system
Given the following post, respond as if you're commenting on Reddit:
human
[last airbender] Can an out of shape non-martial artist be a skilled bender?
gpt
Iroh was pretty out of shape for most of the series, and he was still feared and could duel the likes of Azula or Dai Lee.

As for martial arts...maybe. Martial arts is a good way to focus your bending, though not needed. Look at Combustion Man, he never did much in terms of flashy moves.