We all have a lot of muscles

They work for us 24-hr a day. We use muscles to help us play tennis. They take their orders from the brain, which sends them electrical commands. These commands trigger chemical changes that affect the muscle's actions. The brain is in charge of everything. There are more than 6 hundred muscle groups in the body. But like anything that works hard, muscles get tired. When a muscle moves a lot, it uses up oxygen and food. Your heart tried to keep them satisfied, but it can not always keep up. That's why you need to rest. Muscles need to be pampered. Treat your muscles right, they will trat you right.