On the confusion between static load level and static task.

Electromyography (EMG) is widely used to evaluate muscle activity. EMG can indicate which muscles are active and the relationship between a level of activity and the worker's capacity. Properly employed, EMG assists in evaluating the relative risks of alternative working conditions. Articles reporting EMG results are often used by ergonomics practitioners as guidance in job design. As such, the ability to interpret EMG research is critical to e!ectively utilize research as a guide to practice. In evaluating risk, three levels of muscle loading have been of concern for ergonomists: peak, average, and static. It is generally accepted that jobs should not demand high exertion e!orts over long periods. Likewise, the average exertion level should be controlled. Sustained low-level muscle exertions have also been recognized as a risk factor for musculoskeletal disorders. This is usually referred to as &static work'. However, there has been some confusion regarding the di!erence between the terms &static load level' and &static work'. The confusion becomes misleading when research-based recommendations for allowable levels of static load level are mistakenly applied to static work.