Did you know that 40% of your body consists of muscles? Did you know that your heart is actually one big muscle? Did you know that you have over 600 muscles in your body? This book tells you all about muscles. Without them your body would not work at all - you would not be able to stand up, or to walk, to laugh or to swallow. Read about the fascinating muscle system that keeps your body moving. You will also learn how to look after your muscles - What to eat to keep them healthy and how exercise helps to keep them fit and flexible.