Box lacrosse The roots of indoor lacrosse are obscure, but its invention has been attributed to one Paddy Brennan, a field lacrosse player and referee from Montreal, who, being annoyed by the constant slowing of play from balls going out of bounds in the field game, experimented with indoor games at the Mount Royal Arena during the early 1920s. Joseph Cattarinich and Leo Dandurand, owners of the National Hockey League's Montreal Canadiens in the 1920s, led the participating ice hockey arena owners to introduce the new sport. In the 1930s, 6 v 6 indoor lacrosse came to be played in the summer
Field lacrosse a pass; as in basketball players must remain stationary when screening. Warding off occurs when an offensive player uses his free hand to control the stick of an opposing player. Offside has a unique implementation in field lacrosse. Instituted with rule changes in 1921, it limits the number of players that are allowed on either side of the midfield line. Offside occurs when there are fewer than three players on the offensive side of the midfield line or when there are fewer than four players on the defensive half of the midfield line (note: if players are exiting through the