Freestyle skiers seem to hold their speed well into middle age, and the response relating age to finish time can be split into three linear periods for both genders. Females speed up by an average of 10 sec/yr until they reach the age of 44. From 44 to 64, females slow down by 2:10 min:sec/yr, and, after age 64, they slower further by 6:49 min:sec/yr.
Males slow at 28 sec/yr from age 18 to their first transition age of 52. From 52 to 75, they slow down by 2:53 min:sec/yr. Finally, after age 75 they slow by 9:31 min:sec/yr.
As with the classic technique, there were differences in transition ages between the genders. In the freestyle event males transitioned from stage to stage 8 to 11 years later than females.
(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.