In the last video we had from two Vladimirs they showed various hand-to-hand hand-balancing moves. This time one of them used a head of the other as a rotating hand balancing stand, which clearly shows extraordinary neck strength.
Once again, they finish the act with dangerous move using two knives to balance on top of each other.
Most people neglect training the neck, which I personally believe to be a huge mistake. Make your body (including your neck and spine) indestructible.