Squat Form Deconstructed Part 2 – Ankle Mobility

Ankle Joint

Starting from the ground up, this installment in the Squat Form series will focus on the ankle. In order to squat well, you must have adequate mobility and stability at the ankle to create a stable base to work from. Lots of people I see who have trouble squatting lack these necessary prerequisites at the ankle. The good news is that building up your ankle mobility and stability for squatting will also help your performance in all sorts of other activities like walking, running, cycling, and surfing. Alright, let’s dig into it.

Bony Anatomy of the Ankle

The ankle joint, also known as the talocrural joint, is an articulation between three bones. These are the tibia, fibula, and talus. The tibia and fibula make up the lower part of your leg, while the talus is part of the foot. Check out the picture below for more detail.

Ankle Joint Anatomy



The tibia and fibula are held together by strong ligaments at the ankle joint, forming a bracket-shaped articular surface. This bracket is concave (caved in), while the top of the talus is convex (bulging out). More on this when we discuss biomechanics later on. If you’d like more detail on the talocrural joint, check this link.

Muscular Anatomy of the Ankle

There are many muscles that influence movement and stability at the ankle. When it comes to squatting, the two that contribute the most to the actual movement are the gastrocnemius and the soleus. These muscles make up the bulk of the muscle mass in the calf. The gastrocnemius is a large muscle that actually originates above the knee on the back of the femur (thigh bone). This means that it crosses both the ankle and the knee, contributing to motion at both joints. The soleus sits underneath the gastrocnemius, originating on the back of the tibia and fibula. Both of these muscles insert into the back of the heel via the achilles tendon. You can see them in the picture below.

Gastrocnemius and Soleus



When it comes to stability, the muscles of the peroneal group (longus, brevis, and tertius) and the tibialis posterior are significant contributors at the ankle. I won’t focus heavily on these here, but keep an eye out for my post on knee stability in the squat where I will discuss these in more detail.

I also want to quickly mention the tibialis anterior. Although it is not a primary mover in the squat, it is an integral part of training mobility for the ankle. The tibialis anterior originates on the tibia and inserts onto the top of the foot.

Tibialis Anterior



Squat Form – Ankle Biomechanics

Ankle Movement

Ankle dorsiflexion is the action of narrowing the angle between the top of the foot and the shin. In the squat, this occurs as the knee moves forward over the toes while lowering your hips toward the ground.

During the squat, ankle dorsiflexion is created primarily by the movement of other parts of your body and the relative position of the load you are lifting. The soleus is active in controlling the rate of dorsiflexion through its attachment on the back of the lower leg.

Ankle Dorsiflexion



On the way up, the soleus and gastrocnemius work together to create a plantarflexion moment at the ankle. This force assists in straightening your knee to push you back up to a standing position.

Ankle Plantarflexion



Ankle Mobility

During a squat, your ankle moves from a neutral position into a dorsiflexed position and back again. Since the ankle never moves into a plantarflexed position, limitations in plantarflexion mobility rarely influence one’s ability to squat. However, good squat form requires quite a bit of ankle dorsiflexion mobility. In fact, this is one of the most common limitations I see in people I work with.

Earlier in this article, I mentioned that the joint surface formed by the tibia and fibula is concave, while the upper surface of the talus is convex. This is important because of some basic rules of joint kinematics. Joints like the ankle joint include a primary movement and a secondary movement. The primary movement is a roll, the secondary (or accessory) movement is a slide.


Roll & Slide

As you can see in the image above, if you have roll without slide the joint surfaces separate as one essentially “rolls off” of the other. In order to maintain contact between the joint surfaces, there must be some compensatory “slide”. In this instance, since the fibula and tibia are moving on a fixed talus (because the foot is firmly planted on the ground), we have a concave surface moving on a convex surface. Whenever there is a concave surface moving on a convex surface, the “slide” of the moving surface is in the same direction as the “roll”. So, the tibia and fibula both “roll” and “slide” forward on the fixed talus. You can also describe this as the talus sliding backward relative to the tibia and fibula.

Confused yet? This can sometimes be a complicated concept, but it’s essential to understand when working on joint mobility. I’ll explain more when I go through suggestions for training. Check out this video if you’re more of a visual learner.

Ankle Mobility and Movement in the Squat

When you start a squat, you are in a standing position. Your ankle is in a relatively neutral position – neither plantarflexed or dorsiflexed. As you lower your hips into the squat, your knees move forward over the toes. This creates dorsiflexion at the ankle and limitations in dorsiflexion mobility will limit your ability to squat. As your ankle moves into dorsiflexion, there is some activity in the soleus to control the rate of dorsiflexion. Once you reach the bottom of the squat and start to come back up, your soleus and gastrocnemius both exert force pulling your lower leg backward. This backward force assists with straightening your knees to bring you back to standing as your ankles move from dorsiflexed back to neutral.

Mobility Routine

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How Do You Know if Ankle Mobility is Ruining Your Squat Form?

With so much movement happening at so many joints at the same time, it can be difficult to determine what is limiting your ability to squat. Luckily, there is a quick test that you can easily do at home to measure your ankle mobility. This test is the Knee-to-Wall Ankle Dorsiflexion test. All you need is a tape measure or ruler and a wall.

Place the ruler or tape measure on the floor so that the zero mark is touching the wall. Next, line up the tip of your longest toe with 5 inches or 12.7 centimeters. Then, push your knee forward toward the wall. The goal is to touch your knee to the wall without your heel lifting from the floor. The measurement listed above is considered normal.

If you are unable to touch your knee to the wall without your heel lifting up, your ankle dorsiflexion is limited enough to potentially prevent you from squatting with good form. Gradually scoot your foot forward until you are able to touch the wall with your knee while keeping your heel planted. Record the number at the tip of your longest toe. Repeat this test to track your progress over time. Check out this video to see the test in action.

How to Address Limited Ankle Dorsiflexion

The measurement on this test only tells you whether the motion is limited. In order to determine the necessary action, you must pay close attention to the location of restriction. If you feel restriction in the back of the calf, the restriction is primarily muscular and mobility efforts should focus on the soleus muscle. Conversely, restriction in the front of the ankle indicates a joint mobility limitation that must be addressed. Please note that if you have ANY PAIN please see a physical therapist before attempting to address the mobility limitations on your own. Pushing through pain during mobility work is not only ineffective, it is counterproductive and often results in a reduction in mobility rather than an increase.

If the restriction is in the muscle, I recommend going through some PAILs and RAILs from the FRC system. If you’d like to learn a bit more about this mobility technique, check out my other article here. You can find the specific exercise for ankle dorsiflexion mobility here. This is where the tibialis anterior comes into play. During the RAILs contraction, when you contract the muscle on the front of your shin, you are using the tibialis anterior. This is a crucial part of building ankle dorsiflexion mobility.

If the restriction is in the front of the ankle, I recommend going through some banded ankle dorsiflexion mobilizations. This one requires some equipment and a bit of set-up, but it is the best way I’ve found to work on ankle dorsiflexion mobility at home. You’ll find a video here. The only change I recommend is that you place your back foot on the band, rather than on the floor as in the video. This ensures the band stays below the joint line to properly direct the force into the foot. Check out the picture below to see what I mean.

Ankle Mobility for Squat Form



This banded exercise is effective because it creates relative backward slide of the talus with respect to the tibia and fibula. Thus, it works on the accessory mobility required for ankle dorsiflexion.

Squat Form – Wrapping up the Ankle

There you have it. That’s everything you need to know about the ankle joint during a squat. You now have a solid background on the involved anatomy, biomechanics, and strategies to address limitations. This obviously does not cover the full range of possible ankle issues that could limit your ability to squat. These are just the most common issues I have seen in my practice. Give these a shot and seek professional guidance if you find your mobility is not improving.

Again, I want to emphasize that there should be NO PAIN at all with any of the movements described in this article. If you do notice pain during the Knee-to-Wall test or either of the exercises, get yourself evaluated by a Doctor of Physical Therapy at Stoke.

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Health Advice Disclaimer

This article provides examples that are applicable to many, but not all people.  They are based on typical presentations seen in my personal clinical practice.  This information represents common findings in the population discussed, but can in no way take the place of professional evaluation and treatment by a licensed medical practitioner.  It is impossible to provide 100% accurate diagnosis or prognosis without a thorough physical examination and likewise the advice given for management or prevention of any injury cannot be deemed fully accurate in the absence of this examination. 

If you are currently experiencing any pain or injury, seek professional evaluation before undertaking this or any exercise program.  Ensure that you are medically cleared for exercise before undertaking any exercise program.  Significant injury risk may occur if you do not seek proper evaluation.  No guarantees of specific outcome are expressly made or implied in this article. 

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