Which Events Featured Largest Percentage Gap Between Top Time and No. 2 Performer? (Men’s Edition)
Which male swimmer dominated his event at the highest level during the 2025 season? On the surface, that honor seems to belong to French superstar Leon Marchand, who registered a world record of 1:52.69 in the 200-meter individual medley during the semifinals of the World Championships. That performance was more than a second faster than the year’s No. 2 performer, American Shaine Casas, who went 1:54.30 in the 200 IM.
But what does the math say? The list below indicates the percentage gap between the top time in the world and the No. 2 global effort in the 17 individual events contest at the international level. From a statistical standpoint, Marchand’s 200 medley indeed topped the No. 2 time by the largest margin, 1.41% That was slightly ahead of the 1.38% gap between Russian Kliment Kolesnikov (23.68) and countryman Pavel Samusenko (24.01) in the 50 backstroke.
Here is the complete list of percentage differences between No. 1 and No. 2:
50 Freestyle
World Leader: Cameron McEvoy (Australia) – 21.14
No. 2 Mark: Ben Proud (Great Britain) – 21.26
Percentage Difference: .56%
100 Freestyle
World Leader: David Popovici (Romania) – 46.51
No. 2 Mark: Jack Alexy (United States) – 46.81
Percentage Difference: .64%
200 Freestyle
World Leader: David Popovici (Romania) – 1:43.53
No. 2 Mark: Luke Hobson (United States) – 1:43.73
Percentage Difference: .19%
400 Freestyle
World Leader: Lukas Maertens (Germany) – 3:39.96
No. 2 Mark: Sam Short (Australia) – 3:41.03
Percentage Difference: .48%
800 Freestyle
World Leader: Ahmed Jaouadi (Tunisia) – 7:36.88
No. 2 Mark: Sven Schwarz (Germany) – 7:38.12
Percentage Difference: .27%
1500 Freestyle
World Leader: Ahmed Jaouadi (Tunisia) – 14:34.41
No. 2 Mark: Sven Schwarz (Germany) – 14:35.69
Percentage Difference: .14%
50 Backstroke
World Leader: Kliment Kolesnikov (Russia) – 23.68
No. 2 Mark: Pavel Samusenko (Russia) – 24.01
Percentage Difference: 1.38%
100 Backstroke
World Leader: Thomas Ceccon (Italy) – 51.80
No. 2 Mark: Pieter Coetze (South Africa) – 51.85
Percentage Difference: .09%
200 Backstroke
World Leader: Hubert Kos (Hungary) – 1:53.19
No. 2 Mark: Pieter Coetze (South Africa) – 1:53.36
Percentage Difference: .15%
50 Breaststroke
World Leader: Ludovico Viberti (Italy) – 26.27
No. 2 Mark: Ilya Shymanovich (Belarus) – 26.37
Percentage Difference: .37%
100 Breaststroke
World Leader: Qin Haiyang (China) – 58.23
No. 2 Mark: Kirill Prigoda (Russia) – 58.53
Percentage Difference: .51%
200 Breaststroke
World Leader: Shina Ohashi (Japan) – 2:06.91
No. 2 Mark: Filip Nowacki (Great Britain) – 2:07.32
Percentage Difference: .32%
50 Butterfly
World Leader: Maxime Grousset (France) – 22.48
No. 2 Mark: Noe Ponti (Switzerland) – 22.51
Percentage Difference: .13%
100 Butterfly
World Leader: Maxime Grousset (France) – 49.62
No. 2 Mark: Noe Ponti (Switzerland) – 49.83
Percentage Difference: .42%
200 Butterfly
World Leader: Luca Urlando (United States) – 1:51.87
No. 2 Mark: Leon Marchand (France) – 1:52.57
Percentage Difference: .62%
200 Individual Medley
World Leader: Leon Marchand (France) – 1:52.69
No. 2 Mark: Shaine Casas (United States) – 1:54.30
Percentage Difference: 1.41%
400 Individual Medley
World Leader: Leon Marchand (France) – 4:04.73
No. 2 Mark: Carson Foster (United States) – 4:07.02
Percentage Difference: .93%