Why Do Muscles Crack When Stretching?

women doing a yoga stretch

At the end of a long day, stretching out your muscles feels great. Sometimes those tissues make cracking or popping sounds as you move, and you may feel some relief from tension when this happens. But is this cracking in your muscles and joints safe? We’re going to break down why cracking happens in the human body, when it’s a normal occurrence, and when you should find a local doctor in North Texas.

Why Do Your Muscles Crack?

Medical professionals have identified several things that might be happening in your body when you notice that your muscles or joints are cracking. While the word “cracking” sounds serious, nothing in your body is snapping or breaking. In many instances, tissue cracking is very normal and not harmful. The medical term for cracking tissue is crepitus. Although the cracking may feel like it’s coming from your muscles, it may originate in one of several places.

Pressure Release

One reason you find that your muscles crack while stretching has to do with a release of pressure. Stretching moves your soft and hard tissues around and may open up small spaces between them that were previously compacted. This allows gases to enter those spaces. When the gases are expelled again, you hear a cracking sound.

Synovial Fluid

Your body contains something called synovial fluid, which helps lubricate your joints and the hard and soft tissues that allow your joints to work smoothly. Sometimes stretching in positions that are unusual for your joints in your daily life will move the synovial fluid around. You may hear a crack if the fluid moves quickly, especially if it’s pushed rapidly out of a space that was created.

Soft Tissue Movement

In other instances, what you’re hearing is a tendon snapping in and out of place. If you have a spot on your body that repeatedly cracks but doesn’t hurt or otherwise bother you, a moving tendon may be the cause. Many people notice cracking tendons during repetitive motions like you might make on a job or as an athlete.

Knots in Your Muscles

Knots of tension in your muscles can sound a little bit crunchy when you rub them. This sound shouldn’t be loud and it shouldn’t hurt more than the typical release of tension that comes with massage or stretching. Try seeing a massage therapist or an orthopedic specialist for a knot that won’t go away.


Bones and muscles seem to crack more as you age. Your cartilage starts to wear down, which leaves rougher surfaces inside your body. Tissues rubbing together may produce more of a cracking sound than they did when you were younger.

When Is Muscle Cracking Normal?

It’s normal for people’s tissues to crack during stretching or certain movements. You probably know someone who intentionally cracks their knuckles, neck, or back. If cracking feels good, doesn’t cause any pain, and isn’t related to an injury, you don’t have to worry. When you see an orthopedic specialist for an adjustment, you may notice that some of the posture or joint adjustments also produce cracks.

Doctors used to think that cracking would lead to arthritis or other types of tissue damage, but the evidence shows that cracking your joints intentionally will not lead to arthritis and will not cause long-term damage.

When Is Muscle Cracking A Cause for Concern?

In some instances, muscle cracking will indicate a deeper issue that you should have a doctor check. When any of the following symptoms accompany cracking sounds in your body, make an appointment with an orthopedic specialist as soon as you can. If you aren’t sure, err on the side of caution and make that appointment anyway. It’s better to have a potential problem investigated and find out it’s benign than to put off having it looked at.

Swelling and Pain

Tissue cracking should never be accompanied by swelling and pain. If a cracking joint or muscle causes you pain or you notice the area is swollen, that’s an indicator that you have an injury. Damaged cartilage, torn ligaments, and pinched nerves are all possibilities, and you don’t want to wait before seeking treatment for these issues because they will worsen over time.

Swelling and pain may also be indicators of tendonitis or bursitis. With tendonitis, a swollen tendon can cause your joint to move in awkward ways, which may produce cracking. Bursitis happens when the lubricating tissue between your joints becomes inflamed. If the pain in the cracking joint is constant, bursitis might be the culprit.

Stiffness and Loss of Mobility

Sometimes, along with swelling and pain, cracking tissue also comes with a loss of mobility. This can indicate an injury as described above or it can show you’re developing arthritis. When the tissue is swollen, it can cause the typically smooth movement of tendons to crack as the swollen surroundings impede them. Only a doctor can diagnose arthritis, but other symptoms to watch out for include stiffness in the morning, swelling after movement, and joints that start to appear deformed.

Cracking in the Lungs

If you notice cracking in or around your lungs when you take a breath, seek medical treatment immediately. Crepitus in this area of the body can indicate serious conditions like subcutaneous emphysema. Causes include chest trauma, certain infections, and tears in the airway.

Is it Time to Visit an Orthopedic Specialist?

Pay attention to what’s going on with your body. If you’ve always noticed that certain muscles crack during stretching, that’s normal. When the cracking starts to hurt, if your joints or tendons feel stuck, or if you notice swelling or loss of movement, book an appointment so a doctor can evaluate what’s going on with your body.

At Orthopedic Specialists of North Texas, we offer orthopedic care to the residents of Dallas/Fort Worth and the surrounding North Texas area. Each of our patients receives a personalized care plan meant to heal injuries, improve function, and treat ongoing issues. If you notice any muscle cracking that causes you concern, please make an appointment to see one of our board-certified orthopedic surgeons today.


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