Aun siendo joven

[Perikles]

I'm not sure whether this is a question for translation, vocabulary or grammar. Ah well.

F subía y bajaba las escaleras con un cuidado especial, aun siendo joven, porque siempre había pensado que la vejez empezaba con una primera caída sin importancia, y la muerte seguía con la segunda. (Márquez again)

'aun siendo joven' has to be translated as 'even when he was young' (because in context, he is already old).

This seems to me to be an unusual application of a present participle (=gerundio), and I can't offhand think of another language where it would be used to describe something in the past. Is this 'standard' Spanish, or unusual?

Thanks