To arrive at this graph, the five fastest skiers were identified for each age in each year from 1999 to 2025. There have been 22 “full length” point-to-point Birkies since 1999, so each data point in the graph represents the average of 110 top 5 results for each gender.
Overall performance patterns for the fastest five classic skiers of each age are very similar to those of the average of all classic skiers, with the exception of the more pronounced decline in performance in the older phases.
In the youngest periods, the top 5 classic skiers slow down by an average of 27-30 sec/year. The first transition ages of both genders are similar – 53 for females and 54 for males. Thereafter, the performance curves have similar profiles for both genders
But after the final transition ages, 72 for both males and females, the wheels really come off the cart for top 5 skiers. Performance declines at a rate of over 30 minutes/year for females and 15 minutes/year for males. It is obviously more difficult for elite classic skiers to maintain speed into to the older period than it is for the average skier, although elite skiers are still skiing much faster than their less competitive peers.
(More on statistical significance for estimates of breakpoints and slopes.)
Note: Finish times are standardized to a 55k classical race or a 50k freestyle race.