The squat probably gets more of a bad rap than any other strength training movement, especially the barbell back squat. Many people choose the leg press machine instead, blaming the squat on their knee or low back injuries. Others will only perform partial squats, fearing injury if they go too deep. Avoiding injury is always good, but avoiding the squat is like refusing to walk because you’ve seen other people trip and fall on the sidewalk. Millions of professional and amateur athletes around the world somehow manage to squat regularly without hurting themselves.
The fact that a properly performed squat is inherently safe has been presented many, many times by others who are much more qualified than I am. In spite of this, the misconceptions persist, so I believe that the available evidence bears repeating. This article will deconstruct what may be the three most common squatting myths: Squatting below parallel is bad for your knees, your knees should never go past your toes and squatting is bad for your back. I will also present two very basic guidelines that should keep just about anyone injury-free when squatting.
Myth #1: Squatting below parallel is bad for your knees
Despite the ability of the knee joint to provide an average of 140 degrees of flexion, the idea has been promoted that knee flexion should be limited to 90 degrees during a squat. This myth can be traced back, at least in part, to a single study published in 1961 by Dr. Karl Klein at the University of Texas. Dr. Klein determined that a group of competitive weightlifters displayed greater laxity at the knee joint than a group of non-lifters, and issued a blanket recommendation against squatting below parallel. The study was of very low quality, though, and Dr. Klein was seeking to validate his bias against squatting below parallel. Somehow, this erroneous belief was adopted by the general population and has remained standard dogma ever since, even though it’s been disproven many times over.
Powerlifters squatting double their body weight, to depths of 130 degrees of knee flexion, have been shown in studies to have more stable knee joints than individuals who do not squat. In fact, separate studies have revealed that the knees of those who regularly squat deep are more stable than distance runners and basketball players! In one study of female volleyball players, researchers concluded that there was no statistically significant increase in peak forces at the knee when squatting to depths of 70, 90, and 110 degrees of knee flexion. Yet another study showed that forces on the ACL are reduced as the knee is flexed beyond 60 degrees, and forces on the PCL are reduced as the knee flexes past 120 degrees. Still further studies show that powerlifters who are squatting over twice their body weight experience shearing forces on the knee that approximate only 25% of the maximal tensile strength of the ACL, and 50% of the maximum strength of the PCL.
Obviously, this doesn’t mean that just anyone should attempt to squat with a load equaling twice their body weight on their back. While those feats clearly demonstrate what the human knee is capable of, the important point is that forces on the knee are actually reduced as squatting depth progresses beyond parallel. How deep should you go, then? Well, once you are able to drop below parallel, meaning that the crease at the top of your hips is below the top of your knees, then you should only squat as deep as you can without losing form. If your lower back starts to round, that’s your stopping point. And if you can’t squat below parallel without rounding your lower back, then don’t increase the resistance until you can. It’s also worth mentioning that you should utilize a stance that allows you to squat between your legs and not on top of them, because pressing the hips directly against the calves under a heavy load can create a dislocating effect on the knee.
Squatting below parallel has the additional benefit of significantly increased activation of the gluteal muscles. The deeper you squat, the greater the glute activation. Whether you’re seeking to improve your performance or your appearance, you’re not doing yourself any favors by leaving the glutes out of the picture.
Myth #2: Your knees should never go past your toes
This one is about as mythical as you can get, as it’s hard to find much information at all regarding it’s origin. Search online and what you will find are numerous references to one study from 1978 at Duke University which found that keeping the lower leg as vertical as possible reduced shearing forces on the knee. I wasn’t able to find the actual paper and there’s no available explanation I’m aware of as to why those researchers believed the knee was incapable of sustaining those forces, or how they performed their study. Whether this is the actual origin of the myth or not, an obscure study with zero supporting evidence is hardly any basis for providing any legitimate rules about squatting.
There was one study conducted in 2003 that essentially recreated this scenario by having experienced weight lifters squat under two conditions. First they squatted normally, allowing their knees to travel forward past their toes. Then, they repeated the movement while restricting forward movement of the knees beyond the toes. This reduced torque at the knee by about 22%, and it also increased torque at the hips by over 1000%. (What appears to be a disproportionate redistribution of forces can be explained by a change in torso angle.) This shows that you can reduce torque at the knee by preventing them from going past the toes, but it doesn’t prove that this is necessary. Interestingly, it appears that letting the knees travel past the toes was part of the “normal” method of squatting for those experienced lifters, and the prevention of forward movement of the knees was accomplished by artificial means. In either case, the volunteers in the study seemed to be fully capable of handling the load without incident or injury.
This shouldn’t be surprising, because your knees go past your toes all the time when you run, jump, walk, sit down, and stand up. This is made possible in part by the natural dorsiflexion range of motion at the ankle. Furthermore, when your knee is flexed, some tension is removed from the gastrocnemius muscle at the knee joint. This allows the ankle to dorsiflex through a greater range of motion than when the knee is fully extended, and permits movement of the knee over and past the toes. Why, all of a sudden, will your knees get blown out if they go past your toes during a squat? It’s amazing how our bodies work but it’s a shame that some people remain so unaware of its capabilities.
The actual distance your knees will travel is dependent upon which type of squat you’re doing, as well as your body proportions. Are you doing front squats? Your knees are definitely going over your toes, no matter what. If they don’t, you’re doing them wrong. Do you have long femurs? Your knees will go further over your toes than an individual with shorter femurs, regardless of which type of squat you do. Are you doing split squats? In that case, your front knee may not go beyond the toes at all, but your back knee will travel well past the toes on that respective leg. Are you doing a back squat? As long as you push your hips back into the squat appropriately, and stay balanced on your midfoot throughout the movement, it doesn’t matter where your knees end up. Let them travel as far forward as they need to.
Myth #3: Squats are bad for your back
This is like saying food makes you fat. The idea that squats will hurt your back gets perpetuated by people who perform squats incorrectly, and sometimes by woefully misinformed professionals who claim to know what they are talking about. A recent article posted on Journal Sentinal Online titled, in part, “Squat lifts likely cause of stress fractures in young athletes” claims that performing squats with good form puts the spine at risk of injury, based on a new study. The main problem with the study they reference is that the researchers don’t know how to properly perform a squat. The pars fracture cited as the predominant injury risk is typically an overuse injury involving hyperextension of the spine, and the increase in “sacral slope” they measured is another indication of hyperextension.
By contrast, the goal in any squat should be to maintain a neutral spine. If there is hyperextension of the spine, then the squat is not being performed correctly. Furthermore, as the weight gets heavy in a squat, the challenge is to resist excessive spinal flexion, not extension. It’s much more common to observe a lifter who is rounding their back when squatting, even when lighter loads are being used. This error can easily be corrected by learning proper form and using a manageable resistance. That study and related article fail on such a massive scale, yet the faulty arguments still have the potential to exert undue influence on the general public for many years to come.
Other concerns focus on spinal compression in the squat, and again with the back squat usually being singled out. Some individuals will assert that placing a load on the back is an unnatural movement that should be avoided. The truth is, the human spine is very capable of handling compressive forces. The trick is to load the spine without creating excessive shear, which can be accomplished by keeping the torso as upright as possible (and practical, considering which squatting variation is being used), as well as by keeping the spine in neutral. The ability to maintain an erect torso with a neutral spine will be the limiting factor in the squat for most people. This need not be interpreted as a reason to avoid the squat, though. It simply requires that more attention be given to proper form instead of the amount of weight being lifted. If squats hurt your back and you haven’t had a recent injury or chronic pain issue, then you need to fix your squat. My suggestion is to seek advice from someone who knows how to squat!
Safe squatting and mythbusting basics
Can I promise that no one will ever get hurt doing squats? Well, no, there are no absolute guarantees, and freak accidents do happen. Even the idea that you won’t get hurt if you’re bigger and stronger sounds nice in theory, but in reality it’s impossible to predict and/or protect against all injuries. You can be sure, however, that when you squat correctly, your chance of injury will be very, very slim. Properly supervised weight training has been shown to have an extremely low risk of injury, lower than soccer, rugby, basketball, football, gymnastics, tennis, and even badminton. This may seem surprising or even hard to believe, especially if you’ve gotten hurt while lifting weights, but it makes sense if you understand that weight training can and should be performed in a much more controlled environment, absent the chaos and unpredictability inherent to many sports. Weight lifting injuries can be avoided 99.99% of the time.
There are two basic tips that will help you squat safely and I’ve already referred to them in this article. The first is to squat with proper form, simple as that. Admittedly, the squat can be a tricky movement to master, especially the back squat. How do you know if your form is good? The video in my previous post about Hip Drive should give you a good idea of how a squat should look, comparing three different squat variations. If anything hurts when you squat or the movement feels awkward or imbalanced, those are good indications that you’re doing something wrong or using too much weight. And very importantly, if your lower back is rounding at the bottom of your squat, that is an issue that needs to be addressed before you start adding more weight. I explain how to do this in my post about maintaining a neutral spine in the squat. Take whatever time is necessary to learn proper form.
The second tip is to squat within your limits, adding resistance conservatively. This will allow your body to recover and adapt, a concept that is completely ignored when you read or hear about the supposed dangers of squatting. Amazingly, your body will adapt to the demands placed upon it, as long as you don’t exceed its current ability or its capacity for recovery. Usually, this is more of an issue with men, for whom its tempting to add 50, 75, or 100 lbs. at a time to the bar in an attempt to force progress or prove their masculinity. (Women typically go in the opposite direction, hesitating to add much weight at all out of an irrational fear of getting big and bulky and losing their femininity, another stubborn myth that has no basis in reality.) A good way to avoid this mentality is to approach each squatting session as an opportunity to practice the squat, rather than a chance to show off how much weight you can lift. That’s a bonus tip: keep your ego in check.
Squats are a skill like any other movement, and many of us have been out of practice for a long time. It can be difficult to learn (or re-learn) how to squat and labeling them as dangerous provides a convenient excuse for omitting them from a workout program. You don’t have to be that person who always looks for the easy way out! As long as you’re willing to make the effort required to learn how to squat correctly and patiently allow your body to adapt, you’ll be rewarded by making consistent progress with minimal injury risk. On a personal note, I’ve had numerous people over the years warn me that I was going to destroy my knees from deep squatting. Well, I’ve been squatting well below parallel for the last ten years and I’ve never had an injury. I’ve also never had a client who I couldn’t train to perform some variation of a deep squat, even those with previous back or knee injuries, or both. They squat with skill and confidence, undeterred by unsubstantiated myths, and you can too.
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