This is probably one of the best martial arts kung fu documentaries I've ever seen. This is what people practice years to achieve in terms of physical realm skills. At a higher level up, you practice with chi and shen to cultivate superpowers and paranormal abilities.

 video.google.com/videoplay

So, remember that this wonderful video is about cultivating physical gongfu (kung-fu), not spiritual kung-fu. Yet,  you can use martial arts (wai-kung) to  enter into the path because to get to the next skill level you must practice chi-kung, then nei-kung (internal alchemy) then Tao-kung.