Basic facts about muscles
Did you know you have more than 600 muscles in your body? These muscles help you move, lift things, pump blood through your body, and even help you breathe.
When you think about your muscles, you probably think most about the ones you can control. These are your voluntary (VOL-uhn-ter-ee) muscles, which means you can control their movements. They are also called skeletal (SKEL-i-tl) muscles, because they attach to your bones and work together with your bones to help you walk, run, play an instrument, or cook a meal. The muscles of your mouth and throat even help you talk!
Keeping your muscles healthy will help you to be able to walk, run, jump, lift things, play sports, and do all the other things you love to do. Exercising, getting enough rest, and eating a balanced diet will help to keep your muscles healthy for life.
Why healthy muscles matter to you
Healthy muscles let you move freely and keep your body strong.
Healthy muscles let you move freely and keep your body strong. They help you to enjoy playing sports, dancing, walking the dog, swimming, and other fun activities. And they help you do those other (not so fun) things that you have to do, like making the bed, vacuuming the carpet, or mowing the lawn.
Strong muscles also help to keep your joints in good shape. If the muscles around your knee, for example, get weak, you may be more likely to injure that knee. Strong muscles also help you keep your balance, so you are less likely to slip or fall.
And remember—the activities that make your skeletal muscles strong will also help to keep your heart muscle strong!
Different kinds of muscles have different jobs
Skeletal muscles are connected to your bones by tough cords of tissue called tendons (TEN-duhns). As the muscle contracts, it pulls on the tendon, which moves the bone. Bones are connected to other bones by ligaments (LIG-uh-muhnts), which are like tendons and help hold your skeleton together.
Smooth muscles are also called involuntary muscles since you have no control over them. Smooth muscles work in your digestive system to move food along and push waste out of your body. They also help keep your eyes focused without your having to think about it.
Cardiac (KAR-dee-ak) muscle. Did you know your heart is also a muscle? It is a specialized type of involuntary muscle. It pumps blood through your body, changing its speed to keep up with the demands you put on it. It pumps more slowly when you’re sitting or lying down, and faster when you’re running or playing sports and your skeletal muscles need more blood to help them do their work.
For more information
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
National Institutes of Health
If you need more information about available resources in your language or another language, please visit our website or contact the NIAMS Information Clearinghouse at NIAMSinfo@mail.nih.gov.
This fact sheet was made for you by the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), a part of the U.S. Department of Health and Human Services’ National Institutes of Health. For more information about the NIAMS, call the information clearinghouse at 301-495-4484 or toll free at 877-22-NIAMS (226-4267) or visit the NIAMS website at www.niams.nih.gov.
NIH Publication No. 15-7579(M)
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