What Causes Cracking Joints?

Graphic of women stretching with toddlers
Posted April 23, 2021
Caitlin Williams
BKin(Hon), MSc(PT), MScCl(Manip Ther), DPT, FCAMPT

As physiotherapists, we get asked this question A LOT! Our bodies make a variety of noises and as curious humans, we want to know why! Is this dangerous for our bodies? Why does it have a feeling of relief? Is this safe for our joints?

In short, the sound we hear is completely normal and should not create fear. The only time we should be concerned is if the popping sound is associated with pain or if it occurs with an injury, such as rolling your ankle and hearing a pop.

So what causes this sound? By far, the most common reason is gas bubbles popping within our joints or tendons sliding over joint surfaces.

Is this bad for our bodies? No! A longitudinal study performed by Pazzinatto et al. in 2018 looked to see if knee crepitus (joint noise) was associated with the occurrence of a total knee replacement due to osteoarthritis. The results of this study showed that joint crepitus is NOT associated with having a higher odds of needing a total knee replacement and it does NOT affect physical function and quality of life.

Similarly, a study completed by De Oliveira et al. in 2019 assessed activity level in a group of women with patellofemoral pain. They looked at knee crepitus over a month long period, along with knee pain while stair climbing and squatting. They found that knee crepitus had no relationship with any of the above activities. However, the study did conclude that women with knee crepitus were 4x more likely to experience patellofemoral pain. So what does that mean? The presence of crepitus did not influence physical activity level and pain, BUT it can definitely influence a client’s perception and create a fear response… so he/she stops moving!

In summary, our bodies are made for movement. Motion is lotion. Cracking, snapping and popping joints are completely normal. If the noise is not associated with pain we must not fear the movement. Fear creates rest and then rest outweighs activity…. This is when we can start to see a whole host of other conditions arise from inactivity.

So enjoy those Rice Krispie noises in your knees, ankles and elbows, and enjoy the wonderful spring weather we have been longing for! Movement is one of the best forms of medicine… next to a good laugh!



1. Pazzinatto, De Oliveira, de Azevedo, Pappas. (2019). Knee crepitus is not associated with the occurrence of total knee replacement in knee osteoarthritis – a longitudinal study with data from the Osteoarthritis Initiative; Brazilian Journal of Physical Therapy, Volume 23, Issue 4: 329-336.

2. De Oliveira, Pazzinatto, Del Priore, Ferreira. (2018). Knee crepitus is prevalent in women with patellofemoral pain, but is not related with function, physical activity and pain. Physical Therapy in Sport, 33: 7-11.