Muscle Anatomy 

Anatomy provides names for the structures of the body, usually classified into systems or types based upon this structure. In this section, we are specifically focusing on skeletal muscles, referred to as muscles. The heart, made up of a different type of muscle called cardiac muscle, is technically a muscle too. It is discussed in the Exercise Physiology Basics section under Cardiovascular and Respiratory Systems. There are other types of muscles in the body, but they are not generally affected by exercise so we do not discuss them here.

The human body contains over 600 skeletal muscles. For purposes of this course, we will focus on a few major muscles and muscle groups. Here is a general overview of major muscles and muscle groups.

Muscle Physiology

Physiology has to do with describing the functions of the body. Skeletal muscles produce force and in doing so, move our skeleton so we can do physical work. Bones provide the structure. Muscles connect to bone via tendons. We can alter the length of muscles, which then pull on the tendons, which result in movement of a bone or bones about a joint.

Muscles “activate” or “engage”. We often hear the word “contract” to describe the action of muscles, but contraction means shortening or becoming smaller. Muscles activate while lengthening too! If a muscle is experiencing lengthening while it is activated, we call this an eccentric motion. If it is shortening while it is activated, this is called a concentric motion.