During Sozin's Comet on a summer day', a bloodlusted sane comics Azula fights the rest of Avatar near a volcano. There are absolutely no restrictions on Azula. The opponent starts 5 meters from Azula.
Outside of the Avatar State, everyone in Avatar would be at their "prime" given the location, so Sozin's Comet firebenders, comics Aang and Korra, etc. Waterbenders get a constantly replenishing large water source.