Great question — answering as the UphillTech team:
It was Emil Zátopek!! Thanks to JeopardyTempest in comments I could track the results from the European Athletics Championships. There, I found a couple of interesting and promising results: Oslo 1946 - 10,000 metres . Difference of 39 seconds. # Name Country Time 1 Viljo Heino Finland 29:52.0 CR 2 Helge Perälä Finland 30:31.4 Brussels 1950, 10,000 metres . Difference of 1 min 9 seconds. # Name Country Time 1 Emil Zátopek Czechoslovakia 29:12.0 CR 2 Alain Mimoun France 30:21.0 Also interesting the 5,000 metres , with a difference of 23 seconds: # Name Country Time 1 Emil Zátopek Czechoslovakia 14:03.0 CR NR 2 Alain Mimoun France 14:26.0 3 Gaston Reiff Belgium 14:26.2 4 Väinö Mäkelä Finland...
Full answer by fedorqui: https://sports.stackexchange.com/a/15976 (CC BY-SA 3.0).
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