Sedentary Work Exerting up to 10 pounds (4.5 kg) of force occasionally and/or a negligible amount of force frequently or constantly to lift, carry, push, pull, or otherwise move objects, including the human body. Sedentary work involves sitting most of the time, but may involve walking or standing for brief periods of time. Jobs are sedentary if walking and standing are required only occasionally and other sedentary criteria are met.
Light Work Exerting up to 20 pounds (9.1 kg) of force occasionally and/or up to 10 pounds (4.5 kg) of force frequently, and/or negligible amount of force constantly to move objects. Physical demand requirements are in excess of those for Sedentary Work. Light Work usually requires walking or standing to a significant degree. However, if the use of the arm and/or leg controls requires exertion of forces greater than that for Sedentary Work and the worker sits most the time, the job is rated Light Work.
Medium Work Exerting up to 50 (22.7 kg) pounds of force occasionally, and/or up to 25 pounds (11.3 kg) of force frequently, and/or up to 10 pounds (4.5 kg) of forces constantly to move objects.
Heavy Work Exerting up to 100 pounds (45.4 kg) of force occasionally, and/or up to 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.
Very Heavy Work Exerting in excess of 100 pounds (45.4 kg) of force occasionally, and/or in excess of 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.
Job Classification
In most duration tables, five job classifications are displayed. These job classifications are based on the amount of physical effort required to perform the work. The classifications correspond to the Strength Factor classifications described in the United States Department of Labor's Dictionary of Occupational Titles. The following definitions are quoted directly from that publication.
History: The individual may complain of pain, tingling sensations (paresthesias), reduced sensation (hypoesthesia), or weakness of an extremity after trauma. Sometimes, no specific trauma is revealed.
Physical exam: General physical examination may reveal associated injuries. A complete neurologic exam may show some of the degree of nerve involvement, with confirmation of the complaints noted above. Peripheral nerve testing should include tests of light touch, pain, temperature, and vibration sensation. Other sensory tests include the ability to distinguish two pinpricks applied closely together (two-point discrimination) and the ability to appreciate small movements of the joint (joint position sense, proprioception). Motor testing includes tests of strength of the muscles supplied by the affected nerve. In nerve injuries related to entrapment or compression, lightly tapping over the nerve where it is compressed may cause a painful or tingling, electric shock-like sensation (Tinel's sign). Reflexes typically are depressed or absent in the muscle groups supplied by the affected nerve. Ambulation and balance should be assessed in individuals with lower extremity nerve injuries.
Tests: Electromyography (EMG) helps to differentiate between grade I and higher grades of injury. A nerve conduction study, done by stimulating the nerve using an electrical stimulus on the skin and measuring the nerve response, indicates which motor and sensory nerves are affected. These tests begin to become abnormal within 10 to 21 days after the injury (Hyde, Sharon). A single test cannot distinguish between injuries that will demonstrate eventual recovery (grades I and II) and those that are unlikely to recover (grade III). Nevertheless, repeated tests over time can show whether improvement is occurring. Somatosensory evoked potentials are abnormal immediately after nerve injury; this a useful test for monitoring nerve function during surgery that might compromise the nerve. Since the nerve fibers that control sweating (sympathetic fibers of peripheral nerves, part of the autonomic nervous system) are most resistant to mechanical trauma, the skin supplied by the injured nerve may be examined using a magnifying lens or light scope (ophthalmoscope) or with the "sweat test" or iodine starch test, to examine for patterns of sweating and to determine whether complete interruption of the nerve has occurred. If the nerve injury resulted from trauma, x-rays, magnetic resonance imaging (MRI), and computed tomography (CT) scans may be performed to assess associated injury to bones, cartilage, muscles, tendons, and ligaments; this is especially important with nerve injuries originating close to the spine.
Source: Medical Disability Advisor