How much rest time should you actually bank?
Pace and rest time are the same equation in a Backyard Ultra. Run faster and you earn more time in the tent. But push too hard to earn that rest and you burn the engine you need for 20 hours.
Every lap has exactly one hour. The question is how much of that hour you spend moving, and how much you spend recovering.
Run faster and you earn more rest. But running faster costs more energy, and you need that energy for the next 15 laps. Run slower and you're fresher for longer, but now you've got six minutes in the tent instead of 12, which is barely enough to eat, change socks, and get back out the door.
Getting this wrong in either direction ends your race. Getting it right is most of what Backyard Ultra strategy actually is.
Zone 2
Everything I've learned from my own racing points to the same answer: Zone 2. Stay there as much as possible, for as long as possible. It's not exciting advice. It sounds almost too simple for an event this extreme. But it's correct.
Zone 2 means your cardiovascular system is running in the background, not under pressure. You can hold a conversation. You're burning fat as a primary fuel source. You could, technically, keep going for a very long time. That's exactly what you need to still be able to do at hour 18.
One thing that surprised me: overnight, even running on zero sleep, my heart rate often sits lower than I'd expect. Down into the low 120s. I assumed fatigue and sleep deprivation would push it up. Instead it seems to settle. I don't know the exact mechanism but it's been consistent across my races.
The 10-minute floor
The most important number in a Backyard Ultra is 10 minutes. That's your ideal minimum viable rest window in my opinion (and yes it definitely depends on your course!). Less than 5 minutes in the tent and you're not eating properly, not managing your kit, not giving your body what it needs between efforts.
10 minutes sounds fine. In practice it's tight. Food, fluid, bathroom, anything you need to fix: blisters, kit changes, crew check-ins. It adds up fast. If your loop time is pushing 58 or 59 minutes, you're on the edge of that window every single hour.
On our course with around 100m of elevation, 48 to 52 minutes per loop is about standard. That leaves 8 to 12 minutes in the tent. At the start of the race, 10 minutes feels like plenty. You'll eat, stretch, have a chat. By hour 18, that same 10 minutes disappears in what feels like seconds. You walk in, sit down, someone hands you food, you eat it standing up, and then that bloody bell is going again!
"At the start it feels like you've got plenty of time. By the end of it, that time disappears pretty quick."
Your early loops need to be building the buffer, not spending it. If you come through consistently at 48 minutes, that's the foundation. If you blow out to 55 minutes on loop 18, you still have a margin. If you started at 52 and you're now at 55, you don't.
Run like a machine
The mindset that works is mechanical, not heroic. Same effort, same pace, same loop, every hour. Don't accelerate on the downhills because you feel great in hour four. Don't grind out lap three two minutes faster than lap two because the adrenaline is still high. Don't chase someone else's pace because they look comfortable and you want to stay with them.
Look at the same spots on the trail. Run at the same effort. Come in at the same time. Low RPM, engine in control. The person who runs the most consistent loops almost always outlasts the person who runs the fastest early ones.
You're not trying to be impressive on any individual lap. You're trying to still be running when everyone else has sat down.