Fat Ox
What started as an ‘ultra-experiment’ for young Nathan Coury’s college thesis on “fat oxidation” (fat-ox) and ultra running, becomes a 48 hour family fixed-time festival celebrating our season at Nardini Manor. Note we’ve moved venues to Estrella Mountain Regional Park
Run your own experiment and push beyond your limits on the USATF Certified 0.988178 mile course. It’s perfect for your first ultra, your first 100 mile, or your own personal best; a 48 hour time limit to discover your inner animal!
The coolest of the fixed time series, the Fat Ox returns with a new venue at Estrella Mountain Regional Park for a 48-hour run fest! Participants choose between the 48, 24, 12, or 6 Hour, 100 miler, 100K, 50 miler, or 50K all on a 0.988178 mile certified loop! Run all day and night on this sidewalk path that winds around the turf area of Estrella Mountain Regional Park with the Estrella foothills as a backdrop.
Upcoming Races
Results
6 Hours
| Date | Finishers | Top Result (F) | Top Result (M) |
|---|---|---|---|
| 11/21/25 | 16 | 40.515 | 42.492 |
| 11/22/24 | 10 | 35.574 | 39.527 |
| 11/17/23 | 21 | 39.519 | 40.507 |
| 12/02/22 | 9 | 34.6 | 36.6 |
100 Miles
| Date | Finishers | Top Result (F) | Top Result (M) |
|---|---|---|---|
| 11/21/25 | 21 | 18:54:05 | 18:24:15 |
| 11/22/24 | 18 | 28:47:05 | 22:36:33 |
| 11/17/23 | 12 | 26:30:07 | 18:25:03 |
| 12/02/22 | 12 | 20:47:42 | 23:11:23 |
24 Hours
| Date | Finishers | Top Result (F) | Top Result (M) |
|---|---|---|---|
| 11/21/25 | 11 | 83.007 | 83.995 |
| 11/21/25 (USATF) | 15 | 117.7005619 | 138.345 |
| 11/23/24 (USATF) | 32 | 137.57150408242 | 142.71163540333 |
| 11/22/24 | 20 | 94.865 | 108.7 |
| 11/17/23 (USATF) | 9 | 112.49 | 127.12 |
| 11/17/23 | 13 | 80.026 | 108.678 |
| 12/02/22 | 20 | 67.2 | 103.7 |
| 11/19/21 | 29 | 94.4 | 107.8 |
| 11/20/20 | Race Cancelled | ||
| 11/29/19 | 12 | 80.86 | 101.697 |
48 Hours
| Date | Finishers | Top Result (F) | Top Result (M) |
|---|---|---|---|
| 11/21/25 | 28 | 195.165 | 177.872 |
| 11/22/24 | 32 | 124.511 | 160.085 |
| 11/17/23 | 23 | 124.486 | 224.272 |
| 12/02/22 | 32 | 157.1 | 228.2 |
| 11/19/21 | 20 | 147 | 201.3 |
| 11/20/20 | Race Cancelled | ||
| 11/29/19 | 15 | 146.792 | 185.356 |
12 Hours
| Date | Finishers | Top Result (F) | Top Result (M) |
|---|---|---|---|
| 11/21/25 | 22 | 75.102 | 73.619 |
| 11/22/24 | 16 | 56.315 | 58.291 |
| 11/17/23 | 15 | 49.399 | 49.399 |
| 12/02/22 | 12 | 62.2 | 47.4 |
| 11/19/21 | 18 | 68.7 | 61.2 |
| 11/20/20 | Race Cancelled | ||
| 11/29/19 | 13 | 42.296 | 58.157 |
100 KM
| Date | Finishers | Top Result (F) | Top Result (M) |
|---|---|---|---|
| 11/21/25 | 8 | 12:07:37 | 11:06:06 |
| 11/23/24 | 6 | 12:49:11 | 12:37:01 |
| 11/17/23 | No Ultra Finishers | ||
50 KM
| Date | Finishers | Top Result (F) | Top Result (M) |
|---|---|---|---|
| 11/21/25 | 5 | 3:44:58 | |
| 11/23/24 | 11 | 4:55:40 | 6:08:00 |
| 11/17/23 | 4 | 6:05:03 | 7:18:12 |