woman running with knee crepitus, knee clicking in runners is normal

Why Do My Knees Click When I Run?

Knee Clicking or popping in Runners

Remember growing up our (at least mine) grandmas used to always tells us not to pop or knuckles because it will cause arthritis? Yeah, old wive’s tale that is completely untrue. Do your knees click when you walk or run? Are you afraid something is wrong and you need to get them to stop clicking all the time? The good news is that not all knee clicking when running is bad. In fact, the majority of it is harmless!

image of a group of runners outside on a road, popping and clicking or knee crepitus is normal in runners

What is Knee Crepitus

Let’s first define what you are talking about. Medically speaking clicking and popping in your knee is called Crepitus. The noise, kneecap crepitus, usually occurs after sitting or not moving for a period of time, and then you hear a click or pop when you get up and straighten your knee out.

The big thing that you should know is that this is very, very common and not something to be overly concerned with.

Why Do My Knees Click?

This is a question I hear a lot, and not just in relation to running. I hear all of the following questions on a regular basis:

Why do my knees click when I walk?

Why do my knees click when I squat?

Why do my knees click when I go upstairs?

Why do my knees click when I go downstairs?

They are all related and usually caused by the same thing. But WHAT is the thing that causes knees to go snap, crackle, and pop?

Honestly, this is a very difficult question to answer but there are two main theories of what causes knee crepitus in runners and non-runners alike.

The first is when you hear a loud, isolated, crack or pop. This noise is usually seen during warm-ups and activities that involve crouching down or bending your knee past 90 degrees. Not only will you hear a noise but sometimes people even feel better after their joint has cracked.

In the knee, this sensation is usually caused by either bubbles of gas popping, or due to the patella locating into the groove under it as you warm up and loosen your muscles.  Gas bubbles or alignment in the groove are not any cause of concern and are entirely normal!

xray image of knee, knee arthritis in runners and knee popping during running

Other Causes of Knee Popping in Runners

Iliotibial Band Syndrome can cause Popping

When you have clicking that occurs on the outside of the knee specifically, this could be related to the Iliotibial Band (ITB). What happens is that the band will flick over the bony landmark on the outside of your knee, the lateral condyle of the femur, and cause a clicking noise. IF it is painful then this is referred to as Iliotibial Band Syndrome.

Knee Clicking When Running Caused by Baker’s Cyst

Clicking that occurs at the back of the knee may be due to swelling at the back of the knee, called a Baker’s Cyst, or be due to the medial hamstring tendons.

A Baker’s cyst is a fluid-filled sac at the back of your knee. Typically it causes a feeling of tightness in the back of your knee and can create a visible bulge. It is completely benign but can cause the popping sound due to the hamstring tendons descending next to it.

The medial hamstring tendons pass across the back of your knee and can flick on each other as you bend and straighten your knee, causing an audible sound.

Plica can Cause Knee Crepitus in Runners

A third cause, or type, of clicking, can happen at the front of your knee caused by an anatomical structure called the plica. The plica is a fold in the thin capsule tissue that surrounds the knee joint.

Sometimes the plica can be a little thicker and cause impingements on the surrounding soft tissues or bones of the knees. This can cause a clicking or catching sensation and a clicking sound when you bend your knee or squat. Usually, this is also pain-free but when it is painful it is called Plica Syndrome.

All three of these additional causes of knee clicking in runners are often pain-free, not serious, and don’t indicate any future damage or current structural issues with your joint!

However, if you are having pain, you should definitely consult with a physical therapist or another medical provider to get to the bottom of what is going on! Living with pain is not normal! It is not a badge of honor and something that just happens when you run that you have to deal with!

Can Physical Therapy Help with Knee Clicking in Runners?

Absolutely! A physical therapist, or Physio for those in other parts of the world, can look for what the cause of the knee clicking is in a runner or any person! We will look for muscle imbalances among other tests and observations to prevent the clicking from becoming something worse!

knee clicking in runners is normal, picture of physical therapist with runner for knee crepitus

Physical therapy is beneficial at all times and is even better when you use it as a preventative measure! It is easier to treat a problem that isn’t there yet than to fix a problem that has already developed and is creating pain! All runners need to see a physical therapist regularly!

Knee Clicking and Popping is NOT Arthritis

Many people worry and believe that clicking in the knee means that the bones are running together and causing damage to the joint. Therefore, causing osteoarthritis. This just isn’t the case. It is normal for knees to click when running, jumping, or moving in any way.

Joints are moving parts with many structures that move and glide next to each other. This happens when you are simply walking, going up and down the stairs, or standing up from sitting. It is normal to have things shift around a little and make noise!

picture of knee pain, knee clicking when running, squatting or doing stairs

Interestingly, most knee issues (and other joint issues) that are painful that I have seen as a Physical Therapist in the clinic are often NOT accompanied by any noise at all!

Also, real arthritis noise is more of a creaky door sound and very unlikely to be seen in runners! In fact, running doesn’t cause arthritis and you can still run with arthritis!

Final thoughts on Running with a Knee Click

I have 5 reasons that you shouldn’t worry about that knee click!

  1. There is no evidence it will get worse as you age

2. There is no evidence it will ‘wear out your joint’ and cause osteoarthritis.

3. Painfree clicking shouldn’t stop you from doing the activities you love! (Running, hiking, squatting)

4. No correlation has been found between the amount of clicking and the level of pain or dysfunction.

5. It is not a pain predictor! There is no evidence that it will progress to a painful issue!

When in doubt, always see a physical therapist and get a full assessment to prevent any injuries that may occur. But overall, you shouldn’t be concerned about a clicking noise in your knee when it isn’t accompanied by pain!

Related articles to Knees Popping When Running

The runner doc Injury Prevention Page

Runner’s knee article

Why Runners need Physical Therapy


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References for Knee Crepitus in Runners

Pazzinatto MF, de Oliveira Silva D, Azevedo FM, Pappas E. Knee crepitus is not associated with the occurrence of total knee replacement in knee osteoarthritis – a longitudinal study with data from the Osteoarthritis Initiative. Braz J Phys Ther. 2019;23(4):329-336. doi:10.1016/j.bjpt.2018.09.009

McCoy et al

Is it Bad That my Knees pop all the time?

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