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Disclaimer: Swim of the Week is not meant to be a conclusive selection of the best overall swim of the week, but rather one Featured Swim to be explored in deeper detail. The Swim of the Week is an opportunity to take a closer look at the context of one of the many fast swims this week, perhaps a swim that slipped through the cracks as others grabbed the headlines, or a race we didn’t get to examine as closely in the flood of weekly meets.
King Aquatic Club’s Aiden Hammer had a breakthrough performance on the opening night of last week’s Pro Swim Series event in Westmont, knocking a significant chunk of time off his previous best to claim victory in the men’s 1500 freestyle.
Hammer, 17, flipped fourth at the halfway mark of the timed final in a close battle with age group phenom Luka Mijatovic and Olympians Luke Whitlock and Ilia Sibirtsev, turning in 7:40.34 at the 750.
Hammer started picking up the pace on the back half, distancing himself from Whitlock and Sibirtsev, and managed to fend off a late push from Mijatovic to touch first in a time of 15:15.37, dropping more than 18 seconds off his previous best of 15:33.69 set back in the summer of 2023.
Mijatovic (15:16.37) placed 2nd, while Whitlock (15:23.53) was 3rd and Sibirtsev (15:37.40) faded to 4th.
Hammer negative split the race, 7:40.34/7:35.03, and held his splits 30.75 or faster from the 1000 on, compared to his previous best time where the majority of his back-half splits were 31s.
Split Comparison
| Hammer, 2023 | Hammer, 2025 |
| 28.39 | 28.04 |
| 59.79 (31.40) | 58.47 (30.43) |
| 1:31.24 (31.45) | 1:29.36 (30.89) |
| 2:03.15 (31.91) | 2:00.26 (30.90) |
| 2:34.52 (31.37) | 2:31.10 (30.84) |
| 3:06.42 (31.90) | 3:01.96 (30.86) |
| 3:37.94 (31.52) | 3:32.75 (30.79) |
| 4:09.85 (31.91) | 4:03.82 (31.07) |
| 4:41.70 (31.85) | 4:34.82 (31.00) |
| 5:13.07 (31.37) | 5:05.91 (31.09) |
| 5:43.91 (30.84) | 5:36.56 (30.65) |
| 6:15.36 (31.45) | 6:07.75 (31.19) |
| 6:46.55 (31.19) | 6:38.37 (30.62) |
| 7:17.76 (31.21) | 7:09.55 (31.18) |
| 7:48.90 (31.14) | 7:40.34 (30.79) |
| 8:19.91 (31.01) | 8:11.38 (31.04) |
| 8:51.10 (31.19) | 8:41.86 (30.48) |
| 9:22.28 (31.18) | 9:12.89 (31.03) |
| 9:53.76 (31.48) | 9:43.45 (30.56) |
| 10:24.85 (31.09) | 10:14.20 (30.75) |
| 10:55.82 (30.97) | 10:44.64 (30.44) |
| 11:26.81 (30.99) | 11:15.27 (30.63) |
| 11:58.08 (31.27) | 11:45.72 (30.45) |
| 12:29.24 (31.16) | 12:16.26 (30.54) |
| 13:00.64 (31.40) | 12:46.64 (30.38) |
| 13:31.86 (31.22) | 13:17.15 (30.51) |
| 14:03.06 (31.20) | 13:47.47 (30.32) |
| 14:34.19 (31.13) | 14:17.42 (29.95) |
| 15:05.06 (30.87) | 14:47.17 (29.75) |
| 15:33.69 (28.63) | 15:15.37 (28.20) |
Despite being just 17, Hammer’s swim moves him into 27th all-time in the boys’ 17-18 age group. Since 2020, the only two swimmers who have been faster at 17 are Whitlock (15:08.09) and William Mulgrew (15:12.63), both done last year.
Hammer followed up his victory by placing 5th in the 400 free, setting a new best time of 3:51.35, and adding a 17th-place showing in the 200 free (1:50.87) at the first Pro Swim Series meet of the year.
His time in the 400 free improved on his previous best of 3:52.06 from the 2024 Junior Pan Pacs (which won him the bronze medal), moving him into 28th all-time in the 17-18 age group.
Previously committing to Cal, Hammer flipped his commitment to Texas in February, also announcing his reclassification into the high school class of 2025.
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