This document provides information about the muscular system from a session on anatomy and physiology for sport. It defines muscles and describes the three main types: cardiac, smooth, and skeletal muscles. Cardiac muscle is only found in the heart and works involuntarily to pump blood. Smooth muscle is found in organs like the stomach and intestines and works involuntarily. Skeletal muscle is attached to bones and controlled voluntarily to enable movement. The document identifies major muscles of the front and back of the body and tasks students with labeling them.