You know, This whole thing makes me laugh. I started conditioning my shins when i was about 15 and have thanked my lucky stars many times since. Its not so much as deadening the nerves, its strengthening the bone. Ask any thai kickboxer. I spoke with my teacher about long term effects with his training HE did with his shins (he's a 5 time world champ by the way and is in his late 40's) and his still feel great AND he still fights! Shin conditioning is the same as any other conditioning with the body, its painful at first but with practice, you become stronger.