I think the best way to explain this, is that Sure, maybe it is that fast, but, can it keep it up, maybe it can only run so fast for so long until it gets tired and has to rest, The speed stat, in the game, in a sense, doesn't just refer to the actual speed of the pokemon. In a realistic sense, it would also include things such as reaction time, or how long it takes for the pokemon to understand and perform your commands. And in a realistic view, No human or animal can run at full speed indefinitely. Endurance or stamina, is not something that is used in the game, but may be able to apply a logical explanation as to why it is so fast.

Loved Purugly then, love Purugly even more now.