Stopping Runaway Trains: Superman and the Science of Strength

Stopping Runaway Trains: Superman and the Science of Strength — page 3
SECTION 1 HUMAN STRENGTH Superman gets his strength by absorbing the energy from Earth’s yellow Sun But his muscles still work much like the ones in our bodies What’s a Muscle Muscles are the parts of your body that create movement They either move things inside your body such as blood and food or move the body itself In fact your body has more than 600 muscles They make up roughly 30 to 50 percent of your weight The three main types of muscles are smooth cardiac and skeletal Smooth muscles are also called involuntary muscles Why Because they often move without you telling them to Smooth muscles move food through your intestines push air through your lungs and even help your eyes focus 6