Stack Height: Do You Need A Thick Sole?

What is Stack Height?

Stack Height is a term we use to describe the measurement between your foot and the ground in a shoe.

It includes the outsole, insole or insert or footbed, and everything in between.

Another way to describe it would be the measurement of how thick the shoe's sole is, or how much of a platform you're standing on. In a zero drop shoe, the stack height is equal in all areas of the sole.

There's a misconception that you're not wearing a minimal shoe or a minimal enough shoe if your shoes have a thicker stack height. But often it's the best choice to start with, and sometimes a thicker sole makes sense even for those who have been wearing minimal shoes for years!

Let's break it down so you know what to look for.

What's Your Baseline?

Your personal baseline will help you determine what kind of minimal shoes to start with based on what you're used to.

Often when people are buying a first pair of minimal shoes, they are used to wearing shoes that have arch support, lots of cushioning, an elevated heel, and a pretty tall stack height. If that's what you're used to, your feet may not be ready for a very barefoot feeling shoe yet. You will want to start with a thicker stack height to account for this.

Some folks starting out with minimal shoes are used to non-minimal shoes that are more thin soled, such as a ballet flat or canvas sneaker that would be minimal but for having a pointy toe box or tiny heel elevation. These customers may be more comfortable using a thin soled minimal shoe as a transition shoe, since they are already used to having a lot of feedback from the ground. It can really depend what you are used to!

What Stack Height Makes a Shoe Minimal?

Here's what defines a minimal shoe for us:

• zero drop (the heel is not raised above the toes)
• foot shaped (a wide toebox)
• flexible (allows for full range of motion)
• secure (so that you don't have to walk differently to keep them on your feet)

You'll notice that the list does not include any mention of a thin sole or ground feel.

Ideally those would be on the list, because being able to feel the ground through your shoes helps your brain get more information about the ground in order to navigate well. However, it's not part of our criteria because we want to offer you minimal shoes with a variety of stack heights to accommodate customers' various needs. How thick of a sole we recommend for you may even change over time.

In terms of trying to avoid the damage that "regular" shoes can cause, having a small amount of cushioning and a slightly thicker sole is really the least pressing concern: we're talking millimeters of difference here. A forgiving transition shoe helps you get used to all of the other changes first before introducing a barefoot feeling.

How Thick is Thick?

When we're talking about a thicker stack height, we're talking about shoes that have around 9-15mm between you and the ground. The material of a shoe's sole can also be a factor in how barefoot or how cushioned the shoe feels, so two shoes with the same stack height may feel different in terms of how much feedback you get from the ground while walking.

In general, we recommend that our customers who are just starting out with minimal shoes look for one with a medium to thick stack height, that 9-15mm range.  

When do Experienced Barefooters Want a Thicker Stack Height?

Other reasons you may want to look for a thicker stack height are activity and place specific uses.

If you are looking for a work shoe and your work has cement floors, we will recommend a thicker stack height. To paraphrase Katy Bowman, we can't forget about our environment: if you're trying to go as natural as possible in your movement by wearing minimal shoes, but where you are moving is not natural, then there's a disconnect.

Unnaturally hard surfaces like pavement may increase the impact you feel when walking over the course of a day, even with excellent barefoot style gait. So think about where you will be using your shoes and for how long when you are deciding what kind of stack height would suit you best.

Thin Soles

If and when you feel you are ready to start exploring a more barefoot feeling, you will be looking for a thinner stack height.

A thin to medium stack height range would be any sole that is up to 9mm thick, roughly. How this feels while walking can again depend on the materials.

A firmer sole material like harder rubber will feel less cushiony than a shoe with a gel-like or foam-like midsole material, even if they measure the same in stack height.

The Gait Connection

When people transition from "regular shoes" to minimal shoes, they often change the way they walk.

Most people wearing shoes with elevated heels have a gait that includes a "heel strike." This is when you land hard on your heel first, in every step. "Regular shoes" mask the discomfort you would feel if you walked this way barefoot, especially on hard surfaces like sidewalk.

To get a sense for this, try walking quickly on sidewalk barefoot (be careful!). People who are not used to walking barefoot often walk faster by taking longer steps, that is, they extend their legs way out in front of them and land hard on their heel.

Without the cushioned heel elevation of "normal shoes," this is going to feel very uncomfortable, and yet many of us walk this way all the time without realizing.

When you transition to minimal shoes, you unconsciously shift away from this pattern, as you no longer have an excess of cushioning to mask this discomfort.

A Barefoot Gait

It feels better to walk with a barefoot style gait when you are barefoot, and so you do it without thinking. A barefoot style gait allows your foot to absorb the impact the way it excels at!

When you are barefoot or wearing shoes that allow for you to feel the ground, you will walk with lighter footfalls, with a shorter more frequent step. The landing of each step is underneath the body, or at least your foot lands closer to underneath the body. The area of the foot that you land on ranges from landing on the whole foot with it being already flat to the ground, or in a faster gait it may look like landing on the mid to forefoot, like a sprinter.

In a barefoot gait like this, all the little bones and joints in your feet spread out the impact force evenly and it travels through the body in a gentler manner. This develops over your transition to minimal shoes as it takes time for those joints to start getting mobile again in your flexible yet forgiving transition shoes.

When Should You Go For a Thinner Sole?

Often our customers start looking for a more barefoot-feeling, thin sole around six months to two years after starting their minimal shoe transition. At that point they have shifted to a more barefoot style gait.

When you start wearing a minimal shoe with a thinner sole than before, your gait may continue developing in this direction. It also allows you to increase the sensory input through the nerve endings in the bottom of your feet.

The soles of the feet are packed with nerve endings, and re-introducing them to the world can be very enjoyable if you do it gradually so as to avoid overwhelm. Think of walking barefoot in the sand or grass, it almost feels like getting a massage!

Thinner Stack Height In Context

Minimal shoes that have a thinner stack height are great for spending time on natural terrain, as well as for activities where you need as much information as possible about the relationship between you and the ground, such as barefoot style running and certain styles of weight lifting.

It can also just be personal preference. People who prefer the thinnest soles possible still may want to own one or two pairs of shoes that have a little cushioning in case they are going to be taking a long walk through paved urban areas or for recovery days.

Your Body

The last factor you may want to consider when looking at how thick you want your minimal shoe's stack height to be is your unique body and its history. Some of our customers have medical conditions that impact this decision.

An example may be customers who have neuromas wanting a sole that provides more protection, at least to start with. Another example is customers who have balance issues, who may want to try a thinner sole to aid their sense of where they are in space.

This is very personal and it can change over time depending on what's going on, so we recommend talking to a minimal shoe friendly expert in foot health for recommendations on how any health concerns will affect what kind of shoes will work best for you. We are happy to suggest contacts that we have found helpful.

That said, you are the only expert on what it is like to live in your own body! Often the best way to find out what works for you is to try on the shoes.

If you're shopping online we've added descriptions under most of our minimal shoes under the heading "New to Minimal?" to give you a sense of how much ground feel you will get in different models, and what that means for people with different levels of experience with minimal shoes.

If you have questions, just send us an email and we'll help you out!