hmm, there is no way that this could be done without that person really hurting themself. even if you just jumped pencil style off of an 80 foot cliff, its going to hurt like a bastard.
i landed a little bit leaning over and yes, it did hurt....my hands were stinging (i put them down trying to avoid leaning over too much) and my back hurt a little....but people jump as high as like 140 feet....twice this high...it's definately doable...considering...well...that's me!!!
leaning back...yeah, you know...the motion for a cork spin....you spin with your head uphill for the first part (if you are skiing) so i did the same here