Skeletal muscles comprise 30 to 40% of your total body mass. They’re the muscles that connect to your bones and allow you to perform a wide range of movements and functions. Skeletal muscles are voluntary, meaning you control how and when they work.
The majority of the muscles in your body are skeletal muscles. They make up between 30 to 40% of your total body mass. Tendons (tough bands of connective tissue) attach skeletal muscle tissue to bones throughout your body. Your shoulder muscles, hamstring muscles and abdominal muscles are all examples of skeletal muscles.
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There are three types of muscles in your body:
The skeletal muscles are a vital part of your musculoskeletal system. They serve a variety of functions, including:
There are skeletal muscles throughout your body. They’re located between bones.
Skeletal muscles consist of flexible muscle fibers that range from less than half an inch to just over three inches in diameter. These fibers usually span the length of the muscle. The fibers contract (tighten), which allows the muscles to move bones so you can perform lots of different movements.
Each muscle can contain thousands of fibers. Different types of sheaths, or coverings, surround the fibers:
Skeletal muscle fibers are red and white. They look striated, or striped, so they’re often called striated muscles. Cardiac muscles are also striated, but smooth muscles aren’t.
Although skeletal muscles typically make up roughly 35% of your body weight, this can vary from person to person. Men have about 36% more skeletal muscle mass than women. People who are tall or overweight also tend to have higher muscle mass. Muscle mass decreases with age in both men and women.
A wide range of conditions can affect skeletal muscles, from mild injuries to serious or even life-threatening myopathies (diseases that affect skeletal muscles). A few are:
Some skeletal muscle conditions, such as strains and age-related degeneration, are really common. Muscle injuries account for 10 to 55% of all sports injuries, and about 90% of those are strains. Others are fairly rare. For instance, myasthenia gravis affects between 14 and 40 people out of every 100,000 in the U.S.
Take care of your skeletal muscles by:
Contact your doctor right away if you:
A note from Cleveland Clinic
Skeletal muscles are the most common muscles in your body. You use them to move your bones, so they play a vital role in everyday activities. Skeletal muscle injuries or diseases can have a profound effect on your life. It’s important to keep your muscles as strong and healthy as possible.
Last reviewed by a Cleveland Clinic medical professional on 09/01/2021.
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