Line backing or linebacking refers to the PvP defensive tactic of restraining movement through the use of knockdowns, snares, and creative use of body blocking. This strategy is generally considered a form of melee hate, as it usually is used to prevent the opposing frontline from reaching the party's mid- or backlines and wreaking havoc on the more lightly armored casters and support classes.
Etymology and Principle
The use of this word stems from real-life linebackers in American football. These players hold the line of scrimmage to prevent the players of the opposing team from advancing past the line of scrimmage. Typically this is done by tackling the ball carrier.
The same principle extends into Guild Wars by holding the opposing team at the "line of scrimmage" to keep the allied ranks free of any opposition. This way the team performing the tactic can recover resources without losing ground by making the opposition's targets predictable and increasing the usefulness of preprots and spot-healing. The use of knockdowns for line backing is very analogous to tackling in the actual sport.