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Running, Outdoors

Ultra Running Terms & Glossary

Relaxing at Cottonwood Lakes

Relaxing at Cottonwood Lakes

So you want to get into ultra running or trail running, but you don’t understand all the weird lingo? Well, you’ve come to the single source for all ultra running terms and terminology, no matter how obscure or arcane. If it’s not here, no one’s ever said it, and if they did, they were probably triathletes.

You may wonder why we need another glossary for ultra running. It’s not like they’re aren’t magazines, groups, and religious sects dedicated to the sport; it’s just that they’re all super boring. Ultra running and trail running are awesome; our glossaries should be awesome too. So, here you go.

Table of Contents

The Ultra Running Ultra Glossary

In order to save you time and energy, some of these terms include useful information beyond the basic definition, answering such important questions as “Why should I care?” and “You’re kidding, right?” I’m not kidding. This is some serious stuff right here.

0 (Zero)

The number of legitimate excuses you have for not being an ultra runner or doing a race. It’s hard, but pretty much anyone can finish an ultra, including you.

6 Seconds

How late Gary Robbins was in getting to the Yellow Gate in the 2017 Barkley Marathons, if you ignore his navigational error. That’s six seconds after 60 hours of running in heat and rain on unmarked trails for 130 miles while climbing and descending the equivalent of Everest twice. Gary!!!

6 / 12 / 18 / 24 / 36 / 48 / 72 Hour Timed races

Many ultras are defined by distance — the exact miles you have to run to finish, with time only mattering for cutoffs. Other ultras called timed races are defined by duration — you just keep running until the clock runs out. David Goggins qualified for Badwater using one such 24-hour event. More.

30K Trail Run

The 30 kilometer (18 mile) distance is obviously not ultra-length, but many race directors are now offering 30Ks during 50K+ races as a starter distance for newbies and others who love the trail running but not the distance.

50K Ultra

A 31 mile race and generally the first ultra distance people try. I’d recommend picking the easiest race with the least elevation gain and loss with the best weather in the most beautiful place. Then call me and tell me where it is.

50M Ultra

So, you want to run 80 kilometers? There’s an amazing difference between a 50K and 50M race, far more than “just” another 19 miles would indicate. Fuel and hydration become far more serious concerns, as do foot and general bodily care.

100K Ultra

Sixty-two miles of pure bliss, 100Ks are what do after you’ve done a 50 miler but still can’t commit to a 100 miler.

100M Ultra

Many will say 100 miles (161K) is the first “real” ultra distance, but those people are mean. It is, regardless, exponentially harder to run a 100 miler compared to a 50M or 100K. This is also the distance at which you usually start to see crew and pacers. Some of the most famous (US) 100 milers are Hard Rock, Leadville, Wasatch Front and Western States, but there are many, many more. You should run one. See Grand Slam.

200 Mile Ultra

Yes, they have these. No matter how far you run, someone wants to go farther. Fortunately, many of these have generous cutoff times and are more like stage races than one long push. The Tahoe 200, for instance, has a 100 hour cutoff (more than four days) so you can fast-hike it if you don’t like sleep. More.

Achilles Tendinosis / Tendinitis

The bane of many runners’ existence, these are two different injuries of the tendon that connects your heel to your calf (so, it’s pretty important). Tendinosis vs. tendinitis is a giant topic, and I only mention it here because (a) you should do everything you can to avoid getting either one (b) most of what you’ll read online about them is wrong and (c) it’s very important to know if you have tendinosis (tendinopathy requiring long-term therapy and rest) or tendinitis (more easily treatable inflammation). It’s not going to do you much good to ice it or take anti-inflammatories (e.g., NSAIDs like Ibuprofen) if you have tendinosis. If you feel any tendon injury coming on, take the time to find out what your really have, early, and make sure you don’t let it become a chronic, long-term injury. It sucks. More.

Aid Stations

Where you get your fuel, fluids, positive feedback, information and occasional medical support during ultra races. Most ultras will have aid stations of some type very 6-10 miles, but this varies widely and wildly, often within the same race, so you’ll need to understand spacing before you show up — as this impacts what you wear, what pack you bring, how much water you take, how much you whine, and so on. Aid stations are generally staffed by volunteers, some of whom bring their delicious own food and considerable experience. Please be kind and thankful, and don’t take them for granted.

A few other things to remember: Races might have more checkpoints and cutoff points than just aid stations. Getting outside aid may get you disqualified (DQ’d) in some races. Some aid stations will have medical personnel and support, race captains, bathroom facilities (porta-potties), rest facilities, drop bag options and more, but many will not. Know before you go.

Age Group

(1) People with roughly the same number of injuries and body fat percentage as you. (2) The ones you’re eyeballin’ in the start corral to see if you can take ’em.

Many ultras, like regular marathons, are broken into age groups so you can compete against someone equally decrepit (I mean, young and feisty). Typical age groups are < 20, 20-29, 30-39, and so on (in ten year increments) until you get to 70+. Age group delineations differ sometimes, but rarely do age-group victories come with any prize other than personal satisfaction. If prizes are awarded at all, they’re usually for GP (gender placement) male and female victors. See gender group (GG).

Attitude / Grit / Mental Toughness

Kam at Leona Divide 50M Start

Runner with Positive Attitude

Get some. Running is 90% mental, and the other half is physical, or something like that. But most of this mental fortitude is not innate; it’s trained. It’s what you earn by training your mind and your body on long, painful, endless damn runs when it’s raining and you’re missing your favorite TV show. More.

Back-to-Back Runs

No, it’s not running while ignoring your pain-in-the-butt training partner. Back-to-back runs are longer consecutive runs (say, Saturday and Sunday) done in place of very long single-day runs followed by a relatively short day. Advocates of B2B say it gives you time to rest, eat and more while getting lots of time on your feet, while others say it costs too much in terms of lost family time and physical stress for any potential benefits. More.

Backyard Ultras

Relatively new ultra format invented or at least popularized by Barkley Marathons founder Gary Cantrell, in which there is no defined distance, time or end point — just 4.167 mile (100/24) mile 1-hour loops that continue until only one runner is left standing. Generally no gender or other placements, just one (1) winner and a whole lotta DNFs. See Big Dog Backyard Ultra. More

Bad Ass



(1) An iconic race from Death Valley to Whitney Portal (2) Euphemism for your urine after running through Death Valley (3) What’s left in your hydration bladder three days after your last run.

The Badwater into the category of ultras that also take place under “extreme” conditions. Where the Barkleys is about navigation, vertical gain, random conditions and pain tolerance, Badwater is about heat, and lots of of it. Temperatures in Death Valley often exceed 120 during the August event. The heat is so lethal the National Park Service (NPS) requires the race to start at night so runners are out of the hottest part the valley before sunrise. More.


Runners who enter races without paying or signing up. This is less common in ultra running than marathons, because there’s very little prize money in ultras and it’s hard to significantly cheat in most of the formats. But it’s not impossible, and with timed-runs that include multiple repeating loops, it’s becoming more common. More.

Barefoot Running

Three guesses. These runners are crazy (crazy impressive), and they save a lot on shoes and socks. Not sure about medical bills. Barefoot running surged in popularity in the US after Born to Run was published in 2009, and has declined since. See minimalist. More.

Barkley Fall Classic (BFC)

Once the Barkleys gained notoriety after the 2014 movie, The Race That Eats It’s Young, the race directors created a little starter Barkley called the Fall Classic. It doesn’t follow quite the same course, and it’s closer to a 50K than one of the 26 (estimated) miles of Barkley loop, but it’ll give you a taste. And if you win, you get into the big race. You can signup here, if you make it in before the race fills up. Good luck. I mean, my condolences.

Barkley Marathons (Barkleys)

That race that other people do and you’ll never do but you’re obsessed with it because you can’t believe they do what the do plus, damn, Laz is hysterical. Please make me #1 this year, please! #HumanSacrifice. Don’t bother looking for a website; there isn’t one. More.


You’re not an ultra runner until you watch the movies, read the book, and become weirdly obsessed with all of it. For Barkleys’ specific terms, go here.


One of several motivational animals, bears can be used in interval training or during races to obtain FKTs. If you’re running in Alaska on a narrow single-track in high bush, you might at least want to make a lot of noise so you don’t surprise any cute little ursine families around the corner. My mother sings. You do you, but don’t do it too quietly.

Walmsley tried yelling and even throwing some rocks to shift the bear [in the middle of the Western States course]. It got up on it’s hind legs and forced Walmsley to back off. – Mark Agnew

And then back off, slowly, like Jim Walmsley at Western States. More.

Bear Spray

I honestly used to think this was the same as cat spray, which is what happens if you get to close to an animal’s hindquarters. Turns out it’s a concentrated pepper spray used for defense against bears and people. I don’t want to get into the debate of spray vs. guns vs. whatever, but some runners in some places do take this stuff pretty seriously (as they should). For most of us, the odds of bear attack are close to null. More.


The perfect recovery drink? Sadly, it appears not. But it’s still delicious, and if drunk with lots of water, it probably won’t kill you. More.

Belt Buckles

Most of the 100 milers offer belt buckles as prizes, and the more famous ones are highly coveted. Some lower mileage races now offer buckles as a consequence of inevitable prize inflation. More.


(1) The software version your Garmin is running (2) Trail and route information.

Primarily a climbing term, beta refers to all trail our route details. Finding runners with good trail or race beta can be invaluable in the planning process, especially when you’re concerned about trail conditions, water sources and other transient issues.


What many trail runners think of mountain bikers, fairly or not. See Runholes, Stravassholes and Etiquette.

Big Dog Backyard Ultra

The world-championship and original Backyward Ultra, named after founder Gary Cantrell’s dog, it’s a great way to spend an October weekend clicking desperately for Facebook updates at 40 min past every hour. If you don’t get that, watch it next year. It’ll eat your brain, in a loving and awesome way.


Welcome! Now you’re part of the family. If you’ve got blisters, you’ve got something to brag about on social media other than just your black toenails and GPS summary.

Foot care is one of the key elements of ultra running. If you doubt that, take a look at Brett Maune’s feet during the Barkleys. That tape is not decorative. Blister prevention is a very personal thing. For me, I find it’s pretty easy in almost all conditions with a pair of toe socks and the right shoes. For my shoes, I loosen them slightly on uphills to prevent heel blisters, and tighten them on downhills to prevent toe jam (as delicious as that sounds). But everyone’s feet are different. Take the time to learn what works for you, and how to treat your blisters when nothing else works. More.


(1) Stained plastic container used to raise fungus (2) Body part that is never empty when running and never full when at an aid station.

I assume you know all about your own bladder, so let’s just talk about hydration bladders. Hydration packs and vests generally come with flexible bladders and drinking tubes that are wonders of weight and efficiency. Some people hate the taste of plastic tubing, but if you’re using any kind of drink mix it’ll generally cover the plastic flavor. My only recommendation is to wash them thoroughly after each use so you don’t end up with nasty little growths in the tube (unless that’s your thing). More.

Body Fat

Everybody’s got it. Some runners spend a lot of time trying to burn it more efficiently for fuel with various low-carb or carb-depleted training methods. You should totally do it, and tell me how it went. I’ll enjoy this beer while I wait.

This does however tie into the issue of body image and body type. There is no one body size or type for ultra running. Certainly, there are advantages to being lean and muscular (but not too muscular or too lean) and not to short or too tall, but unless you’re trying to win the Western States or be really competitive, none of that matters. Your body fat percentage is not going to determine whether you finish or not. Your training and attitude are.

On the other hand, if you do want to be competitive (place in the top ten or even win), you may want to take a look at your body fat percentage, training regimen and a billion other things…because body fat percentage is one of the most important factors at the competitive level.

[This] study showed that a low body fat percentage and high-intensity speed training are the two most prevalent factors in predicting race completion times.

But, if you’re not trying be an elite runner, you can ignore all that. More.

Born to Run

(1) Everyone but me; I was born to shuffle (2) One of the secret books you have to read or you’re not really an ultra-runner.

McDougall’s 2009 Born to Run is one of the more inspiring books in a sport full of inspiring stories. One important lesson: Your shoes may not matter that much, or may be slowing you down. Another important lesson: The first lesson isn’t for everyone. See barefoot running and minimalism.

BPM (Beats per Minute)

Your heart’s resting and training BPM is intimately tied into zone training and a gajillion other things. You’re not going to get too far in ultra running (at least if you have specific time and pace goals) without learning about heart-rate training zones and related cardiovascular topics. See resting heart rate and max heart rate.

Buffet / Buffet Stations

What the volunteers and race directors have laid out for you at aid stations. Keep your dirty hands out of the shared food.


(1) Slang for anti-chafing lubricant (2) Top 10 character on South Park. You’ll come across terms like “nut butter” and “butt butter” if you talk about chafing enough, but don’t be scared.


Don’t be me. I have a PhD in bonking, which means suddenly running out of all energy, feeling utterly wiped, and wanting to lie down on the trail and weep. In most cases, this means you haven’t handled adequately fueled your body. Some people recover well from bonks by slowing down, hydrating properly and eating lots of simple-carbohydrate foods, while others recover far more slowly. Everyone bonks at some point, so get used to it and get used to fixing it, or it’s gonna be a long day. See roadkill. Aka crash, hitting the wall. More.

Bragging Rights

What you get after your first ultra, or your first long run, or whenever you think the readout on your Garmin’s noteworthy. See Garmin brag.


The color of your urine right before your kidneys fail. Or is it after? Either way, you’re not drinking enough and time to see someone in the medical profession. See dehydration and hydration. More.


When you’re off trail and plowing through high bush, hopefully not during a race…except the Barkleys, of course. Aka going Barkley.

Cadence / Turnover

Cadence is measured in strides per minute, with higher cadence or turnover indicating a shorter time between footfalls. Most trainers recommend increasing cadence and decreasing stride length to increase speed and endurance while preventing injury. See running form. More.


So, some people swim with dolphins, others yoga with goats, and a few truly crazy individuals run with their dogs. Seriously. Trail racing with dogs is a thing, mostly in Europe, but you know how we do so it’ll soon be all the rage stateside. It’s probably safer than dolphin goat swim yoga, so give it a try. More.

Carb Loading

The idea that you can pre-load carbohydrates and thus glycogen into your body and muscles before a race by eating a ton of calories the night before. Usually an excuse to eat all that stuff you avoided during training.

Having said all of this, I would like to note finally that carbo-loading in general has been shown to enhance race performance only when athletes consume little or no carbohydrate during the race itself. If you do use a sports drink or sports gels to fuel your race effort–as you should–prior carbo-loading probably will have no effect. But it doesn’t hurt to do it anyway, as insurance. – Active.com

Recent studies have shown that carbohydrate loading has to be done a certain way to work, and is most valuable for longer events when you are not refueling during the race. It’s probably best to just eat a healthy dinner and breakfast, even if it’s not as fun. See fuel. More.

Central Governor (Theory)

The central governor is a proposed process in the brain that regulates exercise in regard to a neurally calculated safe exertion by the body. In particular, physical activity is controlled so that its intensity cannot threaten the body’s homeostasis by causing anoxic damage to the heart muscle. – Wikipedia

I only bring up the concept of central governor as a complicated way to say a simple thing; often, when you think you can’t go any further, you’re wrong; your mind’s just lying to you. You can, for instance, trick your body into feeling better by sucking on glucose-rich candies (overriding the central governor) when otherwise exhausted. You can sing, swear, listen to music and just keep moving. As Navy SEAL and ultra runner David Goggins would say, “…when your mind is telling you you’re done, you’re really only 40 percent done.” So, keep on keepin’ on. More.


Uncomfortable rubbing of one body part against another, or a piece of clothing, causing irritation, pain, rash and even bloody nipples. Most people will experience chafing on longer runs, at some point, but most of it is preventable if you plan in advance. I almost never run without wearing liners of some kind — whether built into my shorts or compression shorts — to avoid chub rub, but I do sometimes forget to check the sleeve length on my shirts. Whether by making changes to clothing or using anti-chafing lubricants like Body Glide, you’ll figure it out. Oh, and don’t ever wear cotton. More.


Refers to the dangerous lure of the chair, the temptation to sit, especially at aid stations during long races. Once you sit, you may never get back up, and when you do it will just suck more. I once had to crawl out of a chair which, while funny, is hard on the knees.


Places in an ultra race where runners are monitored, generally to make sure they pass the checkpoint and do so before a given cutoff time. Many aid stations are checkpoints, but there are often more checkpoints than aid stations in a race.

Chi Running

Apparently, running form and style influenced by t’ai chi. More.

Chip / Chip Time

As with regular marathons, some ultras will use runner timing chips (on shoes or bibs) to track runner times. Your chip time is your total time on the course as measured by when your chip crossed the start and (hopefully) finish line.


For a man to be passed by or finish behind a woman (the horror!). A phrase you may hear, and is kinda funny, but is also pretty offensive. Maybe just let it die. If you want to read about some of the great female ultra runners, here’s a good place to start. See sexism. More.

Chocolate Milk

They poor man’s / woman’s recovery drink. I’m still not sure why I pay so much for Recoverite. Is maltodextrin really better? Hell if I know. But it does, sadly, turn out that chocolate milk might not be that great for actual recovery. More.

Chub Rub

No, it’s not that. It’s when your legs run together and cause irritation, which can be a serious issue on longer runs. See chafing and rash.

Coconino Cowboys

A group of excellent ulra runners from the Flagstaff, AZ region, including Rob Krar and Jim Walmsley. More.

Code Brown

When you really have to take a poo. You’re going to be out there on the trail, a lot, and rarely will it coincide with a nice, clean bathroom. Embrace it. Learn to shit in the outdoors and Leave No Trace. Or eat lots of cheese.

Compression (Socks, Tights, Etc.)

I don’t know what to say about this stuff. From what I’ve read, there is very little evidence that compression gear helps with much more than post-race recovery, and then only in very particular cases. Here’s an article about a study that might or might not help. I’m not saying you shouldn’t pay $40 for compression socks; I’m just saying you can buy a lot of beer for $40. Think about it. More.


The starting areas of a large race (e.g., big marathons), partitioned by runner ability. Not used that much in ultra running, but it is courteous to let faster runners move closer to the starting line. More.

Corunavirus *

coRUNavirus Meme

coRUNavirus Meme

Because a global coronavirus pandemic is a great excuse to go for a run and there is, seriously, nothing more socially isolating than some great time alone on the trails. Hope this doesn’t catch on. Argh. See the meme, then wash your hands, please. More

Couch Runner

Anyone who watches reads about running and watches movies about trail running (or blogs about ultra running) when he or she should be running. See beer, body fat and injuries.

Course Marking

If there is any course marking, it’ll be removable ribbons, flags, chalk, flour or cute little signs. Some ultras are well marked, some not so much. And not infrequently, people come through and change or steal the markings. Animals even eat them (flags are delicious). It’s always good to know the course and pay attention lest you end up somewhere…else. More.

Course Record (CR)

The fastest time a given race has ever been run; the FKT of a race. There’s usually an overall CR (often the male time) and a second CR for women. Some races are run on differing routes each year (e.g., Barkleys), so CRs may vary over time and not be comparable year-to-year.


(1) One of several common issues that every runner knows the cure for despite still suffering from them themselves. Hint: They’re either caused by dehydration and salt depletion or plain ol’ fatigue. Let the arguing begin (2) Sorry ladies. Motrin? More.


Some races will allow others to pace you on some or all of the course, carry gear, offer support at designated aid stations, etc. The rules vary widely from race to race, so if you plan on using crew, make sure you follow the guidelines carefully. Then thank your crew profusely. See mules.

Cross Training

Any training that is not running. You’ll find that cross training is great for increasing fitness and workout levels while minimizing injuries. See strength training. More.


(1) Denim shorts worn by old-school dirt bags (2) Times you have to hit to finish a race, and at certain checkpoints or aid stations in order to continue the race.

They key thing to remember about cutoffs, other than planning for them, is that they are the time you have to leave the aid station, not get there. This is true of almost all races except for the final, race-finish cutoff. If you get to the aid station with 60 sixty seconds to spare, start stuffing food in your face, get some water, and get out of there before you’re pulled.

Cutting Trail

Don’t do it. See etiquette, Leave No Trace and runhole.

Courtney Dauwalter

One of the greatest ultra-runners of all time, plus a generally amazing and nice person. Who often beats men for the overall title.  More.

Delayed Onset Muscle Soreness (DOMS)

When you’re fine on Sunday and can’t walk on Monday. Usually indicates a poor recovery routine, or just really hard work on Saturday. No, god is not punishing you. More.

Depth Noception *

That complete lack of depth perception caused by running at night with a headlamp on your head. Mostly treatable by carrying headlamp in hand or strapping to waist. See waist-mounted lights and Peelumination.


Too little water in da body, which is how must of us spend most of our lives, and running just makes it worse.

Spitting: The convenient and inexpensive Spit Test is a good test of hydration status. If you can easily work up a spit, chances are, you are well-hydrated! – Dr. Lisa Bliss

See hydration, hyopnatremia, hypernatremia and urine.

DFL (Dead Fucking Last)

Some people will tell you it’s Dead Freaking Last, but those people can’t be trusted. If you’re going to be last, own it. Celebrate. Post your time on Facebook and point out that you still beat every DNS, DNF, DQ and, mostly importantly, everyone who didn’t even try. You’re still a bad ass.


Any hard fall or trip that’s not a face plant, or maybe it also includes face plants. There are no rules in ultra terminology. Just watch your feet.

Downhill Running & Training

Downhill running and training can be fun, fast, dangerous and exhausting. Because of the risk, especially on technical trails, many runners neglect downhill training and focus on the aerobics of (up)hill work — despite the fact that improper technique and inadequate training on downhills can chew up your quads faster than anything else. See quad buster. More.

DNF (Did Not Finish)

What happens if you drop out miss a cutoff, get pulled, or just don’t finish the race. Some race directors will drop you down to a lower race distance instead of giving you the DNF, either automatically or upon request.

DNS (Did Not Start)

Guess you shouldn’t have been drinking that night on Ultra Signup, eh?


Following someone else to keep pace or because you’re afraid of bears. In sports like road racing, swimming and cycling, drafting conveys a significant physical advantage and is often considered unfair or cheating. In ultra running, given the speeds and variable terrain involved, it’s more often done for pacing, consistency and sanity as there is little or no mechanical advantage (except in strong headwinds or if there are lots of spiderwebs on the trail). Just beware of crop dusters, and don’t trip the person you’re drafting off. See Spiderman and sucking web.

Drop Bags

(1) Bags full of gear and fuel left at aid stations on longer races (2) Small plastic bags dog owners leave at trail heads because they’re nice that away.

If you get into 50M+ ultras, you’re going to spend a lot of time thinking about what to put in drop bags. Is it going to rain (need a shell)? Is it going to be dark (need a headlamp)? How upset will my stomach be (need Alka Seltzer and Saltines)? What about a change of shoes as my feet swell? And so on. Just don’t forget to put batteries in your headlamp. More.

DQ (Disqualified)

See also bandits.


Sudden and often involuntary acceleration when someone passes you or generally threatens your awesomeness. Origin unclear.


Electrolytes are minerals that are essential to muscular function, and which we lose in sweat. The most important in running nutrition are sodium, potassium, calcium, magnesium and phosphate. There are many electrolyte supplements and replacement drinks, most of which are insufficient in sodium and have excessive simple sugars (e.g., Gatorade). See hydration, hyponatremia and salt pills. More and Even More.

Elevation Change

The running equivalent of flammable / inflammable, which either includes total elevation gain and loss or just gain depending on which site you’re on. Mysterious, inaccurate and seemingly impossible to measure. See also total vert.


The speedy runners who finish the race before you make the turn-around. Some are professionals and sponsored, some are just super dedicated. Don’t compare yourself to or be envious; they’re the first to run into bears.

Etiquette (Trail Etiquette)

The most important thing about trail etiquette is knowing that there’s trail etiquette and it applies to you. Don’t be a runhole / jerk / meany. Do everything you read here, here and here. Most of it’s just common sense and decency. And see Leave No Trace and yielding. More.

Euro Walking

I’m not sure this is even the right term. I tried to find out what this technique is generally named, but most sites just describe it as “walking with your hands on your knees.” Whatever you call it, it’s a great technique to decrease quad burn on long / steep uphills if you’re not using trekking poles. More.

Extreme Races

Extreme and ultra are not the same thing. Some ultras can be very mellow, and some marathons can be extreme and frankly dangerous. There are a few specific types of extreme races emerging in popularity, many of which are also ultra distance:

Given so much variation, even if you omit the broader category of adventure racing, it’s hard to define the “hardest race in the world” but pretty easy to find races that’ll make you pray for death. In a good way. More.

Face Plant

(1)Trip (2) Fall (3) Plant face in ground. Happens to us all if/when our hands aren’t fast enough to break the fall. See diggers and Superman.


Fartlek (“Speed Play”) is a mashup of interval and endurance training. Basically, you throw in some faster running or even sprints while maintaining an overall moderate pace in order to train both aerobic and anaerobic systems. There’s probably more too it than that, but mostly it makes you giggle. Let’s fartlek! More.

Fell Running

Dude, I totally just fell running.

Originally a Scottish sport akin to hill running with navigational and hill challenges. They tend to be wet and boggy, so fell running shoes are made to eject and shed water better than other running shoes. More.

FKT (Fastest Known Time)

The fastest time on any route, trail, course or segment. Strava was basically built around FKTs for cyclists, but is now used more and more by runners. The FKT for a race is generally known as a course record. If you really care about FKTs, there’s a whole site for it here. See also PB (Personal Best) and SKT (Slowest Known Time). More.


What runners say when they mean water, flavored water, water with salt and water with carbohydrates, beer, chocolate milk and so on, until they process it, and then fluids means pee. Wait, I guess that’s what fluids means to everyone. See hydration and urine. More.

Emilie Forsberg

A highly accomplished ultra runner and ski mountaineer, and one half of the Forsberg-Jornet power duo. More.


All calories eaten or drunk immediately before and during a run or race. One thing people often forget is that fuel is not just about feeding the machine; it’s also about feeding the brain, or at least conning it into thinking it’s being fed. Sucking on candies, Gin Gins, or something else high in glucose can impart an immediate physiological benefit that is disproportionate to the calories consumed. See central governor theory and nutrition. More.

Garmin Brag

A photo of a GPS watch face shared on social media, “because actually typing how far or how fast you ran would be narcissistic.” Not sure who came up with the term, so attribution pending. See bragging rights and GPS watches.

Gender Group (GG)

If you have binary genitalia, you have a binary gender group. All ultras that I’ve seen have (M)ale and (F)emale groups, with male racers generally completing well before the lead women. Part of this might be genetic, but part is also be that ultras (unlike marathons) are predominantly run by men (See sexism). Don’t let that discourage you — there are great woman athletes in the sport (many!) and it’s an incredibly welcoming environment for newbies.


Go juice stored in your muscles and bloodstream. If you get into ultra running, you’ll read a lot about how it’s stored, how to get more of it, how to recover it faster, and then you’ll just drink more beer because it’s confusing AF. It’s a serious topic if you want to improve performance and avoid bonking. See fuel and nutrition. More.

David Goggins

Who let this guy in here? Seriously, what a bad ass. Next time you’re driving, check out the Joe Rogan Experience podcast about how he got into ultra running. More.

“Good Job!”

What every runner says when they pass you during a race, especially if you’re not doing a good job. Positive feedback that avoids unnecessary conversation.

Golden Stairs *

Every other step on the Bright Angel or Kaibab trails in the Grand Canyon. Also known as Mule Urine Surprise, or Dear Lord What’s That Smell? More.

Fitness Leak

Accidental pee seepage while running. Pretty common. Not sure who came up with the term. See urine. Literally.

Fitness Watches

A watch used for fitness. Not trying to be sarcastic, but it is what it is. See GPS watches. Not all fitness watches have GPS, making them far cheaper in some cases (and prolonging battery life). I only have a Garmin (non-GPS) so I can track my heart rate, and use my phone for everything else. More.


Beaten by an old dude or dudette, the ageist equivalent of chicked.

GP (Gender Placement)

Overall position in a race within a given gender (usually Males or Female). Some races do not have separate gender rankings.

GPS (Global Positioning System)

Awesome global government-funded geolocation system that allows you to check-in at Starbucks and track your runs, including both distance traveled and elevation gain (and loss). More.

GPS (Smartphone) Apps

Almost any smartphone with GPS (all of them?) can support one or many GPS tracking apps, ranging from All Trails to Gaia and Strava, and many more. Your GPS-enabled watch may also tie into phone apps like Garmin Smartphone Link. I’d look for apps that (a) don’t burn a lot of battery (b) work in airplane / offline mode (c) come packaged with pre-existing trails and routes (d) include good topo maps and (e) are free. More.

GPS Tracks

Grand Canyon R2R2R Track, Courtesy of Trail Run Project

Courtesy of Trail Run Project

One of the best ways to learn about a trail in advance is to look at other runners or hikers GPS tracks (literally, GPS records). This will tell you total distance gained, min/max incline, total elevation gain/loss, and far more.

All Trails, Trail Run Project and Strava are all great sites for GPS tracks and other information. Once you have a GPS track, you can often download to Google Maps or Google Earth, or even create virtual movies. See Beta, GPS Apps and GPS Watches.

GPS Watches

A whole giant industry of madness. Do you need a $600 Suuntto Elementum Terra? Of course you do. What you spend on sports / fitness / GPS watches depends entirely on what you need and what you can afford. Some features to think about:

  • Compass / GPS Compass
  • GPS Tracking
  • Elevation Gain / Loss
  • Barometric Pressure (if you’re in the mountains a lot)
  • Temperature
  • Heart Rate / Zones
  • Time (If you’re really spendy)

Enjoy finding what works for you. More.


(1) The last 30% of any 100 mile run (2) Any time you see stuff that isn’t there.

Ultra runners often hallucinate during twilight hours or after dark, and it’s not generally a cause for concern until you start running off trail or the trees come after you. The usual cause is sleep deprivation. More.

Grand Slam of ultrarunning (USA 100s)

The US grand slam of the oldest 100 mile races comprises any four of these five 100s: Leadville 100 in Colorado, Old Dominion 100 in Virginia, Western States 100 in California, Wasatch Front 100 in Utah and the Vermont 100 in Vermont. If you’ve done all four of these ultras in a year, you probably don’t need this glossary. More.


(1) Nutritional supplement company (2) Putting the pedal down / running super fast. When you hammer or put the hammer down, you go super fast and burn out super faster. Great way to intimidate the competition and chew up your quads. See also sucking wind and face plant. See pacing.


Many ultra runners prefer to go without hydration vests or belts, carrying all their fuel and nutrition in handheld water bottles. This works really well until you face plant, then you’re broken and you have no water. I sweat too much (need too much water) for this method, plus I’m clumsy. There is of course a lot of debate about whether handhelds are better than packs. Here is a pro-handheld article that contradicts what I say about falls, and here’s a general overview. Enjoy, then pick what works for you.


All your medals and buckles. Don’t forget to post pictures on social media of how you’ve cleverly built racks and pegs to display them all, discreetly, where everyone can see them. See prizes.


Unless your a bat or a vampire, or you’re running in the summer north of the Arctic Circle, you’ll want one of these at night on trail runs. Ultra runners tend to go for versions that are light, very low powered, with long battery life. They give you just enough light to see what you’re about to trip over. See depth noception, and also consider waist-mounted lights. More.

Heel Strike (Rearfoot Strike)

Most of us (80%?) land on our heel or rearfoot when we run. There is a strong contingent of runners and experts who believe toe (forefoot) striking and midfoot striking are both more efficient and result in faster finish times. More.

Heat Exhaustion

Medical condition related to heat and, well, exhaustion. More.

Heat Stroke

Serious medical condition related to heat and, well, death.

“The mother of all heat related illnesses. Your body temperature rises above 105 degrees F and it becomes a life-threatening situation. Most often, heatstroke results from untreated heat exhaustion, although it’s very possible for heatstroke to come about with no signs of heat exhaustion.”Scientific American

If you think someone is experiencing heatstroke, seek immediate medical help. More.

Hill Training

Training. On hills. It’s not that complicated, but it is necessary. See downhill training. More.

Human Sacrifice

(1) Slow runner in bear country (2) Runner most likely to quit first in the Barkleys.


Basically, prevention of dehydration. Everyone sweats at different rates, and exudes varying amounts of salt and other minerals in their sweat. On shorter runs, say those less than 90 min, you probably don’t need to worry about it that much except on the hottest days (this is not true of everyone). On longer runs, you’ll need to figure out how much water you need to intake, carry, if there are reliable water sources, etc., so that you can stay properly hydrated. I’m a heavy sweater (not the kind you get at Christmas), so hydration is a big issue for me on longer runs. See handhelds, hydration vests and sweat rate. More.

Hydration Belt

For runners who just couldn’t leave their fanny pack at home, hydration belts are a popular alternative to hydration packs and handhelds.

Hydration Pack / Vest

The most you’ll ever pay for the least amount of material that isn’t lingerie, hydration vests are light and generally minimalist ways to carry fuel and water on a run or in a race, while packs are larger and meant to carry more stuff. See hydration belts.


Excessive sweating. Not really a running-specific issue, but if you’re a runner with hyperhidrosis or you’re just a heavy sweater, hydration on longer runs will be a serious concern. More.


Too much salt in your blood (too high a concentration) generally caused by dehydration rather than excess salt intake. Very rarely do you have to worry about swallowing too many salt pills. Gradual water intake is the normal solution (i.e., drink something). See hydration and hyponatremia. More.


Too little salt in your blood (too low a concentration). This can happen when you drink too much water, or if you sweat heavily on a long run and don’t intake sodium as you go, so it often results from dehydration followed by excess water intake. Note that when your feel “off” due to hyponatremia, many runners will suggest you drink water (assuming you’re dehydrated), but this just reduces the concentration of salt in your blood and makes the condition worse. If you have it or want to avoid it, eat salty foods and, well, salt (sodium) — not just salt pills or electrolytes. See hydration and hypernatremia, and my experience with hyponatremia in the Grand Canyon (hint: it sucks). More.


If it’s snowing and you feel like getting naked, you have it. Hypothermia is a serious issue caused by a drop in core body temperature, and can be lethal. One of the mistakes runners (and hikers) make in cold weather is over-dressing, which results in sweat-drenched clothes followed by chills and then hypothermia. Everyone manages heat and cold differently (I would rather run in the arctic than on day hotter than 90 degrees), so practice carefully to see works with your body. More.


Can’t. Breath. Must. Run. Argh!!!

Hypoxia just means you’re not getting enough air, as is common at altitude. To train for Sky Runs and mountain running or just being way up there, some runners advocate hypoxia training to simulate training at altitude — which explains some of the crazy masks you see while running. More.

Interloopal (Period or Time)

Originally a Barkley Marathons term, refers to time between loops of a multi-timed-loop race where runners recover, rest, refuel and (rarely) sleep. In the Barkleys, this time is up to you but counts toward total race time. In Backyard Ultras, it’s whatever time is left in your one-hour-max loop.

Injury (& Injury Prevention)

What you have now but won’t have tomorrow if you’re 25, and you’ll have forever if you’re over 40. Maybe if you just run a little bit further, it’ll go away. Age groups are basically measured by injury-to-weight ratios.

By some estimates, 75% of runners will be injured at some point every year. The most important thing I can say is that you have to get to know your body, and learn when to quit or push forward, or you’re not going to be running for very long. Increase training volume slowly. Cross train consistently. Sleep. More.

Inserts / Insoles / Sports Orthotics

Running shoes will generally have removable inserts, and many runners replace these with Superfeet or other after-market insoles to provide greater padding or arch support. I’d recommend trying store-bought inserts before assuming you need more expensive custom sports orthotics, but of course that’s between you and your doctor. More.

Inshoecurity *

The constant, nagging fear that your heel drop is too much or your shank is too stiff, resulting in substandard running form that costs you 32 nanoseconds in a 100 mile race (+/- 53 nanoseconds) and chronic plantar fasciitis. Are your laces too loose or tight? Should you use a runner’s knot? Is your insert too soft? Arch support? What arch support? ARGH! I thought I made this word up, but it turns out shoe shoppers feel inshoecure all the time.

Inshoenty Principle *

Physical law that proves it’s impossible to find a shoe where both heel and toe fit properly. See toe box, heel cup and whining.

Intervals / Repeats

A type of training using bursts of high-level output followed by shorter periods of rest. One recent Science of Ultra podcast recommended four sets of 8-minute intervals with 4-minute breaks at least once per week (working up to that) as the best way to improve VO2 Max and overall aerobic fitness. See speed work. More.

Iliotibial Band (IT Band)

(1) All-male musical group formed after D&D got boring (2) That thing in your leg trying to rip your hip out.

The IT band runs along the outside of the thigh, from just above the hip to just below the knee, and is made up of fascia, an elastic connective tissue found throughout the body. Though often compared to tendons — the two can serve similar functions — fascia is composed of large sheets, while tendons are more rope-like. – Harvard Gazette

It’s hard to think of anything that injures runners more than their own IT bands. See IT Band Syndrome. More.

IT Band Syndrome (ITBS)

Usually, a pain on the outside of the knee that’s caused by a tight IT band. The recommended treatment is foam rolling and stretching, but there’s oddly little evidence about the true causes of ITB injuries, or that rolling the band helps anything. I don’t want to get it the middle off a debate, but here’s one trainer with a different approach (that worked better for me):

Still, I’m not a medical expert and anecdotes are not science. Do what works for you and listen to your doctor. More.

Junk Miles

Miles in your training program meant to make certain total mileage targets, but no other specific purpose (e.g., not speed work). Largely an attitude problem with LSD? More.

Scott Jurek

World class ultra runner and author of Eat & Run and North. Won Western States a bunch of times. Probably better than you are, and nicer too. More.

Kilian Jornet Burgada

That guys who’s name you can’t pronounce and whose legs you can’t keep up with. Only videos on the internet where professional runners try to keep up with him running downhill and nearly stroke out.

Plus, he climbed Everest or something, or didn’t. GPS is for losers. Also one-half of the and one half of the Forsberg-Jornet power duo. More.


Putting the hammer down or increasing the pace at the end of a run or race.

Kinesiology Tape / Kinesio Tape / K-tape / KT Tape

The most expensive thing that will fall off your body once you start sweating, k-tape is used by many runners for stabilization or protection of injured body parts and joints. Note that “Kinesio” is a brand name, but there are many great makers of k-tape. Aka runner’s tape or elastic therapeutic sports tape. More.

Rob Krar

One of the Coconino Cowboys, Rob Krar is a US endurance athlete and winner of the Leadville 100, Western States and many other events.

My inclusion of Rob here is somewhat random (they all are), but his discussion and thoughts on depression and running are well worth the time. More.

Lactate Threshold

(1) The max amount of milk you can hold your mouth (2) Training just below anaerobic heart rate to build your cardiovascular base. See tempo runs. More.


(1) Where I usually finish (See DFL) (2) Mechanical insert used in shoe manufacturing. Not sure why that’s important, but you’ll see it in shoe reviews.

Lazarus Lake (Gary Cantrell)

Founder and spiritual leader of the Barkleys. More.

Leap Frogging

On longer runs, you may find yourself passing and being passed by the same person or people multiple times. Good way to make friends, or enemies depending on how much you stink or crop dust.

Leave No Trace

Please? See more here.


Trail running isn’t like marathons where you can just toss crap all over the place. See Leave No Trace. Aka micro-trash.

Lollipop (Course or Trail)

A rarely used term referring to courses or trails with a long out-and-back section leading to a loop, creating a rough lollipop shape.

Loop (Course or Trail)

Courses that start and end at the same point without retracing the same ground (much). Many or most time-based endurance runs (e.g., 24-hour events) are on repeated loops, as are the Barkleys.


Many races, including Western States and the Barkley Fall Classic, use lotteries for runner selection because demand is so much greater than supply. Races like the Mt. Marathon race in Alaska will even offer ways to buy your way in if the lottery doesn’t go your way.

LSD (Long Slow Distance)

A label you’ll see on many training plans, telling you to take it easy. LSD miles are just as important as intervals and hill climbing in comprehensive training plans, especially if you want to avoid injury.


(1) Beefy runners (2) The bumps on the bottom of your shoes that are supposed to provide traction.

Maximum Heart Rate (MHR)

Your highest (healthful) heart rate (BPM), which declines steadily with age. MHR is used in zone-based training programs, and is also just helpful to know for reference. More.

Brett Maune

The other guy who’s name you can’t pronounce who holds the Barkley Marathons record but never seems to properly document his FKTs. C2C2C what? Are you freaking kidding me? I said freaking because he seems like the kinda guy who never swears. More.

Midfoot strike

Runners who land mid-foot rather than with a distinct toe strike or heel strike. Nobody pays attention to us.


Runner with a less-is-more, bare feet are happy feet, I don’t need to stinkin’ socks attitude. Sometimes they’re naked.

Minimalist Shoes

A compromise between shoes and barefoot running, minimalist shoes promise the feel of your feet on the ground with a little added protection.

There is no evidence that minimalist running shoes (i.e. Vibram Five Fingers or Brooks) help prevent injuries more than normal running shoes. The fact is, despite our advances in shoe design and safety, running injury rates have changed little in the last 30 years. In other words, $150 shoes are not the answer! – Dr. Matthew Mitchell

See toe socks. More.

Mountain GOATS

(1) Runners who love hill climbs and mountain runs more than their spouses or (2) jaunty animals way better at mountaineering than you are.

Mountain Lions

Another motivational animal, mountain lions are scary. I’d rather run into a shark, but fortunately the odds are about the same on mountain trails. While there are cougars and mountain lions throughout much of the United States, fatal attacks are vanishingly rare. Just ignore that thing at Western States. See bear spray. More.

Mountain Running

A specific, regulated mountain running sport that is also distinct from fell running. Some mountain runs are extreme or ultra distance, many are not. See MUT. More.


(1) Crew members who help carry your stuff on longer races (2) Masters of defecation and urination in the Grand Canyon (See Golden Stairs).

MUT (Mountain, Ultra, Trail)

Runners who race in mountain, trail and ultra events, and an official term of the US Track & Field Association. Here’s some 411 on official MUTs, and here’s more general information on MUT runners.

Negative Split

Basically, the concept that you go faster later in a run, so that your second half is shorter than your first. Same concept if later splits are faster than earlier ones. Also a race timing company. More.


Apparently, a runner dressed in all neon clothing. I prefer to think of them as visibility enhanced.


Any person new to ultra running, to running a particular distance, or even running given race. In the Barkleys, they call them virgins, but they’re crazy like that.


Body parts you try to rub off while running. They make tape for this. See also pasties. To avoid nipple abrasion, see chafing and rash.


Everything you eat (and drink) to keep your body moving. The key components of running fuel are carbohydrates and electrolytes, with a little protein (amino acids) thrown in there. Eat carbs or you’ll burn fat and that’ll slow you down, and you might eventually bonk unless you’re used to running carb-depleted. The general recommendation is to consume 150 – 300 calories (max) per hour, as that’s all you can digest (regardless of how much you burn). This is huge topic, for obvious reasons, and incredibly personal based on your body, training volume, and race length. See glycogen, hydration and runner’s stomach. More.

Obstacle Course Races (OCRs)

See Spartan, Tough Mudder, etc.

“On Your Left!”

What you say / yell (not to loudly) in the US to let people know you’re coming up behind them, or in the UK to mess with people. See etiquette.

Out-and-Back (Course or Trail)

Basically a course where you go out…and then come back by the same route. See time dilation.

Outside Aid

Support for a runner outside of an established aid station. Some events do not allow outside aid, and getting any may result in a DQ as in an infamous recent case at the Hardrock 100.

Over training

Yes, it’s possible, but not as fun as over eating.

Overtraining syndrome is what happens when the body never gets that rest. Through some combination of excessive exercise and inadequate recovery, athletes experience a severe shock to the parasympathetic nervous system, which controls the body’s inflammatory pathways. – Outside

Check yourself before you wreck yourself is real. It’s real, and here’s a great Outside Magazine article about it. More.


Your overall speed on the run.

Pacer / Pacing

In longer races (usually 100M+) you may be allowed a pacer to help keep you company, maintain a consistent pace, navigate and not hallucinate your way off a cliff. Pacing is a serious responsibility, so be sure to use pacers you can rely on. More.

PB (Personal Best) or Personal Record (PR)

What you care about when you realize FKTs are lame. The reality is, most of us will never FKT unless we make up a course for ourselves and don’t tell anyone else about it. But trying to set a personal best can be a great way to motivate yourself for the next race or run.

Peelumination *

Phenomenon caused by strange need to stare at your stream while peeing at night, possibly related to hydration anxiety, but more likely related to sensory deprivation and boredom. What else am I supposed to look at? See also urine.

Perceived Exertion

How hard you think you’re working. Some experts say it’s better to use perceived exertion than heart-rate zones for interval training. More.

Plantar Fasciitis

A pain in the foot that afflicts many, many runners. If you think something’s going on down there (around arch and ball of your foot), take care of it before it becomes a chronic injury. More.

Point-to-Point (Course or Trail)

A route or race that starts in one place and ends in another (e.g., Western States). Aka logistical pain the ass.


(1) The only thing on the race course that smells worse than you do (2) Heaven.

I’m sure you know what a porta-potty is, but did you know you could use them to cheat in ultras? Don’t be that guy. Also, wash your hands. More.

Power Hiking

Most people end up walking during ultras and long trail runs, and on uphills with more than 10% grade it’s actually far more efficient. Power hiking is just a fancy way of saying you’re walking fast with an overly-serious look on your face. Don’t be ashamed!


(1) Salty obsession of all ultra-runners (2) Male runners in tight shorts without liners, or in liners without shorts. See pickle dance. Just kidding, don’t.

Pickle Juice

Juice. From Pickles.

A number of studies have confirmed that pickle brine might be more effective than sports drinks at treating muscle cramps.

Nuff said. More.


How much your foot rolls, naturally, with each step.

If you have normal pronation, your foot rolls inward about 15 percent and optimally distributes the forces of impact – Runner’s World

If your foot rolls inward more than 15%, you over-pronate, less than 15% and you under-pronate (i.e., supinate) which can lead to more ankle twists and other injuries). Rather than trying to correct your natural pronation, as some shoes have done, newer shoes broaden the midsole to provide more stability. More.


(1) How professional runners perceive amateurs (2) What you should have worked on before spraining your ankle again.

When a runner isn’t prepared and doesn’t have a good sense of balance and proprioception, the inherent unpredictability of trails can lead to ankle strains and sprains, common injuries among off-road runners. – Active.com

Proprioception is your body’s innate sense of balance. There are numerous sensors in your feet and ankles to manage proprioception, all of which can be trained to help prevent painful ankle twists and sprains. See injury prevention. More.


In ultras as in other races, the race director and aid station captains, and often other officials, can pull you from a race if you’re injured, dehydrated or generally being a runhole. Getting pulled, unless it’s for a disqualifying (DQ) act, generally results in a DNF on your permanent record. The shame! Kidding. It happens to everyone. Aka yanked. See bandits.

Quad Buster

Any run with a lot of hard, pounding downhill. See downhill running.


Someone who goes out fast, either to help drive the race pace or because they’re just so excited to be there and had way too much coffee that morning. Be careful following rabbits, unless you want to burn out early. See pacing.

Race Directors (RDs)

The kind and dedicated people who organize and run ultra races, take care of our many needs, and put up with our whining. Many but not all RDs are runners, and just about all of them have day jobs. Be nice. More.

Race-Specific Training

Training that matches likely conditions of the race itself. If you’re doing Badwater, train in the heat. If you’re doing a Sky Run, train at altitude. If you’re going to be racing on technical trail with lots of downhill, train on that — and train on the actual course if you can. More.

Race Vest

Stinky thing in your closet used to carry water bladders and other trail essentials. You will become strangely obsessed with the zippers, pockets and fasteners of your race vest. You will wear it until it makes you look homeless. You will love it. Your precious. But it’s just a hydration vest for racing, meaning lighter and more expensive than the one you train in.

Random Transient Pain (RTP)

An additional “bonus” challenge issued to all runners over age 35. Should you ignore that weird pain? Should you quit now before it gets worse? Will it just go away in a few minutes? How long is this going to take to figure out on WebMD?


(1) Your decision-making process last night on Ultra Signup (2) Your inner thighs and nipples three months later.

If you don’t want to get rashes, either use a lubricant or run with an undergarment of some kind. I run in tights on all longer races (or use shorts with built in liners), but have never had nipple issues. Others use lubricants or butters, but heat rashes can still get you. More.


What you should be doing after beer and pizza, and sleep, so you can walk on Monday. More.


What you don’t get after a DNS. Some race directors will offer full or partial refunds if you have to pull out of a race far enough in advance, but it’s entirely up to their discretion.

Repetitive Strain Injuries

Injuries you might get with too much training volume, but you are guaranteed to get with too much training volume and poor running form. More.

Resting Heart Rate (RHR)

My resting heart rate is up to 44, so I need to do more Fartleks tomorrow.

One of several metrics you have to slip into every conversation, especially when talking with non-ultra-runners. More.


What gets posted on Ultra Signup…eventually.

RICE (Rest. Ice. Compression. Elevation.)

The simple answer everyone gives you when you say, I’ve hurt X, what do I do? While a short period of rest is certainly recommended in many cases, icing has recently fallen (somewhat) out of favor as an anti-inflammatory treatment — and has been shown to be counter-productive for some injuries.

Topical cooling (icing) . . . seems not to improve but, rather, delay recovery from eccentric exercise-induced muscle damage – Jrnl. of Strength & Conditioning Research

Before taking the popular treatments for granted, you may want to check for more up-to-date treatments and recommendations. More.

Rim-to-Rim-to-Rim (R2R2R)

Bridge in the Redwall Winter

Bridge in the Redwall Winter

Running 42+ miles across the Grand Canyon and back in under six hours, just like Rob Krar and Jim Walmsley. If you go any slower, you lose an R and have to run the Zion Traverse as a penalty lap. No, you don’t need a permit, but if you do it during the summer, you’ll probably die. More.


(1) Runner laid out on the trail begging for mercy (2) What you smell like after a 24-hour run.


(1) Something good for your hair (2) the sport long distance navigation with topo maps. Aka map trekking. More

Gary Robbins

Amazing Canadian ultra runner who has become famous (more famous) for not (yet) finishing the Barkleys. Also finished a few minor races here and there. More.

Roller (Foam Roller)

(1) Trail with gentle up-and-down contour (2) Sadistic torture device. The tube of terror. The pillar of pain. The cylinder of…agony? Whatever you call your little foam / rubber friend, you’ll probably spend a lot of time rolling around on it if you want to keep your IT Band from killing you. I imagine they’re good for other things too. More.


Any vacation planned around a run. I think there are sites dedicated to runcations, but I’m afraid to look. Honestly, you can put “run” in front of anything running specific and feel inventive. I just made up the word runventive, runcentive and “run in the oven” (when you’re pregnant with running passion). So…


Having a long list of things to do, and going for a run instead. Origin unclear.

Runderful *

I’m sure you can figure it out.


A term initially coined by Run, Selfie, Repeat, runfies are running selfies, or what makes Facebook groups like TAUR tick. More.


(1) An extreme runner’s high (2) Yes, it happens. So often it used to be trademarked.


A term initially coined by Run, Selfie, Repeat, runholes are runners who blab endlessly about running and neglect their friends by running all the time. Now sometimes means any jerk who runs. Don’t be that guy / gal / person. See Stravassholes and etiquette. See also plagiarism. More.

Runner’s High

Wonderful feeling many runners claim they get after running, and for some the purpose of running. Many say it’s caused by endorphins, others that it’s as imaginary as the green flash (ha), and a few never feel it at all. I felt it once, for no apparent reason, and never again. Sad. See beer. More.

Runner’s Knee

An injury not unique to runners, runner’s knee or Patellofemoral Pain Syndrome (PFPS) manifests as pain behind or around the patella (knee cap). More.

Runner’s Stomach

That queasy, bloated feeling that all runners get on some races, and some runners get on all races. There is no magic bullet other than an actual bullet, so try to dial in your hydration and nutrition (fuel) prior to race day. And don’t change things up during the race, or you’ll spend a lot of time in the porta-potty, if you can find one. More.

Running Form

(1) Permission slip and/or legal permit to run (2) How you herky-jerk your way down the trail, arms flailing, in a desperate attempt to keep up with someone twenty years younger (3) That thing other runners have but you don’t.

Once you nail down your nutrition, hydration and training, you might want to take a careful look at your running form, or how you’re running. Are you a heel or toe striker? Do you lean forward or stand up straight? Are you using your Achilles on steep uphills? There are endless opportunities for improvement. More.

Running Skirts / Running Kilts / Running Dresses

Many women and some men find it more convenient and/or fashionable to run in skirts, kilts or dresses that offer greater comfort and more discreet bathroom breaks. More.

Running Volume / Training Volume

Generally, how many miles you run a week. Most experts recommend increasing running volume by no more than 10% per week to avoid injury, but you should probably just find a training plan that works for you.

Runsplaining *

Runsplaining Meme

Runsplaining Meme

When you have to tell other runners how to run better, which usually means running more like you. More.

Runtastic *

How you feel before, during and after every run. See runderful, rungasm and runner’s high.

Salt Pills

Electrolyte replacement pills, usually in capsule form. One of the more common brands is SaltStick, but there are many. Often used to augment electrolyte drinks on especially hot days, or for heavy sweaters. More.


Anyone who downplays their speed, experience or probable finish time. The falsely humble.

Schwag (Swag)

Whatever the spelling, it’s free stuff you get at races (where free means the price of registration).

Service Requirements

Many races will require proof of trail volunteering or other service work, partially to give pack to the local parks and trails used by ultras. It’s more and more common as races grow in popularity and put more strain on the environment.


It’s been scientifically proven that 99.99% of all ultra runners have had sex, or will have sex during their lifetimes. Coincidence? I think not. More.


Yes, it exists in ultra running and, yes, it can get better. The sport could use more women and more encouragement for women. Big topic. See chicked and prizes. More.


(1) No, you’re not in prison (2) Rod in most hiking and running shoes that provides torsional stiffness along length of shoe.


What you wear over your socks if you’re not a barefoot runner. There is an absurd amount of information, debate, controversy and misinformation online about running shoes. I can’t help with any of that, except to say, don’t take it so seriously. Recent studies have shown that one of the best ways to avoid injury is to mix things up (including your shoes) and find shoes that are comfortable.

Shoe Anatomy

You might as well just accept that you’re going to learn a lot about shoes. It’s like skiers and DINs or camber, or cyclists and every damn thing on their bike(s).

Shoe Anatomy, Courtesy of Spotter Up

Shoe Anatomy Bottom, Courtesy of Spotter Up

Here’s a great site. Memorize everything. There’s a quiz before most 100 milers. Just remember that every manufacturer has their own special design and naming conventions.

Shoe Anatomy Bottom, Courtesy of Spotter Up

Shoe Anatomy Bottom, Courtesy of Spotter Up

The Spotter Up page has an excellent overview of show anatomy and terms. Don’t be intimidated; it’ll just help you know what to pay attention to next time you’re dropping coin at REI.

Shin Splints

An injury or collection of injuries on the front of your lower leg, generally known as shin splints because “medial tibial stress syndrome” and “compartment syndrome” sound scary.

The term “shin splints” has multiple personality disorder: it might refer to nearly any of several problems that cause shin pain, depending on what you read or who you talk to. – Pain Science

You can cure whatever it is by never running downhill again, or reading this.

Single Track

Mt. Hood from Timberline

Single Track around Mt. Hood

(1) Your mind five miles from the next aid station (2) Your bladder five minutes after the last porta-potty (3) Trails that are narrow and fun to run on except for all the damn yielding.

SKT (Slowest Known Time)

This isn’t really a thing. I’m putting it here so I could call out to John Fegyveresi for his 2012 Barkley finish in 59:41:21 — thus far the slowest anyone has finished the Barkleys. Props. I was actually more impressed until I looked him up on Ultra Signup and realized he wasn’t just some kid off the street – he’s an accomplished ultra runner. You’d never know that from the movie. Fake news!

Sky Running

Sky running is “an extreme sport of mountain running above 2,000 meters (6,600 ft) where the incline exceeds 30% and the climbing difficulty does not exceed II° grade” (Wikipedia). What it really means is running in beautiful places, mostly in Europe. More.


The most important part of your training that you’ll neglect the most.

…subjects who haven’t slept for 24 hours typically have worsened aerobic performance, which is more relevant to ultrarunners. The decrease is significant, with most studies finding about a 10% shorter time to exhaustion during an exercise test following a single night of no sleep. – Ultrarunning Mag

Apparently, some Kenyan runners sleep up to 14 hours a day. Who knew? More.

Sleep Deprivation

What you forgot to train for prior to your first 100 miler. Unless you’re an elite runner, a hundred mile run (and some of the harder 100Ks) are going to put you into sleep debt pretty quickly. You may be on the trail for 30 hours, and even longer in 200 mile races. learning to deal with sleep deprivation, and how to cope with your body’s response, is one of the more important and most neglected ultra skills. More.


If you run on the trails a lot, and you’re not in the UK, you’re probably going to encounter a snake or two. If you run in areas with poisonous snakes, be aware and take care–they usually just want to get out of your way and be left alone. In the western USA, rattlesnakes are often sited or heard and sometimes bite. The only real first aid is antivenom (which you don’t have) and a trip to the hospital. Don’t try anything else, and please don’t suck on anything. Aka Nope Ropes, Danger Noodles, etc. See also Hallucination and sticks. More.

Snot Rockets

You run and often your nose runs too; its all about solidarity. Many runners forego tissues or handkerchiefs, and simply plug one nostril and blow out the other as hard as they can — shooting a snot rocket into the bushes. Practice makes perfect. Don’t blow into the wind or onto your friends. See etiquette. Aka farmer’s blow.


Key electrolyte (mineral) your body needs to keep on running.

the best *general* recommendation I have found is to supplement with about 300 mg to 1000 mg per hour. It doesn’t matter how you get it, whether it’s through sodium supplements or from the diet. This amount may not replace all the sodium lost in sweat, but we don’t know if a runner NEEDS to replace ALL the lost sodium for optimal results. – Dr. Lisa Bliss

Most ultra runners supplement electrolytes in some way, but might not take in enough sodium. See hyponatremia, hydration and salt pills. More.

Spartan Race

When you want to pay more to run less. Spartan obstacle course races (OCRs) are not ultras (usually), but they are a great way to push your body and enjoy the outdoors while watching others flail about in the mud. More.

Speed Work

Any run or training done at a fast pace, including intervals, fartleks (hee hee) and sprints. More.

Spiderman / Spiderwoman

The lead runner on morning, single-track runs who has the honor of breaking through all the spiderwebs and sucking web. Ideally, this is a the tallest runner in the group, or the second runner will just end up sucking web anyway.


(1) A stretch I can’t do, and never will (2) Run breakdowns into specific segments used for pacing and logistics. One great way to study a future race is to to look at legacy splits between aid stations. Check out Western States splits here. More.

Stage Races

Some ultras are so long and extreme that they cannot (safely) be completed in one push by most people. So, they’re run in stages. I really put a lot of thought into that definition. Here’s a much better source of information.


If you run, you will smell. One of the main sources of stinkiness is your sweat, accumulated in synthetic running clothes over the period of hours or days until your bear spray becomes redundant. Dealing with your stinky stuff, washing it, etc., is a huge topic full of extreme opinions. My only advice here is to (a) get used to it (b) wash everything frequently and (c) invest in all-things smart wool if you can afford it and it’s comfortable. Wool toe socks from Injinji are the (ant-stink) bomb.


(1) What you’ll need on your chin after a face plant (2) Pain in your side (cramp).

Strength Training

A little time training in the gym can make a big difference on the trail.

Strength and conditioning (S&C) is the use of exercise prescription specifically to improve performance in athletic competition. S&C forms the foundation of nearly every single sport, and yet it’s a vastly underestimated aspect of ultra run training – James Eacott



One of the leading GPS tracking membership sites, Strava.com is used for segment FKTs and bragging rights. Started by and for cyclists, but often used by runners. If you can’t find a good race or trail GPS track, this can be a good place to look.


More of a cycling term, but generally referred to anyone who acts like a jerk screaming “Get out the way!” as they try to make their FKT (assuming they’re tracking with the Strava app). See also bikeholes, runholes and etiquette.


(1) The unfortunate results of Code Brown (2) Running naked, because why not (3) Consecutive days of running, hopefully more than one. Don’t mix these; you’ll lose all your friends. If you’re serious about streaking, there’s a site for you. More.


(1) Every step when you run (2) Overall running form (2) Comfortable pace.

Stride often refers to the distance between footfalls when running (i.e., the length of your step). The most common recommendation is to reduce stride length and increase cadence (turnover) to reduce injuries and fatigue. But stride also refers to whether you’re a toe striker or heel striker, etc. Depends on context. You’ll find your stride.


Some runners will do strides, or quick pick-ups, during otherwise mellow runs in order to improve speed and overall performance. I’m not sure how a run with strides is any different from a formalized fartlek run. More.


Nothing about ultra running sucks. It’s always awesome.

Sucking Web

Inhaling arachnid silk on morning runs if you’re the first runner down the trail. Often results in flailing, screaming and other entertainments. See schadenfreude and Spiderman.

Sucking Wind

When you just can’t breathe, and just can’t figure out why. Ultra running is like science in 12 Monkeys; it’s not an exact thing. Your body will do odd things to you, sometimes quite surprisingly, and leave you tired and sucking wind on trails you killed it on just days earlier. It happens. Learn from it, and keep moving. See hypoxia.


A term borrowed from skiing, meaning a trip that results in you flying forward, arms out, like you’re diving down the mountain. Never ends well. See face plant, then see if your shoes are too large (long) or you’re not lifting your feet enough when clearing obstacles. This happens a lot as your legs tire on longer and more technical runs.


(1) Country where they love soup (2) Roll of foot outward (i.e., under-pronation).

Pronation vs. Supination, Courtesy of Body Scientific

Pronation vs. Supination, Courtesy of Body Scientific

I’m a supinator (pity party sounds), but not sure if that started before or after I shredded my ankles in basketball. More.


(1) The one thing I do better than everyone else (2) Something you really need to understand to get your hydration and nutrition right. See hypohidrosis and hyperhydrosis, heat exhaustion and heat stroke, stink, etc. More.

Sweat Rate

One thing that will be important in managing heat and hydration for endurance runs is your sweat rate — how much you sweat each hour (usually between 1.0 and 2.5 liters/hour). This is difficult to calculate accurately, but easy to estimate (be sure to weigh yourself in the nude):

Sweat Rate = Weight After Run – Weight After – Fluid Intake – Pee Output

So, for instance, on a typical two-hour run in hot weather, I’ll lose 5 lbs / hour (at least) and drink 1 liter (2.2 lbs) of water. Let’s assume I don’t go to the bathroom. This means:

Sample Sweat Rate = 205 – 195 – 2.2 = 7.8 lbs

If you convert those pounds to liters (divide by 2.2) you get 7.8 / 2.2 = 3.5 liters of sweat loss, so I’d have to drink a lot more water to maintain balance (homeostasis) and keep running without a loss of energy and performance. This becomes a serious issues on longer runs. This is complicated by the fact that how much salt you lose in your sweat per liter varies highly, and some of the weight loss is not really sweat — it’s the result of burning glycogen. Most runners figure out the right balance of water and salt intake based on trial-and-error. A calculator like this will help, but until you take salt loss into account, you’re not going to have a full picture of your hydration status or how to manage it. More.


Gradually decreasing training volume as you near race day. There’s a lot of debate about tapers. Does size and length matter? Some elite runners taper very little compared to average runners, some taper more. It’s madness. More.

Tarahumara (Rarámuri)

Indigenous people of what is now Mexico, whose ultra running abilities were made famous by Born to Run. More.

Taur (Trail & Ultra Running)

The acronym for Facebook’s primary ultra running group.

Tempo Run

A run at your lactate threshold (anaerobic threshold), also known as a threshold run or T-Pace run. Not sure why this thing has so many names. More.


The fucking enemy.

Threshold Run (T-Pace)

A run at around 85% of your VO2 Max, or approximately 90% of your max heart rate (right on the border of Zone 4/5). A tempo run. More

Time Dilation

Why the second half of any out-and-back run is always longer than it should be.

Timed Runs

6-hour, 12-hour, 24- hour and other runs defined by total cutoff time rather than a fixed distance. See loops. More.

Toe Box

(1) Front interior toe-home in your shoe. It’s never the right size, and if it is, your heel is loose. Heel cup and toe box conflict are regulated by the Inshoenty Principle.

Toe Pix

(1) The only good part of The Cutting Edge (2) Pictures of your mutilated toes and black toenails when they get mangled in your toe box, taken for shock value and shown proudly social media to earn street cred and bragging rights. Points are awarded for blackness, pusiness and swoleness. Bonus scoring for compound fractures and toe-capitations.

Toe Socks

Because you weren’t already pissed off enough by losing a sock in the dryer every damn time. Great for blister resistance if you’v got enough room in your toe box. The primary manufacturer is Injinji. See blisters.

Toe Strike (Forefoot strike)

(1) When your toes join a union after 20 hours on the trail and protest, loudly, for a larger toe box (2) What all the cool runners will tell you is the “right” way to run if you’re a heel striker. Means that your forefoot hits first (you land on the balls of your feet) when you’re running, rather than your heel.

It is true elite runners tend to be forefoot strikers. So, if you are reading this and can run under a 16min 5k (guys) or 20min 5k (girls), beginning the process of gradually converting to a midfoot or forefoot strike may be advisable. But, if that’s not you, think seriously before making a change. – Dr. Matthew Mitchell

This is a giant topic in the gianter topic of running form, but it’s worth reading up on if you’re thinking about being a long-time, competitive runner and you’re willing to make the adjustments required to change your stride. More.

Total Vert

Total vertical (elevation) gain and loss. Sounds a lot like “total perv” when you’re breathing hard.

Trail Money

I’ve heard this term in mountaineering as a toilet paper reference, because you really, really don’t want to run out of TP on a glacier — and you can trade TP for just about anything once people run out. I’m also told it’s used in running, but I’ve never heard it in that context. Probably means I haven’t run enough, damn it. See porta-potties and Leave No Trace.

Trail Running

Running on trails, as opposed to running on roads (where most traditional marathons and training take place). Most ultra runs are also trail runs, but not all.


What you should be doing instead of reading this. More seriously, I got into ultra running because I enjoy trail running; I love it. The long weekend runs in the woods are just plain fun, as long as I’m healthy. My only suggestions for training are (a) find a realistic training plan that work for you (b) train you whole body and mind and (c) try to make it fun and do it somewhere beautiful. If you don’t like the training, which is what you’re doing most of the time, what’s the point? More.

Training Plans

Most training plans are charts of daily / weekly volume with specific workout types such as “speed work” or “long slow distance“. You can find a good list of plans here. If you like reading about the details behind the plan, Hal Koerner’s book is a good option. And Hal Higdon (among others) offers online training plans via TrainingPeaks, such as this 50K example. More.

Ann Trason

Ultra runner who broke 20 world records, set numerous course records, won Western States 14 times, and generally kicked some serious booty. More.


That thing in the gym you run on when it’s snowing, you’re injured, or it’s a billion degrees outside. They get a bad rap, but when you’re starting out, treadmills offer a relatively safe and consistent training environment for intervals and even VO2 Max estimation using the Bruce Protocol. Just don’t believe the calorie indicator. Aka dreadmills.

Trekking Poles

Some races will allow trekking poles for certain racers, some will not. Make sure you know the rules and train accordingly. There are great, light-weight (e.g., carbon fiber) poles specially made for ultra running, but they all basically help (a) take the load off your legs on climbs (b) increase stability in technical terrain and (c) give you something to stab bears with. Kidding. Leave the bears alone.

Aka Pussy Poles, Sissy Sticks or Wizard Sticks.


The only people who care more about their GPS watches than you do.

Type II Fun

You’re miserable now, but you’re remember it fondly later, meaning most ultra runs. I mean, if you’re having fun now and remember it as fun later, that’s just fun (Type I). If you’re miserable now and remember it as miserable later (Type III), that’s probably more rational, but where’s the fun in that? And then there’s the stuff that’s miserable now but fun in retrospect (Type IV), which we call delusional–and which results in immediately signing up for another race right after finishing DFL.

Ultra Distance (Ultra Run)

Any run over 26.2 miles. Technically, if you run to the bathroom after a marathon, you’re an ultra-runner (Yes, 26.3 is a distance). Ultra running and trail running are often conflated, but you can run ultra distances on roads (e.g., Badwater) and trail run sub-ultra distances (e.g., 30Ks). More.

Ultra Signup

The primary site for US race registration, UltraSignup.com will take all of your money. They also do a good job or showing race results and histories, so you can stalk your competition before and after every race.


(1) Your built-in, color-coded hydration indicator. Check out the US Army chart below for recommendations on what various colors indicate. Better yet, stay hydrated.

US Army Hydration Guide

US Army Hydration Guide

(2) Something you’ll have to expel, frequently during ultras and often nowhere near bathroom facilities. Please be respectful of others and do it way off the trail. See Leave No Trace.

(3) What you’ll see other people expelling during ultras, sometimes while they’re still on the trail and running. Not sure what to say about that other than, ick.

Aka pee.

UTMB (Ultra-Trail du Mont-blanc)

One of the more famous mountain races in Europe. Kilian Jornet’s won a few times. More.

VO2 Max

A scientific measure of your bodies ability to consume oxygen, which is largely but not entirely genetic (inherited). Most ultra runners are in the 40-60 range, with world-record VO2 Max counts being in the 90s. Apparently, Kilian Jornet’s max is either 89.5 or 92. You may find it helpful to know your measure, but unless you’re an elite runner, it’s primarily useful for measuring changes in overall fitness. More.

World Record VO2 Max, Courtesy of FISSAC

World Record VO2 Max, Courtesy of FISSAC


People at aid stations, maintaining trails and otherwise giving their time to make trail running and ultra running possible. Love them. Thank them. See service requirements.

Yellow Gate

A mythical destination at the end of impossible runs. Ultra-runners often hallucinate about the yellow gate prior to bonking. Largely a reference to the start and finish line of the Barkleys.


SD Trail Courtesy Sign

Yielding & Trail Courtesy

That thing no one else does as well as you do, especially if they’re on mountain bikes, mules or horses. Did you know there are rules for this? Well, there are.

(a) Always yield to someone doing the same thing if you’re going downhill and they’re going uphill. You know, because they’re working harder.

(b) Runners yield to hikers, I think. I just made that up.

(c) Mountain bikers yield to hikers and runners.

(d) Everyone yields to horses and mules, and bears. I once saw llamas on trail. but I’m not sure what the deal is there.

(e) All the rules above are null-and-void if the other guy is blasting his radio. Hip check that bastard off the trail. Ha ha. Just kidding.

See etiquette.


What many ultra runners to a lot of the time in ultra races, especially on uphills. This is not a sign of weakness; walking is often faster, and saves the legs for flat and downhill sections. See Euro-Walking. More.

Warm Down

Slow, easy workout after your run to speed recovery. Aka cool down. More.

Warm Up

Doing something slow before you do something fast to prevent injury. Oddly, there is no such thing as a Cool Up, though it would be a great name for an icy drink or high school seminar. More.

Jim Walmsley

One of the Coconino Cowboys, Jim Walmsley is a US ultra runner and winner of Western States and many other events. More.

Washing Machine Style

Much like the Barkley, many newer repeating loop races will alternate loop direction to keep things interesting and increase difficulty. This is called a washing machine style race or course.

Water Sources

During many races, the only water will often be at aid stations. When training or just running for fun, make sure you know what water sources are available year-round or seasonally, weather water is potable or requires treatment, and how long you’ll have to go between sources (especially in hot weather). When doing R2R2R, for instance, almost all water on the North Kaibab is off during the winter, but you can still filter from Bright Angel Creek.

Water Treatment

Huge and important topic that boils down (no pun intended) to how to get enough drinkable water for your hike or run. Some runners just drink straight from the creek or lake, but if you don’t want to get sick or die, you’ll want to look into water filters, purification tablets, filter straws, UV pens and so on. My preferred combo for longer backcountry runs is a SteriPEN with iodine tablets as backup. Neither gets rid of particulates, but they’ll keep you healthy if you don’t mind the grit. More.

Western States (Endurance Run) (WSER)

One of the baddest and oldest US 100 mile races, and one of five 100s in the Grand Slam. See lotteries. More.


Not allowed in ultra running. See crying in baseball.


If you ever get tired of clothes that stink, there are many excellent smart wool, merino wool, and other modern branded wool weaves that are both comfortable and odor minimizing. The good stuff can be expensive, but your crew, car mates and life partners will appreciate the investment. More.


That thought going through your head every thirty seconds after the 30-mile marker.


See bad ass.

Zero Drop

Refers to shoes where the heal and toe are level, without the usual 12mm incline rising to toward the heal. Many runners think this reduces injury rates. See Minimalist. Now I have two Z-words!

Zone Training (Heart Rate Training)

I just put his here to have a Z-word. Giant topic.

HR Chart

HR Chart, Courtesy of Unknown

But there’s probably no more basic and generally accepted training model than heart-rate training, so…get on it. Shouldn’t there be a beer zone (Zone 0)? More.

Still Confused?

If you don’t see a word or term here, don’t get the explanation, or just feel belligerent, feel free to leave a comment. I obviously have a lot of time on my hands. If you do submit additional entries, try to let me know where they come from (originally) so I can give proper attribution. Note that I’ve omitted some less common terms if I could only find them on one site to avoid detracting from their creativity.

Some related stuff:

See you on the trail.

About the Author

Just another mediocre ultra runner who thinks too much when he’s injured, largely to avoid PT. See couch runner.

(*) I might have just made these words up.


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