There are several key differences between road running and trail running shoes, as running on road is whole different experience to running off-road. On road – a typically smooth, hard, and even surface – running movements and motions are repetitive and uniform (though higher-impact). Whereas, the softer, uneven and changeable terrain characteristic of the trails, forces the body to constantly react to changes underfoot and forces the muscles to work differently with every step.
Because of the difference of terrain, brands develop and design different shoes for road running and trail running, each constructed to meet the requirements and demands of that particular surface.
Different surface. Unique demands.
Your running style is called your "gait". Simply put, your upper and lower body work together to take you from the left foot, to the right foot, in a cyclical and rhythmical motion. Biomechanics is fascinating!
Running is a high-impact activity and running on hard and uniform surfaces like tarmac, puts greater stress on weight bearing joints such as the knee, hip, or ankle, than running on softer surfaces. Therefore, more often than not, road running shoes incorporate shock absorption technologies and support features, to lessen the impact and provide a stable platform to land on and push off from repeatedly .
With trail running, it's a whole different ball game! It’s a case of finding shoes which adapt most suitably to the unpredictable terrain you’ll be running across and which most closely meet the requirements for grip, traction, cushioning and underfoot protection for that terrain. Most off-road shoes (trail or hill) are neutral and are designed to be highly flexible so that both your feet and the shoes can adapt to the terrain effectively. The levels of support provided by different models will vary according to upper and midsole construction.
Now that we understand why road running and trail running shoes need to be constructed differently, let's take a look at how they are built.
The anatomy of a shoe
There's a lot of science that goes into making running shoes. The differences in the construction and technologies adopted in each model makes them unique. A running shoe is made of several components, that we can split into 2 main parts:
- The upper: comprising of the tongue, laces, mesh and heel tab/collar
- The sole: comprising of the midsole and the outsole
Each of these components will be structured differently in road running and trail running shoes, making them more suitable for the type of terrain they'll be used for.
Differences in the sole
Difference No 1: Cushioning
The midsole is the part that sits between the outsole and the insole of the shoe. It is where the cushioning comes from: the type of foam used will dictate the cushioning and the stability that a shoe will provide.
Road running shoes are typically more cushioned than trail running shoes as they are meant for hard surfaces.
Note: Firmer and more responsive road running shoes do exist though. As do softer, highly-cushioned trail running shoes.
Difference No 2: Heel-to-Toe Drop
In most running shoes, road and trail, the thickness of the midsole is different from heel to toe (thicker at the heel end and thinner at the toe box). This is what we call "heel-to-toe drop" or "offset" or "profile".
In road running shoes, this drop is generally higher to protect your Achilles and legs from the pounding impact on tarmac.
In trail running shoes, it is generally lower (keeping you lower to the ground) to provide a better ankle stability and enhance proprioception (the sense of self-movement and body position). With good proprioception comes enhanced responsiveness and greater awareness on uneven surfaces. Running off-road requires a great amount of trust in your footwear, but if you can increase the feeling of where your foot is landing, then you will have far greater balance.
Difference No 3: Medial Post
Stability road shoes will often feature a medial post – an insert of harder density foam positioned on the medial side (inside) of the shoe's midsole. The purpose of the medial post is to control excessive pronation.
Trail running shoes have no medial post, so as not to restrict the natural motion of the feet. But don't panic, if you wear stability road shoes, you will still be fine to run in trail running shoes. Every trail is different. You can find yourself tracking a river through a beautiful glen, scaling the edge of a gnarly hill or losing yourself in an overgrown forest. Your body has to constantly adapt to the changing terrain and the medial post would only act as a blocker – restricting your movement when you need it most.
The outsole is the part of your shoes that is in direct contact with the ground. This is what will provide traction. The outsole materials and structures differ for road and trail shoes.
In road running shoes, the outsole is generally made of blown rubber to provide superior grip in dry and wet conditions. The design varies from brand to brand, and model to model. The outsole's construction is often segmented to offer a smooth transition from heel-to-toe. Furthermore, the lugs can be shaped to encourage a faster transition from heel-to-toe.
For trail running shoes, Inov-8's tagline 'Get A Grip' pretty much sums it up. Trail running shoes will provide far better traction when the going gets rough. Trail shoes have a stickier compound on the sole to help you grip onto rocky, uneven terrain and have lugs to help grip soft ground. The depth of lugs varies quite a bit, so if you are looking for a shoe to tackle bogs, then the deeper the lug the better. If you need to include a bit of tarmac, then better to opt for a shallower lugged sole, so that the shoe won’t get excessively damaged on road.
In trail running shoes, the upper is made of sturdier and tougher materials to protect your feet and withstand trail terrain and hazards much better than a road shoe. Protection from rocks, tree roots and other obstacles is much appreciated! Most uppers include water repellent fabric to stop water from getting in.
In road running shoes, the upper is generally light and thin, providing great breathability. Most brands now create one-piece uppers that stretch and support in appropriate places.
The shape of the upper and fit/feel will be different from brand to brand, so try a few options to gauge and select the best brand for you.
Shoe sizing advice
As a general rule, a running shoe should feel secure, holding your ankle without slippage at the back and cradling your midfoot without being too tight width wise. The space in the toe box area is key too. If a shoe is too small length wise, you'll risk getting blisters, black toe nails or cutting off the blood flow and circulation. We recommend having a half to one thumb's width of space from the end of your longest toe to the front of your running shoes (when you're standing up).
Find what feels good
Once you've established whether you're sticking the pavements or taking to the trails, head to your nearest Run4It shop to try out shoes from various brands and compare various models. Do not go for what looks best, but for what feels the best!
The best of both worlds
We even have road-to-trail running shoes that can handle both surfaces, These boast a stable, cushioned midsole so you can run comfortably on roads and hard packed trails, as well as grippy multi-lugged outsole to tackle softer trails. Check out the Saucony Peregrine and HOKA Challenger ATR if you want a shoe that does both!