That is the way I have always seen wood split, for safety as well as protection of the edge of the axe. However if you read "The Axe Book", by D. Cook, you will find a very different description of how to split wood. The author recommends leaving the wood on the ground and moving rapidly from piece, moving it with the foot or axe if necessary and splitting it where it lies. He even climbs right onto a wood pile splitting the top wood in a similar manner. There is no doubt that this method is far more time efficient, but I would warn about it requiring more than a little bit of skill.
-Cliff