Static muscle loading is when a muscle is contracting but resulting in no movement of that body part. It can be experienced during many work activities, for example carrying an object. Whilst the legs are involved in the dynamic muscle activity (walking) the arms are often in a fixed (static) position whilst holding the object. Other static muscle activities are involved in maintaining postures for a period of time, for example:
Using a computer mouse with an outstretched arm (shoulder and upper arm muscles)
Leaning over a car bonnet to work on an engine, muscles that are working in a static way involve the back muscles (upper and lower), hamstrings, neck, and shoulders
Constantly gripping a knife when cutting meat (hand and fingers)
Static muscle loading can often contribute to soft tissue injuries. Static activity cause fatigue in the muscles and tendons. During the static position of the muscles blood supply is restricted, therefore restricting the supply of nutrients and oxygen and the removal of waste products such as lactic acid. The longer or more frequently the static loading occurs the greater the risk of injury. The constant muscle tension can lead to swelling and pressure on nearby nerves and static loading with high forces can lead to tears in the muscle tissue.
How do you combat static muscle loading?
Take regular postural breaks and perform stretches to increase blood flow to the muscles
Rotate tasks regularly to incorporate dynamic activities into your work day
Ensure your work station is correctly set-up to avoid any unnecessary static and awkward postures
Keep your body healthy and fit