When you run, you use muscles. When you touch your face, you use muscles. You use your muscles whenever you move. Your muscles help you move your body.
Muscles help you in another way. Feel your arm. Look at the curve of your leg. Muscles give your body its shape.
Many of your muscles you can control. You can control when you want to turn your head. You can control when you want to move your arms or legs. Muscles you can control are called voluntary muscles.