you should note that they said 2 SPRITES, not frames.
I don't know if you just can't understand this or something, but the two sprites are here:

sprite 1: view of pokemon from behind (lucario is using this sprite)
sprite 2: view of pokemon from in front (lucario's opponent is using this sprite)
each pokemon has 2 sprites, front and back. these sprites are never used together in a sequence to form an animation.
actually...
pokemons have 2 FRAMES for an animation, some of them only have 1
2 frames for behind animation
2 frames for front animation
4 sprites in total
it looks like they are using more than 2 frames because they have this sprite distortion system that makes them look moving
but pokemons are now fully animated:
http://www.youtube.com/watch?v=bR7Vig5yZXk&feature=player_embeddedcrystal, instead, had animations:

emerald had too:
