Anatomy of a Trail Running Shoe

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There’s no argument; the most critical piece of gear for a trail runner is his or her shoes. Whether you’re a newbie or a seasoned pro, shopping for the perfect trail running shoe can be daunting – today, there’s a surplus of options, each featuring different technologies, materials, and structures.

We turned to our in-house trail running Expert and softgoods buyer, Carolyn Holliday, to sort through the clutter and break down the anatomy of a trail running shoe.

Carolyn carefully selects our trail running shoes to accommodate three types of runners: door-to-trail runners, who stick to well-groomed, hard-packed trails; technical trail runners, who hit more rugged trails and may run competitively; and the hybrids, who want a burlier running shoe, a light hiker, or the best of both worlds.

Read on to get acquainted with the important components of a shoe, and in turn, uncomplicate the process of finding one that’s best for your skill level, preferred trail styles, and the conditions you run in.

The Outsole

The outsole is considered one of the most fundamental elements of a trail running shoe, because it’s your first line of defense against the ground, and comes into constant contact with it. The outsole is responsible for traction and protection against rocks, roots, and dirt.

What to look for:
Door-to-trail runners will prefer a more even outsole, with shallow tread and small lugs that offer enough traction for smoother routes. More aggressive runners, or those seeking a hybrid hiker, should opt for thicker outsoles with larger, multidirectional lugs, strategically placed to accommodate uneven terrain. If you regularly run in mud or wet conditions, look for lugs that are spaced widely apart.

Outsoles are almost always constructed from rubber, which delivers superior traction and durability. If you frequently run on gravel or rocks, look for “sticky rubber.” La Sportiva shoes, including the La Sportiva Akyra, feature strains of FriXion 2.0 rubber. Varieties of this sole compound yield different degrees of stickiness catered to specific mountain activities; scramblers will appreciate the unparalleled adhesion abilities of La Sportiva shoes with FriXion XF 2.0.

Some brands offer outsole technologies that are essentially an all-in-one package and includes materials, braking system, and the size, shape, and placement of lugs. For example, Salomon equips its line-up with its proprietary Contragrip outsoles, with sub-varieties tailored to specific conditions – Wet Traction Contragrip shines in soggy, slippery conditions and is reserved for more technical options, like the Salomon Speedcross 4; while High Traction Contragrip supplies the extra hold and deeper lugs needed in hybrid shoes.

The Midsole

The midsole is the layer of cushion sandwiched between the outsole and the upper. Usually crafted from a technical foam, it acts as a buffer between the terrain and your foot. It absorbs shock, provides foot support, and determines control.

What to look for:
Midsole cushioning is a personal preference; some favor more for additional support and comfort, while others like less for increased control and better feel of the trail. Whether you run mellow paths or rooty, rocky routes, you can find a shoe with your preferred level of cushioning without sacrificing other attributes you want and need.

If you’re pro-cushion, check out Hoka One One – you could say cushioning is their thing. The brand is known for using a generous helping of lightweight EVA foam to absorb impact, provide top-tier comfort, and improve stability, even in its more technical offerings like the Hoka One One Speedgoat 2.

Salomon and La Sportiva use EVA as well, but in more moderate amounts to accommodate a variety of preferences, with plushier midsoles commonly found in the lower end of the line-up.

“Lower,” as in “lower model,” refers to shoes that are less aggressive, and are designed for well-groomed trails. You can usually identify a lower model right off the bat by its outsole – shallow tread, smaller lugs, and an overall sneaker-like look and feel.

Because of the types of trails that lower models frequent, brands can prioritize comfort without compromising other necessary attributes, hence the availability of extra cushioning. Technical trail running shoes – apart from Hoka One One products – tend to offer a moderate amount of cushioning, just enough to smooth out the ride on rough terrain without sacrificing the agility needed to navigate it.

Manufacturers tweak their midsoles with an array of exclusive technologies, each engineered to provide a different benefit depending on the shoe’s intention. Salomon’s Sense Ride is a great example of the brand’s many midsole enhancements; the Sense Ride, which is a lower model highly-recommended for door-to-trail runners, is equipped with EnergyCell +, OPAL, and VIBE. EnergyCell + foam blend delivers better shock absorption, rebound, and durability. OPAL amplifies comfort and bounce, while VIBE irons out the impact of uneven trails. This combination of materials produces a midsole thicker than a Salomon shoe with one, or none, of these additions.

The Drop

The thickness of the heel versus the thickness of the toe dictates the “drop” of the shoe, and its measurement is linked to the amount of cushioning in the midsole. A shoe with the right drop for you will work with your natural stride to improve your performance.

What to look for:
To determine your ideal heel-toe drop, consider where you strike your foot when you run – heel, mid-, or fore-foot. You can also examine the type of wear visible on your old running shoes or consult a Jans Expert for guidance.

Mid- or fore-foot strikers should aim for a lower drop, 8 mm or below , which takes the heel out of the equation to provide a steady, balanced landing and prevent injuries. Most shoes designed for door-to-trail runners will offer a drop around 8 mm.

Shoes that boast a low or “zero” drop with little to no cushioning are often referred to as “barefoot” or “minimalist” shoes, and offer a superior sensory interaction between feet and ground – favored by runners for improved agility, responsiveness, and efficiency. Not all low drop shoes skimp on cushioning; Hoka One One is famous for their Meta-Rocker technology which pairs a low heel-toe drop (around 5 mm) with copious cushioning to support runners’ natural gait and increase productivity.

Carolyn notes that not everyone is born with low or zero drop foot, and if you are considering a shoe with this heel-to-toe height for the benefits of a minimalist shoe, it is advised to slowly wean off your old shoes to avoid any injuries, discomfort, or pain.

Heavy heel strikers will feel comfortable in a shoe with a higher range of drop, 12 mm and above, which encourages your heel to hit the ground first and relieves stress on lower leg muscles. However, the cushioning that typically accompanies high-drop shoes can negate any ability to feel the trail.

The middle-ground, and the “traditional” drop zone for runners, is 10-12 mm. This Goldilocks-drop allows for “just right” moderate heel-striking, and offers the broadest spectrum of cushioning options. Most technical trail running and hybrid shoes offer a heel-toe drop within this range.

The Upper

The upper is the entire top part of the shoe, including the tongue and laces. It holds your foot and shoe in place, while shielding your upper foot from the elements.

What to look for:
Many brands utilize a combination of materials to achieve superior levels of breathability, durability, comfort, and fit.

Recently, knit uppers are popular due to their seamless construction, excellent breathability, and that sought-after “free” feel; this construction is best suited for the door-to-trail runners.

Technical trail runners and hybrids will want more support in their uppers, to ensure stability on tricky terrain, as well as added protection from thick brush and roots. Keep your eyes peeled for shoes with reinforced uppers, like SpeedFrame construction in Hoka One One shoes or TPU MicroLite skeleton in La Sportiva.

Shoe shoppers will see many options offered with a GORE-TEX lining. While a waterproof trail running shoe seems obligatory at first glance, Carolyn advises to go for the GORE only with your off-season – fall, winter, spring – shoes. Those who run exclusively in the summer months will benefit from the enhanced breathability of a non-GORE-TEX shoe. Don’t worry about the occasional water crossing or rain shower – your shoes are built to resist some moisture, and dry quickly – even without GORE-TEX.

The tongue and laces are often overlooked, though they can have a large effect on the comfort of a shoe. The right tongue is thick enough to relieve the pressure of your laces, but doesn’t rub against your foot. For runners who loathe interrupting their momentum to tie their laces, there’s a variety of easy, speedy lacing systems that require only a quick tug for a secure fit, and stay put throughout your run – check out Salomon shoes with Quicklace or La Sportiva’s Fast Lacing System.

The Last or Lasting

The last or lasting is the mold that dictates the outline of the shoe, and consequentially, the shape and fit of the shoe.

What to look for:
Lasts are categorized into three forms – curved, semi-curved, and straight – and you want the one that best imitates the anatomical structure of your foot. Straight lasts are designed for flatter feet, with no arch. High arches will be happiest with curved lasts, which turn inward at the insole. Semi-curved, with a slight bend, are for those who fall in between. Almost all trail running shoes will be built on a last that boasts some level of curve.

Carolyn notes that a good rule of thumb is lower model levels have wider, more relaxed lasts – like the La Sportiva Lycan, Hoka One One Stinson, or Salomon Sense Ride. With models designed for more technical trails, you’ll find more curved, narrow, and fitted lasts. Some brands, including Salomon, do offer wide-specific fits, and if you can’t find any on the shelves of a Jans store, we are happy to order some for you.

The Sockliner

Also known as the insole, the sockliner refers to the layer of cushioning that your foot rests against within the shoe. It can improve fit and provide additional support and cushioning.

What to look for:
Brands will usually specify sockliners’ materials; you’ll often see the standard EVA foam or, in more comfort-focused models, OrthoLite. This is one of the few components you can replace; runners can swap out insoles to attain their ideal comfort.

The Toe Box

As its name implies, the toe box is that front space of the shoe where your toes live. Because it fits the widest part of your foot, the toe box can be a deciding factor in true comfort and fit. It must be spacious enough to allow your foot to move naturally; if not, you may experience blisters and calluses, or more serious conditions like inflamed nerves and acute arthritis. On the other hand, too much space will make your muscles work harder to keep shoes from slipping and feet from sliding.

What to look for:
Experiment with brands and models to determine which allow your toes to wiggle comfortably and spread naturally, sans crushing, cramming, or squeezing.

If you know you need a broader toe box, remember that lower model levels tend to be wider. Additionally, some designs feature an upper with dynamic materials in specific areas to accommodate bunions and hammertoes, like the Salomon X-Mission 3.

Carolyn emphasizes that every trail running shoe manufacturer offers its own distinct fit and feel. That’s because every person has a unique set of feet – and some people even have two different ones!

Furthermore, everyone has their own preferences when it comes to shoe fit, style, and features, so don’t feel pressured to squish into the box of a door-to-trail, technical, or hybrid trail runner. You can like rugged trails and shallow tread; you can have wide feet and prefer the control of a tight, fitted last. At the end of the day, it’s what feels good to you.

… That’s why nothing beats trying on shoes in-person, where you can skip the guessing games and test options first-hand to get an accurate understanding of what works and what doesn’t. Trust us, when it comes to your trail running shoes, you don’t want to cut corners. Visit a Jans store location in Park City, Utah to work with an Expert one-on-one to find your match so you can tear up the trails.

Expert Recommendations

  • La Sportiva Lycan
  • Hoka One One Challenger ATR 4
  • Hoka One One Stinson ATR 4
  • Salomon Sense Ride
  • Salomon X-Mission 3
Technical Trail
  • La Sportiva Akyra
  • Hoka One One Speedgoat 2
  • Salomon Speedcross 4
  • La Sportiva Akyra
  • Salomon XA Elevate


Note: This post was originally published Summer 2018, and trail running shoe recommendations may be out of date; visit our store to see current available options, or consult a Jans Expert for their recommendations based on your needs.


trail running shoe anatomy
Original image courtesy of Salomon.