If a 20 y/o kicked an unprotected 13 y/o in the head/face with force sufficient to knock the head back in my old TKD classes.... that 20 y/o would then be sparring me and I would make a point to... illustrate... why that is not "the thihng to do."
But, people's opinions on what is "good training" differ.
But, people's opinions on what is "good training" differ.