Bib #1 wrote:
The Mexican women’s 400 m national record is 48.89. That’s not too shabby. Only 2 American women have run faster.
Adding on to the above:
Ana Guevara ran 48.89 in August 2003.
Since then, only Sanya Richards Ross has run faster (48.70 in September 2006)
Most of the other faster times were run in the drug-tainted 80s
Guevara is the #9 performer all-time