There’s not much you can do with so few 20+ yr Birchlegger skiers (21 males and 2 females) in the Birkie classic race. Looking at this graph, though, one thing is striking – there’s very little change in finish times as these Birchleggers age. Fitting a segmented linear response doesn’t really add anything since all skiers, male or female, finish within 4 to 6 hours regardless of age. Only after 70 do skiers markedly slow down. This is more testimony to the long-term endurance and fitness of Birchleggers.
Note: Finish times are standardized to a 55k classical race or a 50k freestyle race.