Physical aggression is not communication.

"Forcing the dog onto its back is the equivalent of an abusive parent beating a child to force it to say, 'I love you.'  Although he or she may have forced the words out of the child's mouth, they cannot force the statement to be true.... Forcing a dog into a submissive position is the Doggish equivalent of this scenario.  Even worse, this technique may actually anger the dog enough to provoke it to attack. ... Forcing a dog into an alpha roll, or shaking the dog, both constitute physical aggression.  Physical aggression is not communication.  If there is good communication, then such confrontations need not occur."

- Stanley Coren, "How to Speak Dog"