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Is it Safe to Squat with Your Knees Over Your Toes?


If I had a dollar for the number of conversations I’ve had with clients over the last 20 years about the safety of the "knees over toes" squat position, I’d be a very wealthy woman. Seriously.


In the 90s, while in physical therapy school, I was taught several “squatting rules,” including “keep your knees directly over your ankles,” “never let your knees cross over your toes,” “keep your hips at knee level or above” and “never let your knees fall inward.” I hung on to these mantras for at least the first decade of my career.


Funny as it seems, I vividly remember the first time this learned philosophy was challenged. I was participating in a Cross Fit class. The coach encouraged me to lower my hips below my knees, therefore, allowing my knees to go over my toes. I was immediately defiant and refused to do so. The PT in me “knew better.” I kept up this stubborn attitude for years and squatted how I knew I was supposed to.


As I grew up and became less cocky, more open-minded, and more respectful of varying viewpoints, I began listening to those professionals doing the “knees over toes” squat. It made sense to me when someone brilliantly pointed out that our knees cross over our toes naturally during several life activities. Climbing stairs, picking something up from the floor, getting in/out of a lower vehicle, and coming up from the floor - to name a few. Why in the world would we restrict this motion when we are strength training? Isn’t the gym the place to teach our body how to get stronger so we can do life easier?


However, I still wondered why it was engrained in medical professionals to avoid this supposedly provocative position. Leaning on my experience as a PT, the various continuing education courses I’ve taken, and my research, I’ve discovered that, like everything, the recommendation to move your knees over your toes varies for every individual.


What Happens During the Knees Over Toes Squat?

When you squat, your joints' compressive and shearing forces change depending on the knee flexion angle. These forces impact the soft tissue structures within your knee at different depths of the squat. Therefore, depending on your knee condition, how low you squat may matter.


The following image depicts which structures are stressed at the various angle of knee flexion:



Image Credit to Aaron Swanson


Generally speaking, the deeper you squat and the further your knees go over your toes, the larger the compressive forces. Shear forces are greatest at 90 and above. Therefore, depending on your knee condition, the recommendation to deep squat will vary from person to person.


What does the research say?

Several studies discuss this knees-over-toes topic, and, as typical, they vary in their conclusions pending on what result they were after. According to this 2013 study that reviewed over 164 articles on the topic, they agreed with the above image that the highest compressive forces behind the knee occur at 90 degrees of knee flexion. However, they have found that the impact of these compressive forces actually decreases as you lower your hips and bend your knees further. This is due to the “wrapping effect” of the hamstrings against the calves.


Furthermore, when comparing a restrictive squat (one that avoids moving your knees past your toes) to a deep squat, this 2013 study found that a deeper squat reduces the stress in your lower back. Therefore, they concluded that the unrestricted squat might be the best option for most people and that practitioners should not be overly strict in coaching against anterior knee displacement during the squat performance.


Another study performed in 2015 concluded that both the ankle and hip joints require adequate range of motion and strength to perform a deep squat safely while preventing injury.


Who Should Avoid a Deep Squat?

Although it is becoming clearer that the research over the past decade generally favors deep squats, some scenarios still indicate careful consideration and occasional avoidance of this position.


Patellar Tendinopathy

You may have patellar tendinopathy if you currently suffer from persistent pain along the front of your knee that is worse with movement. Your patellar tendon undergoes increased compressive forces as you approach 90 degrees or more during a squat. It is important to reduce these forces while rehabbing this tendon. Please note that once this tendon heals, it is critical that deep squats are reintroduced for maximal resiliency and performance.


Femoral Acetabular Impingement (FAI)

This is a condition within the hip joint where the bony surfaces and related soft tissue structures get pinched. FAI occurs for several reasons, including structural abnormalities and core and gluteal weakness. If you suffer from FAI, you must understand the reason why to determine if deep squats need to be avoided. Oftentimes, small adjustments to stance and foot position combined with muscle activation and posture can enable you to successfully and comfortably perform a deep squat despite this condition.


Total Knee Joint Replacement

This 2021 study concludes the ability to squat after a knee replacement highly depends on how well you can squat before surgery and the surgical technique. You should discuss this before surgery, enabling the surgeon to know your goals and best prepare you for your anticipated outcome. Although squatting deeply after a knee replacement is often a challenge, it is not guaranteed to be avoided.


Can a Deep Squat Cause a Meniscal Tear?

This is a tricky one because many of the studies, like THIS one from 2021, only look at the forces on the meniscus from 0-90 degrees of flexion. It states that as flexion increases, the stress on the meniscus also increases. It does not mention what happens if you bend below 90 degrees. One may assume that bending further would be more detrimental; however, as noted in several of the aforementioned studies, this is not always the case.


What we do know for sure is that the menisci are under the greatest stress when your knee is twisting or angled inward while under load. Therefore maintaining good form by using your glutes, pushing your knees outward, and staying under control are good principles to keep in mind to avoid a meniscus injury.


Is it Bad to Squat with Knee Arthritis?

This is one of the most common questions we get at Juniper Physical Therapy & Fitness. Our clients with arthritis are often fearful that deep squats will make their arthritis worse.


First of all, the degree of arthritis varies from one person to the next. Secondly, just because an x-ray indicated degenerative arthritis, it does not mean that the discomfort one feels during a squat is because of that arthritis. Knee pain during squats can be related to tightness in nearby tissues or joints. Deep squats are essential for life and should be attempted if possible.


This 2013 study found that there are no concerns about the apparent high risk for osteoarthritis during the performance of deep squats. However, proper technique and progressive training loads are critical for injury prevention and effective strength building.


Bottomline

Deep squats that enable your knees to cross over your toes are good for you - if your knees are already in good shape. This movement is essential for life as we often do things that require our knees to move in this way. If your knees feel good, do not be afraid to add this movement to your workout routine. It is important, however, that you maintain good control and avoid sudden twisting under load. It is also a good idea to use your hips and glutes to reduce the amount of knee “valgus,” or inward caving of the knee while squatting.


If you have a history of injury, have had your knee replaced, or are currently suffering from patellar tendinopathy, or a case of FAI, it is a good idea to discuss deep squats with a qualified health professional. At Juniper Physical Therapy & Fitness, we are experts at this sort of thing and would be happy to guide you.

 

If you are interested in having one of our physical therapists help you determine if a deep squat is something you should do, reach out to us at (920)320-9838 or email us at hello@juniperpt.com.


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