1. After January 1, 1997, no person shall hold himself or herself out as being a physical therapist assistant in this state unless the person is licensed as provided in sections 334.650 to 334.685.

2. A licensed physical therapist shall direct and supervise a physical therapist assistant. The physical therapist shall retain ultimate authority and responsibility for the physical therapy treatment. The licensed physical therapist shall have the responsibility of supervising the physical therapy treatment program. No physical therapist may establish a treating office in which the physical therapist assistant is the primary care provider. No licensed physical therapist shall have under their direct supervision more than four full-time equivalent physical therapist assistants.