Re: Why do you perceive "internal" superior to athleticism?
Very interesting discussion!
Im not sure if this qualifies as "internal"but there is the concept of "spirit training", as can be found in many different external martial arts. Will power, determination, grit, whatever you want to call it.
I believe in aikido this is achieved in misogi training sessions with very high repetitions of suburi or newaza.
Im sure we have all witnessed many boxing, judo, bjj, wrestling (or even tennis) matches where this will power has determined the outcome.
Dont know if this answers the OP's question exactly.