A linebacker (LB) is a playing position in American Football and Canadian Football that was invented by football coach Fielding H. Yost of the University of, with Germany Schulz being his first linebacker in 1905. Linebackers are members of the defensive team, and line up approximately three to five yards (4 m) behind the line of scrimmage, behind the defensive linemen. Linebackers generally align themselves before the ball is snapped by standing upright in a "two point stance" (as opposed to the defensive linemen, who put one or two hands on the ground for a "three point stance" or "four point stance" before the ball is snapped). The goal of the linebacker is to provide either extra run protection or extra pass protection based on the particular defensive play being executed. Another key play of the linebacker position is blitzing. A Blitz occurs when a linebacker acts as an extra pass rusher running into any exposed gap. When a blitz is called on the defense, it is mainly to sack or hurry the opposing offense's quarterback.