Backyard ultra yards: what they are and how they're counted

A yard is one loop of a backyard ultra course, which measures 6.706 km (4.167 miles). The rule is simple: every hour, on the hour, all the runners set off to complete a yard. Anyone who isn’t back in time for the next start is eliminated. The winner is whoever completes one more loop than everyone else.

The name comes from the backyard — the yard — where the first race in the format was run. In Spanish, «yard» and «vuelta» (loop) are used interchangeably — 14 yards and 14 vueltas are the same thing — and in Spanish results tables you’ll almost always see «vueltas».

Why 6.71 km

The distance isn’t arbitrary, and it isn’t designed in kilometres: it’s designed in miles. One loop is 4.167 miles, and 24 loops add up to exactly 100 miles (160.9 km) in one full day. So 24 yards equal 24 hours and the classic 100 miles of ultrarunning. It’s the unit that puts a round number behind ‘lasting a whole day’.

That’s where the milestone everyone uses to measure themselves comes from: going past 24 yards means you’ve done the 100 miles and are still in the race. In most Spanish races, anyone who crosses that line is already among the top three or four.

The table worth keeping in your head

The figures come from simple multiplication: each yard is 6.706 km, so your kilometres are always yards × 6.706. For your own case — with your pace and the rest you have left each loop — it’s quicker to use the pace calculator.

How it’s counted

• 1 yard = 1 loop = 1 hour. Whenever you set off within that hour, the next bell rings on the hour.
• Only completed loops count. A loop you don’t close within the hour counts for nothing: your official result is the number of valid yards. If you’re eliminated on loop 15 with 14 completed, your result is 14 yards, not 14 and a half.
• The time left over is your rest. The faster you run, the more you rest… but the more you wear yourself down. That balance is the central decision of the format and has its own guide: pace and rest in a backyard.
• The race has no fixed distance: it ends when only one runner is left who can complete the course and set off again.

What yards don’t tell you

A result of 20 yards doesn’t mean the same thing at every race, and this is what causes the most confusion when you look at a results table:

• The course changes the effort, not the distance. The 6.706 km are the same everywhere, but closing them on a flat tarmac course doesn’t cost the same as on one with 150 m of elevation gain per loop. The distance is constant; your loop time, and therefore your rest, is not.
• The start time decides where the night falls. A race that starts at 9:00 sends you into the night on loop 12; one that starts at 17:00, on the fourth. With the same yards, the race is lived in a different way.
• Nobody ‘finishes’ a backyard except the winner. In the official result the winner is the only finisher and everyone else is listed as DNF, with their number of yards next to their name. It isn’t a punishment: it’s what the format measures. We go into it in what happens when you’re eliminated.

The last one standing

The format is called last one standing precisely because of this: your pace and your absolute result don’t matter, only whether you can set off for one more loop. That’s why strategy weighs as much as fitness, and why the runner-up has a name of their own — the assist —: they’re the one who forces the winner to set off one more time.

It’s also why the format’s records are counted in loops and not in kilometres. When the world record is said to be 124 yards, what’s being said is that someone set off running every hour, on the hour, for more than five days. The 831 km are the consequence, not the record. All the context is in what is a backyard ultra.

How you train for yards

The format’s training unit is the yard itself, not the kilometre. The most specific session there is repeats the full cycle — a loop at target pace, real rest, a start on the hour — and it’s explained in loop simulations. If you’re going for your first, start with the guide on how to prepare your first backyard in 12 weeks, and to see what results are being run at Spanish races, take a look at the backyard directory: each race page shows the course record.