PITTSBURGH—Lemon, a five-pound Chihuahua, waited at the starting line until her owner signaled “go,” then pulled a wheeled cart weighing 260 pounds down a 16-foot chute. Amid applause, the pint-size ...

Weight-pull competitions keep surprising trainers, veterinarians, and judges. Verified results show small dogs hauling loads that look more like industrial equipment than their body size would suggest ...