It is the place where true internal power is accessed from, when you stop everything else going on in the mind.
Koichi tohei said "the mind leads the body" descates said "i think therefore I am". Both are mistaken. you are not you mind. its the talking that stops the access. how many stories of you heard of people being able to pull off often super human feats when there has been a disaster, they are able to do this because all identification and mind activity has ceased, and they access this power through deep being and compassion. There is truly no thing more powerfull than love.
Like I said, what you're talking about is not what most of the other folks are talking about. Not that mental state has no relation - just that what you're talking about is not what's being discussed.
Also, the same thing goes for the "lifting the car off the child" thing that you're talking about. Good stuff - but not really what most of the folks talking about "internal power" are discussing.