The 22-year-old caught the eye when the time stood at 49.97 (then corrected to 49.96) after she broke a real dream barrier and entered the exclusive club of sub-50 second indoor runners.
After a few hours' rest, Bol returned and ran 200 meters in 22.87, which was also a Dutch record.
Not even outdoors has she run that fast.
The coach felt that the first 50 meters of the 400 meters were not fast enough and that there is air there.
37 hundredths off the old Eastern State record
- I think that instead of an opening of 23.93 seconds at the halfway point as now, Femke can open a few tenths faster, she proved that with her 200 meters afterwards.
And then she can run the second lap as fast as now, says her trainer Laurent Meuwly to De Telegraaf.
He believes that Jarmila Kratochvilova's "unbeatable" world record of 49.59 from 1982 is under threat.
Yaroslava Mahuchikh won the high jump in a world annual best of 2.02 and then attempted a Ukrainian record of 2.07 without success.
Kajsa Bergqvist still holds the world record of 2.08 from 2006.