Welcome back to Squat University. Last week we discussed the myth that squatting deep is dangerous for the knees. After looking into what actually happens at the knee joint we were able to debunk this misconception. Healthy athletes can perform the squat to full depth without worrying about hurting their knees given proper training methods. We should all feel free to squat ass-to-grass as long as correct technique is used and we don’t max out every day.
Today I want to tackle another common myth of the squat. There is a strong held belief by many that the knees should never go over the toes when squatting.
Just last week, I was guest lecturing to a class of physical therapy students at the University of Missouri. I asked a simple question, “How many people here think we should never have our knees go past the toes while squatting? Following my inquiry, every single student held their hand raised. The next thing I said was, “You’re all wrong.”
No one is certain where this myth started. However, it has become a mainstay in today’s fitness and medical world. The instruction is even a part of the National Strength and Conditioning Associations (NSCA) guidelines for how to teach a proper squat (1).
Yet, is it really all that dangerous? For over 10 years I have had the opportunity to watch and compete on the same platform with some of the best weightlifters in the United States. To lift the most amount of weight during the clean a weightlifter must catch the barbell in a deep squat position. In order to remain upright with the bar secured on the chest, the knees of many lifters will move past their toes. Are these weightlifters putting their knees in harms-way every time they lift the barbell?
Knees over Toes?
The cue to limit the knees from moving past the toes during the squat is really nothing more than a quick fix to a deeper problem. In hindsight the originators of the cue were likely well-intentioned strength coaches or physical therapists.
When an athlete squats poorly, they often move from their ankles first. As the ankles move it causes the knees to hinge forward. The weight of the body is then shifted forward on to the balls of the feet. This type of movement problem has been called the “knees first” approach. Moving in this way leads to greater shear forces on the knee joint and contributes to increased risk of injury and eventually to pain (2).
To many individuals, this issue would appear to be a problem of the knee. Athletes who squat poorly by moving their knees forward often develop pain. Therefore limiting this forward movement solves the problem…right? However, limiting the knees from moving only addresses the symptoms of a bigger problem.
The issue is actually with balance. The knee is only a hinge joint. It will only move forward based on what goes on at the ankle and hip. Instead of focusing so much on what is going on at the knee, we should really be focusing in on the hip and ankle joint when we squat.
One of the absolutes of squatting is that our center of gravity must remain over the middle of our foot. This allows our body to remain balanced and work efficiently to produce strength and power. During a bodyweight squat our center of gravity is located around our belly button. When weight training, the barbell now becomes our center of gravity. The efficiency of our movement is dictated by how well we can maintain this weight over the middle of our foot.
When the knees hinge forward early in the squat the athlete’s center of gravity is shifted forward onto the balls of their feet. Therefore the cue to limit the knees from moving forward is actually correcting for a weight shift problem. It has little to do with the knee joint itself and more to do with ensuring the athlete stays balanced.
Sitting Back in the Squat
So how do we correct for moving from the ankles first? The cue to “sit back” or to “push the hips back” allows the athlete to move from their hips first instead of their ankles during the descent of the squat. This engages the powerhouse of our body (the posterior chain). Doing so also limits pre-mature forward movement of the knees. This allows the athletes center of gravity to remain over the middle of their foot.
However, the cue to limit the knees from moving forward only works to a point. In order to reach full depth in the squat there comes a time when the knees must eventually move forward. The deeper we squat, the more our knees will have to move forward in order to remain balanced. This concept can be hard to understand for many in the medical community. Let me explain.
In order to reach full depth in the squat, the hips must eventually be pulled under the torso. This allows us to remain balanced and keep our chest upright. Because the knee is a hinge joint that moves based on what happens at the hip and ankle, it will be forced forward at this point.
It is very normal for athletes to have their knees move forward even past their toes. It all comes down to weight distribution and the ability to maintain our center of gravity over the middle of our foot.
We should be concerned on when the knees more forward past the toes, not if.
The Barbell Squats
In the sport of powerlifting, athletes will commonly use a low-bar back squat technique. This position secures the bar further down on the back over the middle of the shoulder blade (scapula). The athlete will use the “hips back” approach during the squat with an inclined trunk position in order for the bar to remain balanced over the middle of the foot. This allows the majority of the weight to be hoisted through the strength of the hips and minimal forward movement of the knees (5). Because our hips are extremely strong, athletes use this technique to lift over 1,000 lbs!
However, this squat technique can only descend to a certain point. If an “ass-to-grass” squat were to be attempted with the low-bar back squat, the athlete would eventually fold in half like an accordion!
In the sport of weightlifting athletes will commonly use the high-bar back squat, front squat and overhead squat techniques. These barbell movements resemble the positions an athlete will use during the competition lifts of the snatch and clean & jerk. These lifts require a more balanced approach between the hips and knees in order to maintain an upright trunk. Athletes must descend as deep as possible in order to effectively lift tremendous weights.
By allowing the knees to eventually move forward, the weightlifter can descend into a deep clean or snatch without falling forward. For this reason, the weightlifter cannot perform the front squat like the low-bar technique of the powerlifter.
While shear forces have been shown to increase in the deep squat position with forward knees, the body can handle them appropriately without risk for injury (2). If done properly with a “hip first” approach, the knees going past the toes is not only safe but necessary.
The next time you watch someone squat, focus on what joint moves first. Someone who moves poorly will move with a “knees first” approach. On the other hand an athlete who moves with good technique will move with the hips back first.
Science has shown that the knees of healthy athletes are relatively safe in the bottom of a deep squat (2,6). There is no denying this research. As long as excessive loading is limited and good technique is used, the knees CAN and MUST move past the toes in the bottom of a squat in order to allow the hips to drop fully.
Strength coach Michael Boyle once wrote: “The question is not where does the knee go, as much as where is the weight distributed and what joint moves first” (3). Remember, the knee is only a hinge joint. As long as it is kept stable (in line with the feet) we should not worry about them. Proper squatting is all about moving at the hips first and staying balanced. The rest takes care of itself.
Until next time,