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Ergonomic solutions
Ergonomic principles With some attention to the basic principles outlined below, employers can enhance their employees’ comfort and productivity, while at the same time reducing their risk of MSDs and other costly injuries. As stated by the American Industrial Hygiene Association, “Ergonomic principles are most effectively applied to workstations and new designs on a preventive basis, before injuries or illnesses occur. Good design with ergonomics provides the greatest economic benefit for industry.”
1) Environment affects behavior. This is the driving principle of ergonomics. In other words, a well-designed workstation goes a long way toward ensuring that people work safely. Conversely, a poorly designed workstation can have a negative impact. According to a study published in the journal Occupational Medicine, office workers who were most likely to report pain associated with musculoskeletal disorders (MSDs) were not the ones who spent the most time using a computer, but the workers who said their workstation design was poor. Ultimately, the authors suggested “more consideration should be paid to the ergonomics of workstations, the placing of the mouse, the postures of the upper extremities and the handling of the mouse.” Occupational Medicine 53:443-451 (2003). The impact of environment on health and comfort is even more evident as office work space continues shrinking. As reported by the International Facility Management Association (IFMA) in June 2004, eight years of research by the organization shows that the average amount of square footage allotted to each worker in the United States has diminished by as much as 17% since 1994. Ultimately, workers are being forced to adapt to progressively smaller workspaces. “The shrinking office is not a myth, but a reality, and a clear sign of the economic times,” said IFMA President and CEO David J. Brady. He added that “For the facility professional, balancing the needs of workers in shrinking space takes some additional creativity and ingenuity.” 2) Movement is critical. While the old school of thought suggested that certain fixed postures were ideal (i.e. the 90 degree theory), the overwhelming evidence today shows that fixed postures are inherently dangerous. According to Marvin Dainoff, Director of the Center for Ergonomic Research at Miami University of Ohio, “Any fixed posture, no matter how closely it approaches the optimal, will generate muscle fatigue. Therefore, it is important to build in flexibility to allow operators to shift positions easily.” While constant motion is obviously not the goal, frequent positional changes are vitally important to good health. As stated by the OSHA Federal Register, “Static contraction of the muscle can reduce blood flow. The consequent reduction in oxygen and nutrient supply and waste product clearance results in more rapid onset of fatigue and may predispose muscles and other tissues to injury [and] may result in chronic decrement in nerve function.” Additionally, there has been recent concern on the negative impact of decreased movement with regard to potential for development of deep vein thrombosis (DVT) in the lower extremities. Sitting with the legs immobile for long periods of time can lead to swelling in the lower legs and potentially the formation of a blood clot in the deep leg blood vessels. Some data suggest that immobility from sitting for long periods at a computer workstation may be associated with higher DVT risk (Beasley, et al, 2003). Clearly, incorporating movement into the work day is not only a matter of comfort but one of maintaining overall health. 3) Minimize extreme postures. While movement is important, so too are the postures you assume while performing your daily tasks. Neutral postures, meaning those that require minimal muscle activity to maintain, are synonymous with health and comfort. Extreme postures, on the other hand, such as arms splayed outward or wrists bent upward, are to be avoided at all costs. Maintaining body symmetry is equally important, particularly with respect to the spine. Rowe concluded that “A possible mechanism for disk injury may relate to the fact that lateral flexion [sideways bending] and axial rotation [twisting] of the lumbar spine increase antagonistic muscle activity, thereby increasing the overall disk loading.” In other words, don’t sit for extended periods in bent or twisted postures. 4) Avoid contact stress. Focused pressures on specific parts of the body are extremely dangerous and can cause circulation problems at a minimum and nerve damage in more severe cases. According to OSHA’s Federal Register, “Contact stress commonly affects the soft tissue on the fingers, palms, forearms, thighs, shins and feet. This contact may…inhibit blood flow, tendon and muscle movement and nerve function. Tissue that is compressed for prolonged periods of time may be damaged. The problem becomes worse with extended or repeated exposure.” Such stress can be transmitted to arms and wrists by extended contact with the hard, sharp edges of desks and hard armrests on chairs. Likewise, the undersides of thighs or backs of the knees are at risk from hard seat edges or simply seats that are too high. 5) Take breaks. When performing repetitive tasks, it is extremely important to take breaks from those tasks on a regular basis. Such breaks could include actual work breaks, short exercise or stretch breaks, or simply switching gears and performing a different task for a few minutes. As noted by Dr. Hedge, “…with appropriate rest breaks, combined with stretching exercises, computer workers should be able to sustain work at an appropriate work/rest pace, while at the same time minimizing postural injury risks.” In addition, he states, “Provision of discretionary rest breaks produced a statistically significant increase in keying accuracy [13.4%].” Based on these two points, Dr. Hedge concludes “there is quite a compelling economic case for the use of workflow ergonomic software.” 6) Education, Education, Education. When all is said and done, a worker who has been educated on ergonomics in the workplace is more likely to remain healthy. With an awareness of critical risk factors, healthy working postures, and the warning signs of injuries, employees can begin to arrange their workspace with a strategy for injury prevention. While prevention is ideal, it is important to address early warning signs and symptoms of MSDs. Discomfort that increases with intensity or duration can be a sign of increasing inflammation. Addressing mild inflammation is a much simpler prospect than treating inflammation that has gone on for so long that soft tissues have become damaged. In the latter scenario, costs go up dramatically – not only for the company, but in terms of the negative impact of the injury on the employee. By educating employees and managers about early warning signs and symptoms of MSDs, problems can be addressed before they become severe. Creating a Healthy Workstation by Rhonda Crenshaw, Director of Humanscale’s National Ergonomic Group
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