Proprioception: The ‘missing sense’

Last September, I was very lucky to be invited by Merrell to participate in the New York Barefoot Run.  The aim of the weekend was for a group of bloggers, sports doctors, shoe manufacturers, journalists and generally every one of my idols in the barefoot and minimalist running community to get together and talk about barefoot running.

Many topics were discussed and there were many ‘light-bulb’ moments, but the one comment I still remember was this:

“It is very rare that you get a group of runners together in a room that ALL know the meaning of the term proprioception”

Proprioception. Do you know what it means? Be honest.  Did you just use ‘Google’?

We all have seven senses. The first five are used daily to describe everything on the planet: Touch, Taste, Smell, Sight and Hearing. We also have two additional senses. These missing senses are rarely mentioned unless you are an occupational therapist. They are the proprioception sense and the vestibular sense. Barefoot runners spend a lot of time discussing proprioception.

According to the on-line dictionary, proprioception is defined as:

“The unconscious perception of movement and spatial orientation arising from stimuli within the body itself.”

Still confused?  Proprioception is how your body takes information from your muscles, joints, nerves and the balance functions in the ears and tells you where you are in the world.  In turn it creates your bodies instinctive reaction to the stimuli.  This is the sense that enables you to catch yourself when you slip on ice. It’s why we limp when we have an injury. It’s how we stand up straight.

So why do barefoot runners talk about proprioception so much?

Most of our proprioception is gained from the soles of our feet. For a barefoot or minimalist runner, it’s the sense that allows us to tread lightly when we run. This is how we are able to run barefoot or with no cushioning in our shoes.

Barefoot runners rely heavily on this sense. Without this sense we could force every step into the ground — we would break most of the bones in our feet in a matter of weeks.

The problem is that as soon as we cover the soles of our feet we lose the vital sense of proprioception. The more between the soles of our feet and the ground, the less proprioception we have. If you walk or run barefoot you have the maximum level of proprioception. If you have a conventional running shoe on your feet, you most likely have zero proprioception. Any covering on your feet, be it socks or minimalist shoes, will limit your level of proprioception.

The famous article by Dan Lieberman in Nature,  showed the impact forces between a runner in a conventional running shoe (with a heel strike) and a runner who was running barefoot (with a forefoot landing). I highlighted these two types of runners because these are the most common landings for the aforementioned runners.

The impact forces were less with the barefoot runner, but the amount of time the foot was in contact with the ground was also less.

To clarify, the study did show that a barefoot runner using a heel-strike had the most impact forces.  If you heel-strike as you run, you will need some cushioning.

The study didn’t show the impact forces with a runner in conventional shoes using a fore-foot strike, but I would take an educated guess and say, that the impact forces and duration would be less than a heel-striking runner in conventional shoes but more than a barefoot runner with a fore-foot landing.  As I have mentioned before in a previous article, good running form is important regardless what you have on your feet.

Why would the contact time and impact be less with the barefoot runner?

Some of this would be due to stride-length and cadence.  The main reason however, is that as soon as the barefoot runner landed, the foot sent signals to the brain telling it to “lift the foot”. This was immediate and wasn’t delayed by a rubber sole.

The heel of a running shoe allows you to run with a harder strike because it transfers the larger impact on landing over a larger period of time. This doesn’t necessarily mean that cushioning is a good thing – it may be minimizing the impact forces, but in a bizarre turn of events it is also creating larger impact forces due to the lack of proprioception.  Thus, negating the reason you have the cushioning in the first place.

So if you are a runner, you need to start examining a medical dictionary. You need to learn about proprioception, because if you ignore this sense and your bodies’ reaction to it, you are heading towards an injury.