
Originally Posted by
SamanosukeShiva
No they dont reset, when you look at a gym stat, you'll see their prestige points. When you beat a gym, their prestige point goes down and often they de-level, and when it reaches 0, the gym will revert back to neutral and you can take it over. So for a high level gym you need to beat it a few times to take it over. But you can also battle your own gym to increase its prestige points to level it up, but only with 1 of your strongest pokemon instead of a whole team, this is also a way of "defending" your gym from an attack. The higher level gym, the more pokemon people from your team can put inside to guard it.
So technically if you have friends from the same team, you can level the fuck out of a gym that you own and put a bunch of pokemons to guard it.