2. Muscles have three important functions: to produce movement, maintain posture, and generate heat. Almost all movements by the human body result from muscle contraction. Muscles lend support to the body and help it maintain posture against the force of gravity. Even when the body is asleep, muscle fibers are contracting to maintain muscle tone. Finally, any activity by muscles generates heat as a by-product, which is vital in maintaining normal body temperature. WOAH!

3. Sternocleidomastoid Biceps Triceps Rectus Abdominus Gluteus Maximus

4. Tendonitis Tendons become inflamed for a variety of reasons, and the action of pulling the muscle becomes irritating. If the normal smooth gliding motion of your tendon is impaired, the tendon will become inflamed and movement will become painful. This is called tendonitis, and literally means inflammation of the tendon. Ruptured Tendon A tendon is the fibrous tissue that attaches muscle to bone in the human body. The forces applied to a tendon may be more than 5 times your body weight. In some rare instances, tendons can snap or rupture. Conditions that make a rupture more likely include the injection of steroids into a tendon, certain diseases,such as gout or hyperparathyroidism, and having type O blood. Although fairly uncommon, a tendon rupture can be a serious problem and may result in excruciating pain and permanent disability if untreated. Each type of tendon rupture has its own signs and symptoms and can be treated either surgically or medically depending on the severity of the rupture.