HEALTHY MUSCLES MATTER HEALTHY MUSCLES MATTER
NATIONAL INSTITUTE OF ARTHRITIS AND MUSCULOSKELETAL AND SKIN DISEASE

Healthy Muscles Matter 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, pick up things, play an instrument, throw a baseball, kick a soccer ball, push a lawnmower, or ride a bicycle. 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.

A joint showing muscles, ligaments, and tendons. (Representation)

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.

What can go wrong? How do I keep my muscles more healthy? Definitions What can go wrong? Injuries

Almost everyone has had sore muscles after exercising or working too much. Some soreness can be a normal part of healthy exercise. But, in other cases, muscles can become strained. Muscle strain (streyn) can be mild (the muscle has just been stretched too much) to severe (the muscle actually tears). Maybe you lifted something that was too heavy and the muscles in your arms were stretched too far. Lifting heavy things in the wrong way can also strain the muscles in your back. This can be very painful and can even cause an injury that will last a long time and make it hard to do everyday things.

The tendons that connect the muscles to the bones can also be strained if they are pulled or stretched too much. If ligaments (remember, they connect bones to bones) are stretched or pulled too much, the injury is called a sprain (spreyn). Most people are familiar with the pain of a sprained ankle.

Contact sports like soccer, football, hockey, and wrestling can often cause strains. Sports in which you grip something (like gymnastics or tennis) can lead to strains in your hand or forearm.