The Short Answer
The backyard ultra is the simplest and most ruthless format in ultrarunning. One loop. One hour. Last person standing wins. Read our complete guide for the full breakdown of rules, records, and history.
The Math
| Loops | Distance | Time |
|---|---|---|
| 12 loops | 50 miles / 80.5 km | 12 hours |
| 24 loops | 100 miles / 161 km | 24 hours |
| 48 loops | 200 miles / 322 km | 2 days |
| 72 loops | 300 miles / 483 km | 3 days |
| 119 loops (men's WR) | 495.8 mi / 798 km | ~5 days |
Why It's Exploding in Popularity
The format is brilliantly accessible: anyone can run one loop. The loop distance (6.7 km) is manageable for any runner. What makes it hard is repetition, uncertainty, and the psychological weight of knowing you can't quit and rejoin. It's chess, not checkers. Ready to train? See our training guide and race strategy articles.
Sources
- Backyard Ultra Association (BUA) — Official Rules and Rankings
- DUV Statistics — Global Backyard Ultra Results Database