Progress against the field
Ivo Groot Koerkamp has dropped 1:35 behind the field from Rotterdam 2025 to Maastricht 2026.
The clock says 9:12 faster, but the races themselves got 10:47 quicker for everyone.
The largest gain on the field came from Belgium 2025 → Heerenveen 2025: 4:31 in 34 days.
How this is worked out ⓘ
A finish time moves for two reasons: the athlete, and the race — its course, its floor, its day. For each pair of races in a row in one category, we take everyone who raced both and use the middle of how much they moved (the median) as "the race". Whatever is left is the athlete. Doubles are compared only when the same two people raced both, and told as the pair's; relays are left out. A pair with fewer than 15 athletes in common is not shown.
Every race
12 races · 12 events
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Maastricht19 Sep 2026Individual Open · Men1:02:40 PB8/394Beat 98%
↑ 128 days after Heerenveen 2026 2:28 better than the field Why ↓Close ↑
1:02 faster on the clock in a race that was 1:26 slower for everyone: 2:28 better than the field.
The fieldCompare these two →1:26 slower This athlete1:02 faster -
Heerenveen14 May 2026Individual Open · Men1:03:4230/966Beat 97%
↑ 113 days after Amsterdam 2026 2:33 worse than the field Why ↓Close ↑
2:33 behind the field: no different on the clock, against 2:33 faster for everyone.
The fieldCompare these two →2:33 faster This athleteno different -
Rotterdam15 Apr 2026Doubles Open · Mixed1:03:2415/560Beat 97%
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Amsterdam21 Jan 2026Individual Open · Men1:03:4246/1620Beat 97%
↑ 124 days after Maastricht 2025 1:23 worse than the field Faster on the clock, behind the field Why ↓Close ↑
6:36 faster on the clock looks better than it was: the race was 7:59 faster for everyone, which leaves this 1:23 behind the field.
The fieldCompare these two →7:59 faster This athlete6:36 faster -
Utrecht28 Nov 2025Individual Pro · Men1:12:20 PB35/215Beat 84%
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Maastricht19 Sep 2025Individual Open · Men1:10:1840/584Beat 93%
↑ 133 days after Heerenveen 2025 2:41 worse than the field Why ↓Close ↑
2:41 behind the field: 4:23 slower on the clock, against 1:42 slower for everyone.
The fieldCompare these two →1:42 slower This athlete4:23 slower -
Heerenveen9 May 2025Individual Open · Men1:05:5543/1217Beat 97%
↑ 34 days after Belgium 2025 4:31 better than the field Why ↓Close ↑
4:31 better than the field: 6:59 faster on the clock, against 2:28 faster for everyone.
The fieldCompare these two →2:28 faster This athlete6:59 faster -
Belgium5 Apr 2025Individual Open · Men1:12:54265/1638Beat 84%
↑ 37 days after Rotterdam 2025 1:57 worse than the field Why ↓Close ↑
1:02 slower on the clock in a race that was 0:55 faster for everyone: 1:57 lost to the field.
The fieldCompare these two →0:55 faster This athlete1:02 slower -
Rotterdam27 Feb 2025Individual Open · Men1:11:5251/600Beat 92%
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Amsterdam10 Oct 2024Doubles Open · Mixed1:03:15 PB13/618Beat 98%
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Rotterdam6 Apr 2024Doubles Open · Mixed1:05:3022/534Beat 96%
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World Championships NiceDate unknownDoubles Pro · Mixed1:06:29 PB201/297Beat 32%