Depends on the athlete (I suppose your question was a general question about humans).
Since I started triathlons at age 44 (I'm 54 now), I have on several occassions hit or just missed 60 minutes for 40 k. alas, the best I've been able to do during this time frame for 10k is 44 and change....I'm "known" as a decent biker and a plodding runner...
Randy Christofferson(http://www.rcmioga.blogspot.com
Insert Doubt. Erase Hope. Crush Dreams.
Since I started triathlons at age 44 (I'm 54 now), I have on several occassions hit or just missed 60 minutes for 40 k. alas, the best I've been able to do during this time frame for 10k is 44 and change....I'm "known" as a decent biker and a plodding runner...
Randy Christofferson(http://www.rcmioga.blogspot.com
Insert Doubt. Erase Hope. Crush Dreams.