According to T M.S. Sanders and E.J. McCormick the application of ergonomic principles in the design of objects and environments has two objectives.

1. To enhance the effectiveness and efficiency with which work and other activities are carried out. Included here would be such things as:

• Increased convenience of use
• Reduced errors
• Increased productivity

2. To enhance certain desirable human values, including:

• Safety
• Reduced fatigue and stress (and injury)
• Increased comfort
• Greater user acceptance
• Increased job satisfaction
• Improved quality of life

The purpose of occupational ergonomic interventions in the workplace is to reduce work-related musculoskeletal disorders (WRMSDs).

According to OSHA: Work-related musculoskeletal disorders are physical work activities or work place conditions in the job that are reasonably likely to be causing or contributing to injuries and disorders of the muscles, nerves, tendons, ligaments, joints, cartilage and spinal disc.

Common MSDs include carpal tunnel syndrome, tendonitis, epicondylitis, deQuervain's disease, thoracic outlet syndrome, cubital tunnel syndrome, tension neck syndrome, low back strain, nerve impingement, and hand-arm vibration syndrome.

Risk factors that contribute to MSDs include:

• Repetitive motion
• Force
• Prolonged or static exertions
• Frequent or heavy lifting, pushing, pulling, or carrying of heavy objects
• Prolonged awkward postures
• External compression and stress to the body
• Prolonged exposure to vibration
• Workplace temperature
• Ineffective lighting conditions
• Psychosocial factors

Jobs, tasks, or working conditions that combine risk factors increase the risk for developing discomfort or a musculoskeletal disorder. The level of risk of any one worker is a function of duration (how long), frequency (how often), and intensity (how much), as well as the worker's genetic make-up and their physical condition.

Ergonomic Intervention Strategies
There are two ways to improve work safety in terms of ergonomics. You can reduce or eliminate the ergonomic risks and/or you can reduce or eliminate the worker's exposure to the risks. This can be done through engineering and administrative controls and the use of personnel protective equipment.

Whenever feasible, risks should be eliminated through implementing effective engineering controls, such as redesigning or replacing equipment to improve safety. When a risk cannot be eliminated through the redesign process, other controls should be considered. For example, a reduction in risk exposure time can be achieved by implementing task rotation that allows time for sufficient muscle recovery. Although training workers on how to correctly use equipment and educating them on "best work practices" is very important it is short sighted to think that this alone will eliminate the risk potential in all cases.

Engineering Controls: These controls modify the work, the work environment and/or the tools, equipment and machinery used.

Examples include:

• Modify workstation layouts and heights
• Redesign tools to reduce or eliminate awkward postures
• Alter the method of performing tasks
• Redesign process, schedules and work routines

Administrative Controls: These controls serve to reduce the duration (how long), frequency (how often), and intensity (how much) of exposure to a risk.

• Rotate worker's tasks and jobs to reduce the exposure time to any one risk
• Enlarge or enrich the scope of the work
• Automate processes
• Provide training programs to increase worker awareness
• Encourage early reporting of symptoms
• Provide early intervention services to include proper medical care and job assessment
• Increase rest breaks for workers
• Provide informational aids
• Maintain tools regularly

Personal Protective Equipment: The focus of this type of intervention is to provide the worker with equipment that will improve their safety and reduce their exposure to risk.

• Fall protection
• Safety glasses
• Protective cloths, gloves, hard hats, and footwear
• Hearing protection
• Ventilation and respiratory devices

The best method of control is to eliminate the risk!

The Program Approach
To effectively insure that ergonomic concerns are addressed and will continue to be addressed in the future, an on-going process in the form of a program with appropriate checks and balances must be employed. To make it really simple, you have to do the BIG THREE:

Identify

Modify

Measure

Let's see how the BIG THREE line up with NIOSH's seven-step "pathway" for evaluating and addressing musculoskeletal concerns in the workplace.

• Looking for signs of a potential musculoskeletal problem in the workplace, such as frequent worker reports of aches and pains, or job tasks that require repetitive, forceful exertions. Identify.
• Showing management commitment in addressing possible problems and encouraging worker involvement in problem-solving activities. Modify.
• Offering training to expand management and worker ability to evaluate potential musculoskeletal problems. Modify.
• Gathering data to identify jobs or work conditions that are most problematic, using sources such as injury and illness logs, medical records, and job analyses. Measure.
• Identifying effective controls for tasks that pose a risk of musculoskeletal injury and evaluating these approaches once they have been instituted to see if they have reduced or eliminated the problem. Identify and Measure.
• Establishing health care management to emphasize the importance of early detection and treatment of musculoskeletal disorders for preventing impairment and disability. Modify.
• Minimizing risk factors for musculoskeletal disorders when planning new work processes and operations. It is less costly to build good design into the workplace than to redesign or retrofit later. Modify.

By following these simple steps it is easy to identify, reduce, and measure risks that contribute to MSDs. By including workers as an integral part of the process you can expect to reap other rewards as well. You may see more worker commitment, an increase in overall job satisfaction, a reduction in turnover, improved productivity and morale.