Greetings..
Perhaps we shouldn't be evaluating internal and external as separate issues.. what is more appropriate, in my opinion, is the optimum balance.. we can each cite examples that favor our particular perspectives, but.. as much as is possible, we should look at an overall perspective and find the most beneficial path according to our goals.. some people are willing to sacrifice long-term health for short-term glory.. others, will choose a path with staged progression toward healthier "autumn years".. right and wrong are arbitrary values according to personal standards.. One of the great mistakes is to compare ourselves to extreme examples of our perspectives.. MMA champs, olympic body-builders, diminutive masters with disproportionate powers, mystical monks, etc.. setting realistic goals is a good way to avoid confusion.. realizing, of course, that there are no destinations.. just new points of departure..
Personally, i work with my own body weight.. or, i don't exceed my body weight in my weight or resistance training.. my mentor said that if i can control my own weight, i can control those that oppose it.. endurance, range of motion, and knowledge (technique, anatomy, physics, energy, medicine, etc...) have served me well...
Be well...
TaiChiBob.. "the teacher that is not also a student is neither"