Ergonomics is a widely misunderstood discipline in the U.S. Businesses treat ergonomics paradoxically, advertising it as a benefit when marketing products, yet decrying it as costly and unnecessary when it comes to designing ergonomic workplaces. Poor ergonomics has become linked to workplace injuries that can arise from frequent repetitive movements, especially when made in awkward postures. These injuries, termed work-related upper limb musculoskeletal disorders (MSDs)also variously known as repetitive strain/stress injuries (RSIs) or cumulative trauma disorders (CTDs) and occupational overuse injuries (OOIs) or repetitive motion injuries (RMIs)are soft-tissue injuries such as tendinitis and tenosynovitis or nerve-compression injuries such as carpal tunnel syndrome. Injury risks include long hours of computer use in awkward postures and a high frequency of key presses and mouse clicks. Ergonomics helps protect workers from these injuries and improve workplace performance, yet some politicians have opposed any legislation or standards on ergonomics. As a result, the U.S. lags behind many other countries in the world in terms of ergonomics standards and regulations. Yet despite organized opposition to the field, ergonomics persists as an applied scientific discipline (there are more than 60 university graduate programs in the U.S.) and flourishes in many U.S.-based Fortune 500 companies. Here I discuss the legislative history and public policy developments in the U.S. concerning ergonomics, but first it is worthwhile remembering how ergonomics began as a field.
World War II was the first conflict in which a wide array of new technological systems were used that pushed the boundaries of human physical and mental capabilities, and in which complex coordinated actions between people and technology were required to avoid failure. Airplane pilot fatigue and pilot error were and still are significant problems, and the same issues arise in any 24/7 workplace today, from hospitals to data centers (albeit with different consequences). In 1943 an American psychologist, Alphonse Chapanis, investigated runway crashes of B-17 bombers and found that the instrument panel had identical side-by-side toggles, one to control the flaps and the other to operate the landing gear. Weary pilots sometimes flipped the wrong toggle during landing, retracting the wheels and causing a crash. On both sides of the Atlantic, there was a growing recognition that a discipline was needed that focused on not simply the capabilities of personnel or technology, but also the effective interaction of these components as a human-technology system (originally termed the man-machine system). At a meeting of the British Admiralty in the U.K. on July 12, 1949, Hwyel Murrell, an industrial psychologist, proposed ergonomics as the name for this new discipline, although in the U.S. human factors engineering was often used, and both terms are still in use today.
At the end of the 1940s, computer technology was also just emerging. Ergonomics has substantially influenced the development of computing technology, especially since the 1970s, when the International Standards Organisation (ISO) established its first technical committee (TC159) for ergonomics. Throughout the 1970s, mostly in Europe, extensive ergonomics research on the design and use of computers culminated in the first comprehensive ergonomics manual for “visual display terminals” . The first ISO ergonomics standard (ISO 6385) appeared in 1981, and since then more than 100 standards have been published, the latest one in 2011 .
Early 1970s computers, mainframe terminals, and word processors tended to be all-in-one designs, with the keyboard and screen housed together. Ergonomists often observed discomfort and injuries when people used them because when the screen was optimally positioned for the eyes, head, and neck, the keyboard was not optimally positioned for the hands, wrists, and arms, and vice versa. The result of the all-in-one designs was that users often adopted sustained awkward work postures that ultimately led to discomfort and injury. By the early 1980s, emerging ergonomics recommendations required the separation of the computer screen, central processing unit, and input devices (keyboard, mouse) so that each of these could be optimally located for a computer user. In 1981, IBM introduced its first personal computer (PC) in which the keyboard, monitor, and CPU were separate components, which allowed for better optimization of workspace layout for a user, and this configuration persists today in the design of most desktop computer systems. However, sales of desktop systems are waning, while sales of laptops, netbooks, ultrabooks, and tabletsand maybe even a flurry of new all-in-one systemsare rapidly growing, and as a result many of the musculoskeletal and postural problems associated with using all-in-one technologies are also on the upswing.
Ergonomics has various specializations, and of the 23 different technical groups of the Human Factors and Ergonomics Society (HFES), seven of these are concerned with human-computer interaction: Augmented Cognition, Cognitive Engineering and Decision Making, Communications, Computer Systems, Internet, Product Design, and Virtual Environments. Whatever the specialization, the goal of ergonomics is always to improve human-technology system integration.
A paradox of ergonomics is that U.S. businesses have often opposed ergonomics standards and regulations in their workplaces, yet have readily embraced the ergonomic design of products, and sometimes even market this. Ergonomics is everywhere. From the design of international symbols, icons, and warnings ubiquitous on consumer products to the physical design and layout of workplaces and vehicles that transport us on the ground, on and under the sea, and in the air, ergonomic design permeates our everyday lives.
Ergonomics has benefited many systems, improving their performance, efficiency, and safety. In complex systems, from aircraft, trains, trucks, and cars, to nuclear-power-plant control rooms, ergonomics has helped to improve the design of interfaces (displays and controls), workspace elements (e.g., chairs and desks), and workplace layouts to significantly enhance the safety, comfort, and performance of these systems. A trip to your local computer store will show you a proliferation of ergonomic computer mice and keyboards with non-traditional designs, while in your local hardware store you will find many ergonomic hand tools that are comfortable, easy, and safe to use. TV commercials advertise the benefits of ergonomics for the design of many products, even beds.
However, ergonomic design is not limited only to the physical design of technologies. Cognitive ergonomics looks at the interactions between people and technology, including how we process information, build expectations, assemble mental models of technology and the world, misunderstand and make mistakes, and how mental workload and stress affect performance. Computer technology has been shaped by the desire to increase user friendliness, and ergonomics has helped improve both software interfaces, such as variants of the graphical user interface, and hardware designs, especially for input devices such as computer mice and keyboards. Products that are easy to use can also promote performance. But ease of use isn’t always desirable. For example, a game that is easy to win quickly becomes boring, so the key to cognitive ergonomics is matching system goals to task complexity and the users’ skills and mental capabilities. Of course, these change over time, and novice and experienced users use computers at quite different levels of sophistication.
Ergonomics Policy Outside the U.S.
Outside the U.S., ergonomics is seen as an integral component in the design of effective work processes and workplaces. In 1990, Brazil enacted a Federal Ergonomic Standard, giving data-entry computer workers a 10-minute break every hour and limiting keystrokes to 8,000 per hour . In the 1970s, the International Labour Organisation (ILO) issued several conventions on MSDs and their prevention. In the late 1980s and early 1990s, the European Community issued a series of directives and standards requiring member countries to develop their own ergonomics measures to ensure safe and healthy workplaces for a wide variety of workers. In 2000, the Canadian Standards Association released Z412, its first office ergonomics workplace standard, and an updated standard (Z1004-12 - Workplace ergonomics - A management and implementation standard) in 2012. Since 1992, New Zealand has had a health and safety act to protect workers from all types of injury risks, including the poor ergonomic design of work and the workplace. On January 1, 2012, Australia introduced new work health and safety (WHS) legislation to harmonize occupational health and safety laws across its states and territories. Australia also has specific regulations or codes of practice to control injury risks. Since 2007, Australia has had a National Code of Practice for the prevention of musculoskeletal disorders from performing manual tasks at work, designed for use by employers, owners of workplace facilities, designers, manufacturers, or suppliers of workplace products, and health and safety representatives.
The goal of worldwide actions promoting ergonomics is to give guidance to manufacturers on the design of equipment and to employers and workers on the design of workspaces and jobs to minimize the risk of injuries. Some of the most common computer-related MSD injuries are:
- Tenosynovitis: inflammation from repetitive overstraining of tendon sheaths, such as high frequency forceful keystrokes and/or mouseclicks. For example, De Quervain’s syndrome is a tenosynovitis of the thumb’s extensor and abductor tendons (these days called Blackberry thumb or texter’s thumb).
- Tendonitis: inflammation of the tendon from repetitive overstraining, such as high-frequency forceful keystrokes and/or mouseclicks. Examples include finger flexor tendonitis, characterized by a finger stiffness, and epicondylitis at the elbow, from leaning an elbow on a chair arm or worksurface while mousing or typing.
- Neuropathy: functional or pathological changes in peripheral nerve function. For example, carpal tunnel syndrome (CTS) is a focal peripheral neuropathy caused by median nerve compression inside the carpal tunnel at the wrist, as the hand moves from wrist extension to wrist flexion, as can occur during typing or mousing. Ideally, the wrist angle should be as flat and straight as possible. Any keyboard that is tilted too high or any bulbous mouse shape will increase the risk of carpal tunnel syndrome if it puts the hand at more than 15 degrees of deviation from being straight and flat.
- Muscle strain: damage to a muscle and its attached tendons. Repeated or sustained neck flexion can result in neck-strain injuries such as “iPad neck.”
Many ergonomic products have been developed to combat the injury risk factors, such as split keyboards to help straighten the hands during typing; negative-slope height-adjustable keyboard trays to position keyboards closer to the lap to flatten the hands during typing; slanted mice to straighten the hands during mousing; external Bluetooth keyboards for phones to reduce overuse of the thumbs; monitor arms, riser platforms for laptops, and iPad holders to position screens in optimal viewing positions and minimize neck flexion; and ergonomic chairs to provide good lumbar support and a stable posture for working. All ergonomic designs are based on the principle of positioning the technology being used so that it puts the body in a more neutral posture during product use. “Fit the job to the person, not the person to the job” is a fundamental tenet of ergonomics.
Ergonomics Policy in the U.S.
The U.S. stands alone in the world in having politicians and companies oppose the benefits of ergonomics. The U.S. military embraces ergonomics, though they use the term human-systems integration. For more than 20 years, the Occupational Safety and Health Administration (OSHA) has sought to implement regulations and has issued voluntary guidelines on ways to reduce workplace MSDs. In 1993, OSHA issued its Ergonomics Program Management Guidelines for Meatpacking Plants, and currently has only voluntary guidelines for beverage distribution, nursing homes, shipyards, poultry processing, and retail grocery stores.
In 1992, OSHA began the rule-making process for developing a federal ergonomics standard. Drafting of this standard began in 1995, and on November 4, 2000, the Ergonomics Program Standard was released. It targeted manufacturing jobs, manual handling jobs, and other jobs such as office work involving computers, but it excluded maritime, construction, and agricultural work. It allowed companies with existing and successful ergonomics programs to continue these, even if they didn’t strictly comply with the standard’s requirements. On January 16, 2001, the standard became effective. Almost immediately there was vehement opposition, because it required mandatory compliance and provided for a separate benefit system for MSDs that conflicted with some existing state workers compensation statutes and systems concerning workers compensation eligibility requirements. The ergonomics standard was temporary, and on March 20, 2001, President George W. Bush signed Senate Joint Resolution 6, repealing it.
Today, 23 states have state OSHA programs approved by federal OSHA. Of these, California is the only state with an ergonomics standard, which has been in place since 1996. The California standard requires that an ergonomics intervention is triggered when at least two employees performing identical tasks have been diagnosed by a physician with RMIs within 12 consecutive months. The triggering incidents are not limited to any specific economic sector and the injuries can affect office computer users, industrial and manufacturing workers, agricultural workers, and others. Once triggered, the standard requires the employer to establish an ergonomics program that includes worksite evaluation, control of exposures that have caused RMIs, and training to help avoid future RMIs.
In 2002, OSHA announced a Comprehensive Plan on Ergonomics, designed to reduce ergonomic hazards by calling for enforcement under the general duty clause of the 1970 Occupational Safety and Health Act, which requires that employers “shall furnish to each of his employees employment and a place of employment which are free from recognized hazards that are causing or are likely to cause death or serious physical harm to his employees.” This plan has four parts: voluntary guidelines; mandatory enforcement; outreach, including OSHA-sponsored ergonomics courses and a program targeting the ergonomic needs of Hispanic workers; and assistance and research, including the development of compliance-assistance tools. Both OSHA and Cal-OSHA have developed specific guidance on how to avoid computer-related injuries.
Independent of OSHA’s activities, in 2007 the HFES issued the ANSI/HFES 100-2007, Human Factors Engineering of Computer Workstations voluntary standard, which provides guidance for the ergonomic design of computer workstations, displays, input devices, and furniture, to accommodate a normal range of users. Although not a health and safety standard, the principles in this technical standard will result in the creation of more comfortable and higher-performance workplaces. This remains the only generic voluntary standard on ergonomics for computer users, other than a standard for medical transcriptionists . However, if a sufficient number of employees suffer computer-related injuries in their workplace, this could still be sufficient grounds for an OSHA investigation under the general duty clause described earlier.
Whether or not there is ever any additional federal ergonomics regulation, many U.S. companies, especially those in the Fortune 500, have actively developed their own internal ergonomics programs, as these programs significantly reduce workplace injuries and costs and, if they are a global company, help them to do business in countries with ergonomics regulations.
The world does not stay still. New technologies and new ways of working are constantly evolving, and technical systems are becoming increasingly complex. People, though, change much more slowly and in predictable ways, and ergonomic design principles remain invariant: Always try to position the body and its parts in a neutral posture to minimize injury risks and maximize comfort and strength.
Every developed country has an aging population, and all are struggling with health issues such as obesity and diabetes, which are also known to be risk factors for developing MSDs. This, coupled with the pace of technological change, raises the specter of unanticipated injury consequences as new technical systems emerge. Take, for example, the iPad. The product did not exist three years ago, and now it is associated with a specific injury, “iPad neck” . Anyone poring over books will also develop similar neck problems. Indeed, medieval monks wrote and read books at sloped desks, which allowed them to adopt a straighter neck posture, thus minimizing injury risks and maximizing comfort and performance. Today we see a plethora of products, from notebook risers to iPad stands, that achieve the same ergonomics principle of elevating that which is being read or interacted with, so the head and neck are in a more neutral posture.
Ergonomics provides essential knowledge on how people of diverse abilities can successfully interact with a variety of technologies, especially computer technologies, in the most productive ways without increasing their risks of MSDs (see http://ergo.human.cornell.edu). There are also economic benefits to good ergonomic design. Regardless of what OSHA does concerning any future ergonomics regulations, it is clear that ergonomics is here to stay as an applied discipline. Numerous companies have successful ergonomics programs that protect employees and improve their business performance. As the U.S. gradually aligns itself with the rest of the world and conforms to international standards, ergonomics can play an increasingly central role in the corporate world, as well as in shaping those new technologies that significantly affect the lives of citizens.
1. Cakir, A., Hart, D.J., and Stewart, T.F.M. Visual Display Terminals: A Manual Covering Ergonomics, Workplace Design Health And Safety Task Organisation. The Inca-Fiej Research Association, Darmstadt, 1979. Repub. John Wiley & Sons, 1980.
5. Young, J.G. et al. Touch-screen tablet user configurations and case-supported tilt affect head and neck flexion angles. Work: A Journal of Prevention Assessment and Rehabilitation 41, 1 (2012), 8191.
Alan Hedge is a professor in the Department of Design and Environmental Analysis at Cornell University studying computer workplace ergonomics. He is a Fellow of the Human Factors and Ergonomics Society and recipient of their Design Award (2003) and Outreach Award (2009).
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