Why do Pit Bull owners have the dogs pull weight?

Patch O’ Pits writes:
Weight pull is one of the many performance events that APBTs are involved in doing for fun and to earn titles. There are many breeds involved in weight pull from pugs to mastiffs. It is a dog sport. Since APBTs are a very athletic breed they excel in many many dog sports such as agility, obedience, rally-o, fly ball, frisbee, tracking, dock diving etc

On top of being wonderful family pets & companions they are also used to perform many jobs which
include:
service dog,
therapy dog,
law enforcement dog,
tracking,
herding,
Search and rescue(SAR)