Some associates and I made the highway journey to the 2016 Bighorn Path 100 Mile, and all of us obtained shirts with the course profile on the again. When certainly one of my associates returned dwelling with the shirt and a since-avenged DNF, his sons preferred to level on the highest peak on the course profile and say: “That is the place you failed.” I feel they have been onto one thing — along with simply being laborious on their dad — so let’s attempt to pinpoint what goes right into a DNF.
“Didn’t end” (DNF) is an consequence that runners usually wish to keep away from, so it may be helpful to know the place the dangers of getting a DNF are increased. Are there specific traits a race might need that may drive up the DNF fee? Are there factors in a race the place a DNF is extra seemingly? Strap in for a journey of discovery.
Jim Walmsley (left) ending his day on the river on the 2017 Western States 100, exhibiting that nobody is proof against the occasional DNF. Photograph: iRunFar/Bryon Powell
The Methodology
This text attracts on two datasets: one composed of outcomes from 25 races, and a smaller dataset with 10 years value of splits for a specific race. For each datasets, I managed for distance by specializing in 100-mile races. Please don’t take that as a snub towards different race distances — we love all distances however must create knowledge boundaries someplace.
For the dataset composed of outcomes from 25 races, I deliberately selected races with some selection of their areas, terrain, elevation, and begin occasions (1). My dataset continues to be admittedly small, as a result of it’s comprised of simply 25 races and solely their outcomes from 2023. Nonetheless, it’s a very good place to begin for a just-for-fun evaluation that provides us one thing to debate with our associates on the following long term. I chosen races that have been:
- A part of the World Path Majors
- A part of the UTMB World Collection
- On “UltraRunning Journal’s” listing of the most important North American ultras in 2023, and/or
- Occasions I’ve run personally and I needed to point out them some love
The DNF fee for every occasion was calculated by dividing the variety of runners who DNFed by the variety of individuals who began the race. Runners who didn’t begin due to this fact don’t issue into the DNF fee.
Do Sure Elements Impression DNF Charges?
Relatively than preserve you in suspense, I’ll inform you proper now: “being the 2023 Western States 100” was the one issue that had a discernible affect on DNF charges on this specific dataset. In 2023, over 85% of runners who began the Western States 100 crossed the end line in time to obtain their belt buckle. The share of runners who received a DNF was 13.5%. That was an unusually excessive finisher fee: for the earlier 20 editions of the race, the typical DNF fee was 27%.
The 2023 version of Western States was thought-about a very mid when it comes to the climate forecast. There could also be different elements that give the occasion a better finisher fee (and decrease DNF fee) than another 100 milers.
Jennifer St. Amand, the ultimate official finisher of the 2023 Western States 100, who beat the cutoff by 21 seconds. Photograph: iRunFar/Sarah Brady
For instance, Western States requires runners to qualify to run the occasion. The challenges of gaining entry to Western States additionally imply runners haven’t any assure of with the ability to strive once more subsequent 12 months — or ever — so the runners lucky sufficient to start out the race shall be significantly motivated to coach properly.
Lastly, Western States maintains a waitlist, so runners who imagine they gained’t end the race have the choice of constructing one other runner’s dream come true by withdrawing from the race upfront, so one other runner can have the chance as an alternative.
Via some mixture of those elements, individuals within the 2023 version of Western States collectively crushed it.
Past this commentary, there have been no apparent or statistically important tendencies amongst any of the elements I examined. Whereas the races within the dataset had some notable variations amongst them, most had DNF charges inside a specific vary. The common DNF fee within the restricted pattern dataset was 38%, and also you’ll see within the distribution chart under that the majority races had DNF charges in that ballpark.
Distribution of DNF Charges Among the many 25 Races within the Pattern Dataset
Chart exhibiting the distribution of DNF charges among the many races examined.
DNF Charges by Whole Elevation Change
There isn’t any compelling or statistically important pattern in how elevation change impacted the DNF fee in our dataset.
For instance, the Extremely-Path Snowdonia by UTMB 100 Mile had the very best DNF fee in 2023 of races within the dataset, at 59%, and had 62,336 toes (19,000 meters) of elevation change. It eclipsed the Extremely-Path Kozciuszko by UTMB 100 Mile in each respects, as that race had simply 3,937 toes (1,200 meters) of elevation change and a DNF fee of 31% in 2023.
However there are each mountainous and relatively flat or hilly races inside the 30 to 49% vary for DNF charges.
Feminine winner Emma Stuart on the course of the 2023 Extremely-Path Snowdonia by UTMB 100 Mile. Tchnical terrain in addition to a number of elevation acquire seemingly contributed to the race’s excessive DNF fee. Photograph: Guillem Casanova/UTMB
Correlation between DNF Price and Whole Elevation Change for Every Race
Scatterplot exhibiting the correlation between DNF charges and whole elevation change.
DNF Charges by Time Cutoff
Affording runners extra time to cowl 100 miles doesn’t appear to be a surefire option to cut back DNF charges. A 30-hour cutoff was the smallest period of time races on this dataset provided for runners to succeed in the end line. Among the many races with that cutoff on this dataset — the South Downs Method 100 Mile, Western States 100, Hennepin 100 Mile, Javelina 100 Mile, Rocky Racoon 100 Mile, and Leadville 100 Mile — the DNF fee ranged from 13% proper as much as 56%.
Correlation Between DNF Price and Time Cutoff for Every Race
Scatterplot exhibiting the correlation between DNF charges and time cutoffs.
DNF Charges by Race Begin Time of Day
In pre-race interviews for UTMB, North American athletes will typically consult with the problem of racing an ultramarathon with a night begin. Whereas the UTMB begins at 6:00 p.m. native time, the Rocky Racoon 100 Mile, for instance, begins at 6:00 a.m.
The beginning of the 2017 UTMB. Many runners discover the 6 p.m. begin to be a problem. Photograph: Kirstin Kortebein
Early begin occasions have been pretty widespread among the many North American races on this dataset — although a lot respect to the Black Hills 100 Mile for letting runners sleep in earlier than their comfy 10:00 a.m. begin time.
Whereas particular person runners are more likely to have opinions on the perfect time of day to start out a 100-mile race, the dataset didn’t recommend that begin time has an affect on DNF charges.
Correlation Between DNF Price and Begin Time for Every Race
Scatterplot exhibiting the correlation between DNF charges and begin occasions.
Whither the DNF?
I used to be curious to know the place the “hazard zone” for dropping from a race may be, so I pulled up the splits for the Superior Fall Path Race 100 Mile. I selected this race as a result of it’s a private favourite, and the race director publishes the race splits in a constant and accessible format. The 103-mile course is more difficult within the second half, with essentially the most technical terrains and largest climbs concentrated in that portion.
I’d like to broaden upon this evaluation in a future column and incorporate knowledge from extra races, however the knowledge from the Superior Fall Path Race 100 Mile confirms what I’m certain you intuitively suspected. You’re almost certainly to DNF your 100-mile race throughout that part of the race when your legs are drained, however you continue to have many miles to cowl.
I counted the entire DNFs, by assist station, for this race for the years the place splits can be found on-line — 2014 to 2023. I plotted them within the chart under to point out the factors within the race which have the most important proportion of all DNFs.
As a technical be aware to my fellow superfans of this occasion, as a result of runners are strongly discouraged from dropping out on the distant Sonju Lake Street assist station and timing knowledge is commonly unavailable for that assist station, I mixed any identified DNFs for Sonju Lake Street with the DNFs on the subsequent assist station, Crosby-Manitou at mile 62.9.
Additionally be aware that every one DNFs for this race are marked to have occurred at assist stations.
DNFs on the Superior Fall Path Race 100 Mile, From 2014 to 2023, by Mile/Help Station
Graph exhibiting the place DNFs occurred on the Superior Fall Path Race 100 Mile, from 2014 to 2023.
However Why Did They DNF?
Outcomes and splits solely inform a part of the story in relation to a DNF. To essentially perceive why runners DNF, we have to take a look at the qualitative knowledge as properly.
To the aid of Instagram ultrarunning meme account @yaboyscottjurek, we don’t must learn a bunch of nine-part race recaps on Instagram to know the explanations runners don’t end a 100 miler.
The American Path Working Affiliation (ATRA) conveniently aggregated the experiences of roughly 1,200 survey respondents in a 2022 article on the subject. ATRA’s survey supplied runners with an inventory of causes they could DNF a path race of any distance, and runners may choose the entire causes that contributed to any of their previous DNFs. You possibly can see the ends in the desk under.
Outcomes of a survey by the American Path Working Affiliation about why individuals select to DNF a path race.
Closing Ideas
We could revisit this matter once more in a future column, as a result of there are extra questions I wish to reply. For instance, are DNF charges impacted by whether or not:
- Runners want a qualifier to get into the race?
- The race is kind of aggressive?
- The race is a bucket-list sort race with a hard-to-enter lottery or important and costly travels to?
- Races that appeal to extra “repeat offenders” have decrease DNF charges, maybe as a result of extra individuals have prior expertise with the course?
- There are significantly tough climate or course situations, like excessive warmth, an enormous storm, or extra snow or mud?
- The race is lengthy or brief?
Moreover, I’d like to know if there’s a specific time of day when runners are almost certainly to DNF, akin to in a single day or maybe within the warmth of the day.
I think about many readers are involved in DNFs for a similar purpose I’m: We desire to complete our races. We hope that by understanding DNFs, we cut back the probability of it taking place to us.
Whereas I can’t think about many — if any — runners begin a 100-mile race with the intention of getting a DNF, ultrarunner, race director, and podcaster through the enterprise Ten Junk Miles Scott Kummer jogged my memory that the DNF represents an important side of the ultramarathon.
I requested him concerning the DNF fee for the Badger Path Race 100 Mile, which he organizes. With 18 assist stations and a 38-hour restrict to cowl 100 miles on comparatively flat rail trails, it’s an occasion that we’ve beforehand described as “finisher-friendly.” The race nonetheless had a 26% DNF fee in 2023 — 34 DNFs amongst 133 individuals — which places its DNF fee inside the identical vary because the occasions we examined above.
Bertha Lotje Woehl, pacer Clara Beaudet, and assist station Captain Holly Lindroth on the 2021 Badger Path Race 100 Mile. The race is thought for its beneficiant cutoff occasions. Photograph: Will Harrison
However, as Kummer identified, among the runners drawn to the Badger Path Race 100 Mile particularly select that race over different ultramarathons as a result of their possibilities of ending an occasion with much less beneficiant cutoffs on extra technical trails are too low.
Whatever the occasion or the terrain, many runners are drawn to occasions the place they’ve a professional likelihood at reaching their targets, however they’re challenged sufficient that getting a DNF stays a definite chance.
Talking for myself, this can be a helpful reminder. When life will get busy and coaching falls by the wayside, it’s straightforward to get anxious concerning the rising odds that I gained’t attain my race targets. Finding out DNFs helps me make peace with my very own, and provides me a deeper appreciation for a way all the level of coaching for a difficult race is to spend time pushing the bounds of our potential, whereas repeatedly coming to phrases with these limits.
It applies to life outdoors of operating, too. Heck, I technically DNFed this text as a result of I missed a time cutoff for offering it to my editors and I nonetheless must inform you about…
Name for Feedback
- Do you take into account the share of runners who DNF when judging a race’s issue?
- What’s your private expertise with DNFs?
- We could must take one other take a look at DNFs sooner or later. What different tendencies would you prefer to dig into?
Notes
- In alphabetical order, the 25 races (all 100 milers) are: Bighorn Path, Black Hills, South Downs Method, Doi Inthanon Thailand by UTMB, Grand Raid des Pyrénées, Grindstone by UTMB, Hennepin, Istria 100 by UTMB, Javelina, Julian Alps Extremely-Path by UTMB, KAT100 by UTMB, Kullamannen by UTMB, Leadville, Mountain Extremely-Path by UTMB, Good Côte d’Azur by UTMB, Québec Mega Path, Rocky Raccoon, Run Rabbit Run, Superior Fall Path Race, Path Alsace Grand Est by UTMB, Extremely-Path Cape City, Extremely-Path Kosciuszko by UTMB, UTMB, and Western States.
