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Shoe Anatomy – What Are The Parts Of A Running Shoe?

Runners put a lot of trust in their shoes, but even many experienced runners know very little about the anatomy of a running show. Maybe you’ve been running for a long time or perhaps you just got into running, but there’s a good chance that you have something to learn about how shoes are designed and built.. This article will give you a quick tutorial so you can understand your shoes that much better. Knowledge is a valid end unto itself, but it can also help you make informed decisions about your shoes.

We’ll cover how a running shoe is constructed, and go over every single part that you’ll find on a running shoe.

We’ll start from the bottom of the shoe and work upwards, beginning with the outer sole and ending with the upper.

Outer Sole

As the name suggests, the outer sole is on the outside of the shoe. It is the bottom rubber on a running shoe.

Materials and tread pattern are major features of an outer sole. The sole can be made from carbon rubber, which is durable. Or it can be made from heavy, blown rubber, which is flexible and cushioned. Sometimes a combination of both is used for the best of both worlds.

The outer sole is important for all runners because it’s what will make contact with the ground. It provides traction and is the first layer in creating a durable running shoe.

One downside to the outer sole is that it does add weight to the shoe. Some running shoes – like the Saucony Kinvara – use minimal amounts of an outer sole to make the shoe lightweight. The trade-off for the lost weight is durability. They won’t last as many miles as shoes with a sturdier sole.

Trail runners, who experience all types of terrain and weather, need an outer sole that will grip when it needs to and provide traction on slippery and rough terrain. You’ll likely want more carbon rubber for trail shoes.

Midsole

Midsoles are, all of a sudden, the hot topic in running shoes. This is the inner portion of your shoe, above the outer sole and below your foot. It’s typically the middle foam that is found in a running shoe. The midsole is what determines if your shoe is a guidance, stability, motion-control, or neutral shoe.

Often EVA (ethylene vinyl acetate) foam is used, but there may also be airbags or gels to help provide extra protection so that you get a great performance from your shoe, depending on the brand that you choose.

More than any other part, the midsole determines a shoes feel. It can be cushiony or firm, flexible or responsive. It plays such an important role that World Athletics has recently drawn up guidelines for what types of midsole are legal to use in competition, and which ones constitute an unfair advantage. In other words, pay attention to the midsole.

Medial Post

In stability and motion control shoes, you’ll also find a medial post in the midsole. Unlike the rest of the midsole, which is cushioned and flexible, the medial post is firmer and is used to help control overpronation. It is also made of EVA foam, just a firmer version.

Brooks does not have medial posts in their running shoes. Instead, they use guide rails to help keep feet nice and secure and give you the stability and support you need.

Proprietary Foam by Brand

Shoe brands put a lot of money and effort into their midsoles. Very often, they market their midsole as a key, brand-defining feature. You’ll find a variety of different compositions of foam in the midsole, and many brands have their own proprietary versions they are known for.

Fresh Foam (New Balance)

New Balance’s calls their version Fresh Foam, which I have used in several different running shoes. First debuted in the early 2010s, Fresh Foam is designed to give you a nice, smooth ride.

The foam is comfy and cushioned, and the midsoles are laser engraved. This reduces the weight of the shoe to give you a plush ride.

PWRRUN (Saucony)

Saucony’s newest technology known as PWRRUN adds an additional layer of cushioning close to your feet. That means that your feet will feel nice and cushioned, no matter what mile you’re on.

The PWRRUN technology is designed for excellent energy return and is crafted to be more durable than traditional EVA foam. It’s supposed to stay the same temperature, no matter if it’s super hot or super cold outside.

Boost Foam (adidas)

Boost foam is known for being adidas’s most responsive cushioning. That means that you can expect to bounce back quickly as you pound the pavement. It’s designed to help your feet stay comfortable and stable as you run.

Boost foam came into existence in 2013 when it was common for running shoes to use EVA foam. Unlike EVA foam, Boost foam is crafted from thousands of expanded particles, which help increase energy return. It is known as eTPU in short.

Gel Cushioning (ASICS)

Finally, ASICS isn’t known for foam at all. Instead, it’s famous for its gel cushioning that’s been used for over 30 years. For runners who need a more stable shoe, ASICS is a great choice.

ASICS has been using gel for years because it works. The brand uses small bits of gel in the forefoot and heel of your midsole, designed to help reduce the impact of heel striking.

Carbon Fiber Plate

And now for the controversy…. Nike’s Vapor Fly line pioneered the use of energy-returning, maximally-thick midsoles built around a carbon plate. The idea is that this plate can help reduce the energy that you lose when pushing off. Put another way, they improve your running efficiency. The shoes have been central in Nike’s efforts to break the 2:00:00 marathon barrier, and have become the standard for elite marathoners in the last couples years. Critics claim that the carbon plate gives an unfair advantage, and constitutes a mechanical aid. World Athletics has allowed the use of carbon plates, but limited the allowable thickness of midsoles. 

The technology is here to stay, and every major running brand is introducing carbon-plate shoes. Hoka One One, Saucony, Brooks, New Balance, and ASICS have all joined the fray.

And believe it or not, it works! Many people have seen significant performance benefits and improved their race times by a lot. But it isn’t cheap. Expect to spend more – in some cases a lot more – on a pair of running shoes with a carbon fiber plate.

As a side note, the reason Nike’s innovative first model was called the Vapor Fly 4% is because it was supposed to improve running economy by 4%. Independent research has confirmed this, with some important asterisks. Marathoner Eliud Kipchoge is said to have improved his running economy by an incredible 7 percent! The effects seem to diminish for slower runners, and especially for runners who do not have great running form.

Upper

Let’s talk now about the top part of the shoe – the upper. You have a lot of different pieces in the upper as compared to the midsole and outer sole. The upper can be made from a variety of different materials: mesh, knits, or synthetic leather.

Each type of material has its own benefits. For example, if you want a really breathable shoe, mesh is a great option. If you tend to have issues with chafing, go with a knit upper because it’s smooth. And if you need something durable, synthetic leather is the best option.

The new carbon midsoles might get all the headlines, but there has been a revolution in upper design in the last 10 years as well. Previously, several pieces were stitched together to create the upper’s shape. The seams were reinforced with overlays that added both strength and weight. Now, virtually all shoes, save for heavy-duty trail shoes, are made with a 3D-knit mesh upper. The seams are gone, and the shoes are lighter and more comfortable.

Heel Counter

This part is on the back of your running shoes. It is stiff and inflexible, to surround your heel and give it cushioning, control, and stability. Because you are going to be hitting the pavement hard, it is designed to be durable and protect your feet from these forces.

Heel Collar

Also known as the heel cuff, this is the part that wraps around your ankle. It’s designed to hug your ankle and give you a nice, firm fit that is cushioned and padded.

Insole/Sock Liner

This part is removable, and it’s what sits directly underneath the soles of your feet, giving you a thin layer of cushioning to help protect your feet from the seams below. If you need orthotics or custom inserts, you can take it out and replace with another one.

Tongue

I think we’re all familiar with this part of a shoe. It’s the part that is a separate strip designed to help protect your feet from the laces. Something that to look for is that the tongue is thick enough or has enough padding so that you don’t feel the laces.

If you get trail shoes, the tongue will sometimes be stitched in place so that dirt and debris can’t get into your shoes, but it will be loose for road shoes.

Laces

We all know how to tie our shoes, but there are tons of ways out there to lace up your running shoes so that they give you the support you need or relief you need (if you have a bunion, for example, and don’t want anything to rub).

Although this isn’t true for every running shoe, many have an extra eyelet that you can thread your laces through in order to keep your heel more secure and locked into place. If your shoe feels loose, make sure that you use this extra eyelet at the top.

Most running shoes still use traditional lacing, but there are a few exceptions:

Quicklace

This specialty lace is found on some Salomon shoes, although it can also be added at home. The idea is that you can quickly and easily adjust your laces as needed using a sliding clip. You never have to tie your shoes, and they never come untied, either.

Boa Shoe Lace

This specialty lace is completely different from your normal lace. Instead of using classic laces, boa shoelaces are thin stainless steel wires that you adjust using a turning knob, which can loosen, tighten, or snap your laces into place. They are especially common on other technical footwear like cycling shoes and ski boots.

Last

Okay, so this isn’t really a shoe part, but it does impact the fit and feel of your shoe. The last simply refers to the 3D mold that is used to construct a running shoe. Think of the shape of the shoe when you look straight-on at the outer sole.

They can be curved, semi-curved, or straight to suit different types of feet.

Typically, running shoes use a semi-curved last to get the best of both worlds—good support but also flexibility. A straight last is heavier, but gives more support to the arch, while a curved last is less supportive but is lighter.

Final Thoughts

Hopefully you now have a better understanding of everything that goes into a running shoe, which might help you in knowing what type of shoe will be best for you. Seemingly small changes can make a huge difference in fit and feel for a running shoe.

Knowing if you like to use all the eyelets can help you in ensuring that every running shoe you buy meets your needs. This is definitely the case for me, and I’ve had to not purchase some running shoes because they didn’t have that extra eyelet.

Good luck in all your runs and in finding the best running shoe for you!

The Wired Runner