Ergonomics

Ergonomics is the process of changing the work environment (equipment, furniture, pace of work, etc.) to fit the physical requirements and limitations of employees rather than forcing workers to adapt to jobs that can, over time, have a debilitating effect on their physical well-being. Companies of all shapes and sizes have increasingly recognized that establishing an ergonomically sensitive work environment for employees can produce bottom-line benefits in cutting absenteeism, reducing health care costs, and increasing productivity. The most progressive of these firms have—after careful analysis of the workplace environment and the tasks that their employees have to perform—taken steps to modify that environment (whether in a shop floor or an office) to better fit the physical needs and abilities of workers.

The Occupational Safety and Health Administration (OSHA), an element of the Department of Labor, defines ergonomic disorders (EDs) as a range of health ailments arising from repeated stress to the body. These disorders—which are sometimes also called repetitive strain injuries (RSIs), musculoskeletal disorders (MSDs) or cumulative trauma disorders—may affect the musculoskeletal, nervous, or neurovascular systems. They typically strike workers involved in repetitious tasks or those whose jobs require heavy lifting or awkward postures or movements. These ailments often occur in the upper body of workers, causing injuries in the back, neck, hands, wrists, shoulders, and/or elbows. Carpal tunnel syndrome is the most well-known of these maladies, but thousands of employees have also fallen victim to tendonitis and back injuries over the years. Ergonomics experts say that EDs are particularly prevalent in certain industries. Cashiers, nurses, assembly line workers, computer users, dishwashers, truck drivers, stock handlers, construction workers, meat cutters, and sewing machine operators are among those cited as being most at risk of falling victim to ergonomic disorders.

According to the Occupational Safety and Health Administration, work-related MSDs strike 1.8 million American workers each year. "These injuries are potentially disabling and can require long recovery periods," wrote Charles Jeffress in Business Insurance. Jeffress was OSHA's Assistant Secretary of Labor at the time of writing. "For example," Jeffress wrote, "workers need an average of 28 days to recuperate from carpal tunnel syndrome, which is more time than necessary for amputations or fractures. MSDs are also very costly injuries. Direct costs of MSDs total $15 billion to $20 billion per year. Indirect costs increase that total to $50 billion. That's an average of $135 million a day."

OSHA has cited a set of risk factors that contribute to the likelihood of repetitive strain injuries such as carpal tunnel syndrome. These include:

• Performing the same motion or pattern of motions for more than two hours at a time.
• Using tools or machines that cause vibrations for more than two hours a day.
• Handling objects that weigh more than 25 pounds more than one time in a work shift.
• Working in fixed or awkward positions for more than two hours a day.
• Performing work that is mechanically or electronically paced for more than four hours at a time.

In the mid-1990s, the issue of ergonomics became a subject of considerable debate between unions and industries. The AFL-CIO, for instance, called RSIs and job-related back injuries "the nation's biggest job safety problem," contending that more than 700,000 workers miss work each year because of these ailments. Certainly, for workers who are debilitated by carpal tunnel syndrome or some other injury, the consequences can be dire. Long-term disability (with its attendant diminishment of financial well-being) is a real possibility for many workers who fall victim to RSIs. Some unions subsequently asked OSHA to impose minimum ergonomic standards, and OSHA responded by beginning work on basic ergonomic standards for businesses. The agency completed work on their proposal in the late 1990s; in 2000 the Clinton Administration issued regulations requiring businesses to reimburse injured workers' medical costs, inform workers about repetitive-motion injuries, and compensate them at nearly full salary (90 percent for first 90 days missed) if they miss work due to ergonomic-related injuries. Supporters contended that these new ergonomics program standards would prevent an average of 600,000 ergonomic/musculoskeletal disorders annually (and 4.6 million work-related musculoskeletal injuries over 10 years) and generate $10 billion in savings each year.

Business owners and other opponents, though, claimed that compliance with the new ergonomics standards constituted an unfair burden on small businesses. Some business interests estimated the rules would cost as much as $100 billion annually (OSHA placed the cost of the new regulations to businesses at $4.5 billion a year). Critics also contended that OSHA overstated the extent of the problem of ergonomic disorders in the workplace. In March 2001, the Bush Administration joined with the Republican-controlled Congress to reverse these new work safety rules. This move was widely applauded by small business owners and various business groups but, not surprisingly, denounced by labor unions and other workers' groups.

Whatever the prevailing regulatory atmosphere, numerous business enterprises in a wide variety of industries have shown an increased interest in factoring ergonomics in to their operational strategies, heeding business consultants who claim that an ergonomically sensitive environment can produce major economic benefits for companies. They point out that businesses boasting such environments often see a lower rate of absenteeism, lower health care expenses, lower turnover rates, and higher productivity than do other businesses in the same industry.

For small business owners, building an ergonomically sensitive work environment can depend on a number of different factors. While instituting an additional work break or two during the workday (a simple step that is sometimes cited as a deterrent to development of carpal tunnel syndrome and other repetition-related injuries) does not require the business owner to make any additional capital expenditures, instituting physical changes can be significantly more expensive, especially for established businesses that are small. Buying ergonomic furniture or making significant changes in assembly line layout can be quite expensive, and while the owner of a new business may choose to take ergonomics into account with his or her initial investment, it may be more difficult for the already-established small business owner to replace still-functional equipment and furniture. Each small business owner must determine for himself or herself whether the long-term gains that can be realized from establishing an ergonomically sound workplace (employee retention, productivity, diminished health costs, etc.) make up for the added financial investment (and possible debt) that such expenditures entail.

see also Workplace Safety; Workstation

BIBLIOGRAPHY

Eckhardt, Bob. "On the Horizon." Concrete Products. 1 July 2005.

Ergonomics Desk Reference. J.J. Keller and Associates, 2000.

Jeffress, Charles N. "Ergonomics Standard Good for Business." Business Insurance. 23 October 2000.

Ryan, Sean. "President Bush's Proposed OSHA Budget Would Maintain Status Quo." Daily Record. 24 February 2006.

Sacks, Evelyn. "Emphasizing Ergonomics: How being proactive proves good for business." Industrial Safety & Hygiene. December 2004.

Warner, David. "OSHA is Moving on Ergonomics Rule." Nation's Business. August 1997.

                              Hillstrom, Northern Lights

                               updated by Magee, ECDI

ERGONOMICS

Ergonomics is the science of fitting the job to the worker and adapting the work environment to the needs of humans. An overall goal of ergonomics is to promote health and safety and to optimize productivity.

The term ergonomics comes from the Greek words ergon, meaning work, and nomos, meaning laws—thus, laws of work. The study of ergonomics as a way to reduce human error began in the military during the Korean War. In planes used for pilot training, the eject button was poorly placed and pilots sometimes accidentally ejected themselves—often at too low an altitude for their parachutes to open. The button's location was changed and fewer lives were lost.

Principles of ergonomics are applied to the design of many elements of everyday life, from car seats to garden tools. Many different occupations are involved in implementing these human factor principles in the workplace, such as human factors/ergonomics specialists; safety engineers; industrial hygienists, engineers, designers; human resource managers; occupational medicine physicians and therapists; and chiropractors. Research in ergonomics is ongoing.

Knowledge of basic ergonomics principles is important for both workers and employers because both share responsibility for a safe work environment. One can easily imagine the potential hazards in manufacturing settings where equipment is operated and heavy materials are handled, but hazards exist in other environments, too. And technology (especially computer use) has brought about widespread changes in how work is accomplished.

Attention to ergonomics principles helps to reduce workplace injuries and illnesses that result in workers' compensation costs, medical claims, and lost work time. Many disorders and injuries are preventable when work conditions are designed for human safety and comfort. People need training in how to recognize hazards and safety problems as well as how to control their own behaviors for maximum comfort and health.

One of the key considerations in ergonomics is adjustability of physical elements. People come in all shapes and sizes, and the average workstation configuration will not fit everyone. Making changes during a workday in the physical setup of equipment, such as adjusting chair height, can alleviate discomfort and fatigue. Work surfaces should be at comfortable heights in relationship to a chair or to a standing position. Equipment and related items should be arranged conveniently.

Whenever a mismatch occurs between the physical requirements of a job and the physical capacity of a worker, musculoskeletal disorders can result. People working with intense concentration or at high speeds often work with poor posture. Cumulative trauma disorders (also called repetitive strain injuries) are caused by repeating the same motion in awkward positions or with noticeable force, such as in lifting heavy objects. Carpal-tunnel syndrome, a disorder affecting nerves in the wrist that has the potential to permanently disable, is a condition affecting people in a variety of occupations from meatpackers to musicians. Wrist pain can be severe, with treatment involving wrist splints, anti-inflammatory drugs, or even surgery. And people who use a computer extensively are especially prone to developing carpal-tunnel syndrome. Computer use often contributes to vision problems, too.

Posture in standing and in seated positions is important to avoid musculoskeletal disorders. The natural curve of the spine should be maintained, with the head balanced over the spine. When a person is seated:

• Feet should rest on the floor, with legs and body forming 90° to 110° angles
• The body should be straight, with the neck upright and supporting the head balanced on the spine (not forward or twisted to the sides)
• Upper arms should be perpendicular to the floor; forearms should parallel the floor

Symptoms of musculoskeletal disorders can begin as numbness or stiffness in joints or tingling, aching sensations in muscles. Pain or burning sensations may be evident, too. Often symptoms progress gradually, becoming more severe with prolonged exposure to the condition causing them. Damage to nerves, tendons, joints, or soft tissue can result.

With computer use so prevalent, poor work habits will contribute to musculoskeletal disorders for many people who spend long hours seated at a computer. These include the following:

• Wrists misaligned or excessive force used with a keyboard
• Poor posture used with an incorrect seating height
• A monitor incorrectly positioned, resulting in eye strain and vision problems
• Inappropriate lighting, causing glare on monitors and other work surfaces
• High concentration, causing infrequent breaks

Guidelines for working conditions when using a computer include:

Chair:

A well-designed chair with easy-to-implement adjustability is essential. A user can vary angles of back support and the seat pan to control the degree of pressure on the thighs and back. Weight should be evenly distributed, with no extreme pressure points. An upright posture is a little easier to achieve if the seat pan is tilted slightly forward of horizontal. When a person is seated, feet should rest on the floor and the chair seat pan should be even with the back of the knee, ranging from 13 to 19 inches above the floor depending on an individual's height. A foot rest may be used to relieve pressure on the thighs. Both lumbar and mid-level back support are needed. Arm rests, adjustable for height, are helpful to many people. The chair should have a five-point base for stability and casters for easy movement.

Keyboard:

The keyboard provides the primary means of interacting with a computer. The keyboard should be in a comfortable position, and wrists should float over the keyboard when keying with a light touch so wrists and forearms remain straight. Although wrist pads are helpful for resting when not keying, they can actually create problems when a user keeps wrists on them when keying because the wrists can bend down. Different opinions exist on the appropriate angle of the keyboard; some people prefer a flat position while others find a reverse incline more comfortable. Split and curved keyboards are available, too. However, the most important part of keyboard use is keeping the wrists straight in line with the forearm and not bent to the side. When voice-recognition technology becomes commonly used, dependency on the keyboard will be reduced.

Mouse:

A mouse should be positioned next to the keyboard, reachable without extending the arm in an awkward position. Again, a light touch is needed and users should avoid gripping or squeezing the mouse. A wrist support or adjustable mouse platform may be helpful if a user begins to develop wrist problems. A variety of shapes are available for these pointing devices, and a trackball can be used for the same purpose.

Monitor:

A monitor should be directly in front of the user, with the top of the screen at or below the line of sight, 18 to 30 inches away from the eyes, and tiltable to avoid glare from overhead lighting and windows. If necessary, antiglare filters can be added. Screen size should be large enough for easy reading of screen character sizes with a screen refresh rate fast enough to avoid a visible flicker. An individual can experience blurred vision or fatigue from a poor monitor viewing angle, reflected glare, or a low-quality monitor. Because glands in the eyelids produce tears that cleanse eyes as the eyelids blink and the eyes move, irritated eyes can develop because one's blink rate tends to decrease when one is concentrating.

To avoid neck and eyestrain, an individual should:

• Use a copyholder positioned near the monitor to support material used with computer work.
• Use lower levels of lighting to reduce glare on monitors. Many older offices have high illumination levels that are necessary for paper-intensive tasks—but are too highly lighted for computer work. Softer overall, or ambient, lighting should be used, with task lighting added to surfaces as needed for more illumination.
• Relax eye muscles by shifting focus from the computer screen to distant objects for a few seconds every 5 to 10 minutes.
• Take microbreaks to stretch the neck, shoulders, hands, wrists, back, and legs as well as to rest the eyes. Stretching exercises can be simple neck rotations, shoulder shrugs, fists clenched and then released, or arms hanging down naturally for a few moments. Get up and move around about every 30 minutes. Take a brisk walk if possible. Exercises with hand weights will help with stretching and will give the body isometric exercise.

While it may be ideal to have individually adjustable temperature controls, this is not feasible in many work situations. For business offices, most people are comfortable with temperature levels at 68° to 72° in the winter and 72° to 76° in the summer. Humidity levels should be maintained between 40 to 60 percent not only for comfort but also for proper functioning of office equipment. Indoor air quality involves more than heating and cooling—air should be cleansed of pollutants (bacteria, dust, fumes, etc.), with fresh air added before circulation. Many factors affect the efficiency of HVAC (heating, ventilation, and air conditioning) systems. These systems must be designed for the number of people and the equipment to be used in each area because computers and other devices can produce almost as much heat as a human body produces.

Another important concept is adjustability of work pace. Jobs may require redesign to allow workers to accomplish tasks at varying speeds or to enable workers to rotate to different tasks or to use a variety of work methods that permit different movements. Rest breaks are important, too, and microbreaks can be taken to interrupt intense situations, to rest arms and wrists, or to rest eyes.

Much ergonomics information is available in print and on the Internet, published by organizations such as the Occupational Safety and Health Administration (OSHA), the National Institute of Occupational Safety and Health (NIOSH), the National Safety Council, the Human Factors and Ergonomic Society, and others. OSHA is developing ergonomics program standards that were to be published in 2000 (OSHA 1999). Consultants can provide technical expertise to help with all phases of ergonomics assessment and the implementation of corrective measures and/or training programs.

see also Office Layout

bibliography

"Occupational Safety and Health Administration." Retrieved October 18, 2005, from http://www.osha.gov/SLTC/ergonomics/index.html. 1999.

Patricia R. Graves

ERGONOMICS

Ergonomics (used by many interchangeably with such terms as human factors, human engineering, engineering psychology, and the like) can be thought of as the field in which the social and biological sciences are applied to various problems related to the use of products, equipment, or facilities by humans in the performance of specific tasks or procedures in a variety of natural and artificial environments. Ergonomics attempts to evaluate and design the things people use, in order to better match their capabilities, limitations, needs, or physical dimensions (Sanders and McCormick 1993). General elements of the ergonomics field may include the study of humans as (technology-based) system components, design of human-machine interfaces, and consideration of the health, safety, and well-being of humans within a system. Specific areas of study may examine human sensory processes and information processing or anthropometric data to allow professionals in this field to design more effective displays or controls for an engineered system.

Examples

There are many examples of the kinds of successes that the ergonomics field has achieved over the years. As the military is one of the primary users of ergonomic advances, the evolution of military equipment serves as an excellent example of how ergonomics has changed the way things are. The development of the infantry helmet from a shallow "steel pot" to a protective device fabricated from advanced materials formed into a highly functional shape demonstrates the efficacy of ergonomic design.

Ergonomic advances are, by no means, limited to the military. The changes over the years in consumer products such as snow shovels, electric razors; or even more recently, cellular telephones establish the role of human factors in people's everyday lives.

Background

The term ergonomics is a combination of the Greek ergon, work, and nomos, law. The term was created in 1857 by the Polish scientist Wojciech Jastrzebowski (1799–1882) as a name for the scientific study of work. More than a century earlier, however, the Italian physician Bernardino Ramazinni (1633–1714) had initiated the study of work-related illness in the second edition of his De Morbis Artificum (1713). And it was not until a century later, in 1952, that the name was given official status in the formation of the British Ergonomic Society.

In the United States, the development of the principles of scientific management by Frederick W. Taylor (1865–1915) and his followers Frank Gilbreth (1868–1924) and Lillian Gilbreth (1878–1972) initiated similar research. It was out of this tradition that the Human Factors Society was founded in 1957. What began as research on work in the civilian sector became during the 1950s and thereafter heavily associated with the military, especially the Air Force Research Laboratory Human Effectiveness Directorate.

Ethical Issues

Given that one of the objectives of this field is to adapt technological systems to the needs, capabilities, and limitations of human beings, there is an inherent ethical dimension in ergonomics. Certainly the members of this profession must consider their ethical responsibilities. For example, practitioners should not function outside their areas of competence. They should have the proper education, professional training, and work experience. They should avoid and must disclose any actual or perceived conflicts of interest (Human Factors and Ergonomics Society 1989). While these principles seem obvious, they may prove to be problematic for those in the ergonomics field.

Because there is limited formal training in ergonomics and many practitioners come from other disciplines (for example, experimental psychology, industrial engineering), care must be taken so that individuals engaged in ergonomics truly understand their own professional "capabilities and limitations." This is especially true because ergonomics is such a broad and diverse field. For example, someone who works primarily in the area of visual perception may be qualified to work in the allied area of visual cognition, but not be qualified to perform work in the area of bioacoustic protection (that is, mitigating the effects of harmful noise).

Experts in many professions provide forensic testimony that goes beyond the mere recounting of facts. These experts are retained primarily to offer opinions regarding certain elements of a case. This is no different in the ergonomics field. The conduct of ergonomic experts in these types of proceedings should be governed by their professional ethics. The principles they should follow in these matters cover subjects such as the objectivity of their testimony; respect of the integrity of other witnesses; discretion regarding the disclosure of details about the case with outside parties; or discernment if making any public statements regarding the matter, as imprudence here may influence the judicial proceedings or be harmful to the litigant's interests (Human Factors and Ergonomics Society 1989).

As with many fields where the recruitment and use of experimental subjects is a key component in the performance of much of the work (such as in sociology and medicine), the treatment of subjects is of paramount importance and lapses in this area could lead to serious ethical criticisms. Approval of the work and the qualifications of the professionals involved by an institutional review board (IRB) is an important concern. Further, complete disclosure regarding the general nature of the work that the subjects will be involved in and specific risks they may be exposed to are requisite elements of any methodology involving humans.

Examining ethical issues entirely within the realm of ergonomics, Yili Liu (2003) considers several questions. Can ergonomically-based approaches be used to address ethical issues in general? This could also be thought of as whether a better understanding of humans from a psycho-physical standpoint can contribute to a greater understanding of ethical issues. An example of this might be whether providing avionics to fighter pilots that extend their ability to identify a friendly or enemy aircraft is helpful when considering the morality of war. Can ergonomics make human-machine systems more ethical? This might seem obvious given the objectives of the field; however, is an improvement in an individual assembly line process that reduces a worker's exposure to hazardous conditions (for example, the mechanization of a manual chemical dipping process to treat a material), but also speeds up the assembly line, which may cause increased levels of stress for all of the workers, really "ethical"?

Such questions point toward moral responsibilities for those working in product planning, design, or evaluation—with "product" including systems, processes, and more. Most professionals engaged in ergonomics work for paid compensation. Most of the products they plan, design, or evaluate are used by others. There would seem to be a compelling moral responsibility on the part of those employed in these practices to inform employers or clients if they know of an inherent danger or serious hazard associated with the use of a certain product. However, if the ergonomicist knows that use of the product would be inconvenient, inefficient, or difficult, and the cost to correct or change the product so that any problems could be ameliorated might be sizeable, what then is the proper course of action? Does the designer give allegiance to the client or the consumer? If one thinks of the ultimate user as the controlling factor here, how would one's opinion change if the inconvenience were characterized as slight and the cost as monumental? Specifics of a case often make it difficult to reach a final decision.

The advent of ergonomics in the twentieth century brought about great improvements in the design of technological systems from the standpoint of the user or the person in the system. Ergonomics has contributed to the improved safety and usability of technology. Given that this specialized field of knowledge holds the keys to understanding the soft boundary between humans and technology, it must be applied within a moral and ethical framework that, in many respects, is still evolving.

MARTIN T. PIETRUCHA

SEE ALSO Taylor, Frederick W.

BIBLIOGRAPHY

Liu, Yili. (2003). "The Aesthetic and the Ethic Dimensions of Human Factors and Design." Ergonomics 46(13/14): 1293–1305.

Sanders, Mark S., and Ernest J. McCormick. (1993). Human Factors in Engineering and Design. New York: McGraw-Hill.

INTERNET RESOURCE

Human Factors and Ergonomics Society. (1989, amended 1998). "Human Factors and Ergonomics Society Code of Ethics." Available from http://www.hfes.org/About/Code.html.

Ergonomics

Ergonomics is the science of designing machines and environments that are well suited to the people working with them. Ergonomics, or human factors, considers the design of machines, workspaces, jobs, health issues, and the human-machine interfaces. For example, an ergonomic design of an automobile's dashboard means that the controls can be reached easily and that all displays are visible for a range of drivers, whether they are 1.83 meter (6 foot) tall men or 1.52 meter (5 foot) tall women. Since the last decade of the twentieth century, ergonomics has become an important issue in the use of computer technology.

Before the start of World War II, emphasis was placed on conditioning people to fit the machines in their lives. Machines were created, then human beings were trained to operate them according to the machine's requirements; an example of this is training pilots to fly complex airplanes. However, during World War II, machine systems were inexplicably failing. Airplanes with well-trained pilots were flying into the ground with no apparent mechanical failures. Experimental psychologists were asked to analyze the human-machine interface to discover what was going wrong and to make recommendations. In many cases, they found that the machine systems were poorly designed and confusing, even for trained personnel. This led to the redesign of existing systems such as the altimeters on airplanes. Scientists also started looking at how best to distribute tasks, according to what people do best and what machines do best. Eventually, they realized that instead of changing systems after problems were found, they should use their knowledge about how humans process information to design more "people-friendly" systems from the start.

Many scientists have studied the problem of how to allocate separate pieces of a task to humans and to machines, respectively. Ernest J. McCormick, in Human Factors in Engineering and Design (1976), presented lists of what humans do well and what computers do well. In general, he wrote, humans can respond to perceptual changes in the environment. That is, humans can quickly sense low-level changes in sounds, images, smell, or touch. They can store large amounts of information over long periods of time and retrieve pertinent information. When it is necessary, humans can go beyond the information given to react to unlikely events and create entirely new solutions. Thus, human performance can be described as flexible. Although this flexibility is good, it can also cause problems since humans do not exhibit the same response to the same circumstances in every instance. People's responses can vary from one time to the next and can include errors.

By contrast, McCormick's list of machine strengths noted that such devices are good at sensing stimuli outside of the human's normal range of sensitivity (e.g., X-rays, ultraviolet light, and radar wavelengths). Machines can store and retrieve large amounts of information rapidly and respond consistently to signals. They perform repetitive actions reliably such as putting caps on bottles of soda pop and do not get tired or bored, as a human might under similar circumstances. McCormick believed that an understanding of the relative strengths and weaknesses of people and machines would help designers create more effective systems.

Ergonomics and Computers

For people who use computer systems, ergonomic design is crucial. Early computer systems of the 1950s and 1960s were extremely difficult to understand and operate. People had to devote much effort to learning how to manage the technology. In fact, operators of the early mainframe computers formed an elite group of men and women who were sometimes referred to as a " priesthood of computers."

As computer technology became more common, it was important to make the technology easier to use by a wide range of people. In the late 1970s, computers evolved to include microcomputers that could be operated by a single person. The first microcomputers were built by their users from components, and users had to write their own programs to make the computer do anything, even play a game. Once the business and education potential for microcomputers was recognized, ease of use became very important. Now, microcomputers are designed for use by store clerks, teachers, business people, students, and children, as well as by people with special needs. These diverse users may not have much training or computer background. This means that the human-computer interface must be carefully designed by user interface designers and ergonomic specialists.

Designers must ensure that the technology is designed with sensitivity to human capacities and needs and that the resulting work environment is safe and comfortable. Ergonomic design considers the physical, psychological, cognitive, and social aspects of the interaction between the human and the machine. Use of computer technology has been associated with several health issues including eye strain, migraine headaches, muscle and body pain (especially backs and shoulders), repetitive stress injuries (e.g., carpal tunnel syndrome) and stress. For example, repetitive stress injuries can be caused by awkward positioning of wrists and hands, extended periods of rapid repetitive motion, and staying in one position for a long time.

Following ergonomic workplace guidelines can help minimize injury. Suggestions by experts include:

• Positioning the screen at or below eye level to avoid muscle strain;
• Reducing glare with glare deflectors and careful positioning of the computer screen;
• Changing lighting to eliminate glare or eye strain;
• Positioning the keyboard low enough to avoid arm and wrist fatigue;
• Using an adjustable desk so that the user's feet are firmly on the floor;
• Positioning the seat back of the chair to support the lower back;
• Taking frequent breaks to stretch shoulders, neck, and wrists;
• Training people to use and understand both hardware and software to reduce stress and fear.

The ergonomic principle of flexibility is important to the design of computer technology. People of different sizes, physical characteristics, and varying preferences need equipment that they can adjust. Taller people usually want their computer screens at a height that shorter people would find uncomfortable. Some people see best with desk lamps; others prefer natural light. Many organizations, including the Social Security Administration, microchip maker Intel, and retailer L. L. Bean, have implemented ergonomics programs. These programs include new equipment, workspace design changes, and training programs. Employees learn how to create healthy work environments by adjusting desks and chairs and taking frequent breaks. Companies implementing such programs find they can greatly reduce productivity losses due to work-related injuries.

see also Keyboard; Microcomputers.

Terri L. Lenox

Bibliography

McCormick, Ernest J. Human Factors in Engineering and Design. New York: McGraw-Hill, 1976.

Shneiderman, Ben. Designing the User Interface: Strategies for Effective Human-Computer Interaction. Reading, MA: Addison-Wesley, 1998.

Wickens, Christopher D. Engineering Psychology and Human Performance. Glenview, IL: Scott, Foresman and Company, 1984.

ergonomics Why is the video recorder one of the most frustrating domestic items to operate? Why do some car seats leave you aching after a long journey? Why do some computer work-stations confer eye strain and muscle fatigue? Such human irritations and inconveniences are not inevitable — ergonomics is an approach which puts human needs and capabilities at the focus of designing technological systems. The aim is to ensure that humans and technology work in complete harmony, with the equipment and tasks aligned to human characteristics.

Ergonomics has wide application to everyday domestic situations, but there are even more significant implications for efficiency, productivity, safety, and health in work settings. For example:(i) Designing equipment and systems, including computers, so that they are easier to use and less likely to lead to errors in operation — particularly important in high stress and safety-critical operations such as control rooms.(ii) Designing tasks and jobs so that they are effective and take account of human needs such as rest breaks and sensible shift patterns, as well as other factors such as the intrinsic rewards of work itself.(iii) Designing equipment and work arrangements to improve working posture and ease the load on the body, thus reducing instances of Repetitive Strain Injury/Work Related Upper Limb Disorder.(iv) Information design, to make the interpretation and use of handbooks, signs, and displays easier and less error-prone.(v) Design of training arrangements to cover all significant aspects of the job concerned and to take account of human learning requirements.(vi) The design of military and space equipment and systems — an extreme case of demands on the human being.(vii) Designing working environments, including lighting and heating, to suit the needs of the users and the tasks performed. Where necessary, design of personal protective equipment for work in hostile environments.(viii) In developing countries, the acceptability and effectiveness of even fairly basic technology can be significantly enhanced.The multi-disciplinary nature of ergonomics (sometimes called ‘Human Factors’) is immediately obvious. The ergonomist works in teams which may involve a variety of other professions: design engineers, production engineers, industrial designers, computer specialists, industrial physicians, health and safety practitioners, and specialists in human resources. The overall aim is to ensure that our knowledge of human characteristics is brought to bear on practical problems of people at work and in leisure. We know that, in many cases, humans can adapt to unsuitable conditions, but such adaptation leads often to inefficiency, errors, unacceptable stress, and physical or mental cost.

The components of ergonomics

Ergonomics deals with the interaction of technological and work situations with the human being. The basic human sciences involved are anatomy, physiology, and psychology. These sciences are applied by the ergonomist towards two objectives: the most productive use of human capabilities, and the maintenance of human health and well-being. In a phrase, ‘the job must fit the person’ in all respects, and the work situation should not compromise human capabilities and limitations.

The contribution of basic anatomy lies in improving the physical ‘fit’ between people and the things they use, ranging from hand tools to aircraft cockpit design. Achieving good physical fit is no mean feat when one considers the range in human body sizes across the population. The science of anthropometrics provides data on dimensions of the human body, in various postures. Biomechanics considers the operation of the muscles and limbs, and ensures that working postures are beneficial, and that excessive forces are avoided.

Our knowledge of human physiology supports two main technical areas. Work physiology addresses the energy requirements of the body, and sets standards for acceptable physical work-rate and workload, and for nutrition requirements. Environmental physiology analyses the impact of physical working conditions — thermal, noise and vibration, and lighting — and sets the optimum requirements for these.

Psychology is concerned with human information processing and decision-making capabilities. In simple terms, this can be seen as aiding the cognitive ‘fit’ between people and the things they use. Relevant topics are sensory processes, perception, long- and short-term memory, decision making, and action. There is also a strong thread of organizational psychology.

The importance of the psychological dimension of ergonomics should not be underestimated in today's ‘high-tech’ world — remember the video recorder example at the beginning. The ergonomist advises on the design of interfaces between people and computers (Human Computer Interaction or HCI), information displays for industrial processes, the planning of training materials, and the design of human tasks and jobs. The concept of ‘information overload’ is familiar in many current jobs. Paradoxically, increasing automation, while dispensing with human involvement in routine operations, frequently increases the mental demands in terms of monitoring, supervision, and maintenance.

The ergonomics approach — understanding tasks … and the users

Underlying all ergonomics work is careful analysis of human activity. The ergonomist must understand all of the demands being made on the person, and the likely effects of any changes to these — the techniques which enable him to do this come under the portmanteau label of ‘job and task analysis’.

The second key ingredient is to understand the users. For example, ‘consumer ergonomics’ covers applications to the wider contexts of the home and leisure. In these non-work situations the need to allow for human variability is at its greatest — the people involved have a very wide range of capabilities and limitations (including the disabled and elderly), and seldom have any selection or training for the tasks which face them.

This commitment to ‘human-centred design’ is an essential ‘humanizing’ influence on contemporary rapid developments in technology, in contexts ranging from the domestic to all types of industry.

David Whitfield, and Joe Langford

Bibliography

Kroemer, K. (1997). Fitting the task to the human, (5th edn). Taylor and Francis, London.
Norman, D. A. (1988). The psychology of everyday things. Basic Books Inc., New York. (Reprinted in paperback as The design of everyday things. Doubleday, New York, 1990.)