I think you have the definition of linebreeding and inbreeding reversed:
Inbreeding is a breeding technique which pairs closely related animals, such as father-daughter, brother-sister, or cousins. However, the strict scientific definition of inbreeding counts all relationships that are duplicated on both sides of the pedigree. Animal breeders by tradion consider distantly related crosses to be linebreeding rather than inbreeding, but the scientific basis of this concept is not obvious. Linebreeding is in essence a moderate form of inbreeding.