Different Animation Qualities? How?

I have been working on a game for a while now, and I am getting to the animating point, but I want it to be as optimized as possible. I have seen some games such as Phantom Forces and Apocalypse Rising 2 which have animation quality settings in their graphics settings. I was wondering if anyone knows a way that animation quality can be changed like that. I know that Phantom Forces uses CFrame animations, not normal animations, but I am pretty sure that Apoc uses normal animations. Either way, How is it done?