Have you ever gone into a squat, or pressed some dumbbells overhead, or fired up a fresh round of leg extensions, only to hear (or worse, feel) cracking or popping sounds in your joints?
“Do my elbows have knuckles?” some will wonder. Well, the answer is, kind of, yeah.
Popping and cracking sounds are believed to be caused by two things. The most common cause is the entrance of air bubbles into the synovial fluid between the bones that constitute each joint and escape when the bones are slightly separated (which occurs when you “crack your knuckles” or "crack your back").
The other cause is the movement of a ligament (a connective tissue which attaches bones to other bones) or tendon (which attaches bone to muscle) entering this between-bone area. The sound is caused by that ligament or tendon snapping out from between the two bones.
Or, the tendon moves during the joint movement (which is inevitable) and the snapping is the sound of the tendon snapping BACK to its original position.
Are your eyebrows raised? Lower them. Most of the time, these popping and cracking sounds are nothing to be concerned about; they are merely the result of tendons and ligaments that are doing a good job of holding your musculoskeletal system together, like they’re ‘sposed to.
Sometimes this tightness is partly the result of tightness in the surrounding muscles, putting pressure on the tendons. But even this is normal enough and no need for concern.
Still, stretching can help reduce the popping and snapping and any discomfort or unease that accompanies. And you should probably stretch more anyway.
The only time to be concerned is when the sounds are accompanied by swelling and/or pain in the joint. This indicates that an injury may be causing excessive tightness in the surrounding tendon, which is pulling the connective tissue into the joint itself.
To reiterate, if joint popping and cracking in some area of your body is pronounced enough to actually make exercising that area uncomfortable, or if it "weirds you out," it is possible to reduce or eliminate it through targeted stretching and strengthening.
Here is an article on reducing knee popping from the very no-nonsense and reputable website StrongLifts, and here’s another from Prevention. And lastly, here’s one from Running World on removing sounds that accompany what’s ominously called Popping-Hip Syndrome.
Every physical peculiarity is an opportunity to get to know your body better. Popping joints are no exception. So get stretching, get strengthening, and get smashing those obstacles!!!