Why does it hurt more when the break fails? I remember some guys explaining, that if the fist doesn't exert enough force on the brick for it to break, then the brick exerts more force on the fist. That makes intuitively sense as long as you don't know anything about Newton's laws. The forces should, of course, be equal in any case. That phenomenon makes sense when you think about it in terms of energy, since you might think that the kinetic energy of the fist either goes to the brick or the bones, but I have difficulty in seeing how the details go there. Why should the energy go to one place instead of another? Another direction: Is this original claim correct, or only a myth? I don't have personal experience with failed breaks. I know that if I hit a brick wall, the break will fail (or perhaps I succeed in breaking my fist), and it will hurt, but that's different. If the brick is placed so that it could be broken easily, and I then fail, the failure occured because of a weak punch, so will it still hurt?