Repetitive Motions

Repetition refers to performing the same types of motions over and over again using the same muscles, tendons, or joints. When motions are repeated frequently for prolonged periods, fatigue and strain can occur. Repetition is affected by the pace of work, the recovery time provided, and the amount of variety.

The pace of work is the speed at which the work is done. This may be controlled by the worker or by a machine. Many factory jobs, such as working on an assembly line, a quality control line, or packaging, involve machine-controlled pace.

Recovery time is the amount of time when a worker stops working to rest from physical exertion and relax the muscles. Frequent, short breaks are more effective than less frequent, long breaks.

Variety in working tasks allows continued work, but rotates tasks so that workers use different muscle groups, which provides recovery time for the muscles used in the previous task.

The more frequently repetitive motions are performed (fast pace), the longer they are performed (long sessions without a break or more than 8 hours a day), or the more risk factors that are involved, the greater the risk of injury due to overuse and lack of adequate recovery time.

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