Squats are one of the best exercises you can do. However some people experience discomfort when performing them. I want to preface this article by first stating that I am NOT a chartered physiotherapist, and that you should 100% find a good one to treat your pain. What I've outlined are simply anecdotes of what I've seen work for myself and others.
That being said, I know the reader will more than likely do what most people do and try to fix the issue themselves / see if it just ‘works itself out’. If you’re going to do that, you may as well try some of the approaches in this article that I have actually seen work for resolving knee pain in the squat.
1. Fix your form
This is number one for a reason, and it’s because shitty form is the most common cause of people getting hurt during squats. Thankfully, it is also one of the easier corrections for relieving knee pain.
In an ideal squat, we should be able to do the following things:
Maintain a neutral spine
Keep the entire foot in contact with the floor at all times
Squat to a position where the top of the knee is parallel to the crease of the hip
Maintain the knee cap’s position of tracking over the middle of the foot
If any of these technical points are being performed poorly, we can begin to experience pain. Of particular interest for this article is the last point in bold. This is because a common symptom of poor squat mobility and/or weak glutes is when the knees cave in (also known as ‘knee valgus’). This places disproportionate stress on the ligaments and tendons of the knees, and is an unstable position for absorbing and generating force in a squat.
The image on the left shows the knees tracking over the middle of the foot. The image on the right depicts 'knee valgus', where the knees collapse inward, over-stressing the soft tissues of the knee joint.
Common solutions for this are to use glute bands around your knees, elevate your heels (with a plate or liftings shoes), temporarily reduce the depth of the squat, or simply have a coach cue you on how to properly align your lower limbs in the squats.
2. You do no posterior chain exercises
Your posterior chain muscles are those on the back of your body. Generally speaking, large imbalances in strength ratios between anterior and posterior chain muscles ends up leading to bad things. Most gym-goers do zero work for their hamstrings and glutes, and as a result their knee joint lacks muscular balance. This is not unlike people who suffer from shoulder pain who also never train their back.
Every lower body training session you perform should include some kind of posterior chain exercise for the sake of balance. It could be a leg curl, or it could be a hinge/hip extension exercise like a Romanian Deadlift or a hip thrust. Just get it done.
3. Your knees are doing too much
Even with perfect form and plenty of balancing work for your posterior chain muscles, there is only so much training load that a joint can tolerate in a single session or week until overuse injury starts becoming a significant risk.
This 'training load' is one of the best predictors for injury. Every soft tissue in your body has an upper limit to how much stress it can withstand before it becomes injured, and excessively loading your knee joint can lead to such problems.
Therefore, if you are someone who performs a lot of knee-intensive exercise such as squats, lunges, cycling, running, jumping, etc., then you may need to pull back on some of these to take the stress off your knees. Now, your knee joint may be able to be conditioned for such training loads eventually. However, that needs to happen gradually over time and sensible recovery protocols (i.e. plenty of sleep and good food) has to be implemented as well.