Physical medicine and rehabilitation involves the management of disorders that alter the function and performance of the patient. Emphasis is placed on the optimization of function through the combined use of medications, physical modalities, physical training with therapeutic exercise, movement & activities modification, adaptive equipments and assistive device, orthotics (braces), prosthesis, and experiential training approaches.

Physical Medicine & Rehabilitation physicians may also perform electrodiagnostics which are used to provide nervous system functional information for diagnosis and / or prognosis for various neuromuscular disorders. The common electrodiagnostic tests performed by physiatrists are nerve conduction studies (NCS) and needle electromyographies (EMG). The nerve conduction study involves electrical stimulation to peripheral nerves and the nerves' responses are measured such as onset latency, amplitude and conduction velocity. Needle electromyography requires needle electrode insertion into the muscles to detect the electrical potential generated from muscle fibers. Abnormal electrical potentials such as fibrillation potential or positive sharp waves detected by EMG needles indicate the presence of muscle fibers that have abnormal nerve supplies.

Common conditions that are treated by physiatrists include amputation, spinal cord injury, sports injury, and stroke, musculoskeletal pain syndromes such as low back pain, fibromyalgia and traumatic brain injury. Cardiopulmonary rehabilitation involves optimizing function in those afflicted with heart or lung disease. Chronic pain management is achieved through multidisciplinary approach involving psychologists, physical therapists, occupational therapists, chiropractors, and interventional procedures when indicated. In addition to the previous methodology, stroke is often treated with the help of a speech therapist and recreational therapist when possible.

Six formal sub-specializations are recognized by the field in the United States:

• Pain medicine
• Pediatric rehabilitation
• Spinal cord injury medicine
• Neuromuscular medicine
• Sports medicine
• Hospice and palliative medicine

Many in the field also sub specialize in areas of the care of patients with amputations, musculoskeletal medicine, electro diagnostics, traumatic brain injury (TBI), and cardiopulmonary rehabilitation.