I wanted to practice it. My teacher is well known for Chi Kung (Sun Dafa).
However, after reading a lot and talking to senior students who train with him I came to the conclusion alot of it is bullshit, or simply skills trained mundanely.
Now, that is a sweeping statement...and I don't mean to say there is no merit in chi kung.
Breathing can affect a persons state...calm you, energise you etc. Visualisation meditations also may do this.
However, the Chinese love to exaggerate especially when it is about anything Chinese. It may be good for relaxing, maybe to focus and get your energy up...but you won't fly...or have iron body or be able to lift people up with one finger.
Now, iron body is a form of hard chi kung...but there is nothing "mystical" in it. Anyone with iron body has actually trained the body for it (it may involve breathing and visualisation, but these alone won't do it). And I have seen people in my class do techniques often attributed to chi and explain the training for them.
In all cases the training is HARD and GRADUAL. It isn't from some mystical energy.
Like I said though...the stuff can work...but be careful coz there is SO much bs out there. And don't expect breathing and meditation to make you physcially strong....it can help in coordination with exercises....but it makes sense that they alone won't do it.
A guy from my class said to me stand in a dark room, relaxed, and try to clear your head of all thought. Even ten minutes of this a day is hard to do. He said unless a person can do that they won't get far with any real chi kung anyway. It is a good starting practice that can't harm you. And it will show you how tense we are.
But energy is energy. Runners have it, weight lifters....don't loose your logic in the bs.
And BLACK WISDOM, the I Ching is great...stare at those symbols till they make sense