Penetration into opponents playing area

Players may partially or completely cross the center line below the net or outside the poles, either before, during or after a legal play of the ball, provided that this does not interfere with the opponents play. Incidental contact with an opponent is ignored, unless such contact interferes with the opponents opportunity to play the ball. While opposing players are not required to avoid the ball or the player, they cannot intentionally interfere with any legal attempt to play the ball on their court.If a player crosses the center line and interferes with an opponent during the continuation of a play, it is a fault.