Physical and biological hazards of the workplace. Wald PH, Stave GM, eds. New York: Van Nostrand Reinhold, 1994 Apr; :13-41
Ergonomics has been defined as the science of fitting the job to the worker. Given that the abilities of workers vary, ergonomics could be redefined as the art of matching job demands with worker capabilities. When job demands overwhelm an employee's mental or physical capacity, his or her health, comfort, and productivity may be adversely affected.. Although it is also important to consider comfort and productivity levels, this chapter will focus on the effect of ergonomic hazards on the musculoskeletal system and the peripheral nervous system of the upper extremities. Ergonomic hazards are physical stressors and environmental conditions that pose a risk of injury or illness to an individual's musculoskeletal system. Physical stressors can be divided into four main categories: repetition, force, posture, and vibration. These stressors can arise from excessive job demands; improperly designed work stations, tools, or equipment; or inappropriate work techniques. In addition to these physical stressors, ergonomic hazards may arise from potentially deleterious environmental conditions, such as poor job designs, or deleterious work organizational factors. Examples of these factors include excessive work rates, machine- versus self-paced work, shift work, an imbalance in the work-to-rest ratio, demanding incentive-pay or work standards, restriction of operator body movement, and confinement of the worker to a work station without adequate relief periods. Ergonomic hazards have occupational and non- occupational sources; however, only work-related hazards will be addressed in this chapter.