We tapped a top physical therapist to weigh in on noisy joints.
According to many studies, there is no one clear answer for what causes joints to make a cracking sound, but some research shows that the sound you hear when cracking your knuckles is caused by “popping” gas bubbles in the synovial fluid, the fluid that lubricates your joints. So what does that mean for the joints cracking in rest of your body beyond your knuckles?
In most cases, cracking joints do not have any detrimental effects and can be present in healthy or abnormal joints, Dennis Cardone, D.O., primary care sports medicine specialist at NYU Langone Sports Health tells Runner’s World. Muscle or tendon popping is also usually a normal and common occurrence, he adds.
That “cracking” you hear is the result of a change occurring at the joint or muscle and tendons. At joints with certain movements, there may be air trapped or a vacuum produced that leads to the audible “crack,” says Cardone. This is known as “cavitation.”
“For muscles and tendons, the ‘crack’ or ‘pop’ is related to its movement over a bony prominence. In the hip, for example, it is common for runners to feel ‘popping’ or ‘cracking’ caused by the abductor (iliotibial band) or flexor muscle (iliopsoas),” Cardone says.
And, according to Cardone, most cracking is benign and leads to no problems. However, in some cases the snaps and cracks can cause pain.
“Remember that joints make noise and that in most cases it is a normal, common occurrence,” says Cardone. “For most people, running is good for the joints and will promote lubrication of the joints and less ‘cracking.’”
But if cracking joints bother you, especially if they are causing pain, it’s something to bring up with your doctor. Rehab exercises directed at strengthening of the involved muscle groups will usually cure the discomfort that comes from your joints cracking, Cardone says.
In same cases like a constant, continued crack in one joint, it could indicate an issue with your mechanics or alignment. “With proper joint mechanics, there should be no cracking of the joint,” says David Reavy, physical therapist and founder of REACT Physical Therapy in Chicago. “Remember that soft tissue [the muscles and fascia] crosses joints. If a joint is making a ‘crack’ sound, the joint mechanics could be off. A repetitive cracking or snapping means something is aligned wrong. You’re hearing either joint contact and friction or the snapping and rubbing of a tendon or muscle. That’s not good and can lead to problems.”
It may be easy to ignore a few of those cracks and pops, but you want to pay close attention to when and how often they happen. Cracking or snapping that’s repetitive with every step or motion, is accompanied by pain, or that leads to swelling afterward can spell bad news. Grinding noises are also a bad sign, as surfaces in the body are designed to move smoothly over each other.
In cases where your joints cracking leads to discomfort, Reavy recommends seeking medical help or an assessment by a trained physical therapist or doctor to adjust any improper motion and alleviate repetitive stress. If the snapping is occurring in the same place, especially if there is pain, this can lead to bigger problems and may even be a sign your body could be developing a musculoskeletal imbalance, but seeing a trained professional can stop a problem before it gets worse. “Bringing your body into better alignment, in general, will help to eliminate those repetitive abnormal joint forces,” Reavy says.
Otherwise, small noises that happen occasionally and are not accompanied by pain may actually be a sign of good joint health. “Little snaps and pops while working out probably mean that you’re pushing your body outside of your day-to-day, which isn’t a bad thing!” Reavy says. “We like to say, ‘Motion is lotion,’ as joints like to move, and a joint moving through its full range of motion is a healthy joint.”