Performing squats for functional strength and mobility can be a great way to keep you in shape and engaged in all the activities you enjoy. There are various types of squats to target muscle groups differently, and as such, this exercise is also very common in exercise-based rehab program.
However, what does it mean if you experience knee pain when squatting? Can you keep going? Have you injured something in the knee? These are common questions facing those trying to stay active with any lower body exercise.
This article will discuss some of the most common sources of knee pain with squatting with a focus on atraumatic injuries (for example, excluding acute injuries sustained in a contact sport) and some general treatment strategies for those issues.
Meniscus Injuries
The meniscus is a figure-8 shaped piece of cartilage that sits inside the knee joint. The role of the meniscus is to distribute forces going through the knee, or in layman’s terms, it can act as a shock absorber in the knee. Without the meniscus, you would have a round surface of the femur (thigh bone) sitting on the flat surface of the tibia (main shin bone).
Given that the meniscus’ role is to dampen forces going through the knee, it should be able to withstand most functional activity, but keep in mind that as a passive tissue you cannot voluntarily control it, and therefore the meniscus is at the mercy of the forces placed upon it, which sometimes might be too aggravating.
What causes meniscus injuries?
There are many different ways you can hurt the meniscus. Some of the most common ways include excessive twisting with the foot planted on the ground, deep squats (especially with lots of weight), uncontrolled impact (e.g. landing awkwardly from a jump), and trauma (e.g. getting in a bike accident).
Experiencing knee pain when bending is one clue that the meniscus may be irritated or injured, but matching this with the patient’s account of what happened, as well as ruling out a wide variety of other injuries that could cause knee pain when bending, are also important to narrow the differential diagnosis.
What are common signs and symptoms of a torn meniscus?
A torn meniscus usually results in pain with weight bearing, with more pain and apprehension occurring with higher impact activities. Twisting is usually painful as well. A sign of a severe meniscus injury that needs to be address urgently is a locked knee (more on that below).
Deep inner knee pain with squatting or bending the knee can also be a sign of an irritated or torn meniscus. While this symptom isn’t exclusive to only meniscus injuries, it’s one of the most common complaints people have when they have sustained a meniscus injury.
A couple safer ways to assess for a torn meniscus includes having the person carefully perform a deep squat into a baseball catcher stance and see if it is painful or they simply don’t want to do it. Firmly palpating the medial and lateral joint line of the knee can also be a more direct test for meniscus injuries.
Unfortunately, an MRI is often required to confirm the size, location, and shape of the meniscus tear, but things can still be missed on MRI. Sometimes, if there is a high likelihood that arthroscopic surgery will be required for the patient, this will all be confirmed once the surgeon is actually looking inside the knee with a camera.
What is a locked knee?
A locked knee is a classic sign of a severe meniscus injury that needs to be addressed urgently. One question that is often asked during an assessment of a knee injury is “Were you able to fully straighten your knee at the time of injury”?
This can sometimes be a difficult question to answer, but the reason it’s important is because the inability to fully straighten the knee can potentially mean the meniscus has torn, flipped upwards, and is blocking the knee from fully straightening. For example, a bucket-handle meniscus tear often leads to this presentation.
The reason we include this piece of information here is that while the meniscus is often stressed with deep bending and squatting, the loss of full extension with full, or near-full flexion, can be a sign of a severe meniscus injury that you wouldn’t want to miss.
How do you treat a torn meniscus?
A torn meniscus can be treated conservatively, or with surgery, depending on the extent of injury.
A recent study suggested that arthroscopic surgery for a torn meniscus can lead to better improvements in pain and function relative to conservative care (physical therapy) in the first year after injury, but after that first year, there doesn’t seem to be a difference in pain and function between types of care (Li et al, 2020).
Regardless of the approach, protecting the injury to allow for proper healing will be required in the initial stages of recovery, which usually means avoiding deep flexion or squatting past 90 degrees of knee flexion, and sometimes even non-weight bearing altogether.
As the injury gradually heals, exercise-based rehab is of upmost important to restore knee range of motion and functional strength of the entire lower body. Building knee stability through functional strengthening can help reduce the load on the meniscus and ensure proper mechanics when reintroducing activity.
The rehab protocol for a torn meniscus will vary based on the individual, extent of injury, and the individual’s goals for recovery.
As such, we highly recommend checking in with your local physical therapist to ensure the development of a safe and effective rehab program.
Patellofemoral Pain Syndrome (PFPS)
Patellofemoral pain syndrome, more commonly referred to as PFPS, and also known as runner’s knee, is an umbrella term for anterior knee pain that often occurs with functional movements, such as bending and squatting. The term “patellofemoral” refers to the joint formed by the patella (knee cap) and femur (thigh bone).
People with PFPS usually experience knee pain somewhere around the knee cap on the front of the knee, so it can cause both inner knee pain when squatting, as well as out knee pain.
When you see the word “syndrome”, that usually means there can be multiple causes, or that the cause may be unknown. In the case of PFPS, the cause is often mechanical, relating to muscular imbalances, or patellar maltracking, the latter of which refers to how the knee cap moves as your knee bends and straightens.
What are come common causes of PFPS?
There can be multiple things that factor into the development of PFPS and knee pain while squatting. Common factors include, but are not limited to:
– Weak quadriceps muscles especially the inside portion of the quad muscle
– Weak gluteal muscles (Glaviano and Saliba, 2022)
– An excessively tight iliotibial band (IT band)
– Tight hamstring or calf muscles
– An increased Q angle
– Generalized hypermobility
– Previous knee injuries
In addition to those anatomical factors, lifestyle can also influence the development of PFPS. For example, those who participate in a lot of repetitive activity such as long distance running are more prone to developing this condition, hence the term runner’s knee.
Those who are involved in repetitive jumping sports may also have a higher risk of developing PFPS, especially if combined with the factors listed above.
Taking a step back and looking at all the factors that can facilitate the development of PFPS, it’s easy to see why it’s hard to pin down one single cause of PFPS. This is partly why having your knee examined in person by a physical therapist can be crucial for proper recovery, as they will be able to identify factors unique to yourself and develop an individualized exercise program.
How can PFPS cause knee pain when squatting?
The presence of PFPS can lead to knee pain when squatting of a variety of reasons. First, if the patellofemoral joint is irritated, then anything that compresses that joint may provoke symptoms.
In the case of a squat, bending the knees will pull the quad muscle on stretch at the knee and will subsequently pull the kneecap in towards the femur, and added quadricep contraction will also enhance this (Pereira et al, 2022).
Second, if there are muscular imbalances that cause the knee to collapse inwards while squatting, also known as excessive knee valgus, then the outside thigh muscles will be pulling on the knee cap while it is being compressed towards the femur, leading to an uneven distribution of forces. This often results in inner knee pain when squatting.
Third, if the glute muscles or other hip muscles are not doing their job, there can be an over-reliance on the quadricep muscle, and this may also promote a knee-dominant squat. While there is usually nothing wrong with a knee-dominant squat, being unable to avoid this in the presence of PFPS can definitely lead to knee pain while squatting.
There are other reasons that PFPS can cause knee pain when squatting, but these issues listed above are the most common and encompass many smaller issues that can be identified by a physical therapist.
How do you treat PFPS?
The treatment for PFPS depends on what factors listed above have been identified as a part of the problem.
For example, for someone who has very strong quadriceps, but is found to be lacking strength in their glutes, their program may focus on a variety of glute strengthening exercises to help support the patellofemoral joint and prevent any excessive knee valgus, thus helping to prevent knee pain.
As such, understanding biomechanical factors unique to the individual with PFPS is crucial for safe and effective rehab. Understanding that this will vary among individuals, here are some more common treatment methods that I often use in the clinic:
– Glute strengthening, with a focus on gluteus medius and minimus, which are highly involved in preventing knee valgus and supporting the knee.
– Glute strengthening, with a focus on the deep internal and external rotators, which are also involved in knee control and are often overlooked in knee-specific conditions.
– Gluteus maximus and hamstring strengthening, which will help support the knee with functional movements. These muscles provide a lot of power in terms of hip extension, and the hamstrings also cross the knee to be the primary knee flexor. These muscles are very important during exercises like squats, but also provide a huge amount of power for daily activites that may provoke PFPS pain, such as climbing stairs.
– Eccentric quadricep strengthening with a focus on vastis medialis oblique fibers (VMO), such as those exercises found within a drop squat program. This muscle group is necessary to adequately control the kneecap while it moves within its trochlear groove of the femur. This will help prevent the patella from tracking laterally, which can directly change the forces acting on the joint, thus reducing knee pain with squatting. The eccentric component means the quad is lengthening but contracting at the same time, which is highly valuable for strength and control, and tends to be very functional.
– Stretching the quad, stretching the hamstrings, rolling the IT band, and potentially glute stretches can often provide relief for PFPS knee pain while squatting. While this can be an effective component of a rehab program, I have personally found that strengthening represents a more permanent solution, but may take longer to have an effect.
– Manual therapy, such as dry needling, active release, patellar mobilizations, and massage therapy, can all help address imbalances of tight muscles around the hip and/or knee and help to reduce pain at least temporarily.
– KT tape, also known as kinesiology tape, can also help provide support for the patellofemoral joint, and while it’s not a permanent solution, it can offer an effective way to relieve pain while engaging in rehab or general activity. The goal of the tape job is to alter the forces acting on the knee cap, which can reduce knee pain when bending (Ferreira et al, 2023).
Keep in mind this is a basic summary of common physiotherapy treatment approaches to PFPS that causes knee pain when bending the knee, and that this may vary quite a bit across cases.
Patellar Tendinopathy
Patellar tendinopathy, also known as jumper’s knee, can occur as a result of atypical reaction to new activities or a sudden uptick in activity, an altered cycle of repair in response to repetitive loading, or degenerative changes to the tendon itself.
Similar to Achilles tendinopathy, repetitive activities that involve a high rate of loading, such as repeated running and jumping (hence the name “jumper’s knee”), can facilitate the pathophysiological processes mentioned above, and as such, and contribute to the development of patellar tendinopathy.
Therefore, patellar tendinopathy is more common in sports like volleyball, basketball, long distance running, jumping events in track and field, etc.
Additionally, there is some evidence to suggest that ongoing patellar tendinopathy, particularly in the case of substantial degerenative changes, may potentially be a risk factor in sustaining a patellar tendon tear or rupture (Rosso et al, 2015), which is just another reason to try and address tendinopathy as early as possible.
How can patellar tendinopathy cause knee pain when squatting?
While there are many different forms of squats, some of which are more hip-dominant, and some of which are more knee-dominant, the quadricep muscle will have to contract to some extent regardless, thus loading the patellar tendon.
Furthermore, as the knee bends, this will place the tendons on the front of the knee on stretch (i.e. the quad and patellar tendon) while the muscle is simultaneously contracting, which means there is a lot of force going through the patellar tendon.
This is entirely normal during a squat, but if the patellar tendon is dysfunctional and a source of pain, then loading the tendon in this fashion can cause some knee pain while bending, particularly during squats.
How do you treat patellar tendinopathy?
It may seem counter-intuitive, but the long term solution for rehabbing patellar tendinopathy should emphasize loading the tendon, very similar to Achilles tendinopathy, which really happens through specific forms of strengthening.
Isometric loading where the muscle is contracting but not moving, and eccentric loading where the muscle is contracting but also lengthening, have been shown as effective methods of strengthening to help treat patellar tendinopathy (Everhart et al, 2017).
In this case, slow heavy loading frequently throughout the week is usually advised, even if there is some discomfort. Additionally, avoiding other very provocative activities like running or jumping may be advised depending on the severity of the tendinopathy.
Shockwave therapy is also a common treatment that occurs in physical therapy clinics, and this can be highly effective in treating tendon disorders (Poacher and Thompson, 2023).
Additionally, wearing a patellar tendon strap during activity can help redistribute the forces going through the tendon, which can help minimize or prevent knee pain while squatting.
In terms of prevention, tendons usually don’t like sudden upticks in repetitive activities that involve a high rate of loading, such as jumping.
In other words, try to avoid “surprising” the tendon if you are starting a new activity or returning to a training regime that you haven’t done in a while, ensuring to progressively build up over time with adequate rest between bouts. This will help prevent the onset or progression of patellar tendinopathy, and will also reduce the risk of a patellar tendon tear.
Knee Osteoarthritis
Osteoarthritis is an extremely common condition in the knee. It’s a degenerative joint disease, whereby the cartilage lining the bones wear down and can create uneven concentrations of stress within the joint.
This can happen in the patellorfemoral joint between the knee cap and the femur, or within the tibiofemoral joint between the femur and the tibia, especially if there is a history of underlying knee problems.
Osteoarthritis can develop slowly, and people often complain of joint stiffness and pain with impact activities or even prolonged rest. Knee pain with squatting, lunging, and kneeling can be quite common.
How do you treat knee osteoarthritis?
Given that knee osteoarthritis involves degenerative changes to the cartilage within the joint, the mainstay for treatment is exercise to improve mobility of the joint and to provide additional support for the knee joint by strengthening the leg muscles that help support it (Raposo et al, 2021).
For example, the quadriceps, hamstrings, and calf muscles all cross the knee. Strengthening exercises for these muscles with a focus on proper form can help provide direct support to the knee joint, and as such, the muscles then become more capable of taking the load.
Additionally, even muscles that don’t cross the knee joint, but are highly involved in functional movement patterns and have an influence on knee control, such as the gluteal muscles, can have an impact on osteoarthritis. By strengthening these muscles as well, we can improve biomechanical control of the knee and reduce symptoms associated with arthritis.
Eventually, combining pure strengthening with exercises that focus on more appropriate lower body mechanics can be quite effective to help achieve your rehab goals.
For example, this may include different forms of squats, and while that seems counter productive if it was previously painful to perform squats, strengthening and working on form under the supervision of a physical therapist can provide a means to build tolerance to those previously aggravating movement patterns.
For those with severe knee osteoarthritis that have a lot of trouble participating in exercise-based rehab due to pain, some medical interventions like cortisone injections, hyaluronic acid injections, or topical anti-inflammatories may be prescribed by a physician to assist in relieving pain, but this is usually only if necessary.
Knee replacements represent a last resort for treating severe knee osteoarthritis; however, exercise-based rehab is just as important, if not more important, to prioritize after a knee replacement, so it’s not always the quick fix most people imagine.
Summary
There are many different injuries and conditions that can cause knee pain when squatting or bending the knee. The injuries and conditions listed above simply represent some of the more common presentations we see in the clinic.
We always recommend checkin in with your local physical therapist for advice specific to your current condition and goals. This will help ensure a safe and effective approach to treatment, which will improve your recovery in the long run.
References
Everhart, J. S., Cole, D., Sojka, J. H., Higgins, J. D., Magnussen, R. A., Schmitt, L. C., & Flanigan, D. C. (2017). Treatment options for patellar tendinopathy: a systematic review. Arthroscopy: The Journal of Arthroscopic & Related Surgery, 33(4), 861-872.
Ferreira, D. C., da Silva, R. A., Zamboti, C. L., Pesenti, F. B., Mazzer, L. P., & Macedo, C. D. S. G. (2023). McConnell patelar taping improves unipodal squat postural control in women with patellofemoral pain syndrome: A randomised trial. Journal of Bodywork and Movement Therapies.
Glaviano, N. R., & Saliba, S. (2022). Differences in gluteal and quadriceps muscle activation during weight-bearing exercises between female subjects with and without patellofemoral pain. Journal of Strength and Conditioning Research, 36(1), 55-62.
Li, J., Zhu, W., Gao, X., & Li, X. (2020). Comparison of arthroscopic partial meniscectomy to physical therapy following degenerative meniscus tears: a systematic review and meta-analysis. BioMed Research International, 2020.
Pereira, P. M., Baptista, J. S., Conceição, F., Duarte, J., Ferraz, J., & Costa, J. T. (2022). Patellofemoral pain syndrome risk associated with squats: A systematic review. International Journal of Environmental Research and Public Health, 19(15), 9241.
Poacher, E., & Thompson, J. (2023). The effectiveness of shockwave therapy to improve pain and symptom severity in patients with chronic patellar tendinopathy: a literature review. International Journal of Therapy And Rehabilitation, 30(12), 1-13.
Raposo, F., Ramos, M., & Lúcia Cruz, A. (2021). Effects of exercise on knee osteoarthritis: A systematic review. Musculoskeletal care, 19(4), 399-435.
Rosso, F., Bonasia, D. E., Cottino, U., Dettoni, F., Bruzzone, M., & Rossi, R. (2015). Patellar tendon: From tendinopathy to rupture. Asia-Pacific journal of sports medicine, arthroscopy, rehabilitation and technology, 2(4), 99-107.
Disclaimer:
The content here is designed for information & education purposes only and is not intended for medical advice.