Certified by one of the following: Certified Medical Assistant (CMA) by the American Association of Medical Assistants (AAMA), Registered Medical Assistant by the American Society of Medical Technologists (AMT), Certified Clinical Medical Assistant (CCMA) by the National Healthcareer Association (NHA), National Certified Medical Assistant (NCMA) by the National Center for Competency Testing (NCCT), or. The work requires some physical exertion, such as long periods of standing; walking or jogging unaided over rough, uneven, or rocky surfaces; recurring bending, crouching, stooping, stretching, reaching, or similar activities; or recurring lifting of moderately heavy patients or equipment.