This vault is rarely performed by itself, but it is included here as a skill that must be learned to continue improvement – it is a basic.  The Half On Vault is performed by twisting the body one half turn before the hands come in contact with the Vaulting Table.  When performed correctly, there is a slight arch in the beginning, and then the body snaps to a hollow position.  It is similar to a Round Off Vault, although the Round Off has only a ¼ turn in its first phase.