ABSTRACT
Static, or isometric, muscle strength is defined as a muscle contraction that results in no movement of the object that the muscles are resisting. Common examples of static muscle exertions include pushing against a solid wall, or pushing your hands together. When relating muscular activity to work, many ergonomists are concerned with only the dynamic aspects of the work activity. However, there are many examples of static muscle activity in industry. One example involves the carrying of loads, while the legs are involved in the dynamic muscle activity of walking, the arms are often in a fixed (static) posture, holding an object as the worker walks. Other static activities are associated with postures and maintenance of postures for long periods of time without moving. Typically, such activities are referred to as static muscle loading. Upper extremity problems can occur when workers have to hold their arms up while working. The actual hand work may be very dynamic, but the shoulders and upper arms may be under a great deal of static load to maintain a required posture.
