Dog strength is typically measured in three separate categories: bite strength, endurance level and muscle composition. The English mastiff has the strongest bite, while Siberian huskies have the highest endurance level. American pit bull terriers are the most muscular.
The English mastiff has up to 552 pounds of force in his bite. The mastiff bite is closer to that of a lion or great white shark than to that of a human. Siberian huskies were bred specifically to pull heavy loads over large distances. This breed has the endurance, stamina and fortitude to travel through frozen terrain that would be dangerous for other dog breeds. American pit bull terriers are the most muscular dogs when both size and strength are taken into consideration. The average male American pit bull weighs 50 lbs but is mostly muscle, whereas a male English mastiff might have more brute strengt but tops out around 250lbs and has more body fat.