Trail running glossary
Trail races assume you already speak the language. This is that language, in plain words: what the numbers on a race page mean, what happens on race day, and how a place in a race is handed out.
Course and terrain
How a trail race course is measured and described.
- Elevation gain
The total amount of climbing on a course, added up over every uphill section rather than measured from the lowest point to the highest.
A course can gain thousands of feet without ever reaching a summit. Elevation gain is the best single measure of how hard a trail race will feel, and it is why two races of the same distance can take wildly different amounts of time.
- Elevation loss
The total amount of descending on a course, added up the same way as elevation gain.
On a loop course the two numbers are roughly equal. On a point-to-point course they can differ a lot, and heavy net descent is hard on quads late in a race.
- Technical terrain
Ground that slows you down for reasons other than the gradient: loose rock, roots, scree, stream crossings, snow, or exposed scrambling.
Trailrace.co scores technical terrain from 1 to 10, so you can compare two courses that share a distance and a vertical gain.
- Vertical kilometer
A short, extremely steep uphill race that climbs 1,000 vertical metres.
The distance is usually only 3 km (about 2 miles) or so, and the entire course goes up.
- Loop course
A loop course is a route that starts and ends at the same point, where most or all of the course is run in a single direction.
- Out and Back course
An out-and-back course is a route that goes from the start point to a turnaround point and back, allowing for a straightforward return.
- Lollipop course
A lollipop course features a loop section with an out-and-back segment at the start or end, resembling a lollipop shape on the map.
- Point to Point course
A point-to-point course is a route that starts at one location and ends at another, often requiring transportation for participants.
- Multiple Loops course
A multi-loop course in which runners must complete multiple laps on the same route. For example, a 100 mile race that consists of five 20-mile loops
Also called: vert, vertical gain, climbing, D+
Also called: descent, D-
Also called: VK
Race day
What you meet on the course, and who is allowed to help you.
- Aid station
A staffed stop on the course where runners can get water, food and help.
Aid stations also act as checkpoints: races record you through each one, and many of them carry a cutoff time. Where the stations sit on the course determines how much you have to carry between them.
- Cutoff
The latest time you are allowed to leave a given point on the course and stay in the race.
A race has an overall cutoff at the finish, and usually intermediate cutoffs at aid stations along the way. Miss one and you are pulled from the race, whatever shape you are in.
- Crew
The people who meet you at set points during a race to hand over food, kit and dry shoes.
Races decide where crew are allowed, and some do not allow them at all. Crew access is limited by the road network as much as by the rules, so a station a mile from a highway may be crew-accessible while one deep in the mountains is not.
- Pacer
A runner who joins you partway through a race and runs with you to the finish, or to a set point.
Pacers keep you moving, watch your eating and drinking, and help you navigate at night. Races set their own rules about when a pacer may join, where they can swap, and whether they may carry anything for you.
- Drop bag
A bag you pack in advance that the race transports to a named aid station, so your spare socks, headlamp batteries and food are waiting for you there.
Only some aid stations accept drop bags, and you often do not get the bag back until after the race.
- DNF
Did Not Finish — you started the race but did not reach the finish, whether you stopped yourself or missed a cutoff.
In long trail races a DNF is common and says nothing about the runner: finish rates below 60% are normal at 100 miles.
- DNS
Did Not Start — you had an entry but never began the race.
Races often report DNS counts separately, because a big gap between entrants and starters changes how the finish rate should be read.
- Sweeper
A volunteer who travels at the back of the field behind the final cutoff, making sure nobody is left on the course and taking down course markings along the way.
If the sweeper catches you, you are behind the cutoff.
Also called: checkpoint
Also called: cut-off, time limit, cutoff time
Also called: did not finish
Also called: did not start
Also called: sweep
Getting an entry
How places in a trail race are handed out and earned.
- Lottery
A random draw used to hand out entries when far more runners apply than a race can take.
Many lotteries weight your chances by how many years you have applied, so the odds improve each time you are turned down. Trailrace.co flags every race that uses one, shows its draw date, and calculates your odds.
- Qualifier
A race you must already have finished before you are allowed to enter another one.
Hard races use qualifiers to check that entrants have covered the distance and terrain before. Each race publishes its own approved list, so a finish that qualifies you for one event may not count for another.
- Qualifying window
The span of dates in which a qualifying finish must have happened for it to count.
A finish from before the window opens is too old to use, however good it was.
- Qualifier submission deadline
The date by which you must send your qualifying result to the race.
It is usually earlier than the entry deadline, and missing it costs you the entry even though the qualifying run itself was valid.
- Waitlist
The ordered queue of runners who get an entry as other people drop out.
Movement depends entirely on how many entrants withdraw, so a low waitlist number early in the year is usually a good sign.
- Service requirement
Hours of trail maintenance or race volunteering you have to complete and log before you are allowed to enter.
Races that run on public land often use it to give back to the trails they use. It is a hard entry condition, not a suggestion.
Also called: ballot, draw
Also called: qualifying race
Also called: trail work, volunteer requirement
Race types and distances
The standard trail and ultramarathon distances and formats.
- Ultramarathon
Any race longer than the marathon distance of 42.2 km (about 26 miles).
In practice most trail ultras start at 50K. The word says nothing about terrain — but on trails, distance, climbing and rough footing usually all arrive together.
- 50K
A 50 km (about 31 miles) race, and the usual first step past the marathon.
On mountain trails a 50K can take several hours longer than a road marathon.
- 50 mile
A 80.5 km (about 50 miles) race.
Long enough that eating properly, pacing the climbs and looking after your feet all start to decide the day.
- 100K
A 100 km (about 62 miles) race.
Most runners are out long enough to run into darkness, so a headlamp and a night plan are usually required.
- 100 mile
A 160.9 km (about 100 miles) race — the classic ultramarathon distance.
Nearly everyone runs through at least one full night, and the biggest 100-milers fill by lottery.
- 200 mile
A 321.9 km (about 200 miles) race.
Long enough that sleep becomes part of the race strategy rather than something you skip.
- Stage race
A stage race is a multi-day event where runners complete a set course each day, called a stage. Times from each stage are combined to determine overall rankings. Distances and terrain vary by day, and rest is provided between stages.
- Timed race
A time-based race format in which participants aim to cover as much distance as possible within a fixed time limit, such as 6, 12, or 24 hours.
- Backyard ultra
A Backyard Ultra is a last-person-standing race where runners complete a 4.167-mile loop every hour, on the hour, until only one runner remains. Failure to finish a loop in time means elimination.
Also called: ultra, ultra marathon
Also called: 50M, 50 miler
Also called: 100M, 100 miler, hundred
Also called: 200M, 200 miler
Also called: fixed-time race, 6 hour, 12 hour, 24 hour
Also called: last person standing
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