What are we checking for? I view balance from the perspective of an alignment i.e. tripod. I am sure there are more complete definitions. I have also noticed that the only way I can stand on a crate (like Mr. Doyle does) is to keep my head between my feet. I used to work on a "steady head" , but it was was seldom a centered head. Balance is indeed essentially without it there is little chance of a centered arc for impact etc.