Why do my knees crack when I squat ? Causes & Treatment

  • Home
  • /
  • Blog
  • /
  • Why do my knees crack when I squat ? Causes & Treatment

Last updated on September 4, 2023

As biological organisms, we make lots of loud and weird noises. Knee cracks and knee pops when squatting are two of them. I’ve explained the possible causes, treatments, and situations which may be a cause for concern below.

When you perform a squat, you don’t just use your muscles. Squatting puts a lot of pressure on joints which includes your knees. Experiencing a range of knee sounds when your knee bends during a squat such as clicking, cracking, or popping isn’t uncommon.

Knee clicking isn’t usually a serious problem. If it results in pain when squatting, it may be a sign of an underlying condition. First, let’s take a look at the anatomy of the knee before understanding the causes and treatment options.

Quick answer – Whilst you may initially think it’s a cause for concern, knee popping or ‘noisy knees’ is most likely a result of changes in pressure from gas bubbles and synovial fluid moving around as you squat. Knee clicking accompanied by pain or instability may be a sign that you need physical therapy.

Knee Joint Anatomy

The knee joint is a hinge-like synovial joint that allows mainly for flexion and extension which are the main two movements during a squat. It also allows for a small degree of lateral and medial rotation.

It’s one of the most complicated joints in the body, formed by articulations between the femur, tibia, and patella. In Between the bones, the meniscus reduces friction between the tibia and femur whilst the synovial fluid keeps the joint lubricated and keeps the ligaments and bones connected.

Possible Causes

Performing regular squats, especially heavier ones, places your knee joints under increased pressure. This can commonly lead to a popping sound or cracking sound when your knees flex as you squat down.

Whilst initially, this may seem like a cause for concern, it can be a result of many different things and usually isn’t a problem if it isn’t accompanied by pain.

Joint Mobility

During a squat, your body undergoes multiple movement patterns including ankle dorsiflexion, hip flexion, and internal hip rotation. Clicking sounds when squatting may be due to mobility issues in one of these joint movements rather than in the knee joint itself.

Before moving to the knee joint, check the range of motion in these joint movements first. I’ve discussed some possible treatment options if you’re experiencing tightness below.

Synovial Fluid Gas Bubbles

In the knee joint, synovial fluid is a thick liquid between your joints that provides a cushion at the end of your bones and reduces friction as you move your knee up and down when you squat.

Synovial fluid comprises various gases including oxygen, nitrogen, and carbon dioxide. As your knee joint moves beyond its normal range of motion, the pressure changes which causes the build-up of gas bubbles.

The good news is that this is not a cause for concern unless it is accompanied by knee pain. If so, consult a doctor and physical therapist.

Knee Injury

Knee injury as a result of a sudden impact on the knee cap may cause knee problems that result in a cracking sound or pop when squatting.

Knee Injuries can be commonly grouped into three categories:

  1. Runners Knee (Usually causes a dull pain at the front of the knee. Causes include a tight knee cap, weak thigh muscles, tight hamstrings and/or achilles tendons, and excessive training.)
  2. Meniscus Tears (The meniscus is a rubbery C-shaped disc that acts as a shock absorber and helps to spread weight evenly. Tears are commonly caused by sudden twisting of changes in direction.)
  3. Chondromalacia Patella (Damage to the cartilage under the knee may develop through overuse or injury. Treatments may include strengthening and stretching exercises which I’ll talk about below.)

Knee Surgery

Changes in knee anatomy and joint alterations are common practices during surgery. This can lead to noisy knees when squatting following surgery.

For the most part, this shouldn’t be anything to worry about unless accompanied by pain or instability issues.

Knee Osteoarthritis

Osteoarthritis is the most common form of arthritis in the knee. It becomes more common in men and women over the age of 50 but can also occur in younger people too on rare occasions.

Osteoarthritis is a degenerative wear and tear disease that causes progressive loss of knee cartilage. As it wears and becomes rough, the protective joint space between the articulating bones decreases.

This rubbing may cause knee joint pain and get worse over time, with an accompanying cracking sound and other knee problems when squatting.

Treatment Options

As I’ve mentioned above, some of the causes of knee clicking are harmless and don’t need any treatment unless accompanied by pain. However, some may be addressed by the treatment options below:

Joint Mobilisation Exercises

If your knees are clicking when squatting, performing joint mobilization exercises to check ranges of motion is usually the best place to start.

Check your ankle dorsiflexion, hip flexion, and hip internal rotation.

Ankle Dorsiflexion – Stand in front of a wall with your feet in-line about 4 inches away. Bend your knee and try to touch the wall. If your ankle comes off the floor, you need to improve your ankle mobility. Perform the same test for both feet and regularly hold the stretch for 20 seconds each time you exercise.

Hip Flexion – lie on your back and pull your knee into your chest. Use your fist to measure the distance between each knee and your chest. Perform the same exercise during each session, aiming to have no gap between them.

Internal Hip Rotation – Sit on a chair with your hips and knees bent 90 degrees. Place your firsts side by side between your knees with your thumbs touching and squeeze them together using your knees. Keeping your knees against your fists push your feet apart by raising your lower legs out to the sides. A shin angle of 45 degrees indicates normal internal rotation. Perform the test twice a day, holding the position for 10 reps.

Stretching Exercises

If the forces pulling the muscles surrounding the knee joint are unbalanced when squatting, the knee cap will sit out of position. This is likely a result of muscle tightness.

Foam rolling your quads, hamstrings, and glutes before squatting using a foam roller can help to loosen the muscles and reduce the incidence of knee noises and pain.

Move up and down the length of each muscle and pause briefly in tight spots to work deeper into the tissue.

Strengthen the Surrounding Muscles

During a squat, your hips and legs should track in a straight line as your knee joints flex and extend. As you activate your hip flexors and perform a hip hinge, the surrounding muscles (your glutes, quads, and hamstrings) work to keep your body in the correct position.

If your knees feel unstable and often click when squatting, it could be a sign that the surrounding muscles are weak. Add banded glute bridges and clamshells alongside your normal squat routine to strengthen your glutes and hips. Banded monster walks are a great way to strengthen your quads and can also be added to your routine following your compound movements.


Experiencing knee cracking and popping sounds when squatting is fairly common and usually nothing to worry about. It may just be the result of gas bubbles forming in the synovial fluid or the result of surgery.

If the knee joint noise is accompanied by pain, it may be time to see a physical therapist for further help. Perform the mobility routines and strengthening exercises above to address common causes of knee noise when squatting.

Steve Theunissen has qualified from the International Sports Sciences Association (ISSA) and is a certified Personal Trainer and Nutritionist. He has over 30 years experience in fitness and nutrition and currently working with famous fitness professionals. He is currently living in New Zealand with is wife and daughter.

Your Signature