Most dogs are built for endurance, not speed, and their muscles reflect this. The muscle structure of the dog is much the same as its ancestor, the wolf. Muscles allow the animal to jump, run, stalk and engage in battle. Muscles can be under voluntary or involuntary control. Voluntary muscles, such as those found in the arms and legs, can be controlled by thought. Involuntary muscles are those that are automatically controlled by the nervous system and cannot be moved at will. Examples of involuntary muscles are the muscles of the heart, diaphragm, and intestines. There are three types of muscle tissue: Read more at: http://tr.im/5RIuZ