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A-Z Running Terminology: Glossary of Trail Running Terms And Definitions

Most popular trail running terms and definitions

Welcome to our A-Z of trail running terms and definitions! This definitive list explains the running terms and definitions you may come across when reading our blog, other websites and books, and speaking with other runners.

If you are looking to find out the jargon used by trail runners, from understanding what a ‘Round’ means, how do you define an ultra marathon, to deciphering what someone may mean by referring to by being ‘Chicked’ or having a ‘Code Brown’, it’s all in here without you having to actually ask someone else to explain 🙂

Being so passionate about trail running, we have focused on terms you may come across relating specifically to off-road running, as well as some of the more ambiguous general runner lingo.


Aid Station

An aid station is a point during a race where you can replenish your water and food stashes, see supporters and seek medical assistance if required.

The level of support and supplies at an aid station varies depending on the race and the individual aid station – some may be very basic, with just water on offer, others can include a sit-down buffet and sleeping arrangements for longer races. Aid stations are also sometimes referred to as Checkpoints, but note that in some races, there are Checkpoints but no food or water offered, they’re just time-checkpoints.

Altitude Training (aka Elevation Training)

Training at a higher altitude than sea level, often done in mountain towns sitting at higher elevations, such as in the Alps and Colorado.

Because you get used to training in thinner air when you train at altitude (and develop more oxygen-carrying red blood cells), your performance is relatively better when returning to sea-level. People also emulate training at altitude by using elevation-training masks (although wearing one does make you look like Bain from Batman, and sound like Darth Vader :-)).


Barefoot Running (aka Minimalist Running)

Barefoot running can either mean running literally bare-footed, or, more commonly, wearing minimal, zero-drop running shoes to emulate the movement and feeling of running barefoot, but with a shoe to still protect your feet.

Read more about barefoot running in this barefoot running guide.


Before I started running I thought ‘bonk’ meant something very different… in the running world, a bonk describes the feeling you get where you run out of energy and feel a sudden wave of fatigue during a long run. Follow these strategies to be able to run longer without getting tired.

The key to avoiding ‘bonking’ or ‘hitting the wall’ is making sure you get your running nutrition sorted, so that you don’t run out of energy.

See our running nutrition articles for more advice in this area, and our nutrition reviews section for our buyer’s guides to plant-based running nutrition, as well as reviews of popular running nutrition, protein powders and recovery shakes.


Ok, so you may know what a running blister is, but how do you stop getting running blisters? Our popular posts: how to treat running blisters, stop getting blisters from running and blisters on the ball of my foot (from gait, not shoes) are a good place to start! Also make sure you have the best running socks and best running shoes.

Buffed Trail

A buffed trail is a smooth, runnable off-road trail, with few obstacles and typically over rolling hilly terrain, as opposed to steep, tricky rocky, muddy or uneven terrain.



A canicross race is a type of trail running race you do attached to your dog!

In canicross, the dog is attached to their human via a harness and you run the race as a team. The dog’s harness is specially designed like a dog-sled harness, to allow the dog to pull from their shoulders and reduce the risk of injury to their back. You, as the human companion, wear a low waist-belt that attaches to the dog using a bungee leash, which helps to absorb shock and take advantage of your center of gravity to keep you from being pulled over by your beast.

trail running with your dog trail and kale

RELATED READING: Trail running with your dog

Chafing / Chafe

Chafing in running is where your skin rubs raw from either rubbing against fabrics (such as your running clothes) or other parts of your body. You may more commonly experience chafing in delicate parts of your body, such as between your thighs, under arms and on nipples!

To reduce the risk of chafe, make sure you have running clothes that fit you properly and minimize the risk of chafing. For women in particular, I find long shorts help avoid thigh chafe – such as these Title Nine Holy Grail shorts. Also, anti-chafe balm can really help.

RELATED READING: What to wear trail running


A checkpoint in a trail running race can be another word for an Aid Station during a race, although generally a checkpoint does not promise a smorgasbord of goodies, it may literally be someone checking your timing chip or bib number at a certain point during a trail race.

Chicked/ Chicking

If you just got chicked then you have just been overtaken by a badass female trail runner during a race 😉

Code Brown

Ah, the dreaded CODE BROWN. This is code for the sudden urge to find a porta-potty or public conveniences during a run – easier said than done on a trail running race in the middle of nowhere! To reduce your chances of experiencing a code brown, work on getting your pre-race routine down to a fine art, and make sure you have a good race day breakfast planned.


In a running context, cramping is usually used to describe a muscle cramp, such as your calf or quad muscle – painful and stops you in your tracks!

Mount Tamalpais State Park Marin California trail and kale web wm 50

Cramping is often a result of over-exertion and/or loss of vital salts, and you can reduce your risk of getting painful muscle cramps by following the advice in this post.



Not a term exclusive to running, but dehydration is very important to understand and manage as a runner. Make sure you have appropriate means to carry water and replace vital salts when out running, to help reduce the risk of dehydration.

The best way to carry water when trail running is to wear a hydration vest. Click the buttons below to visit our men’s and women’s running hydration vests guides.


DNF means Did Not Finish. Some races are just not meant to be, we live and learn, and come back stronger next time.

DOMS (Delayed Onset Muscle Soreness)

You know when you have a big training session, such as doing a longer-than-normal run? Feels good, right? Even the next day you feel ok, and rather pleased with yourself. But then…. Day 2 post-run – GAH! Those quads/hamstrings/calves ache like crazy! Yep, that’s DOMS, it takes a while to kick in.

To reduce your experience of DOMS, or sometimes even prevent it from happening at all, make sure you have a good recovery routine for after your long and challenging training runs and races. A key element of this should include a good quality plant-based protein shake to help your muscles recover efficiently.


A ‘door-to-trail’ run means running from home (usually via a road/pavement) to the trails. Door-to-trail shoes are designed to be comfortable on both hard surfaces and moderate trails, for these situations – and are also great for running on mild trails, such as in city parks. For a selection of the best door-to-trail running shoes, read our ultimate guide to the best trail running shoes.


Elevation Profile

broken arrow skyrace - elevation profile
Broken Arrow Skyrace 26k race elevation profile

A side-view (or 2-dimensional cross-section) of a route, showing where a planned running route climbs and descends, as well as how steep those ascent/descent sections are. Trail running race organizers often provide these, together with markers showing where you can expect checkpoints and aid stations.

Elevation Mask (aka Altitude Training Mask)

A mask you can wear to emulate altitude training (see also ‘Altitude Training’).


Fartlek Training

Fartlek training means a type of running speed training (translated from the Swedish term ‘Speed Play’) where you vary your pace between fast and slow at varying intervals, for example, running fast and slow between park benches or trees during a training run.

Fartlek training makes speedwork a bit more interesting than fixed distance/time interval training.

Fast and Light

The term ‘fast and light’ refers to the principle of carrying a minimal amount of essential kit on a trail or mountain adventure, to enable you to move quickly and efficiently over off-road terrain.

There is a fine line between having just enough kit and being underprepared, so it takes a level of skill and experience to make sure you are adequately prepared with the right safety kit (such as enough clothes) when playing out in remote / potentially dangerous places.

Fell Running (aka Hill Running)

Originating in the UK, Fell Running is off-road running, however often does not involve running on defined trails.

It’s common for Fell Running races to involve simply running up and over a hill (or up and down again) via whichever route you choose. This often means you’re running over bogs, scree, heather and other scrambly terrain, so it can get pretty messy and technical!

FKT – Fastest Known Time

A speed record on any given route. FKTs are getting popular amongst elite and fast trail runners, who seek out epic challenging routes and aim to complete them in the fastest recorded time, typically supported by witnesses and GPS data.

There are no defined courses or rules, although people may set different times for doing a route (eg. circumnavigating a mountain or lake) depending on whether they did it ‘supported’ (with people meeting them at points along the way to provide food, shelter, etc) or ‘unsupported’ (where they carry everything they need themselves without outside assistance). I achieve FKTs by creating my own Strava segments and being the only person running them 🙂



Gaiters are fabric (such as neoprene or parachute material) garment that wraps around the top of your shoe and ankle to keep debris out.

Running terms - Gnarly terrain
Navigating technical terrain and distracting views on Buff Epic Trail, Spanish Pyrenees

Gnarly Trail

Gnarly Trails are the opposite of a Buffed Trail! Uneven, tricky, possibly slippery (eg wet roots and mud) or loose scree and stones to navigate.


Hill Repeats

Like Interval Training (see below) but training by running up and down hills of varying lengths and gradients, to improve running performance and strength.


Intervals / Interval Training

A type of speed training to help you train to run faster. Read our speed training post to learn more.




Loop Course

A running route that starts where it finishes, but doesn’t simply go out-and back – so you see as much different scenery and terrain as possible.


Mandatory Gear / Equipment

The items that race organizers stipulate you must have with you for your race, for your safety and to avoid being disqualified.

Mandatory gear for a trail running race may include a minimum amount of food, water, clothing and emergency items such as a foil blanket, whistle and mobile phone.

RELATED READING: Trail Running Gear Guides, What to Wear Trail Running, Essential Trail Running Gear for Emergencies.

Mountain Goat

Name used to describe an agile, speedy mountain or fell-runner! Also, a generic name for mountain-dwelling goats, such as the beautiful Chamois that can be found in the Alps.

MUT – Mountain Ultra Trail

An ultramarathon trail race, being held in mountain environments. Some of the World’s most famous ultramarathons, such as the UTMB, are MUT races. To learn more about popular world-class MUT races visit our events database.

Multi-Day / Multi-Stage

An ultramarathon race that take place over multiple days. Some require runners to be self-supported and carry a significant portion of their equipment, including all their food and clothing for the 3-6 days of the race.




My least favourite course, one that returns the way it came, so you repeat the ground you just covered, but in the opposite direction. There are good things about out-and-back runs, though. You should know the route (so you’re less likely to get lost) and you get to run down all the steep terrain you just climbed.



A companion runner who may accompany an ultrarunner on certain sections of a race, usually for 100 mile races or longer. Common for North American ultramarathons, but rarely permitted in European races.

Poles (hiking or running poles)

Lightweight hiking or running poles are usually foldable so they can be stored in a Race Vest when not in use. Very popular with mountain runners in Europe, and gaining popularity for mountain running races in North America. To learn more about using poles for trail running, click here to read our guide.

Best Trail Running Poles trail and kale min


A one-way running route or race, i.e. one that finishes in a different place than where it starts, unlike an out-and-back or looped route.

This is a great format for a running race where you want to travel as far as possible from A to B and not have to return to where you started! Examples of point-to-point races we have done include Transgrancanaria Marathon and Race to the Stones.

Power Hike

Most experienced trail runners find it more efficient both speed and energy-wise to adopt a fast hike for steeper uphill trails, rather than trying to run these sections.



Race Vest

Also referred to as a hydration vest or pack, this is a specially-designed form-fitting backpack for runners, typically used when running more than a few hours through to multiple days at a time on the trails. They come in different sizes and male and female-specific fits.


A Fell Running (see above) route originating in the UK, where runners cover a set loop course involving covering a certain number of summits.

Perhaps the most famous is the Bob Graham Round, a 106k loop in the UK’s Lake District that covers 42 fells and peaks with more than 8,000m of climbing and descent involved.


An adventurous holiday that revolves around running – our favorite type of holiday! For inspiration and trail running holiday ideas, read our Runcation articles and check out the running films on our YouTube channel!

Run On Clouds

Brand slogan for unique running brand On Running. Their shoes include rubber ‘cloud’ soles. For more about On Running read ‘Best On Running Shoes’ and see the On Brand page.

Run Streak

Running every day for several days in a row. Read more about the Benefits of a Running Streak.



Narrow trail, usually only wide enough for one person at a time.


Skyrunning is mountain running above 2,000m of altitude over very technical terrain with a significant amount of climbing and descent.

Matterhorn Ultraks 30k Helen Finishing Trail Kale
Helen finishing Matterhorn Ultraks in the Swiss Alps

Traditional skyrunning races are typically between 25k and 50k long, and are often organized on a weekend involving a Vertical Kilometer race and an Ultra-distance skyrace. Skyrunning races are difficult but so rewarding as they’re run in such beautiful mountains.

RELATED READING: Skyrunner World Series.

Matterhorn Ultraks 30k and the Buff Mountain Festival Marathon are both European skyrunning races; Broken Arrow Skyrace is a great example of such a race in North America.


Technical Trail

Like beauty or the spiciness of food, the technicality of a trail depends on who is contemplating it. An elite ultrarunner once told me that a certain ultramarathon course was not technical in the slightest. Maybe not for him, but I found certain sections were impossible to run!

A technical trail is usually one which is very uneven and steep, with tricky rocks, roots and loose footings to navigate. It may also involve semi-rock-climbing scrambles and descents – dangerous for the inexperienced and/or unprepared!

Tempo Run

A tempo run is a high-effort run intended to help you train to run faster.

Trail Dog

Loyal furry buddy who accompanies you on trail running and hiking adventures. An athletic, healthy and fit trail dog may well out-run you!

Our Trail Dog is the handsome Kepler, a border collie with a passion for trails, frisbees and herding. He reviews dog-related products and writes about being a Trail Dog on the Trail & Kale blog.

Trail Running

Aka the best pastime on Earth! Trail running means running primarily off-road, such as on dirt and forest trails. Taking up trail running changes your life!

For more trail running inspiration, browse the articles on our site, where you can also read popular interviews with trail runners of all backgrounds and experience levels.


Ultramarathon / Ultrarunning

An ultramarathon is running any distance greater than a marathon (26.2 miles), with the shortest race distance usually being a 50k race. Ultramarathons can be run on paved surfaces, but are most commonly run on trails, where the ground is often softer underfoot, the terrain undulates, and the landscapes are more peaceful and varied.

Common ultrarunning distances are 50k, 50 miles and 100 miles, however the distances vary depending on the location and geography. For examples of ultramarathons we have run, have a read of our ultrarunning posts.

UTMB – Ultra Tour de Mont Blanc

UTMB is a famous 100 mile MUT race in the French Alps, which follows the Tour de Mont Blanc trail to circumnavigate the highest peak in Western Europe, Mont Blanc.

READ MORE: What is the UTMB? Everything you need to know.

what is th UTMB trail race ultramarathon trail running trail and kale


Vert / Vertical Gain (and Vertical Loss)

How many feet (or metres) a running route gains, and therefore how much climbing (and descending) you would have to do on the route.

The ratio of vertical gain to distance covered gives you an indication of how tough the route is, and how long it may take you. For example, a half-marathon distance with 1000 metres of gain will be relatively easier than a 10k with the same amount of gain. 

Vertical Kilometer / Vertical Kilometre

Aka a ‘VK’ or ‘KmV‘, a point-to-point mountain running route that is less than 5km long, but climbs more than 1,000 metres (around 3,300ft) in that distance. VK routes and races are popular in the European mountain running community, and are only found in mountainous regions where it’s possible to climb this much over such a short distance. Read our summary of the Best Vertical KM races in the World to learn more.





Zero-drop running shoes

Zero-drop running shoes with no height differential between the heel and toe area. Traditional running shoes may have a differential of 10mm or more.

One of Trail & Kale's co-founders, a mom, and guardian of our resident trail dog, Kepler, Helen can be found trail running with Kepler and enjoying road runs with her mini in a jogging stroller, all while testing out the latest running gear for our readers.


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