According to research by Peter Riegel, a person's speed declines by approximately 6 percent when distance doubles. You can use
his formula in order to predict a race time. The following is my predicted 20K (12.4 miles) times based on my training times and this formula. The top 33% of results are highlighted in green.
| Effective 20K Times - 2020 Training |
| Date | Result | Effective 20K |
| 3/16/20 | 13.31 miles in 54:13 | 66:59:03 |
| 3/17/20 | 4.3 miles in 30:04 | 73:32:06 |
| 3/21/20 | 4.49 miles in 48:04 | 85:03:36 |
| 3/22/20 | 10.36 miles in 41:10 | 61:51:37 |
| 3/25/20 | 15.41 miles in 9:15 | 65:17:57 |
| 3/28/20 | 20.52 miles in 42:21 | 61:27:22 |
| 3/30/20 | 7.03 miles in 37:07 | 61:03:33 |
| 4/2/20 | 8.32 miles in 18:08 | 60:03:45 |
| 4/5/20 | 20.27 miles in 50:20 | 56:10:42 |
View my 20K effective times (cycling).
View my 5K effective times (running).