An interesting side issue on this that I have been thinking about is:
If the principles of Aikido, correct posture, breathing, awareness, not freezing up in a fight, relaxation etc... are so effective and powerful.
Why do we have to work so hard to develop them? Shouldnt we already have all these if we managed to survive and evolve to the point we are at right now?
Wouldnt natural selection have weeded out the members of our species with weaker strategies like tensing up, freezing, holding their breath, having bad posture etc.