... or you could approach it from the view that 'chi' is the key idea in a practitioners 'users manual' of how to synergise mind, breath and body in a way that gets the optimum use of body and mind for martial arts. If you tried to explain it scientifically (which in theory, you'd eventually be able to), you'd never get around to training!
supporting standards in the martial arts www.shikon.com www.masa.org.uk