Bone conditioning isn't focused mostly on deadening the nerve, that's only a perk. It's focused on hardening the bone overall. When you get into a match and do a few kicks and snap your shin in half, that means it wasn't proper bone conditioning. You should use a heavy bag and try 50-100 roundhouses/round kicks on it with each leg(Distribute the kicks on different parts of your shin, and on your insteps.) Do this for 4-6 years, then move to something harder, like banana trees, or some soft wood. Be sure to have a good calcium rich diet, but DO NOT go over 2000 milligrams of calcium a day. This will give you little progression in strengthening your bones(if any at all.) That can also result in a kidney stone. The more you progress, your nerves will deaden, but don't target the nerves only(tapping your shins. I'm glad you don't already)Work on hardening them and the loss of feeling will come too.