Not sure if this subject has ever been brought up. What can a person do to improve his chin so he is harder to knock out? I realize that some of this is genetic: 1) Bone thickness and jaw size 2) Skull cap size and durability 3) Amount of cerebral fluid in the brain 4) Strength of the neck and length of the neck 5) Whether or not you tuck the chin 6) Some people even think growing a beard helps (hehe) I've seen some people slap train or get lightly punched to slowly build toughness. What can you do, or is this futile? What's the smartest way to change a glass jaw into a decent or good one? I don't believe Leben has the right idea by letting his buddies punch him full power.