Again, you are misreading my words. I am not saying one learns how to take hits by bending the laws of physics or even bracing for hits. You learn how to take hits by taking hits and then coming back despite the hit. (Read my earlier posts if you think I am changing my position.)
If you take a hit in week 3 and then become gun shy and never recover, you have not learned how to take a hit. If you are gun shy for a week and then regain comfort in that situation by week 5 or 6, you have learned how to take a hit. Now take another hit. Keep taking hits until you are done taking hits. If that point where you are done occurs in 5+ years (Merril Hoge, Troy Aikman, Steve Young), then you go down in history as one of those guys who suffered numerous concussions but continued to play long enough to retire. Plenty of athletes do it, which is why certain positions can demand more salary--they need the money for medical bills for concussions, broken bones, and torn muscles.
Again, learning to take a hit has nothing to do with bracing for impact. Learning to take a hit has more to do with coming back after a hit.