Composed of 32 teams, it is divided equally between the American Football Conference (AFC) and the National ...

it is legal to clip above the knee in close-line play. The

Canadian Football League The Canadian Football League (CFL; , LCF) is a Professional gridiron football, professional Canadian football league in Canada. It comprises nine teams divided into two divisions, with four teams in the East Division (CFL), East Division and f ...

has similar definitions, prohibitions and exceptions, including that "application of penalty is determined by the initial contact". In most leagues, the

penalty Penalty, The Penalty, Penalization, Penalisation, Penalize or Penalise may refer to: Sports * Foul (sports) ** Penalty (golf) ** Penalty (gridiron football) ** Penalty (ice hockey) ** Penalty (rugby) ** Penalty (rugby union) ** Penalty kick (assoc ...

is 15 yards, and if committed by the defense, an automatic

first down A down in gridiron football is an attempt by the offensive team to run a play to advance the ball, while the defending team simultaneously attempts to halt their advance. The down is a distinguishing characteristic of the game compared to othe ...

. It is prohibited because it has the potential to cause injury or death. Injuries that can be caused by a clipping violation include those to the collateral and cruciate ligaments and the meniscus. Clipping was first banned in 1916 in the

NCAA The National Collegiate Athletic Association (NCAA) is a nonprofit organization that regulates College athletics in the United States, student athletics among about 1,100 schools in the United States, and Simon Fraser University, 1 in Canada. ...

, and rules prohibiting it gradually went into effect in various leagues in the years that followed. In recent years, clipping has not been called as a penalty as much as a block in the back.

References

{{American football concepts Gridiron football penalties