Based on past worlds and Olympic medalists' performances, most male figure skaters seem to peak in early 20s. There are some exceptions. But most male skaters seem to be technically at their best in their early 20s. It could be due to a combination of stamina and training.
Up til now, I’d assumed Hanyu’s lightness would contribute to his longevity as a skater. As I’d spent more time around dancers’ bodies in my life, his physique is unusual to me. For example I’d seen recent clips going about of his shirt flying up during jumps in the ice shows, and as I’m very used to dancers’ bodies, it struck me how small he was in that area of his body, which is why the shirt flies up more than with the other performers, there’s just nothing there under the shirt. (the shirt’s really loose on him to begin with) It’s not leanness per se, dancers are very lean, but Hanyu’s small in thickness of his skeletal structure and very much longer than most from his ribs to his hipbones… so I thought it helped to rotate without using up his stamina too much. ergo longevity. (the height of the skates balances out his physique, but it is an unusual one, though less unusual amongst asians perhaps) However considering the frailty of a smaller frame, (and I’m not saying he does not have the condition of a champion athlete in his prime) as super conditioned and trained as he is, I’m not sure whether that lessens his longevity despite the efficiency of the light frame. Sorry just observances and questions i have about the skating physique as fs is comparatively new for me (versus dance)