Ergonomics, human engineering or human factors engineering is the science of creating products or designing machines which maximize safety, comfort or efficiency of people who use them.

People who work with ergonomics apply general principles of industrial engineering, psychology, anthropometrics, which is the science of human measurement, and even biomechanics to adapt certain designs of products or workplaces to peoples constitution, strengths and limitations.

This science also takes into consideration peoples reactions and the amount of time they need to process a specific task or information received from their environment, as well as the capacity of dealing with certain psychological factors, mainly stress and isolation.

Once a study about a certain group of peoples reactions to their environment has been made, people who design with ergonomics attempt to develop the best possible design for a system or product.

Ergonomists view people and a the object or machine they will use as a sole unit, and the ergonomic approach to design blends the persons abilities with those of the machine.
When designing one must take into account the several limitations of both the mechanical and the human factor involved in a certain workspace. Human beings need to rest or experience less stress when realizing a certain task or they will spend their energies quickly and begin making mistakes when working, they are also subject to illness, accidents and the need of rest. The mechanical factor is also subjected to several limitations, for instance, they cannot repair themselves nor adapt to dynamic or unexpected situations as well as human.

An ergonomically designed system should therefore take advantage of the strengths of each of the components involved to provide optimal performance, an almost "symbiosis" between man and machine.

Ergonomists contribute to the design and evaluation of tasks, jobs, products, environments and systems in order to make them compatible with the needs, abilities and limitations of people.

Ergonomics are commonly divided into three main domains:

• Physical ergonomics

• Cognitive ergonomics

• Organizational ergonomics

Physical ergonomics usually deals with the field of the human body's reaction to physical or physiological work. Relevant to this field of application is the materials a workers has to work with, the layout at his workstation, the physical demands of his job and different types of risks such as repletion, vibration, forces or awkward and static postures since all of these factors have been determined to cause musculoskeletal disorders known as repetitive strain injury's.

Repetitive strain injury, also called repetitive stress injury, is a group of conditions that comes from the overuse of computers, typewriters and other similar motions or tools. It is considered an overuse syndrome affecting muscles, tendons and nerves in the upper section of the human body.

Medical research points to the fact that these disorders occur when muscles in a certain area are kept tense for very long periods of time, mainly due to poor posture or repetitive motions. These conditions are very common among assembly line and computer workers. Better ergonomics, or limited exposure time to these stressful conditions help preventing these disorders.

Cognitive ergonomics or engineering psychology is and emerging branch of ergonomics that places special emphasis on the mental processes such as perception, attention, and workers cognitive abilities, as well as motor control and memory storage and retrieval, and how they affect a workers interactions among co-workers and the elements of the system.

Important to this specific field is the mental workload of the workers, their vigilance, their ability to make decisions, the human error, the workers performance and training and the human-computer interaction.

Cognitive ergonomics seek to enhance the performance of cognitive tasks by four different interventions:

• HCI, human computer interaction by designing human centered machines.

• The creation of cognitive artifacts.

• Training programs.

• Work redesign to manage cognitive workload and increase human reliability.

Ergonomic design in this field require a thorough understanding of the work environment and the limitations of human cognitive factors. Sometimes, the tools or artifacts necessary to realize a certain task carry their own limitations, for instance, navigating through a large amount of GUI (guided user interface) screens.

It is very important to analyze the tools the workers use since many times they co-determine the nature and ability of the user to realize a certain task, this is specially true in control panels, software or expert systems, as they are increasingly sophisticated.

Special emphasis is made on how to design the human – machine interfaces so that the cognitive performance of the user is sustained in the work environment, where stress or overload of work may cause unreliable information, conflicting goals and performance decrease.

This sort of knowledge is usually applied in workplaces where the situations is familiar but variable, even at an accelerated rate, such as chemical plants, air traffic control rooms, operating theaters and command and control centers.

Organizational ergonomics are mainly concerned with the optimization of socio-technical systems (STS), this is an approach to complex organizational work design that recognizes the interaction between people and technology at their workplaces, including their structure, policies and processes. This branch of ergonomics focuses on work shifts, schedules, the workers satisfaction, workers motivation, worker supervision, teamwork and work ethics.

Designing with people in mind sometimes requires advanced technology, such as computers and robots to simulate human reactions, and sometimes may be relatively simple. Researchers often use dummies or mannequins that represent a particular piece of the human body, then design with the average user in mind. To allow evaluation of their design they create replicas of workstations, scenarios or products and observe people operating equipment or using these products.

Ergonomic applied in the field of job design helps employers assess both the individual task necessary to perform a particular job and the skill needed to accomplish each task. By grouping tasks and skills jobs can be redesigned to maximize efficiency, because all tasks will be performed in the vicinity of a specific workstation to increase the workers productivity. Of course the worker has to be allowed to have adequate breaks and rest periods as well as clearly defined tasks. This is the case of a receptionist that will perform other tasks such as sorting mail and bookkeeping.

Ergonomics also allow an employer to analyze the best candidate for a particular job, by defining physical, mental and even social skills to perform a task, the basic set of qualifications necessary for selection are laid out.

The ergonomic design of products makes them safer, easier to use and more reliable, modern industry is constantly developing new products that will fit the bodies and meet the expectations of the users.

Cars are some of the products that have suffered the biggest changes since the introduction of ergonomic design. Larger contoured adjustable seats allow users of all sizes to fit the vehicle, padding has also made them more comfortable for users who have to drive for extensive amounts of time, headrests that fit different heights to avoid injury to users in an accident, the center mounted rear brake light which is now an enforced piece of equipment of all new cars is an ergonomic cognitive device.

One of the biggest improvements in product ergonomics have been computers. Computers changed from the complex tools to accessible aids with the creation of the GUI. GUI or graphical user interface uses pictorial representation to create a familiar environment for the user and take advantage of his cognitive skills. By pointing on objects inside the computer and clicking them a user can easily and quickly display lists of files and other options. This system has allowed computers to be accessible to almost every person.

S O U R C E S

Bridger, Robert S. (2003). Introduction to Ergonomics. 2nd edition. Taylor & Francis. England.

Rogmans, Wim & Rosenberg, Mark (2006). International Journal of injury control and safety promotion. Taylor & Francis. England.

Tom Stewart. (2006). Behavior & Information Technology. Taylor & Francis. England

S/D. (2006). Ergonomics in design. Human factor and ergonomics society. S/D.

S/D. (2006). "Ergonomics", Wikipedia. http://www.wikipedia.org/wiki/Ergonomy.
Last update: 10/10/06.