As podiatrists, we all know how important proper footwear can be for our patients! It is equally as crucial as a podiatrist that we know the qualities that make up a running shoe to make the best recommendations to our patients. This article will serve as a review of shoe anatomy, essential running shoe technologies, and tips to help make the best suggestions for footwear for your patients.

1. Avoid the one brand fits all strategy.

Two of the biggest pitfalls are #1 suggesting the identical shoe to all the patients and #2 presenting a specific name brand and not a particular type of shoe. One big mistake people make with running shoe suggestions is giving the same suggestion to all of their patients. 

What we will see throughout this article is that different foot types and pathologies require other qualities in their footwear. So, if the identical shoe is recommended for all patients, then a subset of those patients will be in the wrong shoe. What we see is that there is significant variability in quality and also type of shoe within certain brands. It is not uncommon to see someone having been given just the name brand to get, and they often pick the worst shoe for their foot type from that name brand.

2. Gain an Understanding of Basic Running Shoe Anatomy to be able to make good recommendations that are customized for your patients.

Knowing the components and their purpose is critical to help you better understand running shoes.  

The Upper:

The quarter refers to the rear and sides of the upper that covers the heel. The heel tab, collar, and cuff are all extra pads and cushions to help protect the malleoli and Achilles. One of the essential parts of the quarter is the heel counter. The heel counter is a firmer material, either externally or as an insert, to reinforce and support the heel. This is why it is vital to counsel your patients to untie their shoes before they take them on and off. Stepping and pushing into tied shoes will damage the heel counter which impacts the integrity of the shoe. The size and firmness of the heel counter can vary. For instance, the heel counter will be stiffer and more prominent in a motion control shoe, as this can improve rear foot stability. In more minimalist shoes, the heel counter will still be present however may be thinner, smaller, and less firm.  

The Vamp refers to the part of the upper that goes from the toe box to the quarter. Most modern running shoes and many walking shoes will be a lightweight, flexible, and breathable materials. Most of these are woven knit or mesh. An essential part of the upper is the tongue. Of course, the tongue protects the foot from lace pressure. Tongues can either be free (meaning they are only connected at the distal edge) or gusseted. A Gusseted tongue is stitched in place or attached to the midsole by a flexible fabric. 

The purpose of a gusseted tongue is to protect the foot from dirt and debris entering the shoe. You will find this in many trail running shoes, hiking boots, snow boots, and work boots.

Outsole:

The outsole is commonly referred to as the tread pattern of the shoe. The treads used for traction will vary based on what type of surface the shoe is designed for. For example, a road running shoe will have small, low profile, uniform, shallow, lightweight, and flexible treads. On the other hand, trail running shoes, like snow tires, will have deeper treads for better traction. 

The outsole pattern is one of the significant differences between Road and Trail running shoes. Trail running shoes are further broken down into light versus technical trail shoes. Light Trail shoes will be for harder-packed trails and will have deep treads that a still lightweight and flexible. Technical trail shoes are for softer, muddier trails, so the footprints are much more profound, thicker, and firmer.

Last: 

The last is the form that the shoe was made on. There are three main types of lasts. The curve last is very common in lightweight and less supportive shoes such as racing flats and spikes. In a curved last, when looking at the shoe's footprint, there will be a lazy C-shaped curve bisecting the heel, curving toward the great toe. A straight last is found in motion control and orthopedic stability style shoes. They are heavier but more stable, with the bisection of the heel and the forefoot forming a straight line. Finally, most running shoes on the market are a Semi-curved last, a hybrid between the two. There are also differences in how the components of the shoe are attached.   In slip-lasting, the shoe's upper is glued and stitched directly to the midsole, which allows the shoe to be lighter. In comparison, with board lasting, the upper is attached to a board which is then placed on top of the midsole. This is used in more stability-type shoes, but the tradeoff is that it is heavier. There is also a combination lasting which uses a board last method in the heel and a slip last method in the forefoot, which allows for a stable heel and a more flexible toe.

Midsole:

The midsole is the part of the shoe that has seen the most change, advancement, and controversy in the past decade. This is also where we will start seeing more differences of opinion as to which type of midsole is best and where the current hot-button topics in footwear design are. The midsole is typically a shock-absorbing material such as polyurethane or EVA foam. Brands then also add their additional elements, such as air or gel. There are two essential terminologies when describing the midsole: the stack height and the offset (AKA drop). These terms are related but not the same, and it is essential to know the difference. 

Stack height refers to the amount of shoe material between your foot and the ground, essentially how thick the midsole is. A lower stack height will have a more natural ground feel with less cushioning. A higher stack means a more considerable amount of material for a more cushioned feel and a higher degree of shock absorption. The offset refers to the height difference of the midsole between the rearfoot and the forefoot. A low offset is defined as 0-6 mm.  A high offset is typically between 7-12 mm, meaning that the heel height is 7-12 mm higher than the height of the forefoot. However, a high-stack height shoe can have a low offset (a maximalist shoe), so it is essential to distinguish these terms. In the question of what type of heel offset and stack height are better, the answer is that it depends on several factors such as, but not limited to strike pattern, BMI, and injury history.  

One factor to consider is the foot strike pattern. Foot strike means what part of the foot contacts the ground first, the rearfoot, midfoot, or forefoot, when running. A shoe with a low offset and a low stack height lends better to a midfoot or forefoot strike. A low offset and high stack height shoe can also be appropriate for mid to forefoot strikers. A runner with a rear foot strike will need more shock absorption and cushioning at the time of a heel strike. Therefore, a rearfoot strike will typically be in a higher stack height and/or a higher drop shoe for better shock absorption. When looking at the different types of shoes (minimalist vs. maximal vs. traditional) in conjunction with foot strike patterns, it is not that one of these has more injuries. It is that they have different injury and force loading patterns.  

Someone who is a heel striker and wearing a higher drop shoe will place a more significant eccentric load on the quadriceps during running gait. They will have a higher vertical load but lower shear stress at the ankle, greater impact through the knees, hips, and back, and an increased degree of ankle dorsiflexion and knee extension at the contact phase of gait. These runners will potentially have an increased risk for anterior knee pain, tibial stress fractures, shin splints, and possibly plantar fasciitis. Someone who is a forefoot striker will shift the eccentric load away from the quadriceps and to the gastroc-soleus. They will have a more significant impact and shear stress at the ankle and MTPJs, higher max peak force, and more ankle plantar flexion and knee flexion at contact. These runners will potentially have an increased risk for calf muscle strain, ankle instability events, forefoot pathology, and, debatably, Achilles tendinopathy. There are two recommendations/theories that are starting to emerge. One is that if someone is switching to a shoe where the offset is > 4 mm different than their current shoe, it is advisable to transition to that new footwear to avoid overloading structures gradually. Another is that some suggest switching up the type of shoe and the foot strike pattern during running training to help prevent repetitive loading on the same musculature.

Arch Support:

There are several ways that arch support can be built into the running shoe design. One method is straight and board lasting.  In the more traditional type of running shoes, arch support was achieved using a medial post of higher-density material in the midsole to help prevent excess pronation. This was the key component defining a "stability" shoe. Stability shoes can be broken down into mild-moderate-high stability based on the volume and size of the higher-density medial midsole post. However, a couple of the running shoe brands are getting away from the medial posting and shifting more towards what is called a J-frame. This is a thinner J-shaped higher-density material insert in the midsole that wraps around the lateral heel and extends through the medial longitudinal arch. This higher-density material does not encompass the entire thickness of the midsole like the medial post does. Rather than push the foot out of pronation, this technology tries to stabilize the foot in a neutral position. Arch support can also be achieved by adding a rigid shank. The shank is a supportive structure integrated between the midsole and the outsole that runs through the area underneath the arch. A more rigid shank ensures that the shoe will not flex under the area of the arch, offering more stiffness and support through the midfoot.

Outsole/Midsole Stiffness and Rocker:

This is how much flexibility there is to bend between the heel and the toe. Traditional stability, motion control, and maximalist shoes tend to be stiffer. In comparison, a minimalist shoe will tend to be much more flexible. This is another debatable topic regarding which is best, and the decision is primarily based on individual needs. There has been limited data in a few studies that show that recreational runners and walkers who wear overly thin and flexible soles while also building distance too quickly can have an increased risk of forefoot pathology.  

There is a current trend in marathon race shoes to be extremely stiff. For example, a maximalist shoe with a carbon fiber plate in the midsole was used to run the first sub-2-hour marathon. As these shoes are being talked about more, it is essential to discuss with your patients that this type of stiff carbon fiber-plated marathon running shoe is designed for elite runners to improve their running economy during a long race, and they are not designed for everyday training shoes.  

A forefoot rocker helps transition the foot quicker to the push-off phase of gait and helps propel the body forward. Almost all running shoes will have a slight rocker, and the degree can vary quite a bit between brands and models. Another emerging trend in running shoes is to have more of a forefoot rocker built into the shoe. The rocker can start at the level of the toes, MPJs, metatarsal midshaft, or more proximal to encompass the entire forefoot. The more proximal the rocker begins, the more help the shoe offers to help propel motion forward. Shoes with a higher degree of forefoot rocker will benefit those patients with significant hallux limits and other forefoot pathology.  

Toe Box:

It is important to make patients aware that the width of the toe box frequently does not correlate with the width of the shoe. The difference in the last size in wide vs. regular-width shoes is the volume of the midfoot. Not all wide-width shoes have a wide toe box. When looking for a wider-toe box shoe, you must counsel your patients to look for specific brands and models, as this is more of a design feature and not a product of the shoe width. Patients with bunions, tailor's bunions, and interspace neuromas can benefit from a wider toe box. In recent years, with some of the newer running shoe brands that focus on a broader toe and more of an anatomically foot-shaped shoe becoming more popular, many other brands are starting to integrate this feature into some of their models.  

Types of Shoes:

After reviewing the basics of shoe anatomy, here is a breakdown of the various categories of shoes on the market.  

Minimalist Shoes: Lightweight, low stack height, low drop, with a more natural feel. This type of shoe lends towards the forefoot to midfoot strike. Very similar to a lightweight racing flat.  

Barefoot shoes: A minimalist shoe. It will have very little to no midsole, be very lightweight, have a 0 drop, and have outsole flexibility. Best suited for a small subset of forefoot strikers.

Maximalist Shoe: High stack height, firmer sole, low drop, forefoot rocker with a lightweight but cushioned bouncy feel. This shoe can be utilized with all foot strike patterns and is popular with forefoot pathology patients and those needing more shock absorption. They can be divided into neutral and stability models.

Traditional shoe: A moderate stack height and high offset shoe. These shoes are further broken down into neutral, stability, and motion control.  

Neutral shoe: has no additional arch support features built into the shoes. Traditionally recommended for a neutral foot type or mild supinator

Neutral Cushioned Shoe: a neutral shoe with additional shock absorbing and cushioning material, such as more air or gel incorporated into the midsole. For those runners needing more shock absorption, and traditionally recommended for over supinator's.  

Stability Shoe: It is further broken down to mild-moderate-high stability based on the components that add additional pronation support to the shoe. Traditionally mild to moderate overpronators.

Motion Control Shoe:  Will have all the features that add support and stability, a straight last, board lasting, rigid shank, and higher density extensive medial posting that wraps around to the lateral rearfoot. This type of shoe will be significantly more stable but also much heavier. Patients with severe overpronation, obesity, or instability in the rearfoot will traditionally be recommended this type of shoe.

3. Lastly, How to Make the Best Shoe Recommendations:

While discussing the various aspects of shoe anatomy, it has become evident that many factors go into shoe selection. Unfortunately, there is not a one size fits all approach, and the best way to make shoe suggestions is to individualize the recommendation to the specific patient. Historically and traditionally, we used solely foot type to determine what shoe a patient should be in, but it is more complicated than that.

The critical factors to consider are:

• Individual Needs
• Running Surface
• Foot Strike Pattern
• Foot Type
• Injury History
• BMI
• Experience Level
• Training Distance/Intensity
• Race/Performance Expectations

Sources:

• Metabolic and Performance Responses of Male Runners Wearing Three Types of Footwear: Nike Vaporfl y 4%, Saucony Endorphin Racing Flats, and Their Shoes. 
•  Hébert-Losier K, Finlayson SJ, Driller MW, Dubois B, Esculier JF, Beaven CM. J Sport Health Sci. 2020 Nov 29:S2095-2546(20)30163-0.
• Biomechanical Differences of Footstrike Patterns During Running: A Systematic Review With Meta-analysis. Journal of Orthopaedic & Sports Physical Therapy. Published Online: September 30, 2015Volume45Issue10Pages738-755. https://www.jospt.org/doi/10.2519/jospt.2015.6019
• Three-Dimensional Biomechanical Analysis of Rearfoot and Forefoot Running. Orthop J Sports Med. 2017 July 24;5(7):2325967117719065. doi: 10.1177/2325967117719065—eCollection 2017 Jul.
• Rearfoot, Midfoot, and Forefoot Motion in Naturally Forefoot and Rearfoot Strike Runners during Treadmill Running. Journal of Applied Sciences. Alessandra B. Matias 1 , Paolo Caravaggi 2 , Ulisses T. Taddei 1 , Alberto Leardini 2 and Isabel C. N. Sacco. Appl. Sci. 2020, 10, 7811.
• Hoenig T, Rolvien T, Hollander K. Footstrike patterns in runners: concepts, classifications, techniques, and implications for running-related injuries. Dtsch Z Sportmed. 2020, 71: 55-61. doi:10.5960/dzsm.2020.424
• Anatomy of a Running Shoe – with Infographic. Website: https://www.runningshoesguru.com/ content/anatomy-of-a-running-shoe-with-infographic/
• How to Pick the Best Running Shoes Website: https://www.runningwarehouse.com/ learningcenter/gear_guides/footwear/how_to_pick_running_shoes.html
• Guide: Flexible vs. Stiff Running Shoes. Website: https://runrepeat.com/guides/flexible-vs-stiff-running-shoes