The predicted minimum times were computed on the aging part of
this site: Aging in Sports and Chess.
Both the 2007 and 2018 age factors have been used to see how much
difference the new factors make.
These calculations are based on an age corrected best time of
22:30 at age 64.
This is not Barbara's best time, which is 20:11
at age 42, but it is the best age corrected.
Barbara has been close to her line for most of the races. She is someone who
has slowed down no faster than predicted. Her last 7 times are remarkably
close to predicted except for the 2017 race. This provides support to
the regression line in that there are at least some people who can stay on it!
Using 22:30 at age 64 as the base, the new age factors predict slightly
faster times at the earlier ages. By age 40 the difference is 48 seconds.
The big picture is the same, but the new age factors have slightly larger
decline rates and thus smaller predicted times for earlier ages. The new age
factors say that Barbara should have been able to run a 17:46 at age 40 (and
then slowed down faster)
compared to 18:43 for the 2007 age factors (and then slowed down slower).