In gridiron football, clipping is the illegal act of a blocker contacting a non-ballcarrying opponent from behind and at or below the waist. In most leagues, the penalty is 15 yards, and if committed by the defense, an automatic first down. It is prohibited because it has the potential to cause injury. 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, and rules prohibiting it gradually went into effect in various leagues in the years that followed.