Punching

As many of you know, I am a martial arts aficionado under the tutelage of Grandmaster Ernesto Presas. It's been a while... er... a long time since I trained in our dojo there in Quiapo. For the past 6 months or so, I have been improvising my training by myself, trying to develop anaerobic routines.

I was doing a shadowboxing routine last week when I suddenly checked my form, my punching form. I begin to wonder if what I'm doing is correct, since no one at that time would correct it for me since I'm training on my own. Although I train for efficiency, not aesthetics, mind you.

Then I remembered the basic punching fundamentals--to tense the fist JUST BEFORE THE IMPACT for maximum speed and power. So i practiced my punches according to that principle. Hours later I watched a video in youtube and an FMA grandmaster there said that when punching, you pull the energy back towards you while when you slap, you eject it. So the latter is better, according to my interpretation to what he said.

When I got back home I tried it, and when I was punching the air and clenching my fist just before the imagined impact, I thought that I was indeed pulling the energy back to my arm instead of ejecting it to the target. When I did the straight punch, my fist was relaxed until about two inches before the impact when I clenched it. I'm getting the feeling that I was indeed pulling or holding the energy back because I suddenly clenched my fist.

I AM CONFUSED. WHAT SHOULD I DO?