More than a dozen police officials and law enforcement experts told NBC News that the particular tactic Chauvin used — kneeling on a suspect's neck — is neither taught nor sanctioned by any police agency. A Minneapolis city official told NBC News Chauvin's tactic is not permitted by the Minneapolis police department. For most major police departments, variations of neck restraints, known as chokeholds, are highly restricted — if not banned outright.
Thus taken as gospel - heh
I heard differently - that Minneapolis PD trains the use of the knee restraint for extreme cases.