The thing is - they don't (figure it out, that is).
I haven't seen anybody, physically talented or not, figure this out in a conventional way. OTOH, there are a number of people around teaching who have figured it out the "regular" way.
From looking at the idea of resisting a push for the last few days, I can't see how 'internal' people would resist a push any differently than an athlete would.
I'm sure if we keep examining things, we'll find out, at least in the realms of body movement, 'internal' people aren't doing anything significantly different than athletes would, given the same task (lifting, pulling, pushing, hitting, moving).