These calculations use the updated running age factors in Fair and Kaplan (2018). See 2018 Updated Age Factors. They are based on world single age records for men compiled by ARRS: World Single Age Records. Four road races were pooled---5km, 10km, half marathon, marathon---along with two outdoor track events---5000 meters and 10000 meters. The data are as of June 2, 2017. As with the 2007 age factors, these age factors should be used for all running events except 100, 200, and 400 meters. They can also be used for women. However, since the swimming results in Fair (2007) suggest that women slow down a little faster than men, these age factors may be a little too low for women.
The results in Fair and Kaplan (2018) begin with age 40 rather than age 35 and end with age 95 rather than age 100. The following age factors thus begin with 40 and end with 95, where the factor for age 40 is 1.0000. This means that any decline between ages 35 and 40 is not accounted for. It is just assumed that decline begins at age 40. There is probably some decline between 35 and 40, but it is quite modest, possibly about one percent total over the five-year period. Although this possible decline is ignored here, the user can if desired just increase each factor by about one percent to get factors with a starting age of 35. The age factors are: