That's why I said I don't think there could ever be a double blind study to test it, because the guy doing it would always be aware of the fact that he was doing it, or supposed to be doing it, and that may influence him. Even if there is nothing actually going on, the simple belief that there
is some qi in his fist might make him hit harder. It's kind of like how the right pep talk/pump up can cause a powerlifter to add a few more pounds onto a lift and successfully complete a lift with 10 more pounds than he just failed with on the previous lift 10 minutes beforehand. Nothing measurable changed.
I don't doubt that you feel stuff. I did qigong for a long time I and I also felt stuff. The energy in the dan dien, the rushing of water over the arms feeling, etc. When I would do iron forearms training I could feel the qi (or whatever) in my forearms. The subtle tingling-yet-heaviness feeling. But I don't think that had anything to do with my ability to take a hard strike without damage. I banged my inner forearm on stuff a couple times on accident and it didn't hurt, and I didn't have my qi "charged up" or anything at those points.
All I'm saying is, I don't doubt these people can hit hard. I just want to see a qi iron palm breaking demo where it's not an (often ridiculous) use of leverage and body mechanics being blamed on qi. Or some parlor trick like lifting the edge of the brick up the moment before impact. That's not qi power, that's physics and leverage.
If someone wants to do a qigong break, he should break a bunch of bricks with no spacers flat on the ground by actually projecting his qi into it rather than using muscle or strength and tons of leverage, and he certainly shouldn't begin by jumping into the air so he can come down on it with all his body weight. Lightly tap the stack of bricks and have them shatter or something, something that obviously can't be explained by physics. That would be more believable.
Show me an iron body demo where a guy gets hit in the stomach and he isn't flexing every muscle in his torso at the moment of impact. That's not qi protection, that's physical protection; the same way anyone takes a hit.
Blindfold a guy, have him move his qi to his abdomen so he's "protected" or whatever, and let someone punch him in the gut at a random moment so he can't be all waiting with his muscles flexed. Bonus points if it's not a fat qigong master, because fat people can take punches easier anyway since they have more mass between them and their organs. On a related note, there sure are a lot of fat qigong masters. (I'm not the first to notice this:
link)
Some people want to talk about throat training. The spear bending thing is a stage trick (physics). It has nothing to do with qi. They have to put it in a specific point on their throat and push a certain way, otherwise they die (not that the spear is super sharp, anyway). Physics and slight of hand and audience misdirection, not qi. Notice everyone puts it in the same place at the bottom of the throat and pushes down. Hmm, I wonder why? They're trying to tell the audience that they can withstand strikes to the throat so the audience believes they have super human power. Nonsense. They're doing the same stage trick that performers have done for years.
It's a disservice to TMA. No wonder people make fun of qiblasts.
But there are always going to be people who believe it, or who want to believe in it. Dozens of people think their master can move them with kong jing. How many hours do you think they spend on kong jing training exercises? We all know what happens when kong jing people fight real fighters (or even people outside their own school).
Again, I stress conditioning is important. You don't want to break your hand in a strike. But your hand is becoming stronger because of Wolff's Law and a slow desensitization to pain, not because magic energy is protecting it.
I would stand up and applaud if I ever saw a kung fu school or Shaolin monk demo where they said "this guy is going to break some bricks. He has been conditioning his hand for a long time and has strong bones and the mental focus to perform the break. This type of training requires months/years of practice and is highly indicative of a skilled practitioner." But they never say that. They say junk like "you can see him moving his qi into his hand. Qi protects the hand and blah blah blah superhuman powers. These special exercises blah blah blah."
Why is it so important that they mislead the audience like that? Why do so many (but not all) TCMA people need other people to believe they have supernatural powers? Ego? Fear? Legend? Or do they need to keep normal people afraid of their super powers so they never actually have to fight a resisting opponent?