Weight pulling

Weight pulling is a dog sport involving a dog pulling a cart or sled loaded with weight a short distance across dirt/gravel, grass, carpet, or snow. It is a modern adaptation of freighting, in which dogs were used as freight animals to move cargo. Many breeds participate in this sport, with dogs being separated into classes by weight. Sled dog and bull breeds excel within their respective weight classes, having been historically bred to pull sleds and carts as working dogs, respectively. 
The dog is hitched to the cart or sled with a specially constructed harness designed to spread the weight and minimize the chance of injury. Since IWPA's organization in 1984, no dogs have been hurt in competition.
Dog weight pulling competitions are sanctioned by various non-profit organizations. In North America the International Sled Dog Racing Association has sanctioned contests in association with their races. The International Weight Pulling Association was organized in 1984 to promote the heritage of the working dog. IWPA operates in North America.
Since 2000, the American Pulling Alliance has also offered sanctioned competitions in North America as well as Europe. The United Kennel Club also includes Weight Pull as one of their dog sports. Alaskan Malamute Clubs in the UK, and Australia offer sanctioned weight pull competitions based on the Alaskan Malamute Club of America's weight pull rules. Other breed clubs also offer weight pull, such as American Dog Breeders Association. In the 2010s other organizations started offering sanctioned competitions, such as National Working Dog Association. In 2012, GPA (Global Pulling Alliance) was formed to focus on educating the general public about the sport of weight pulling as a positive outlet for active canines across the globe. GPA holds competitions in 6 countries; United Kingdom, Mexico, Puerto Rico, Philippines, Ireland, and the United States, and continues to add to their list as the sport grows in popularity. Other organizations are springing up in Europe and Asia as the sport becomes increasingly more popular.
Bulgaria also has started to promote the sport by a club called Weight Pulling & Sporting Dogs Bulgaria. Since 2014 Lithuania has a dog weight pulling club called "Weight Pulling Lithuania".
Criticism.
The activity has being criticised for cruel or harmful by animal rights activists.