Learn
What is a
Backyard Ultra?
One loop. 4.167 miles. Every hour. The last runner to finish a loop wins, even if they've run 300 miles to get there. Everyone else is a DNF.
A backyard ultra (also called a last-one-standing race or backyard ultra marathon) is a format with no set finish line and no set distance. Runners complete identical loops of exactly 4.167 miles (6.706 km), one per hour, starting on the hour, every hour, until only one runner makes it back in time. That runner is the winner. Everyone else, no matter how many loops they ran, is recorded as a DNF.
The result: races that routinely stretch past 100 miles, past two days, sometimes past five. The distance is determined by how long the field can keep going.
How a backyard ultra works
At the start of each hour, every runner still in the race must cross the start line to begin their loop. The loop is always exactly 4.167 miles. Most runners finish in 45 to 55 minutes early on, using the remainder of the hour to eat, rest, and prepare for the next loop.
Early loops. As the race wears on, rest windows shrink.
Any runner who doesn't start the next loop on time is out. Any runner who starts but doesn't finish before the next hour begins is out. The race ends when only one runner is left: that runner must complete one final solo loop to officially claim the win.
Backyard ultra rules
- One loop per hour. Loops start on the hour, every hour, from the moment the race begins.
- Every loop is 4.167 miles. Exactly. No variation. The distance is fixed so that 24 loops equals precisely 100 miles.
- You must start each loop on time. Missing the start means you're out. There are no exceptions once the loop has begun.
- You must finish before the next loop starts. If you're still on the course when the next hour ticks over, you're out.
- Only one winner. The winner is the last runner to complete a loop. Every other finisher, regardless of how many loops they ran, is classified as a DNF.
- The winner must run one more. Once the penultimate runner drops, the remaining runner completes one additional solo loop to claim victory.
- Crew and pacers are allowed at most events within the designated corral area between loops. Rules vary by race; check with your specific event.
How long is a backyard ultra lap?
Every loop is 4.167 miles (6.706 km). The distance is deliberate: 4.167 × 24 = 100.008 miles, a clean hundred. Any runner who completes 24 loops has run a full hundred miles, and the race may still be going.
Loop courses vary by race. Some are road, some trail, some alternate. Big's Backyard Ultra runs trail loops during the day and road loops at night. The terrain changes; the distance never does.
Backyard ultra vs. other ultramarathons
Most ultramarathons have a fixed distance and a cutoff time. You train for a target, pace toward it, and if you finish, you're done. A backyard ultra works on a completely different logic.
| Standard ultra | Backyard ultra | |
|---|---|---|
| Finish line | Fixed distance | No set distance |
| Winner | Fastest finisher | Last one standing |
| 2nd place | Real result | DNF (same as last) |
| Duration known? | Yes | No |
| Can you train to a target? | Yes | Not exactly |
| Winning margin | Seconds or minutes | Exactly one loop |
This changes strategy entirely. Pacing isn't about covering a distance efficiently. It's about surviving one more loop than everyone else. Races are won by patience and stubbornness as much as fitness.
Where backyard ultra came from
Gary "Lazarus Lake" Cantrell, creator of the Barkley Marathons, invented the backyard ultra format at his farm in Bell Buckle, Tennessee. The inaugural Big's Backyard Ultra was held in 2011 with a small field of runners. The format spread gradually, then rapidly, as race reports and videos circulated online.
Today there are hundreds of backyard ultras worldwide. The sport's unofficial world championship is held at Big's Backyard Ultra each October — won by Phil Gore in 2025 with 114 loops. The outright world record of 119 loops (496 miles) is held by Phil Gore, set at Dead Cow Gully Backyard Ultra in Australia in June 2025. A network of sanctioned Last One Standing qualifier events feeds into the Big's championship, giving runners around the world a path to the sport's highest stage.
Common questions
Why is the loop distance 4.167 miles?
4.167 miles × 24 = 100.008 miles, close enough to exactly 100. The format was designed so runners who survive a full day have covered a clean hundred miles. It's a built-in milestone in a race with no external finish line.
What happens if two runners finish the last loop together?
They both go out for another loop. The race continues until one runner completes a loop and the other doesn't, or one runner drops before the next loop starts. There is no shared win; the format allows only one winner.
Can you sleep during a backyard ultra?
Yes, if you can sleep, wake up, run 4.167 miles, and return within the same hour. In practice, elite runners go without sleep for 24 to 48+ hours. Managing fatigue without sleeping is a core part of backyard ultra strategy.
Is there a women's backyard ultra record?
Yes. Women compete in the same field as men at most backyard ultras, and many events track women's records separately. The women's world record has been contested at Big's Backyard Ultra and other major events.
How do I find a backyard ultra near me?
Backyard ultras now run on every continent. Local events are listed on UltraSignup and RunSignup. A searchable race finder is coming soon to backyards.run.