Le 10 July 2026

Backyard ultra

Complete guide · Backyard Ultra

The race with no
finish line in sight.
The last one standing wins.

Everything you need to know about the Backyard Ultra format: rules, strategy, nutrition, gear, and current records.

6,7056 km per loop

1 h per loop, exactly

119 loops men's record

The concept

What is the Backyard Ultra?

The concept is as simple as it is ruthless: run a loop of 6.7056 km every hour, on the hour, without exception. The time remaining after each loop is used to recover, eat, drink, change clothes — or sleep for a few minutes.

There is no set final distance. The race only ends when there is just one runner left able to complete an additional loop. All others receive a DNF (Did Not Finish), regardless of their loop count. There is only one winner, or no one.

It's not a speed race. It's a race of consistency, clarity, and willpower.

— Philosophy of the "last one standing" format

The format was created by Gary "Lazarus Lake" Cantrell, one of the founders of the legendary Barkley Marathons. The original race, the Big Dog's Backyard Ultra, is held in Bell Buckle, Tennessee, on his property — named after his dog.

The rules

Official rules you need to know

The rules are minimalist but strict. No tolerance on timing.

Rule	Explanation
Distance	6.7056 km per loop (4 miles + 880 feet)
Start	Every hour, on the hour — no delay tolerated
Corral	The runner must be present in the starting area at the bell
Loop	Each loop must be completed in under one hour
Assistance	No personal assistance during the loop itself
Poles	Prohibited under official rules
Winner	The last runner to complete a loop alone
Standings	All others: DNF, regardless of distance covered

Warnings are given 3, 2 and 1 minute before each start. The course can be a loop or an out-and-back depending on the organization.

The distances

Why 6.7056 km? The calculation of 100 miles

The distance is not chosen at random. It is calculated so that a runner completing 24 loops has covered exactly 100 miles (≈ 160.9 km), one of the great symbolic milestones of ultra-endurance.

Loops	Distance	Meaning
6	40.2 km	Almost a marathon
12	80.5 km	Confirmed ultra
15	100.6 km	100 km milestone
24	160.9 km	100 miles — 24 hours of racing key milestone
48	321.9 km	2 days of racing
72	482.8 km	3 days
95	637 km	Current women's record record
119	798 km	Current men's record record

Records

Current records (June 2026)

Men's record

119

loops · ~798 km

Phil Gore

Dead Cow Gully Backyard Ultra, Australia · June 2025

Women's record

loops · ~637 km

Sarah Perry

Big Dog's Backyard Ultra, Tennessee · October 2025

The term assist refers to the last competitor eliminated, meaning the one who pushed the winner all the way to the end. Without this opponent, the winner would not have accumulated as many loops — the assist is almost as celebrated as the victory itself.

Why it's so hard

The six invisible adversaries

Mental repetition

Same course, same start, same routine — hour after hour. The mind often gives out before the legs.

Sleep deprivation

After 24 hours, every additional hour becomes a battle against falling asleep.

Downtime management

Finishing too fast leads to fatigue, finishing too slowly prevents recovery. The right pace is a constant compromise.

Nutrition

Eating regularly without overloading the stomach, over dozens of hours — a challenge in itself.

Weather

Heat, cold, rain, wind, night — all conditions follow one another in long events.

Feet

Blisters, maceration, chafing, nails — feet are the first weak point in this type of event.

Strategy

Running fast is not always an advantage

This is the great paradox of the Backyard Ultra. A runner who finishes in 35 minutes has 25 minutes of rest, but may have run too fast. Another who finishes in 50 minutes only has 10 minutes to recover, but has saved their legs.

Managing time between loops

5 min

Drink, quick snack, head back out

10 min

Drink, eat, change a layer

15 min

Sit down, check feet, eat

20 min

Power nap possible (watch out for wake-up)

25 min+

Long rest — risk of getting cold

The main danger: resting too long, getting cold, starting again stiff — or mentally checking out.

Nutrition

Nutrition: eat often, in small amounts

The golden rule is to never wait until you're hungry or thirsty. In a Backyard Ultra, the refueling window shrinks as the pace increases — or as fatigue slows digestion.

Frequently used foods: salted potatoes, pretzels, noodles, rice, soup, applesauce, energy bars, electrolytes, coffee or tea with caution — and "comfort" foods to boost morale during low points.

Nutrition should not be presented as a one-size-fits-all formula. Every runner must test their diet in training — what works for one person can be disastrous for another.

Classic mistakes

10 mistakes that eliminate runners

01 Starting too fast — feels easy at first, blows up later.
02 Neglecting your feet — wet socks, blisters, chafing left untreated from the start.
03 Eating poorly — too much, too little, too sweet, not salty enough.
04 Changing strategy too late — waiting for the crisis instead of anticipating it.
05 Getting cold between loops — especially at night, without warm clothes ready.
06 Overthinking — fatigue makes every decision costly. Have a pre-defined strategy.
07 Missing the start — the bell is unforgiving. Immediate DNF.
08 Underestimating the weather — rain, cold, heat, wind change everything.
09 Untested gear — never wear a brand new pair of shoes on race day.
10 Thinking it's "just 6.7 km" — the distance isn't the problem. The repetition is.