Aiya...
Today is the Iron Bone conditioning.
This workout is about using striking and relaxation to increase the density of the bones. Really any time you move, you are increasing the density of the bones. You walk, you knit, you do dishes or you chase little kids you are conditioning the bones for that activity.
Training is about moving the body and causing trauma. The body then heals from the trauma and builds that area for another round.
Iron Bone conditioning is about using strikes, kicks and blocks to accelerate the density growth of the bone in those areas. We started with padded targets, move onto makiwara training, then bone on wood and eventually punching cinderblock and marbles.
Hardest part of this training is to relax while striking things your parents told you to never do. By relaxing, the bones take more of the shock. If you tense (which is only natural) the muscles reinforce the bones, but also take on part of the shock and trauma.
Why have bones made of steel? To protect ourselves of course. Look at sports now days, everyone is training to be stronger, show off their sexy muscles. Now look at the injuries, tendons and ligaments mostly. Muscle strains and tears are easy to heal, the rest not so much.
In the martial arts we know this fact: Muscle builds six times faster than tendons, tendons build four times faster than ligaments, ligaments build 10 ten times faster than bone.
To build muscle, you contract during exercise. Easy to build muscle.
To build tendon strength, you have to contract through the full range of muscle. Not to easy to be honest with this one.
To build ligament strength, you have to stretch the focus joint with momentum through the entire range of the limb.
To build bone, constant hammering along the axis of the bones.
This training is for overall health and welfare of the body. Oh, and don't forget recovery through diet and rest.
Good luck,
DarkArashi