Wednesday, May 25, 2011

Understanding Compression When Squatting

Every time I receive a new batch of students to instruct in my personal trainer courses at the local community college, I always throw up this image of 3 squats and ask them the same loaded question: Which squat is being performed incorrectly?

Before I reveal the students' answer, let me explain to you that most of these students are "fresh" into the fitness world and are looking to achieve a basic certification. Every time I shine this image on my power-point,  the answer I get is "all three are wrong/incorrect". When I ask why, the number one response is:

"Because the knees goes over the toes".

Incredible. I find it even more incredulous that this myth is still alive in the minds of many incoming fitness fanatics. When I uncover to the class that all three squats depicted in the image are actually ALL CORRECT--they are flabbergasted! It sort of hits them like elbow drop from "Macho Man" Randy Savage that saves us all from the Rapture.

The truth is, the three squats above are actually 3 different types of squat techniques. The first squat is a front squat,  the second squat is a "bodybuilder's squat", and the third is a "power-lifter's" squat. Each has its own technical differences that make it unique to the person executing it and it's intended goal.

But why does the public still believe that squatting with knees projecting past the toes is a bad thing? It's a myth that began years ago around Step Aerobic and Jazzercise circles and has stuck around for years. Without getting into a discussion on knee tracking under loads coupled with sheer force, how can we understand this myth in simplistic terms? Easy...and I will do my best.

When we think in terms of squatting, many visualize the squat as a one-dimensional movement pattern that resembles a folding lawn chair.
Those that visualize the movement like this do not take into account 3 things:
1.) Path of Motion
2.) Sequential Pattern of Movement
3.) Displacement of Body Mass during Path of Motion

A folding lawn chair is somewhat "robotic" if you will. All the parts are moving in a one plane of motion. There is no "give and take" in a lawn chair metal frame. The only "give and take" is within the lawn chair fabric. The human body differs from this analogy. The human body actually has a little more "give and take" when it comes to movement patterns in the form of compensations. When the body senses a heavy load or sudden changes in its environment; or needs to adjust because of an obstacle, collision, or change in direction--it does so through compensatory means. In corrective exercise,  we think of compensation as bad things or things that we need to address when working with the musculature of the body. This is true...however,  the body is a fascinating machine that uses compensations to execute whenever the brain tells it. Let's go back to the squat. Most people can either squat flawlessly (although I haven't seen many), can squat with some compensation, or simply cannot squat at all. When the knees project over the toes it is a compensation that reveals that  body mass  has been displaced. And that displacement is caused by a heavy load on one's back.

For instance, in order to avoid our knees translating past our toes when we walk up stairs, we would have to keep our torso completely erect with each step. This is un-natural and not an automatic mass displacement. Our bodies need to regulate its center of mass/gravity during any activity.
We walk with our torso leading towards the locomotive direction. The human body compensates because of the environment it is forced to move in (steps), and the constant displacement of mass (taking the stairs with or without holding objects)--including the measure of speed. I am sure you probably want to see some elaborate formula, right? 

So the squat is not a one dimensional movement pattern that resembles a lawn chair. The squat resembles more of a compression--whereas the body is compressed between the ground and the load.

And during the squat movement, the body DOES compensate because of this unique "vice grip". Does this mean that this is acceptable in weak, unhealthy individuals that have not progressed adequately in the loaded squat? No. This spring-like compression is produced through a system of levers that vary in function, tension, and strength. In order to safely compress during a squat, you must have adequate tissue quality, mobility, and flexibility.

The "knees over the toes" myth is a great example of compression during a squat. The problem lies in that we believe that sheer forces only travel down femurs [as in a waterfall] causing harm to the patella and quadriceps tendon. However, because of this compression, sheer forces disperse and are "absorbed" by the antagonistic muscles--mainly glutes and hamstrings--providing that the squat technique is coached and executed correctly.


  1. Why then do so many experience pain when the knees travel beyond the toes and no pain when they don't ?


  2. very useful info here, thanks!! i love having myths disproven with sound logic and biomechanics!! the picture is great too, I didn't realize how much bar position affects upper body lean (which I tend to have too much of)

  3. Anonymous,
    That's because when the knee doesn't travel ahead of the toe, the person is forced to sit back into the hips. Sitting back into the hips takes pressure off the knees and puts an emphasis on the posterior chain.
    John is technically correct on this but IME if you teach the squat like this, people will just initiate the movement with the knees. Every....single....time. Getting clients to sit back into the hip is very important IMO so I don't let the knee go over the toe until their hip mechanics are good.

  4. People experiencing pain from the knees traveling over the toes likely have other underlying pathologies that lead to that particular pain.

    As far as squatting without hip movement, it isn't possible if a decent depth is achieved. If you initiate the movement with ankle dorsiflexion/knee flexion you will not get very far. Most people respond well to the cue of sitting back in a chair.


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