What is Supination? Understanding Your Feet

As runners we’re almost obsessive about improvement. Improving our diets, improving our training, improving our gear and even improving our mindsets. This is all based on the need to be better, to get the edge over competition. Now there is merit to this madness, as nine out of ten of us are competitive at heart.

And yes I know, you run for the freedom it brings, you run for your mental health, the runner’s high etc. All these points hold true, but only until you and your mates start comparing splits and PBs. And all of a sudden our motivation to run becomes deeply routed into our motivation to perform. A deep rooted desire to be better, to run faster and further.

Therefore, in this series of articles we’re going to take a deep dive into one specific facet of running that I, from personal experience, know all too well. No, this aspect cannot be bought or measured with the latest smart watch or running app. In fact, it is something that most of us, if not all of us have in common - Our feet.

Not All Feet are Equal

Simply put, when it comes to our feet it is kind of a “luck of the draw” situation. We don’t get to choose how our feet work. And unfortunately, how our feet work (the biomechanics of our feet) plays such a crucial role in how we run and how we perform while we run. We don’t get to choose how they look, how big or small they are or even how narrow or broad our feet will be.

And unfortunately, all these aspects of our feet determine so much about our gait. That is why I want to zoom in on an area of our feet that is well documented, keenly studied and yet not easily understood - our gait.

Even more specifically the biomechanics of our feet.

What is Gait?

It is our goal today to simplify and breakdown the biomechanics of our feet, allowing us to educate you on how your gait works, how pronation and supination affect your running performance.

Gait is the scientific term used to describe our manner of walking or our walking style. Our gait refers to how our feet interact with the ground during walking or running. Our feet either pronate, supinate or in some cases overpronate when hitting the ground during our walking cycle or full stride.

Supination vs Pronation

Supination and pronation refer to the up or down orientation of the foot during gait. And the easiest way for you to understand and remember the difference between pronation and supination is how I remember it all the way back to my university days:

Supinate - Soup in your hand, and that is how the bridge of your foot is shaped during supination.
Pronate - Pour the soup out of your hand, and that is how the bridge of your foot is shaped during pronation.

It might sound a bit silly, but this memory trick has saved my behind in exams, more times than I’d care to admit. But anyway, it is also applicable to other parts of the body such as your palms/hands and forearms.

In essence, pronating feet are flat feet. Your arches collapse when they make contact with the ground. A supinating foot on the other hand maintains its structure when making contact with the ground. That is why supinating feet remain in their hollowed shape during gait. I.e. Maintain their arched form. But why? Why do feet supinate or pronate?

To answer that question we need to look at two factors. The intrinsic factors influencing your biomechanics such as your anatomy and body mass index and the extrinsic factors such activity profile, conditioning, postural habits etc. that may also determine how your feet end up developing.

Understanding the Intrinsic Factors Influencing Your Feet's Biomechanics

Anatomy of the Foot

There is a general consensus amongst orthopedic specialists that the hands, the wrists, the feet and the ankles are the most difficult joints to operate on. Why? In simple terms, there are so many bones that make up the joint. Not to mention all the tendons and ligaments and associated connective tissues. These joints are so intricate in the fact that they rely on so many levers, forces and loading patterns to operate optimally. And it is this sensitivity to different stimuli that make these joints so difficult to manage as doctors, therapists and coaches alike.

Now we’ve got to cover some basic anatomy and biomechanics, yes I know, but just breathe because this won’t be anything crazy. We’re just trying to give you a crash course in order to understand your feet. Sounds good?

Okay, let’s get going and cover some basic anatomy:

The Calcaneus - this is your heel bone.
The Talus - this the bone immediately above the calcaneus and is more commonly known as the ankle bone.

Let’s move on to some biomechanical terms:

Adduction - This is when you turn your whole foot towards the middle/midline of your body. I.e. Turning your foot inwards.
Abduction - This is when you turn your whole foot outwards away from the middle/midline of your body.
Inversion - When your foot is in a neutral position, lifting your big toe up from the ground and inward towards your midline, is inverting your foot.
Eversion - Is the opposite of inversion, driving your big toe into the ground while turning the rest of your foot outward away from your body.
Plantar flexion - Driving your foot downward and away from your body. I.e. Think of it as if you are pressing down the gas pedal of your car.
Dorsiflexion - Is the opposite of plantar flexion; pulling your foot toward your body. I.e. Lifting your feet off of the gas pedal.

Okay but what does this have to do with pronation and supination you ask? Well, let’s put it all together shall we.

Supination is the action where your heel bone (calcaneus) and the foot moves through inversion, adduction and plantar flexion while the ankle bone (talus) remains fixed in position.
Pronation is the action where your heel bone (calcaneus) and the foot moves through eversion, abduction and dorsiflexion while the ankle bone (talus) remains fixed in position.

Lower Limb Posture

Lower limb posture is a tricky one as most people have a very unique posture, affecting their gait. Lower limb posture usually affects the knee joints and their alignment. But the two most commonly seen postures affecting the lower limb are:

Valgus Posture - More commonly known as “knock-knees”, is a maligned posture of the lower legs. Valgus legs usually result in prone or overpronated feet. This is a direct result of the compromised leg angles caused by the valgus posture.
Varus Posture - More commonly known as “bow legs” this maligned posture is earmarked by the fact that your knees never make contact even when your feet are tight against each other. Again, this compromised posture results in supinated feet.

Weight and Loading and the Relationship With Our Feet

Weight or body mass index does play a significant role in our posture and subsequent biomechanics of our feet. This is much more evident in people that have been overweight or fall within the upper limits of the body mass index scale. Individuals that are or were overweight in their preadolescent and adolescent years, tend to have pronating or even overpronating foot posture. This isn’t always a given, but there is a definite correlation between obesity during the pre-adolescent stage and prone feet.

To Conclude

And that is why I had to give you a crash course in biomechanics and anatomy of our feet. Because in order for you to truly understand your feet you need to understand all of it. And that is not something you can digest in one bite. But luckily we’re here to break it down into bite size pieces. Not only for easier comprehension but also to make it interesting.

Because when information is delivered in a unique way it usually sticks with us. We are going to cover our feet, their biomechanics and everything else in between. So, bare with us as we put an interesting spin on a relatively uninspiring topic such as our feet.