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You have more than 600 muscles in your body that you use almost constantly. Some move your body — others help your internal organs keep you alive. It’s OK to feel the occasional ache or muscle pain, but don’t ignore chronic (long-term) soreness or weakness.
Your muscles are made of thousands of small fibers woven together. These fibers stretching and pressing together is what moves your organs or body. Your muscles weave together like a quilt that covers your body VSports注册入口. They run in all directions and work together to move you.
Healthcare providers organize muscles by tissue type. There are three types of muscle tissue in your body: V体育官网入口.
Skeletal muscles are part of your "VSports注册入口" musculoskeletal system VSports在线直播. They work with your bones, tendons and ligaments to support your weight and move you. Tendons attach skeletal muscles to bones all over your body.
Skeletal muscles are voluntary — they move when you think about moving that part of your body. Some muscle fibers contract quickly and use short bursts of energy (fast-twitch muscles) V体育2025版. Others move slowly, like your back muscles that help with posture.
Cardiac muscle (myocardium) makes up the middle layers of your heart. It doesn’t exist anywhere else in your body. Cardiac muscle squeezes and relaxes to pump blood through your cardiovascular system.
Your heart is an involuntary muscle — it beats on its own without your input.
Smooth muscles are involuntary muscles that line the inside of some organs. They do essential jobs like moving waste through your intestines and helping your lungs expand when you breathe.
Smooth muscles play an important role in many body systems, including the:
There are more than 600 muscles located almost everywhere throughout your body.
Your first thought when picturing muscles might be the biceps in your upper arms or the quads in your thighs, but muscles support almost every part of your body, many of which you’ll never notice.
Muscle strains (pulled muscles) are the most common muscle injury. They happen when you overuse a muscle. The strands of muscle fiber are stretched beyond their limit and tear apart. You’ve seen this happen if you’ve ever tried to use an old bungee cord to hold something in place.
Many health conditions can affect your muscles, too, including:
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The most common symptoms of a muscle injury or health condition include:
A healthcare provider may use a few different kinds of tests to diagnose muscle conditions or injuries:
Which treatments you’ll need depends on the health condition or injury you have. Some conditions that affect your muscles are short-term issues. Others are chronic conditions and you’ll need to manage your symptoms for a long time.
You can manage many muscle injuries at home with the RICE method:
Stretching and warming up before exercise or physical activity are the best ways to prevent muscle injuries. Increasing your overall flexibility will also protect your muscles from injuries. The more flexible you are, the more room your muscle fibers have to stretch before they begin to tear.
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Increase your activity level gradually. Don’t suddenly ramp up your training intensity or start exercising way more often than you usually do.
Visit a provider if you’re experiencing muscle pain that doesn’t get better in a week with rest and other at-home treatments. Go to the emergency room if you have any of the following symptoms:
Muscles are tissue. Smooth muscle tissue lines some of your organs, but most organs are also made of other types of tissue, too. Providers sometimes refer to the muscular system as one anatomical group that includes all your muscles. They might also include muscles as parts of other systems throughout your body.
Your heart is the only organ that’s also a muscle. It’s made of a special type of muscle tissue called cardiac muscle. Your heart is the only place in your body that has cardiac tissue.
Fitness trainers or physical therapists may talk about strengthening or working out specific muscle groups. These are usually loosely defined.
It’s common to group muscles together by their location (like your chest muscles, leg muscles or back muscles) or what kind of movement they perform (abductors, flexors or extensors, for example).
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Healthcare providers usually only classify muscles based on the type of tissue they’re made of.
You have more than 600 muscles, and you use them constantly whether you’re thinking about them or not. Some muscles you can see and feel (especially after a big workout). Others — like your heart and the muscles that line some organs — silently keep you alive. It’s normal to feel sore or achy sometimes, but visit a healthcare provider if you’re constantly feeling muscle pain. You shouldn’t feel sore or painful all the time. Muscle pain can often be a sign of a condition a provider needs to diagnose and treat.
Remember, you don’t have to look like a muscular professional athlete to be healthy. Talk to your provider about ways to support your muscle (and overall) health. They’ll suggest exercises, movements or physical activities that’ll keep you strong, safe and healthy.
From sudden injuries to chronic conditions, Cleveland Clinic’s orthopaedic providers can guide you through testing, treatment and beyond.
Last reviewed on 01/23/2024.
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