Snap, Crackle, Pop: Why are My Joints So Loud?

Q. When I lift weights or stretch, my joints pop, and it sounds as if I’m cracking my knuckles. Some of my friends hear it and get alarmed, it’s so loud.  It doesn't hurt, and as far as I can remember, I’ve always had a noisy body.  Is this normal?

A. It’s unclear exactly what causes some joints to pop. There appears to be a variety of contributing factors.

Joints are fairly complicated structures: Two or more bones meet at a junction, along with various tissues: ligaments that attach to the bones, tendons connected to the muscles that move the bones, cartilage that pads the joints, and fluid for lubrication. 

Different bones have different shapes, especially at the joint ends. A ligament sliding over a uneven or arthritic surface when a body twists into a deep stretch, or even simply bends a joint; an air pocket being created from the movement of the various tissues when the body performs a movement such as a high jump; or lifting a weight—these are some of the things sports medicine doctors and physical therapists point to when trying to figure out why joints make popping sounds.

These actions might be triggered from a movement as gentle as a stretch, or as vigorous as a high jump or heavy weight move.

Do noisy joints cause any harm? The general assumption by health professionals is that if you feel no pain, it’s not something to worry about. Still, it’s probably not a good idea to purposely crack your knuckles, neck or back.

Some people notice that they pop and crack when they overdo their exercise. Overloading too much too fast may, in fact, stress the joints; talkative joints could be an early signal that the body is not adapting as smoothly as it could to the increased stresses being imposed.

When you increase your exercise intensity by changing what you do, you can add more stress to your body. If you’re used to walking and you suddenly shift to workouts that emphasize running and jumping, for example, or when you bump up the amount of weight that you lift, the overload to the joint may be just enough to safely challenge the body to work harder—or it might be too much, cause the body to strain to cope with the new stimulus.

But it’s not just the super-hard stuff that can overload your body. If you go longer and increase the total time you spend exercising (going from thrice-weekly jogs to long hours every day to train for a marathon, for example), the body could experience stress if it isn’t ready to cope with the endurance required to maintain the movement. (Ever feel sore after a day of walking on vacation in a foreign country, or even a long day at the shopping mall?)

It’s always a good idea to build up to greater or harder levels of activity slowly. So if you notice that your joints are getting noisy and you don’t feel any pain, a good first step is to tone down what you are doing—especially if you have recently increased it.

Joints move smoothly and with less friction when the body is warmed up and synovial fluid is released. If you start any workout—no matter what type—with light, easy movements that mobilize the joints prior to vigorous action for at least five to 10 minutes, you’ll best prepare your body for a harder or longer challenge. Try to move the specific joints you’ll be working in their natural ranges of motion during the warmup.

So, you may walk or march in place or get on a cardio machine to increase your body temperature, and then—either simultaneously, or after you’re done—move your arms and legs in ways that target each joint. For example, you could make shoulder circles, raise your knees up and down, or reach your arms forward and back.

If you experience persistent joint pain, consult a health professional.

More Expert Fitness Advice From Martica:

• Feeling Sore From Cardio
• Stuck Doing Unsafe Exercises
• Must I Exercise Every Day?

Find all articles by Martica.

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Martica is a Manhattan-based exercise physiologist and nutritionist and an award-winning fitness instructor. She has written for a variety of publications including Self , Health , Prevention , The New York Times and others. Martica is the author of seven books, including her latest, - Cross-Training for Dummies . (Read her full bio.)