Lunges or split squats can be done a variety of ways and are a staple for most fitness programs. That being said, it’s not unusual to hear or feel a click or pop from your knee when performing this movement.
Although the sensation isn’t necessarily painful, it’s reasonable to be curious or concerned as to why it’s happening and if it is potentially dangerous!
London, Ontario Kinesiologist A.J. Stephen explains why your knee clicks during lunges, how serious it is, and what to do to fix it from a scientific perspective.
Cause 1: Cavitation
If the pop only occurs every once in a while, you’re probably experiencing Cavitation. Air becomes trapped in the knee joint over time, and then is expelled when the knee bends or extends. It is kind of like popping bubble wrap, except way less amusing.
This process is normal and not something to stress about. However if you have a chronic click when you lunge, it’s a different story…
Cause 2: Form Issues & Muscle Imbalances
As your knee tracks during the lunge, many muscles and tendons slide over the knee cap, which produces some noise, but typically not enough to be heard or felt.
If there is scar tissue built up from a previous injury or you have certain muscles that are under trained, or neglected, they might become weak and stiffen. This causes an increase in muscle tension, particularly within the glutes, hip flexors and quads which may shift certain joints like your hip and knee out of optimal working position.
So instead of little to no noise, you end up with more aggressive contact between the bones and tendons during movement which often translates into a louder “pop” or “snap”. This is common with people whose lunge form is not ideal, or are dealing with muscle weakness and imbalance.
Is This Dangerous?
Obviously this isn’t an ideal scenario; but because there’s no pain, is it really that bad?
I wouldn’t go into full blown panic mode; but something should be done.
Research has found that people who experienced chronic knee clicking and had no intervention were 3x more likely to develop pain in the form of osteoarthritis than people who did . Once pain starts to set in, it is much more difficult to fix.
Knee clicking also makes you less efficient during big lifts; which means you won’t be able to make nearly as many strength gains compared to if your joint was aligned correctly.
So how do you fix this? Here are two ways…
Solution 1: Fix Your Form
The two biggest form faults with lunges involve excessive hip internal rotation, and insufficient glute and hamstring activation.
To fix this, first focus on keep the knee slightly outside the ankle during the range of motion. Not just the eccentric, but concentric movement as well. Second, keep your front heel down and use your whole foot to drive up into your finished position.
This will fire up your glutes and hamstrings much more. This leads to better alignment and efficient movement.
If these adjustments don’t work, move on to solution 2.
Solution 2: Mobilize Stiff & Weak Muscles
Start by doing a lunge or two to assess the extent of the click. Note how loud it is and how it feels.
Next pick a muscle group and do some stretching and mobility. Common culprits are quadriceps, calves and IT bands, but you might have tightness in the hamstrings and gluteus medius which can contribute as well.
Re-test the lunge. If the clicking goes down, the muscle you stretched is likely contributing to the problem and you should spend some extra time working on it while you’re at the gym!
If the noise is unchanged, choose a different muscle group to mobilize, and re-test.
Work With A Pro:
At Stephen Fitness & Rehabilitation, we provide premium one on one personal training and exercise therapy in the comfort of home.
We prescribe and supervise exercise routines that are specifically designed for individuals in London & Oakville, Ontario dealing with crepitus within the knee joint.
Contact us to learn more about how we can help you or your loved one(s) become stronger, more mobile and independent in the comfort of home!
 Lo, G. H., Strayhorn, M. T., Driban, J. B., Price, L. L., Eaton, C. B., & McAlindon, T. E. (2017). Subjective Crepitus as a Risk Factor for Incident Symptomatic Knee Osteoarthritis: Data from the Osteoarthritis Initiative. Arthritis Care & Research.