Clipping is a penalty in football that is called on a player who blocks or falls into an opposing player from behind and below the knees. Clipping is penalized due to the risk of injury presented, especially to the player who is being blocked. The team whose player committed the penalty will be penalized 15 yards for the infracture. Clipping can occur on both offense and defense, though it occurs mostly on special teams alongside illegal block in the back. Clipping is very similar to a chop block and the two penalties are used interchangeably.