Can The Knees Go Over The Toes? (Debunking Squat Myths)

Lu Front Squat

 

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?

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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).

Incorrect Squat "Knees First".png

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.

Balanced Squat Explination.png

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.

Correct Squat "Hips First".png

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.

Bodyweight Squat Transition.png

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.

Squat Balance Shot

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.

Take Away

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,

SquatBottom
Dr. Aaron Horschig, PT, DPT, CSCS, USAW

With

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Dr. Kevin Sonthana, PT, DPT, CSCS

 

Resources

1) Earle RW & Baechle TR. Essentials of Strength Training and Conditioning. Champaign, IL. Human Kinetics, 2008. Pp 250-351.

2) Schoenfeld BJ. Squatting kinematics and kinetics and their application to exercise performance. JSCR. 2010;24(12):3497-3506.

3) Boyle M. “Knees over toes?” Strengthcoach.com. Web. 25 Jan. 2016.

4) Fry AC, Chadwick Smith J, & Schilling BK. Effect of knee position on hip and knee torques during the barbell squat. JSCR. 2003; 17(4): 629-633

5) Swinton PA, Lloyd R, Keogh J WL et al. A biomechanical comparison of the traditional squat, powerlifting squat, and box squat. JSCR. 2012;26(7): 1805-1816.

6) Hartman H, Wirth K, & Klusemann M. Analysis of the load on the knee joint and vertebral column with changes in squatting depth and weight load. Sports Med. 2013;43:993-1008.

 

 

 

 

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22 thoughts on “Can The Knees Go Over The Toes? (Debunking Squat Myths)

  1. I agree with what you are saying but when one starts working out at 12 and continues to 53, one realizes that repetition injuries are painful and can be irreversible. When one has been working out that long and the knees travel outside certain boundaries (bad form): shoulders, toes etc. it can be very painful and difficult to move around for a few weeks (and I am only in my 50s). Lunges have the same issue with the back foot. You should hang around athletes that are older and have been doing this for decades. Check out Dave Drapers articles as 70 is a whole other ball game. All of us aren’t in our 20s and 30s and for some this is a marathon not a sprint.

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    1. Gonzalo it is always a marathon and never a sprint. I agree with you that repetition injuries can be paniful and irreversible. The most important thing I tell every one of my athletes (young and old) is that pain should never be pushed through. Pain is like our cars warning light. If we continue to drive (squat in this case) with pain, we will develop overuse injuries that will last a lifetime. For this reason, the knees over the toes debate must always come with the line “you should never squat through pain.” If this motto is upheld you should be able to squat late into life!

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  2. Aaron, very good article. I am participating in a trainers licence course of the german olympic sports federation. I had the assignment to demonstrate the (bodyweight) squat. When I mentioned that it is no problem for the knees to go over the toes in a deep position, there was an uproar with the teachers and students who already had experience assisting in group training. They told us, you should never go knees over toes, but no satifactory explanation was offered, it is just bad. And by the reaction you would think the knee is going to explode or something…
    So I started a research and among others came across your article. I also found the reason why the myth started in the first place.
    According to the authors of ‘Literaturbasierte Belastungsanalyse unterschiedlicher Kniebeugevarianten unter Berücksichtigung möglicher Überlastungsschäden und Anpassungseffekte ‘ https://www.bisp-surf.de/discovery/Record/PU201406005893, german language paper but an abstract in engish…well according to them it all started with ‘Ariel B.G. (1974): Biomechanical analysis of the knee joint during deep
    knee bends with heavy loads. In: Biomechanics IV, Nelson R., Morehouse
    C. (eds.), University Park Press, Baltimore, pp. 44–52.’ http://www.arielnet.com/articles/show/adi-pub-01263/biomechanical-analysis-of-the-knee-joint-during-deep-knee-bends-with-heavy-load
    This is so ridiculous, that a study on 12 subjects and an article with the data of only 3 of those can have such a big impact on sports associations and federations world wide for 42 years.

    Achim

    Liked by 1 person

  3. This is such a relief, for years Iv’e been convinced I will never be able to do a squat properly and have really resented my inability to balance during a squat. Knowing I can safely put my knees over my feet means I can now add squatting to my workout routine with some understanding of the correct technique. Thankyou!

    Liked by 1 person

  4. Hi there, I have just had a full argument with a lecturer at Moray College about 30 minutes ago about this topic and I am a bit slow, so I just need to know is it a necessity for your knees to be above your toes? Thanks

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    1. Sam, during a squat that requires an upright trunk position (high bar, front squat or overhead squat) or even a clean or snatch movement, the knees MUST move past the toes in order to maintain that upright trunk and squat to the deepest position possible.

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  5. Thank you so much for this erudition. I have been teaching group exercise classes for a few years, and the basic instruction that I was given is that a squat is initiated from the hips but that the knees stay behind the toes. I recently did an squat in a boot camp class holding a weighted bar overhead and had a lot of trouble squatting deep but keeping my knees behind the toes. The trainer told me that I needed a much wider stance (presumably because of tight hips). I’m also a yoga teacher and my hips aren’t tight. So I have been obsessing about this for a while now, trying to figure out why I was having trouble with this movement. If I understand this correctly, the bar changes the center of gravity and the knees must come forward (along with the hips moving under the torso) in order to stay balanced.

    If someone is just doing a body weight squat or a squat with dumbbells on the shoulders or held at the side is it still ok for the knees to come forward if someone lacks mobility in the hips?

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