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Ergonomic Techniques for Preventing MSDs

Musculoskeletal disorders (MSDs) are also known as cumulated trauma disorders or repetitive stress injuries. In all three of these situations the body cannot keep up with the physical demands placed on it. Physical demands can be work-related; but we cannot rule out recreational and leisure-time activities. The joints most often affected are the neck shoulders, elbows, wrists and back. The causes of the MSDs are: not enough rest for the part of the body performing the activity, working in the middle to extreme end of the joint range of motion, high repetition, and working in awkward or high risk work positions. The onset of MSDs can be sudden, due to seasonal changes in activities, or from specific job tasks. The onset can be slow and gradual, due to work design, work style or repetition.

The work site should be designed to place the employee in the most efficient work position. This does two things: it maximizes the individual’s level of productivity and reduces their risk of MSDs. To reduce the risk, evaluate the work style, or the way in which the employee performs the essential job tasks. Have work styles changed due to a change in the process, or to the passage of time, or from training by another employee who demonstrates an inefficient work style?

Identify high-risk work styles, such as repetitive lifting from below knee level, by counting the number of repetitions per hour. If an employee works at repetitive lifting on a frequent to constant basis and demonstrates improper body mechanics for lifting, then the employee is at a much higher risk for an MSD of the back.

One of the keys to reducing joint or soft tissue inflammation (MSDs) is through changing activities on a regular schedule. In addition, there should be sufficient rest given to employees, particularly with highly repetitive tasks. Currently, more frequent rests periods of 25-30 seconds versus longer rest periods of 3-5 minutes are recommended during the course of the work activity.

Prevention of MSDs should consider the amount of stress or pressure the individual is under when performing their job responsibilities and the level of the employee’s job satisfaction. The higher the individual’s job satisfaction and the better the individual can control the stress levels at work, the less effect the above issues have with the identification of work-related MSDs.

--Edward Swanson is an Assistant Professor, Division of Physical Therapy, American International College.

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