The backyard ultra was invented by Gary 'Lazarus Lake' Cantrell, the man behind the Barkley Marathons. The rules fit on a postcard: a loop of 4.167 miles starts every hour, on the hour. Finish inside the hour and you can rest until the next start. Fail to finish, or fail to be in the start corral when the bell goes, and your race is over.
There's no set distance. The race keeps going until one runner completes a lap that nobody else does. That runner is the only finisher — everyone else, even the person who ran 60 hours, goes down as a DNF.
How far is it?
4.167 miles is 1/24th of 100 miles, so the maths is simple: 6 laps is roughly a marathon, 12 laps is 50 miles, 24 laps is exactly 100 miles. Record-holders have gone past 100 laps — over four days without proper sleep.
Why people love it
Nobody gets left behind. The whole field starts together every hour, so the fastest and slowest runners share the same start line all day. And because you're credited with every lap you finish, you choose your own goal: a first marathon, a first 50, a first 100.
How to pace it
Most runners aim to finish each lap in 45–55 minutes. That leaves time to eat, drink, use the toilet, change socks and sit down. Running the lap fast doesn't win you anything; it just burns energy you'll need at 3am. Walking the hills from lap one is normal.
What to bring
Because you pass your base every hour, you can carry very little on the loop. What matters is your 'crew area': a chair, a box of food you actually like, spare shoes and socks, layers for the night, a head torch with spare batteries, plasters, lube and something warm to drink. A crew member who can hand you things as you come in is gold.
Choosing your first one
Look for a mostly flat, runnable loop, a time of year with mild weather, and a reasonable cap on field size. Smaller events are often friendlier for a first go. Our UK backyard ultra calendar lists every event we can find with dates, terrain and entry links.
