I will be as specific as I can, but I highly doubt anyone will know the name of the movie I'm looking for. It is an old Martial arts movie, likely Kung Fu, so Chinese. I seen it as a kid in the late 80's, so obviously it would pre-date that. What I remember from the film is the signature move of the Hero; he would knock an enemy to the ground then jump high into the air and come down like a dive, as you would into water, with his hands out, palms forward, and land on the chest of the enemy, crushing his chest, a fatal move. I vaguely remember him not being able to use it for a while, because he had a bad experience with it once, but as you do he had to overcome that in order to defeat the evil bad guy in the movie. Anyway, I'm sure even the most seasoned of Martial Arts movie addicts will have trouble figuring out what I am talking about, but here's hoping, it was one that has stuck in my memory, unfortunately the name of it didn't.
Any chance it might be Snake in the Eagle's Shadow? it's an early Jackie Chan and he develops his own cat style (complete with cat shrieks), which sounds like what you describe, but his hesitations were not due to bad experience with this move, rather his horrid uncle. If it's not, it's a movie worth watching if you haven't already - for the comedy value alone!
If you're still looking, might it be Kung Fu Hustle (2004)? It features a move called the Buddha Palm which involved jumping straight up (to a ridiculous height) and diving down hands first.
Sing (the Hero) previously tried to use the techniques (though not the finishing move) in his childhood to defend a girl after teaching himself out of a manual but failed and got beat up and peed on.
Video of Sing's childhood humiliation:
As an adult he finally mastered the technique and used it to epically defeat the same (now adult) bully that beat him up as a child.
Video of the epic version of the Buddha Palm in action: