This zone is more popular at the earlier stages of lacrosse development.This name String arises because the defender in the middle (#5) is covering a straight line much like he is being pulled up and down by a single string. This is a very simple man down defense to run as it just requires players to honor their zone. The player in the middle has to cover a lot of ground moving up and down and may also need a little courage as he could be in the line of some shots.
The idea is to have one defender responsible for the middle of the field while being supported by 4 defenders around him.This defense can be easily manipulated by an offense who understands how to overload parts of a zone, attack the seams and move the ball with a lot of efficiency.But at the levels where the kids are learning this can be a great zone to start with to teach the fundamentals.