I once heard about a kung-fu master who trained himself by punching into a barrel of water 500 times a day. When he got stronger, he switched to a barrel of beans. Then, sand. I have been attempting to duplicate this kung-fu training by punching into a barrel of sawdust. However, I cannot do it 500 times a day. I can only do it a few times, every once in a while, when no one is around. This is because all my barrels of sawdust are at work.