How Footwear Affects the Way We Move [Part 3 in The Case For Minimalist Footwear]

This article was originally published on May 29, 2009 at ADVENTUREinPROGRESS. It has been moved to this site so that all of my minimalist footwear articles exist in one place.

If you're following along with this series you might remember that in my last post I left at the point where I started to experiment with walking barefoot. My body was in pain from what I suspected was the footwear I was wearing and the way I was walking. In a last ditch effort (after doctors and orthotics failed) I decided to try a very natural but radical approach... going barefoot.

At first I started just walking around the house in bare feet, focusing on technique. It was almost like learning to walk again; consciously landing on my forefoot required focus and the usage of muscles that were very underdeveloped. I felt awkward, clumsy, and my feet and calves began to hurt. The difference this time was that the pain felt different - it kind of felt good. From my years of weight lifting experience I knew that kind of pain meant muscle building, not injury. I felt encouraged and I hoped that as my feet got stronger I would start to see results.

But what I wondered was how did my feet get so weak? After all I was using them every day! As it turns out the answer was in the very footwear I thought was helping my feet.

The upper portion of footwear (otherwise known as "uppers") constrain the feet. When barefoot - whether it be walking, running, or jumping - our toes spread and our foot expands and molds to the terrain. Shoes with narrow, stiff, or otherwise restricting uppers prevent this from happening and hence create instability. In addition to instability, restrictive uppers can cause the bones, joints, nerves and muscles to cram together (sometimes under great pressure) creating situations which can lead to injury. General foot pain, Morton's neuroma, hammer toes, and many other problems can usually be attributed to constrained feet.

Have you ever asked yourself why shoes have heels? When talking about athletic or casual shoes, the heels are often considered to be the primary area in which cushioning occurs. When talking about dress or fashion shoes, the heels are mostly there for looks. The real reason heels were invented was for horseback riding: to prevent the feet from slipping forward while in the stirrups. As with many things invented for a practical purpose, heels became a fashion, and after widespread adoption, a requirement. Now almost all shoes have a raised heel in some form or another and we don't think twice about it.

The interesting thing about heels is that they change the mechanics of how we move. In Part 2 of this series, I described the way that our feet were designed to work while moving: by landing on the ball of the foot and using touch, the flexibility of the joints, and the strength of the muscles to provide balance, shock absorption, and stability. When wearing footwear with an elevated heel, our body changes it's gait, causing us to land on our heel (heel striking) instead of the forefoot. This can be clearly seen in the following photos of my daughter on a treadmill:

Walking - note the heel-stike and straight leg.

Running - as with the walking, note the heel-stike and straight leg.

The first thing that can be seen from the above photos is that the leg is straight when impacting the ground, rather than bent as is the case when landing on the forefoot. As was described in Part two, bent joints are required for proper stability and shock absorption. When the leg is straight it is unable to provide the spring action required to absorb the force of impact. As a result that force is transferred straight up the leg to the hips and lower back (not unlike having a peg-leg). Since the hips and back weren't designed to function this way, the end result is a jarring stride that can lead to pain and excessive wear on these parts of the body. To make matters even worse when the knee is straight (think peg-leg again), the muscles surrounding the knee relax causing the knee to become unstable. The combination of the shock being transferred through the knee joint coupled with the instability due to relaxed muscles, creates a scenario where many different knee injuries are possible.

Footwear manufacturers realized that the shock caused by landing on the heel with a straight leg was a bad thing and decided to try to correct the problem. They did this by cushioning the bottom of shoes. The problem with this approach is threefold. First, there is no way that an inch of foam cushioning can compare to the natural cushioning created by flexing joints and muscles. Secondly, cushioning creates instability. Have you ever tried standing on a soft surface such as a mattress? It is difficult to balance, especially on one foot. Our body needs to feel a solid surface under our feet in order to balance correctly. Wearing shoes with cushioning makes it more difficult for our body to balance because the surface under the foot is not solid. Thirdly, cushioning reduces ground feel. When walking in cushioned shoes, our feet are unable to feel the ground. In fact, no matter where we walk, the ground feels the same to our body. We are unable to discern, through touch, if the terrain is soft, hard, pebbled, slippery, etc. This gives us a false sense of security, making us less cautious about how we are stepping.

Footwear manufacturers also realized that instability in our movement was a bad thing (those smart folks) and decided to try to correct the problem by firming up certain parts of the shoe. Rather than recognizing that an elevated heel and cushioning were likely causes of pain and injury, they decided to take the angle that it was due to having bad biomechanics and poor genetics. Manufacturers began to experiment with stiffening various regions of the shoe in an effort to try to straighten things out. This was eventually given the technical name "motion-control", and now comes in a variety of flavors depending on your gait. Because everyone's body is different, some people "require" shoes that prevent pronation, some require shoes to prevent supination, while others are ok with a neutral shoe. Of course since there is no standard by which to measure this, a person can never really know if the correction a shoe is attempting to apply to their body is adequate for them. More often than not, people will try all different brands, models, and styles of shoes in an effort to try to minimize pain. Many people, realizing that they will never find the perfect shoe will then begin to experiment with insoles in an attempt to further add stability and control. Sometimes people are lucky enough to find a combination that works well for their body and stick with it as long as they can. Most won't and will continue to suffer some form of pain.

Motion control systems are designed to work on a straight, flat surface such as a road or sidewalk. As soon as uneven terrain is added to the mix, then most motion control is not really much use since the ground under foot will have more of an affect on stability than density in the cushioning and foam. The primary way that footwear manufacturers attempt to increase stability on uneven ground (i.e. hiking) is through stiffer footwear. This is done by stiffening the cushioning, soles, uppers, and in some cases making the footwear extend up above the ankle to restrict ankle movement as well. The footwear essentially becomes like a cast: immobilizing the bones and joints, and causing the muscles to atrophy (the stiffer the footwear, the weaker the muscles become). When the joints in the foot are immobilized, shock and stresses normally dissipated by the flexible joints of the foot become concentrated in the ankle, knee, and hip. In the case where the ankle is immobilized as well, the majority of the stresses become concentrated in the knee and hip. Is it any wonder why the primary injuries sustained by hikers occur in the knee and lower back? Our legs and feet were designed such that all of the joints and muscles work together to share the burden of stability and shock absorption. The more we progressively restrict our feet, the more concentrated those forces become in the remaining joints.

Hard soles also reduce stability. When standing on an uneven surface with a stiff sole our foot is unable to mold to the terrain. When standing on something such as a rock (or the edge of a sidewalk or curb) our foot becomes like a teeter-totter, sitting on a very unstable point. Hard soles also contribute to a reduction in ground feel. Everything feels flat, which is not necessarily the best message to be sending the body. It gives us a false sense of security. Through the combination of cushioning and a hard sole, our body is lulled into believing that the ground is the same, no matter where we are walking. It will cause us to plant our feet with the same vigor no matter what the situation. Some times it will be ok, and other times it will be a mistake but we will have no way of knowing in advance until after the problem has occurred.

Hard soles - the foot is unable to mold to the terrain, creating instability.

Hard soles side view - again, the foot is unable to mold to the terrain, creating instability.

Recipe for injury - hard soles creat the potential for twisting ankles and knees.

So... back to my story. Healthy, natural movement requires strong, developed foot muscles, not over-engineered footwear. Footwear has changed the way we move such that it puts less of an emphasis on muscles and has us rely more on the stability, rigidity and cushioning of shoes. The less our muscles get used, the weaker they become. The weaker our muscles become, the more susceptible we become to injury and the more we depend on our shoes to try to fix it. It is a cycle that can only be broken by going with less rather than more. My feet and legs had gotten lazy and weak and those first days of going barefoot really showed it! The good news is that within a short period of time, as my muscles developed and my body adapted to new forms of movement things began to heal.

Other Articles in the Series

• Part 1 - My Journey to Discovery
• Part 2 - How We Move
• Part 4 - What Does the Research Show
• Part 5 - Selecting Minimalist Footwear
• Part 6 - Making the Transition