Yeah exactly, "over use", it's true for everyhting with the body. Cardio training for instance, you do none it's bad for the heart, you do too much it's equally bad. Both ways it makes it age faster Walking barefoot too, it's another example, it can turn super bad with over use, depends Spartans for example used to make their kids walk barefoot to fortify the feet, but then when the skeleton gets much heavier crica adulthood, they were allowed to wear shoes