It is difficult to determine which breeds of dogs are the strongest, as strength can be subjective and can depend on a number of factors, such as the size and muscle mass of the dog, as well as its training and conditioning. However, there are three breeds that are generally considered to be strong and powerful. The English Mastiff is a large breed of dog that is known for its strength and size. Adult males can weigh up to 220 pounds or more, and females can weigh up to 190 pounds or more. The Doberman Pinscher is a medium to large breed of dog that is known for its strength and athleticism. Dobermans are often used as police dogs and guard dogs due to their protective nature and ability to deter intruders. The Rottweiler is a large breed of dog that is known for its strength and muscular build. Rottweilers are often used as working dogs due to their strength and endurance.