I'm just a beginner, but my experience with animation and poser is just that animation is hard enough.

Slowing something down in Premiere elements or something like that, is a lot easier. You can simply break your video into the pieces you want to slow down, and then, slow them down. You have more control IMHO. Plus, you'll need an external video editing program anyway to add sound effects. Oof, Pow, Zap etc.