A Data-Driven Primer for the Backyard Ultra World Championships

A look at the history or and trends in backyard ultrarunning through the lens of data.

By on October 18, 2023 | Comments

On October 21, 2023, a small, invitation-only group of athletes will run 4.167 miles in a single hour. Then the runners will do that again every hour, for as long as they can. Welcome to Big Dog’s Backyard Ultra, what is the Backyard Ultra World Championships, and the world of backyard ultrarunning.

Since the backyard race format differs from most other running races and it’s comparatively new, we use this article to explain the origins, logistics, and appeal of backyard races. As you’d expect from this column, we draw on quantitative data to inform our discussion of the event’s popularity and runner performance.

[Editor’s Note: We kindly remind readers that the Running the Numbers column is a just-for-fun analysis. While we always endeavor to analyze accurately, we limit the scope of each article in order to make the work doable for author Mallory Richard, and the results digestible for readers like you.]

Team USA runners at the 2022 Big Dog's Backyard ultra

Team USA on day 1 of the 2022 Big Dog’s Backyard Ultra. Photo: Keith Knipling


The information for this article comes primarily from an interview with backyard race creator Gary Cantrell, and a dataset created for the Backyard Ultra website to track various events using the backyard format and acting as qualifiers for Big Dog’s Backyard Ultra, which acts as the Backyard Ultra World Championships. (Qualification for this most prestigious backyard ultra is achieved through winning one of the various national championships, or through achieving a high position on the format’s world rankings. We will get back to this later.)

We supplemented that dataset with more recent race results, and results for newer events, where we could obtain those results from either the DUV Ultra Marathon Statistics website or UltraSignup. The dataset that was thus compiled should not be considered a comprehensive record of all backyard ultra results, but you could call it a very large sample set.

It Started with Big Dog

Gary Cantrell, also known as “Lazarus Lake,” held the first-ever backyard ultra in 2011. He and Sandra Cantrell hosted it in the backyard of their farm in Bell Buckle, Tennessee. The course was 4.167 miles, meaning that a runner who completed 24 loops would cover 100 miles in that time. Runners complete the 4.167-mile loop on relatively flat trails during the day, then on a gravel road while the sun is down.

In order to remain in the race, runners need to run 4.167 miles and be on the starting line for another loop at the top of the next hour. Runners are given a DNF if they fail to complete a loop on time, or refuse to begin the next loop on schedule. Only the final runner standing is considered a finisher of the event.

Because many participants run each loop in under one hour, they can use the time between finishing a loop and beginning their next loop to consume calories, change clothing or gear, take a bathroom break, or get a few minutes’ sleep. And because many participants are motivated to run for as long as possible to set a new personal best and/or be the last person still running, success requires a particular combination of fitness, toughness, logistical preparedness, and strategy.

Gary Cantrell's dog - 2022 Big Dog's Back Yard ultra

Race Director Gary Cantrell’s dog overseeing the 2022 Big Dog’s Backyard Ultra. Photo: Keith Knipling

Explosion in Popularity

According to Cantrell, other races adopted the backyard format within months of the inaugural edition of Big Dog’s Backyard Ultra in 2011. He estimated the number of parallel events has roughly doubled every year. As of 2023, he reports there are roughly 400 races in 78 countries that are affiliated with Big Dog’s Backyard Ultra. There is no cost to race organizers or participants to affiliate a race, so it’s common for race directors to submit their events and results to the Backyard Ultra website. “UltraRunning” magazine recorded results for 73 backyard ultras in North America in 2022, and 63 for the year to date, at the time of writing.

Number of Self-Reported North American Backyard Ultras per Year

Backyard Ultra data - Graph 1. Ultrarunning Mag graph of Backyard Ultra Events

Graph showing the number of backyard ultras recorded per year, since the format was first established. Of note, “UltraRunning” magazine had also included one small event from 2010, but as little information could be found on this event and Cantrell did not formally establish the format until 2011, we have not included it. (Source: “UltraRunning” magazine)

Cantrell credits the popularity of the race format to a few reasons:

  • It’s comparatively easy to host a backyard race, compared to other ultramarathons. The timing system can be as simple as a watch and a piece of paper. They only require one aid station. It is significantly easier to obtain permission for using a 4.167-mile section of trail than, for example, a point-to-point race covering 100 miles.
  • The events foster more camaraderie and socializing than point-to-point races, because the participants and crews spend more time together. Even among runners with competitive aspirations, they have a vested interest in seeing their fellow runners do well for at least the first 24 hours, so they can draw strength from each other in the early miles.
  • The event embraces people who do not run ultramarathons. Cantrell shared the story of a runner who proudly ran for two hours (two “yards,” in the parlance of the event), setting a personal best. He highlighted how the format allows runners to run whatever distance suits them best, whether that is a new personal best, or simply an enjoyable and well-paced training run in preparation for a goal event.
  • The format forces smart pacing on anyone aspiring to run 100 miles within 24 hours. For many experienced ultrarunners, going 24 yards at a backyard ultra gives them a new personal best time for the 100-mile distance.

Interest in Big Dog’s Backyard Ultra has grown so much that a qualification system now governs which runners get invited to the event. The entrants’ list for the 2023 event is composed of winners from national championships events and top runners from an at-large list on the Backyard Ultra website. Since 2020, there has been a World Team Championships in backyard ultrarunning, occurring every other year. Each participating nation can assemble a roster of up to 15 athletes, all of whom are scoring members. They run in a backyard event in their respective country. Members of each team work together to keep their team in contention for as many yards or hours as possible. Once a team is down to a single runner, that runner has won the individual national championships for their country. The next World Team Championships is scheduled for October 19, 2024.

Ivo Steyaert and Merijn Geerts

Ivo Steyaert and Merijn Geerts after breaking the backyard ultra world record. Photo courtesy of Frédérique Van Cauwelaert and Tim De Vriendt.

Backyard Racing Strategy

“It’s really like a different running sport,” Cantrell says of backyard ultras. Runners don’t aspire to be the fastest over a given distance. Rather, they challenge themselves to see for how long they can keep going. Cantrell is quick to point out women, masters, and grandmasters runners are all well-represented among backyard event overall winners. He argues that because pure speed offers fewer advantages in backyard ultras, the format rewards the runners who excel at troubleshooting and refuse to quit.

Cantrell suggests that time management between loops is extremely important. “You need to be really efficient,” he says, noting the best performers have dependable crews that work well together to prepare their runners for the next lap.

Using the 2019 Backyard World Championships, held at Big Dog’s Backyard Ultra, as an example, the Backyard Ultra website published data on each participant’s fastest, slowest, and average times to run the 4.167-mile loop. Interestingly, eventual race winner Maggie Guterl did not have the fastest lap, the slowest lap, or the fastest average of any participant that year. Guterl’s pace left her with, on average, slightly more than nine minutes per loop to rest, refuel, and prepare for the next loop.

Loop Times for the 2019 Backyard World Championships

Backyard Ultra data - Graph 2. Average loop times 2019 World Championships

Loop times from the 2019 Backyard Ultra World Championships.

Maggie Guterl

Maggie Guterl (left) and Courtney Dauwalter at the 2018 Big Dog’s Backyard Ultra. Photo: Tracey Outlaw

Backyard Racing Top Performances

It’s common for trail running and ultramarathon records to stand for years. For example, Patrick Reagan’s 2017 course record at the Javelina 100 Mile stood until 2022, when Dakota Jones finished some three minutes under it. Ellie Greenwood set the course record at the Western States 100 in 2012, and her mark remained unbeatable until Courtney Dauwalter and Katie Schide ran faster at the race’s 2023 edition. Matt Carpenter held the course record at the Pikes Peak Ascent for 30 years until Remi Bonnet bettered it in September, 2023.

Against that backdrop, records in the niche of backyard ultrarunning hurtle forward by leaps and bounds. Since the 2019-2020 season (the Backyard Ultra website groups performances by a period running from August 16 of one year to August 15 of the following year), the annual record for most yards covered in a backyard ultra has increased by a sizable margin. The event has seen a new world record every year since John Stocker ran for 81 hours in June 2021.

Top Backyard Ultra Performances by Year

Backyard Ultra data - Graph 3. Top performances by year

Table showing the annual backyard record for each year since the 2019-2020 backyard season.

It’s not only the record-setters who are breaking new ground, either. As the Backyard Ultra website’s world ranking list shows, there are more runners running beyond 24 hours in this race format every year.

Backyard Ultra Performances by Distance and Year

Backyard Ultra data - Graph 4. Backyard distances by year

Distribution chart showing a breakdown of backyard ultra performances, by distance (in yards) and year. (Source: Backyard Ultra website)

Backyard Ultra Performances of Over 49 Hours/Yards by Distance and Year

Backyard Ultra data - Graph 5. Backyard performances over 49 yards

A zoomed-in view of the above chart, showing performances of 49 hours and longer. (Source: Backyard Ultra website)

More runners are running farther, and some are running for more than 100 hours in this race format. But that doesn’t mean it’s easy. The backyard ultra is deceptively simple — it requires running at a pace that most ultrarunners would consider manageable, but doing it for so long that runners and their crews must be completely dialed in with how they manage fueling, fatigue, and the myriad issues runners encounter during an ultra. The event is “more mental than physical,” Cantrell says.

The Backyard Ultra website included a dataset with the rate of attrition for 67 backyard ultras in 2019. Virtually 100% of participants completed the first yard or loop at every event. Beyond that, the percentage of race participants who completed any subsequent loop drops off sharply. As the chart below shows, for most backyard ultra races, the field was reduced by at least half by the 16-hour mark. Very few races had more than 10% of participants still running after 24 hours. Big Dog’s Backyard Ultra was the notable exception. In 2019, it served as a championships event and was considered to have a deeper field of elite competitors than any other backyard ultra that year.

That trend was true across races, regardless of event size. I had been curious if runners performed better when they registered for larger events. I thought perhaps a larger group of runners would encourage each other during at least the first 24 hours. I categorized events with fewer than 75 participants as small, 75 to 100 participants as medium, 100 to 174 participants as large, and 175 or more participants as extra-large events.

In the end, it may be a question of personal preference and strategy whether a runner with competitive goals is better served by attending a larger race, where there is a larger pool of runners to potentially run beyond 24 hours, or a smaller race, where runners may benefit from a more intimate start/finish area and less congestion on the trail.

Rate of Attrition Within a Race Field in 2019, Grouped by Event Size

Backyard Ultra data - Graph 6. Attrition Rates in 2019

The line graph above shows that for most backyard ultra races, the field is reduced by at least half by the 16-hour mark. Very few races have more than 10% of participants still running after 24 hours. Big Dog’s Backyard Ultra is the notable exception. In 2019, it served as a championship event and was considered to have a deeper field of elite competitors than any other backyard ultra that year.

Closing Thoughts

The entrants’ list for the upcoming 2023 Big Dog’s Backyard Ultra is star-studded. Thousands of fans will be following the race from afar. If you’ll be one of them, hopefully this primer helps you understand the race format a little better, and reminds you of an important point: these runners are going to make backyard ultras look easy, but they most certainly are not.

Call for Comments

  • If you’ve run a backyard ultra before, can you share some insight on your experience and your strategy?
  • Who will you be following at the upcoming 2023 Backyard Ultra World Championships?
Mallory Richard

Mallory Richard is a data analyst and trail runner in Winnipeg, Canada.