> So taekwondo people who train to hit concrete pillars don’t get stronger from the repeated hits, do you confirm?
Stress from repetitive microtrauma is not the same as a fracture (stress to failure). Increased mechanical loading (hitting a concrete pillar, exercise) can absolutely strengthen bone in a similar mechanism to decreased load weakening bones (little old lady, astronauts).
Breaking a bone completely disrupts the internal architecture and what is deposited is unequivocally weaker than what was there before.
> And “what doesn’t kill, makes you stronger” is false too
I have no professional opinion on this aphorism. I do have one on bone healing.
Loading your bones close to the breaking point does make them stronger. At least as long as you give them time to recover in between, otherwise you get a stress fracture. It's a balancing act. Do it well and you get stronger, overdo it everything spirals downwards. Same for most of the rest of your body. If something gets close enough to killing you, it will definitely make you weaker.
My claim was not that everything that hurts you must make you stronger, not weaker. I only made the much weaker claim that what fraction of things that hurt you make you weaker, not stronger, is highly variable from person to person. That does not imply that anyone would be made stronger by having each of their major bones broken--still less that doing so should be standard practice, just to see if it makes some people stronger. Having a major bone broken might not be in the set of things that makes anyone stronger by hurting them. There are lots of things that hurt besides having a major bone broken. Many of them do not do any physical damage to you at all.
So taekwondo people who train to hit concrete pillars don’t get stronger from the repeated hits, do you confirm?
And “what doesn’t kill, makes you stronger” is false too?