So I would like to ask Ki is natural of supernatural according to you?
If i may i think its more of an evolved/learned understanding of physics. And controling your body to do a task with the least effort on your part but doing something that seems to require a lot of effort.
-Punching trough something that should brake your arm or should be impossible.
Firstly if you wont punch trough then it will brake your arm or as some say it will punch you back. Basic physics either the energy of your blow gets transferred to the object and dispersed as the object is braking or it gets distributed trough the object and your hand thus causing you pain or braking your arm.
-Punching with inhuman force
Basically you have to "gather" your energy from the furthest point on your body and move it all the way to the point that makes contact with the object. Kind of like a whip as the energy is transferred from the thick end of the whip t words the thin at the end it causes the final part of the whip to go supersonic thus causing the popping effect.
-Making yourself to "heavy" to lift
Centre of gravity we humans can easily shift our centre of gravity to all sorts of positions placing your centre of gravity low and away from your body you can make it significantly harder for someone to lift you.
-Throwing giant heavy people around like they are made of Styrofoam, again centre of gravity you just have to apply enough force to shift their centre of gravity and let gravity do the rest or redirect their kinetic energy just enough so they land on their face or a combination of both
Id call placebo effect on this one if you convince yourself to let someone poke needles in to you then you must have convinced yourself that this will work
Basically everything can be explained and is not supernatural because it follows natural laws even though some people may do amazing things using qi it all falls down back to basic physics im not saying that they are not masters of their body, their mind, and physics but i am saying that its not supernatural.
Christianity, One woman's lie about an affair that got seriously out of hand