The Anatomy of a Shoe: What You Need to Know Before Buying Your Next Trail Runner or Hiking Shoe
We may earn revenue from the products available on this page and participate in affiliate programs. Learn More ›
The fact that most people don’t understand the anatomy of a shoe leads to a near universal shopping experience: You see a particular trail running shoe or hiking boot hyped online. Molded EVA sockliner. 4D Advanced Chassis. Gore-Tex Waterproof Membrane. Vibram Outsoles. But then when you try the shoes out for yourself, everything seems wrong. Your heel is slipping around while your toes are bunched up. You get blisters underneath your arch. No matter how you lace up the shoe, your ankle feels ready to give out from under you. Plenty of people end up thinking that, if this shoe is really so great, there must be something wrong with their feet that it’s not working for them.
But the real problem is that it’s easier for shoe manufacturers (and online reviewers) to highlight the technical extras in their ad copy over the mechanical features that determine whether a shoe’s fit is right for your individual foot. After testing and writing about everything from the best barefoot shoes to the best winter hiking boots, it’s become clear that this is detrimental to consumers, particularly consumers that, because of geographic availability, need to do the majority of their shoe shopping online.
To help readers better understand what specs are essential to finding the right fit for their particular feet, I’ve divided the the anatomy of a shoe into two categories. The first is a look at mechanical features. This includes features like a high heel drop, rocker bottom, and toebox, that will affect different people’s foot shape, strength, and flexibility in different ways. The second is the technical specs: waterproofing, outsole materials, rock plates, and more. Consider these only after you’ve honed in on the right mechanical features for your feet and found a few ideal options that work for that.
Anatomy of a Shoe, Mechanical Features
Mechanical features of footwear affect fit, biomechanics, and gait. While footwear companies typically advertise technical features — like waterproofing technology or outsole material — over mechanical features, this is what your primary focus should be on when choosing a trail runner or hiking boot.
Last Shape
The “last” is the secret sauce of all footwear. It is the foundation on which all shoes are built and yet it is so difficult to describe its nuances that most footwear reviews don’t even mention it. So let’s start here.
The “last” is the foot-shaped mold around which a shoe is constructed. Lasts are created by third-party companies, like Jones & Vining, and are proprietary to the shoe company that ordered them. The nuances of last shape is the reason why one shoe will fit like a glove, and another simply feels wrong. And comfort isn’t just a subjective issue, studies have shown that comfortable footwear is highly correlated with injury prevention.
While shoe companies can describe to retailers, including pedorthists, in general terms what a last shape is like, including when a hiking boot or running shoe’s last changes from year to year, they do not provide measurements. Typically, individuals at shoe stores end up evaluating fit simply by trying the shoes on their own feet and noticing the differences. Your best bet for finding a last shape that works well with your foot is simply to try on as many shoes as possible.
The Benefits of a Pedorthist
If you’ve struggled with finding the right footwear in the past, it may benefit you to find a pedorthist. Unlike podiatrists, who are medical professionals that you would see in a doctor’s office, pedorthists are trained in matching individuals with the right footwear based on their biomechanics and gait. Many pedorthists work in shoe stores, and are familiar with how the different shoes their store carries work with different foot shapes, flexibility, and strength. If you have an injury diagnosis from a podiatrist for an issue like plantar fasciitis or achilles tendonitis, they can also help you find the right shoe for your recovery.
For trail runners, overall comfort is king, but for hiking shoes and hiking boots there is one other fit element you should check: the heel cup. It’s important that your heel locks in place at the back of the shoe, neither sliding up or down or side to side. Hiking boots and hiking shoes have rigid soles that can help to stabilize your feet and ankles on tricky terrain. But that effect goes out the window (and can actually make things worse) if your heel is sliding around inside your shoe.
Because most last shapes are designed with a so-called typical foot in mind, it can be especially difficult to find a shoe that fits if you have an especially narrow, wide, or girthy foot. Note: Because Europeans typically have narrower feet than Americans, lasts designed for European shoe companies are often narrower than lasts designed for American shoe companies.
Read Next: Best Hiking Shoes for Wide Feet
Individuals with wide feet should note that not all wide-width footwear is made using a different last than regular-width footwear. Because lasts are expensive, some footwear manufacturers will attempt to make a wide-width shoe or boot using a regular-width last.
The Bottom Line: The only way to know if a shoe will fit your foot comfortably is to try it on. For hiking boots and shoes, check that your heel is locked into place when you lace it up.
Toebox
One of the most noticeable differences in last shape is the toebox on different brands, with some having a very narrow profile and others extending out so that the toebox is the widest part of the foot. There are a few reasons that shoes have narrow toeboxes. Hiking boots have long been inspired by the needs of mountaineers looking for a so-called technical fit. By completely securing the foot, including minimal movement of the toes, this group could tackle technical climbs with more confidence, trusting that their shoe would stay where their foot put it, even if it was just a couple of toes on a tiny rock ledge. Another influential category of shoe that has long had a narrow toebox are racing flats. Similarly to mountaineers, professional runners do not want their shoes to slip around on their feet when they are running, as this will negatively impact their speed and efficiency.
Finally, it is worth noting that, historically, narrow toeboxes have been seen as “more fashionable.” Some shoe brands, including brands that serve the outdoor space, may be influenced by this history. While likely less of an impact than the other two reasons given above, it is worth keeping in mind when making a purchase decision.
Wide toeboxes became popular in the early aughts with the original barefoot shoe fad and the general rise of natural movement features in footwear. If you’re used to footwear with a narrower toebox, which most casual and professional footwear has, then expect a wider toebox to feel noticeably different. For some people, the wider toebox comes as a relief, as it reduces pressure on the metatarsal (the part of the foot where the bones of the toes and the bones of the rest of the foot meet) and allows their toes to move somewhat. For others, it contributes to an overall feeling that their footwear is not secure, or locked in, on their foot.
There are a couple of ideas behind this to consider when making a footwear purchase. For hikers, a wider toebox can improve balance. When your toes spread out, your foot forms a triangle with the heel, big toe, and pinky toe. This “tripod” shape is more stable, and less likely to result in an ankle roll, than the classic “torpedo” shape of conventional footwear. An easy way to see this for yourself is to test your balance barefoot, with your toes spread out. Then apply a thick band to your toes and repeat the experiment.
While runners will also benefit from better balance with a wider toebox, there is another reason that wide toeboxes have become fairly standard on the most popular trail runners: better alignment of the big toe. Whether you heel strike or forefoot strike, pushing off with your big toe is how you propel yourself forward. The more aligned your big toe is, the more efficient your gait is.
The Bottom Line: There is no practical reason for non-professional runners or non-technical hikers and backpackers using trails to have a narrow toebox despite their continued prevalence in the marketplace. While some individuals may prefer the feel of a “technical fit,” there are advantages to consider from footwear with wider toeboxes. If your trail runner or hiking boot is compressing your metatarsal, especially if it is constricting bloodflow, then the toebox is too narrow. Individuals with bunions may also find some relief from switching to footwear with a wider toebox.
Arch Support
Arch support is such a standard feature in trail runners and hiking shoes that most people assume they need it. This is not the case. Like with narrow or wide toeboxes, much of this comes down to personal preference. To help you make your choice, let’s look at how the foot arch works, and then arguments for and against having arch support in your shoes.
The arches in your feet serve the same purpose as an arch in a bridge: It’s an effective load-bearing design. This load-bearing functionality comes into play when standing and walking, but is especially important for running, as there is a greater impact force with each footfall. Unlike a bridge, however, the arch is not a static feature. When walking and running, the foot will transition from a pronated position to a supinated position. In the pronated position, your arch rolls inward and flattens some as it absorbs the impact forces. It then bunches back up as it transitions to the supinated position before pushing off. Pronation and supination are both natural parts of the gait cycle.
The argument against any kind of arch support is that it is interfering with your foot’s ability to move through the gait cycle and absorb impact forces naturally. This can especially be an issue for individuals who have been wearing shoes with arch support for many years as the muscles in their arches that control this motion may have atrophied.
Read Next: Best Minimalist Shoes for Trail Running
The argument for arch support is two-fold: Our modern sedentary lifestyle means that the muscles in most people’s feet are no longer strong enough to move through the gait cycle naturally. The second part of the argument is that we walk on a number of unnatural surfaces — especially concrete and asphalt — that our arches did not evolve to handle. Running especially long distances or carrying especially heavy loads can also put unnatural levels of force on the arch of the foot.
How Mixing and Matching Can Help Reduce Injuries
For many people, the goal of footwear shopping is to find the perfect shoe: one that is comfortable, functional, and keeps them injury free. But recent research has suggested that a better strategy might be to choose shoes with different mechanical features, and alternate between them. For instance, rather than only running in shoes with a 10mm heel drop, you could purchase a running shoe with a 4mm drop and use that for some of your training. That way, you could benefit from increased strength and length in your Achilles while minimizing the risk of developing Achilles tendonitis. Think of this as cross-training for your feet.
A small percentage of the population overpronates or oversupinates. However, because pronation and supination are a natural part of the gait cycle, it’s important to not self-diagnose for this issue. If you think you may be overpronating or oversupinating, have a professional conduct a gait analysis. They may then recommend physical therapy, insoles, or motion-control shoes.
When looking at your own feet, remember that there is a wide range of what is normal for the arch. Some people naturally have high arches; others naturally have low arches. Both types of arches can be strengthened or weakened, which will affect whether or not support is needed. Some individuals may have so-called flat feet or true fallen arches as a result of muscle atrophy or excessive weight being placed on their feet over time. This is another situation that would benefit from a true diagnosis and physical therapy to help strengthen the arch.
The foot’s arch, it should be noted, develops during childhood. All babies start out with flat feet and don’t develop arches for a number of years. For this reason, children typically find footwear without arch support to be more comfortable.
Read Next: The Best Hiking Shoes for Kids
If you prefer your trail runners or hiking boots to have arch support, choose one with the right level of support for your foot. Like with other aspects of mechanical features, the best way to figure this out is to try a pair on. While you can switch out insoles in most shoes, keep in mind that a certain level of arch support is often built directly into the structure of the midsole and outsole.
The Bottom Line: If the arch support in a shoe aggravates your foot, don’t purchase it. If you have been using arch support and are interested in experimenting with a shoe with no arch support, do so carefully, as the muscles in your arch may need to strengthen before they can support you for longer distances. If you are concerned that you overpronate or oversupinate, get a gait analysis before purchasing footwear designed for motion control.
Heel Drop
If you are going to understand the anatomy of a shoe, you also have to understand the anatomy of your own foot, as your personal physiology and current footwear play a huge role in which choice is right for you.
Heel drop refers to the difference in a shoe’s height between the forefoot and the heel. A women’s high heel shoe, for instance, has a massive heel drop. Flip-flops, conversely, would be a zero-drop shoe. Most trail runners and hiking boots are between 14mm (about a half an inch) and zero drop, with some outliers running as high as 25mm.
Heel drop impacts the Achilles tendon. The Achilles tendon connects your heel to your calf muscle, expanding and contracting as you walk, run, and jump. Too much force on the Achilles tendon can result in inflammation, including Achilles tendonitis. Like with the arch muscles of your feet, use and disuse affect the strength of the Achilles tendon.
Read Next: What Is Heel Drop?
High-drop shoes reduce the load on your Achilles tendon by reducing the length that it has to stretch to when you walk, run, or jump. However, high-drop shoes can, over time, result in the muscles that connect to your Achilles tendon shortening. And the less distance your Achilles has to expand and contract, the less effective it is at storing and releasing energy as you run and walk. High heel drop can also affect your foot strike: It’s not uncommon for heel strikers to switch to low-drop or zero-drop shoes and find that their gait shifts to a mid-foot strike.
All this means that the heel drop you choose for your running or hiking footwear should be based on what your Achilles tendon can handle. If you have been running or hiking in high-drop shoes, you can give yourself Achilles tendonitis if you switch to a zero-drop shoe too quickly. Your Achilles tendon needs time to adjust. For that reason, serious runners and marathoners are advised to wait until they are in a slower part of their training schedule to switch to a lower drop shoe. However, the benefits of lower drop and zero-dorp shoes are such that this feature is increasingly common among the most popular brands and models, including Hoka, Topo, and Altra.
Read Next: The Best Zero-Drop Running Shoes
If you’re looking for a low drop or zero-drop shoe, watch out for misleading mid-foot drop measurements, which measure the change in height between the midfoot and heel only.
The Bottom Line: Choose the lowest-drop shoe that doesn’t aggravate your Achilles tendon. If you currently use a high-drop shoe, and your training or personal schedule allows, consider purchasing a zero-drop shoe to wear on short outings. This will help to strengthen and lengthen your Achilles tendon so that it is more effective at storing and releasing energy. Over time, you may be able to transition to a lower drop shoe for your regular training.
Stack Height
Heel drop measures the height differential between the heel and the forefoot. Stack height measures the height of a shoe from the bottom of the outsole to your foot. Which stack height is right for you comes down somewhat to preference, although there are physiological reasons why you may want to opt for a lower or higher stack height.
Low stack height is associated with barefoot style or minimalist shoes. This can range from 5mm for Vibram Fivefingers to close to 20mm for a pair of Xero shoes. These shoes may have a thicker outsole with heftier lugs, depending on the type of terrain you are going after. Typically they have no midsole, or at most a very thin foam layer.
High stack height is associated with maximalist shoes, such as Hoka and Brooks. This can range from 33mm for the Hoka Bondi to 41.5mm for the Asics Novablast. Maximalist shoes usually have a significant amount of midsole foam, typically EVA.
High stack proponents appreciate the extra protection from the ground, as it minimizes the discomfort from not only rocks or roots that you might run into on the trail, but also from hard surfaces such as concrete or asphalt. In addition to reducing foot fatigue, many high stack proponents say that the extra cushion feels good to their feet and sometimes also their knees.
Low stack height proponents argue that the increased ground feel increases proprioception, which is essential to proper running form. The idea here is that the nerve endings in your feet (of which there are a ton) can detect micro changes in the ground beneath them, resulting in micro changes to your posture and form that keep your body aligned and reduce stress up the kinetic chain. I wear low stack height shoes, and over the years I have also noticed my feet’s sensitivity to rocks or roots underfoot (the “ow” factor) has substantially reduced. Low stack height shoes are also associated with lower impact foot falls which can reduce stress on your knees and hips.
Read Next: It’s Time to Give Barefoot Shoes a Try
One other advantage to low stack height shoes is that it increases your balance. Not only is your body more attuned to changes to what’s underneath your foot, but it’s simply much harder to roll your ankles when you’re barefoot than when you’re wearing platform shoes.
The Bottom Line: The maximalist and barefoot camps are sharply divided on stack height, but you don’t have to be. Consider choosing shoes with different stack heights for different terrains, and listen to your body if either the underfoot sensation becomes too extreme, or your balance feels negatively affected by too much material underfoot.
Toe Springs and Rocker Bottoms
While most footwear is flat across the outsole from heel to toe, there is some footwear that incorporates an upward tilt at either the toe, called a toe spring, or at the heel and the toe, known as a rocker bottom. Both these features reduce the range of motion required to go through the gait cycle during both walking and running. The toe spring reduces the amount of flexibility needed in the big toe, while the additional curve on the rocker bottom reduces the amount of flexibility needed in the ankle. Occasionally trail runners will have these features because the sole itself is so thick and stiff that it will prevent the runner from engaging in typical gait cycle mechanics.
The downside to toe springs and rocker bottoms is that they can themselves reduce big toe and ankle mobility. And, since your toes are sticking up in the air, you’re interfering with your foot’s ability to maintain balance in a neutral position on tricky terrain. Finally, there is some evidence that reducing load on your big toe and Achilles (which is less engaged when you flex your ankle less) can cause problems up the kinetic chains, including hip, knee, and plantar fascia issues.
The Bottom Line: Try to avoid trail runners with toe springs unless you have mobility issues in your big toe or ankle.
Anatomy of a Shoe, Technical Features
You’ve gone through the mechanical features and figured out what the right combination is for your physiology and goals. Now it’s time to look at the fun stuff: technical features. These are the extras that help to improve your experience across a variety of terrains.
High Tops
In many cases, the only true difference between a hiking boot and a hiking shoe is the addition of extra material that wraps around the ankle. While many people erroneously believe that the material wrapping around their ankles with hiking boots prevents rolls, this is not the case: You can absolutely still roll your ankle in a hiking boot unless the material is truly rigid, such as you would see with a mountaineering boot.
What uppers are good for is providing protection for your ankles against accidental kicks and scuffs, as you are hiking. They are also effective at preventing small rocks or other forest debris from getting inside your boot.
Lugs and Outsoles
It’s honestly shocking what a difference proper lugs or a technical outsole material can make to the hiking and trail running experience. There are a number of brands for outsoles, the rubber or other specialized compound, on the bottom of your shoe, including Michelin, MaxTrac, and more.
But the most popular, by far, is Vibram. I’ve had great experience with a number of Vibram outsoles in the past, but have been particularly impressed with their Arctic Grip on snowy and icy conditions and their MegaGrip for steep terrain and scree.
Waterproofing
Shoe brands love to tout their use of Gore-Tex for waterproofing and, despite recent PFAS legislation that makes the vast majority of their line illegal in major parts of the country, that will likely continue to be the case for some time. However, it’s worth considering if you actually want or need waterproofing in your hiking shoes or boots. For many people, hiking boots are mainly used in the summer months. In hot conditions, your feet might actually end up damper with a Gore-Tex boot than not, as the waterproofing material limits breathability, preventing sweat from wicking away effectively.
Read Next: PFAS Explained
Laces
While hiking boots and shoes still have the standard shoelaces that have been used on footwear for hundreds of years, trail runners have been experimenting with other options. The most popular of these are BOA laces, which somewhat simplifies getting a secure fit compared to regular shoelaces. The disadvantage to BOA laces is that they take longer to replace than regular laces if they break, and are less available compared to regular laces (which you can find just about anywhere).
Gaiter Attachments
If you are purchasing hiking shoes or trail runners, which are cut low so that your ankle is exposed, these will sometimes come with gaiter attachments built into the heel. Most hiking and trail running gaiters are designed to hook onto your laces in the front and at the heel in the back. While you can glue on a gaiter attachment to the back of your heel if the trail runner you’re eyeing doesn’t already have it, my experience with this is a mixed bag. Built-in gaiter attachments are a major advantage if you know this is something you will use on a regular basis.
Rock Plates
This feature, which is common in technical trail runners, provides additional protection from sharp stones underfoot when running up and down rugged trails. The advantage of rock plates is that your feet are less likely to bruise, even if you step on a particularly nasty rock. The disadvantage of rock plates is that they limit proprioception and can result in sloppier foot placement, which can lead to injury over time. I would recommend avoiding rock plates unless you have especially sensitive feet or you are looking for a pair of trail runners for especially gnarly trail runs (as opposed to your standard training footwear).
Toe Caps
If you’ve ever banged your toes against so many rocks while hiking that your big toenail turns purple and eventually falls off, then the value of a toecap will make perfect sense to you. The only true disadvantage here, besides added cost, is the extra weight at the front of the foot, which can affect energy expenditure and the efficiency of your gait.
Final Thoughts
Online shoe shopping is a fairly nightmarish experience. If at all possible, find a shoe store, ideally with a trained pedorthist. But if you can’t, find an online retailer with a generous return policy so that you can order a variety of shoes and try them on at home for yourself. Finally, remember, the right shoe for someone else is unlikely to be the right shoe for you: Everyone’s feet have different shapes and needs.
The post The Anatomy of a Shoe: What You Need to Know Before Buying Your Next Trail Runner or Hiking Shoe appeared first on Outdoor Life.
