erm... you get hurt (in real life) from landing incorrectly. doesnt matter if your jumping up and down or falling off of something... unless you're too high of course.
But in-game we assume that the player always lands correctly. So for example: after falling more than a certain minimum distance the player takes 'x' damage, then add on to that more depending on how far the drop is. I suggest limiting the maximum damage though.
Obviously if a chracter can jump very high, it wont take any damage from that as it would have already be adapted to falling that distance. (hehe: hint hint, there might be some chracters with cool jumping abilities)
I hope this answers your question, I didnt quite understand it :/