When someone not familiar to martial arts training come across the term "Bone Conditioning", it may sound like a brutal idea or, sometimes, useless. But if you've fought at least once, outside (not encouraged) or inside the gym, you know that your body is not that strong or 'made' to get beaten. And there comes the bone and muscle conditioning to get you more resistent. The concept is simple: punch or kick hard surfaces and you'll eventually get used to it. That's the principle, but soon enough you realize that in order to make it work without major injuries you'll need a lot of knowledge, patience and guidence. The top problems with bone conditioning are related to rush, when not following the proper initial steps, and the parts of the body that are not that easy to be conditioned being strongly punished. There are bone and muscle conditioning programs and each need to be carried out differently. The bones must be injured creating microfractures and then letting it recover. This repetitive process should make the bone harder and less susceptible to pain. The muscle conditioning, in the thigh or forearm muscles, is easier to deal with (at least I think so) once it is less painful. The process is done by mildly or strongly striking the muscle while hardening it.