| 1) | Leake, Clifton | Arizona | 51.10 (04/06) | 51.12 (05/04-05/12) | 51.29 (04/18-04/20) | 51.42 (03/29-03/30) | 51.65 (05/04-05/12) | 51.91 (04/27) | |
| 2) | Koroknai, Tibor | Nebraska | 51.10 (05/10-05/12) | 51.17 (03/29-03/30) | 51.53 (04/24-04/27) | 52.00 (04/06) | 52.02 (05/10-05/12) | 52.66 (04/17-04/20) | 53.04 (04/17-04/20) |