What is the purpose of ergonomics



what is the purpose of ergonomics ergonomics (or human factors) is the scientific discipline concerned with the understanding of interactions among humans and other elements of a system, and the profession that applies theory, principles, data, and methods to design in order to optimize human well-being and overall system performance. If your desk has a hard edge, pad the edge or use a wrist rest. The ergonomics field draws practitioners and researchers from various specialties, including engineers, safety professionals, industrial hygienists, occupational and physical therapists, and other health care specialists. This site is intended to share a remarkable discovery to solve that problem. National Institutes of Health, Office of Research Services, Division of Occupational Health and Jun 04, 2021 · Ergonomics. They apply to workers, supervisors, ergonomic specialists, ESH coordinators, and the ergonomics program manager; and the Occupational Health Center (OHC) and Building and Space Management. When your workstation is appropriately configured, you may: Be less prone to have migraines or eye strain. Make sure the keyboard/mouse height and monitor height are all ideal in both sitting and standing postures. Ergonomics is a people-centred approach that aims to fit the work to the person, not the person to the work. Ergonomists contribute to the design and . The construction industry is among the most hazardous and accident-prone working environments. Since having good workplace ergonomics is synonymous with protecting your employees’ safety and health, business leaders can save on lost workdays, injury claims, and compensation . According to a . Oct 30, 2018 · Ergonomics Goes Back a Long Way Today’s ergonomic industry offers products that contribute to health and productivity. III. Assist in the ergonomic process by voicing their concerns and suggestions for reducing exposure to risk factors and by evaluating the changes made as a result of an ergonomic assessment. edu Ergonomics Program Purpose The purpose of this program is to effectively eliminate or control Work-related Musculoskeletal Disorders (WMSD) and hazards by providing management leadership and employee involvement in the identification and resolution of hazards and by providing training, medical management and evaluation as an on-going process. , Wogalter, Michael S. Ergonomics today is the science of designing and evaluating systems, products and environments to be efficient, safe and satisfying for users. The primary goal is to fit jobs to people, not people to jobs. A thorough understanding of the specific tasks an object is intended for is central to achieving the ergonomic design goal of aiding the human form in executing them. Nov 19, 2020 · One example of products designed with office ergonomics in mind is ViewSonic’s Office Ergonomic Monitor collection which has been designed specifically for the purpose of providing office monitors that improve comfort at work and reduce work-related injuries. DEA 3250/6510 CLASS NOTES. It is designed to systematically 1 Purpose The purpose of these procedures is to prevent ergonomic injuries. What is Ergonomics and its purpose in the workplace? Ergonomics, pronounced "ur go nom iks," is the field of study concerned with finding ways to keep people safe, comfortable, and productive while they perform tasks at work and home. The specialist will review your entire office space, as well as several individual aspects, including furniture, working conditions, and the supplies workers have at their disposal. Cornell University Ergonomics Web. Ergonomics is designing and improving the workplace, workstation, tools, equipment, and procedures of work in order to limit fatigue discomfort and injuries, while efficiently achieving personal and organizational goals. Oct 05, 2020 · An ergonomics team is a group of individuals who use science to ensure that a working environment and its specific equipment are placed in an arrangement that allows for the most efficient and safe use by employees. Ergonomics Technical Advisory Group Annex Patient Care Ergonomics Resource Guide: Safe Patient Handling and Movement Developed by the Patient Safety Center of Inquiry (Tampa, FL), Veterans Health Administration and Department of Defense October 2001 (rev 8/31/05) Feb 28, 2018 · The goal of ergonomics (i. Barrier Solution It costs money. Definition and Applications. Cognitive ergonomics is the discipline of making human-system interaction compatible with human cognitive abilities and limitations, particularly at work. It also provides guidance on where to source further information. The goal of this self-assessment is to help you set up your workstation for optimal comfort and performance. “Ergonomics is the scientific discipline concerned with the understanding of interactions among humans and other elements of a system, and the profession that applies theory, principles, data and methods to design in order to optimise human well-being and overall system performance. If you are using a stool, make sure to obtain a elevated foot rest as well. Jul 31, 2014 · Implementing a strong ergonomics program can nip MSDs in the bud, improve the health and productivity of employees, and boost the company’s bottom line. Jun 04, 2021 · Ergonomics. (2000). . Jun 14, 2020 · Importance of Ergonomics In The Workplace. Provide Training - Training is an important element in the ergonomic process. Mar 07, 2019 · Ergonomics. In recent years, the growth and development of technology has pushed ergonomics in new directions . For more information, refer to the . May 07, 2019 · An ergonomic mouse can ease existing wrist pain and help prevent you from developing Carpal Tunnel or RSI. There are a number of ergonomic chairs that are ergonomically sculpted with a lumbar support curvature built into the chair. The purpose of this booklet is to help you reduce your chances of being injured. Ergonomics aims to achieve this and more. Sample Ergonomics Program Purpose. Cognitive ergonomics utilises the knowledge emerging from the cognitive sciences on mental processes such as perception, attention, memory, decision making, and learning. D. In simplistic terms, ergonomics seeks to fit the person to the job and vice-versa. It also involves all the measures taken to enhance the performance of individuals at work. As a science, ergonomics identifies the physical properties of work and how the way it is done affects the body. Ergonomics uses anthropometrical data to determine the optimum size, shape and form of a product, and make it easier for people to use. Jan 04, 2021 · The word ‘ergonomics’ is made up of two Greek words: ergon (work) and nomos (law, rule). Ergonomics is a science related to the suitability of an office design to people. Fifteen years treating cumulative trauma as a physical therapist, and then twenty years as an ergonomic consultant led me to realize that poor spine posture is a common observation for injured workers, and that the problem is rarely . When you sit for hours on end, this eventually results in poor circulation. Any ergonomically sound work Ergonomics definition is - an applied science concerned with designing and arranging things people use so that the people and things interact most efficiently and safely —called also biotechnology, human engineering, human factors. Ergonomics also takes into account the need for movement throughout the day. The word ergonomics — “the science of work” is derived from the Greek ergon (work) and nomos (laws). • Ergonomics leads to healthy and pain-free workers who are more likely to be engaged and productive. Page 4 of 9. Federal jurisdiction. topics and material on ergonomic risk factors. From seat or table stand <do-follow> adjustment according to […] What is an Ergonomic Assessment? An ergonomic assessment is crucial for the fitness of the workforce in an organization. Ergonomics and Systems Thinking ¾ The concept of a system is fundamental to ergonomics ¾ “A system is an entity that exists to carry out some purpose” (Bailey, 1982) ¾ “A system is an organized or complex whole: an assemblage or combination of things or parts forming a complex, unitary whole. The purpose of this program is to effectively eliminate or control Work-related Musculoskeletal Disorders (WMSD) and hazards by providing management leadership and employee involvement in the identification and resolution of hazards and by providing training, medical management and evaluation as an on-going process. The user experience is the core of the design process. With the adaptations of tools and equipment, there is a price tag. This site was created to provide basic information useful for employers, workers and others in designing an effective ergonomics program to prevent work-related musculoskeletal disorders (WMSDs). On construction sites, workers are exposed to dangers on a daily basis that can result in serious injuries or even . Ergonomics is therefore the optimum interface between people, environment and machine. It outlines practical strategies for identifying and correcting ergonomic deficiencies in a variety of workplace settings. Job hazard analysis (JHA) is the process of analyzing and breaking down a task into smaller parts so as to eliminate or minimize job hazards. This topic explains how it can be used in all aspects of work from tool, equipment and software design to work organisation and job design. Ergonomics (or ‘human factors’ as it is referred to in North America) is a branch of science that aims to learn about human abilities and limitations, and then apply this learning to improve people’s interaction with . There are many aspects of ergonomics including human anatomy, machine performance, human-machine interaction and much more. Dec 30, 2019 · Eliminating existing ergonomic issues is the first step in optimizing your workplace. However efforts will be made to give the reader an Ergonomics is the design and engineering of human-machine systems for the purpose of enhancing human performance. digital sustainable mobility ERGONOMICS IS THE SCIENCE THAT STUDIES THE MAN-MACHINE INTERFACE The purpose… Ergonomics and human factors at work A brief guide Introduction This leaflet is aimed at employers, managers and others and will help you understand ergonomics and human factors in the workplace. The implementation of proper ergonomics at work can be a lot easier if employees are trained and educated on the same. Step 2: Find Hazards. Oct 06, 2018 · There are two main disadvantages when it comes to ergonomics. Stand on an anti-fatigue mat. , & Hancock, Peter A. See full list on ehs. Through an understanding of the human form, muscle systems . By incorporating movement into the work day, employees can also reduce their risk of work-related musculoskeletal disorders. doi: 10. If the desk is too low and can't be adjusted, place sturdy boards or blocks under the desk legs. . digital sustainable mobility ERGONOMICS IS THE SCIENCE THAT STUDIES THE MAN-MACHINE INTERFACE The purpose… A recent article on the Knife News website provided insights into the ergonomics of knife handles. Aug 08, 2019 · Ergonomics is an important part of research in the product development process. Solutions to common barriers Workers come in all different sizes. If the job and the tools used are designed in a way that is logical and minimizes wear and tear on the body, risk of injury is reduced, people will be more comfortable and productivity increases. 1. Step 5: Check for Success. Implementing ergonomic solutions can make employees more comfortable and increase productivity. Ergonomic Principles to Keep in Mind Answer to Define ergonomics. g. Wear supportive shoes and replace them frequently. , the AET, and the Nordic questionnaire), there is a general lack of ergonomics norms and protocols of evaluation with respect to the different aspects of work and environment. It gives some examples of ergonomics problems and simple, effective advice about how to solve them. The word ergonomic is the study of the interaction between individuals, machines or appliances in their environment that can affect their performance and productivity. The objective will be to provide the user with the resources to identify ergonomics-based interventions to human performance problems encountered. Create employee awareness. Ergonomics is an important part of research in the product development process. Answer to Define ergonomics. Work related injury is usually due to awkward posture, forceful movement, and external factors such as noise which can affect health and work output. If the desk is too high and can't be adjusted, raise your chair. NKOSINI NGWENYA explores the topic of ergonomics in the construction industry. Ergonomics is designing a job to fit the worker so the work is safer and more efficient. The word 'ergonomics' comes from Ancient Greek and basically means rules or study of work. To set everything up in an ergonomic fashion, there needs to be the following equipment, depending on the employee: Keyboard; Desk; Chair Mar 07, 2019 · Ergonomics. Applying ergonomic principles to work stations can help prevent a variety of conditions, such as back pain and carpal tunnel syndrome. The reason for this breadth of scope is that its basic aim is efficiency in purposeful activity—efficiency in the . Furthermore, good workplace ergonomics can also help your worker avoid various health issues, like migraines, joint problems, and eye strain. Ergonomics (or human factors) is the scientific discipline concerned with the understanding of interactions among humans and other elements of a system, and the profession that applies theory, principles, data, and methods to design in order to optimize human . What's in a name? Using terms from definitions to examine the fundamental foundation of human factors and ergonomics science. 4172/2165-7556. digital sustainable mobility ERGONOMICS IS THE SCIENCE THAT STUDIES THE MAN-MACHINE INTERFACE The purpose… Ergonomics is the science of matching tools and tasks to the work environment. Remember, issues surrounding these areas can directly lead to lost productivity. Follow these easy steps to help set up your computer workstation. With this in mind, ergonomics can also be defined as the scientific study of people’s efficiency in the workplace. WORKPLACE ERGONOMICS PROGRAM INTRODUCTION 2 • Communicating with supervisors and employees on ergonomics solution alternatives. Human factors is an established science that uses many disciplines (such as anatomy, physiology, Ergonomics Process. Quality ergonomics is thought to reduce the risk of injury and . By performing these assessments through collecting and analyzing data, a company can ensure that its staff has the ability to work . The purpose of this short guide is to provide information to the reader on the subject of Ergonomics. Jul 05, 2014 · Ergonomics applies to the design of anything that involves people – workspaces, sports and leisure, health and safety. You may have heard the term ‘ergonomics’. Ergonomics is the study of the interaction between humans and system elements with the goal of increasing efficiency and compatibility. The purpose of an ergonomic evaluation is to identify occupational injury risk factors and make appropriate recommendations based on current What does ergonomics mean? Design factors, as for the workplace, intended to maximize productivity by minimizing operator fatigue and discomfort. To test if the ergonomic chair fits well, the user should sit up straight, with the head, spine, and buttocks in alignment. In order to achieve success in the highly competitive market, the innovation should walk side by side with the deep . The Fundamentals - Ergonomics. Human factors can, and should, be included within a good safety management system and so can be examined in a similar way to any other risk control system. Step 1: Chair. To use either index finger as your primary click, change mouse buttonsettings in the Workstation Ergonomics Self Assessment Computer Workstation Ergonomics: Self-Assessment Checklist . Scope The Workplace Ergonomics Program involves all Virginia Tech employees whose job duties expose them to ergonomic risk factors. Cognitive Ergonomics – the mental processes including mental workload, decision-making, perception, memory, and reasoning required by a task. The purpose of this research was to develop broad, theoretically derived measure(s) of deviant behavior in the workplace. Ergonomic programs seek to reduce or eliminate risk factors that lead to musculoskeletal and other types of injury. However efforts will be made to give the reader an Assist in the ergonomic process by voicing their concerns and suggestions for reducing exposure to risk factors and by evaluating the changes made as a result of an ergonomic assessment. 1000130. Purpose. Ergonomics The purpose of this chapter is to provide an overview of the relationship of ergonomics to the other elements of a typical human factors program. 2 Procedures COMPUTER ERGONOMICS GUIDE Using this booklet This booklet is intended for use by desktop computer users. Ergonomics (or human factors) is the scientific discipline concerned with the understanding of interactions among humans and other elements of a system, and the profession that applies theory, principles, data and methods to design in order to optimize human well-being and overall system performance. Push your hips as far back as they can go in the chair. Ergonomics is the study of human capabilities in relationship to work demands. the scientific study of people at work) is to prevent soft tissue injuries and musculoskeletal disorders (MSDs) caused by sudden or sustained exposure to force, vibration, repetitive motion, and awkward posture. Industrial design, physiology, biometrics and other disciplines working together have created some extraordinary equipment, such as under desk bikes. Jun 19, 2014 · An ergonomic keyboard is a keyboard designed to interface more easily with the natural positions of the hands. We are available via email to help resolve any ongoing issues. ” (von Bertalanffy, ~1935) Ergonomics is simply “fitting the task to the worker” rather than forcing the worker to fit the task. Goals 1. Environmental Ergonomics – the way in which humans react in a specific environment, e. ” Ergonomics is the science of matching tools and tasks to the work environment. The purpose/goals of workplace ergonomics applications include: Occupational injury and illness reduction Ergonomics is designing and improving the workplace, workstation, tools, equipment, and procedures of work in order to limit fatigue discomfort and injuries, while efficiently achieving personal and organizational goals. From seat or table stand <do-follow> adjustment according to […] Ergonomics aims to achieve this and more. Its purpose is to increase the safety, comfort and performance of a product or an environment, such as an office. Purpose To recognize, identify, and effectively eliminate or reduce work-related Musculoskeletal Disorders (MSD’s) and hazards to which employees may be exposed, provide training through a work place analysis; prevent pain and suffering as well as costs associated with ergonomic related illnesses/injuries. Dempsey, Patrick G. Use a supportive adjustable stool or ergonomic chair to sit periodically. What is the purpose of ergonomics in the workplace? Ergomonics along with risk factor assessment and intervention and decrease the risk of injury/illness, enhance worker productivity and improve quality of work life. They reduce the range of motion necessary for operation and allow you to extend your hand and arm naturally. Jun 08, 2007 · Ergonomics is the adaptation of equipment, procedures, and surroundings to best fit the people who use them. temperature, noise, light, etc. What is ergonomics and its benefits? Ergonomics improves productivity – Implemented correctly, an ergonomic solution improves productivity from 10 to 15%. The assessments are conducted by occupational therapists and assess a number of key factors that can impact your ability to work comfortably. Additional links provide information on lifting and computer workstation concerns. Ergonomics is the scientific discipline concerned with the understanding of interactions among humans and other elements of a system, and the profession that applies theory, principles, data and methods to design in order to optimize human well-being and overall system performance. Ergonomics can help make the work more comfortable for the individual worker. ” The scope of what we mean by human factors includes organisational systems and is considerably broader than traditional views of human factors/ergonomics. Much of it amounts to looking at routine activities from a new perspective — putting on your ergonomics glasses. Worksite Evaluation EH&S offers ergonomic a worksite evaluation for a fee. It will be clear already that the benefits of ergonomics can appear in many different forms, in productivity and quality, in safety and health, in reliability, in job satisfaction and in personal development. You will learn to identify common desktop computer work station problems and explore some improvement goals. Ergonomics is based on one simple principle: Make the task fit the person performing it without overly . May 01, 2019 · Ergonomics is a study about the efficiency of people at workplace and factors influencing it. Your posture provides a good starting point for evaluating the tasks that you do. The purpose of Ergonomic is to assess the interaction, or relationship between each component for determining optimum improvement in performance. Then sit all the way back against the seatback. digital sustainable mobility ERGONOMICS IS THE SCIENCE THAT STUDIES THE MAN-MACHINE INTERFACE The purpose… Definition and Applications. Reduces Overall Costs. Ergonomic Program Purpose & Scope The purpose of an ergonomic program is to apply ergonomic principles to the workplace in an effort to reduce the number and severity of musculoskeletal disorder (MSD), thus decreasing workers’ compensation claims and, where possible, increase productivity, quality, and efficiency. Ergonomics is the science of designing . e. Of the GoldTouch Semi-Vertical Mouse one user reported, “It’s saving me. Ergonomic chair. To create an ergonomically sound work environment, NIOSH ergonomists and industrial hygienists recommend . The following benefits are just some of the ways an ergonomic footrest can support your employees and in turn, the success of your company. hand for a while • Try switching to the other to give your uncomfortable hand a rest. Ergonomics training can empower companies and individual workers Ergonomic design is human-centered design that focuses on usability and harmonizing the functionality of tasks. Ver Steeg is a plastic surgeon, an outdoorsman and a custom knife maker. Sitting and Chair Design 1. Introduction - An estimated 50% of people in the industrialized world suffer some form of back complaint and many of these are related to poor seat design. Jan 31, 2017 · An ergonomic assessment, also referred to as a workstation assessment, analyzes a person’s workstation to ensure it is designed to minimize injury and maximize productivity. It is not within the bounds of this guidance to discuss in detail all the main aspects of knowledge in the field of Ergonomics. Ergonomic Principles to Keep in Mind Jan 04, 2021 · The word ‘ergonomics’ is made up of two Greek words: ergon (work) and nomos (law, rule). Your employees are the experts in their work. Aims of Ergonomics. when completing a task. By understanding how you perform Chapter 7. Apr 23, 2021 · Under the desk, make sure there's clearance for your knees, thighs and feet. Ergonomics is improving the design of jobs and workstations that have unsafe qualities or have caused injury. So it involves being aware of the user's limitations and also knowing how to make the best of their capabilities. Step 3: Assess Hazards. Sep 01, 2017 · Workplace Wellness: The Role of Ergonomics and Movement. To protect your employees from injuries, improve productivity and reduce workers’ compensation costs, follow any of these steps that meet your needs. Office furniture has traditionally encouraged stiff, fixed postures and little movement. The scope of what we mean by human factors includes organisational systems and is considerably broader than traditional views of human factors/ergonomics. We can arrange for you to have a virtual evaluation with an Ergonomist or an in-person evaluation at an additional cost if required. Whether you are a new employee or at a new workstation there are a four ergonomic points to keep in mind. Jun 11, 2019 · The Purpose of Ergonomic Assessments During an ergonomic assessment, a specialist will come out to your office and evaluate the quality of its ergonomics. Their purpose is to prevent repetitive-stress injuries and discomfort. digital sustainable mobility ERGONOMICS IS THE SCIENCE THAT STUDIES THE MAN-MACHINE INTERFACE The purpose… Sep 28, 2018 · Related: Desk Ergonomics 101. WHAT IS ERGONOMICS? Ergonomics is the science of fitting workplace conditions and job demands to the capabilities of the working population (interaction between the operator and the job demands). Step 1: Involve Employees. II. Among the shortcomings of the general-purpose checklist format employed in ergonomic job analysis are the following: · With some exceptions (e. However, a balance between sitting and standing, which can be aided with a height-adjustable desk , is a proven way to combat the effects of sedentary workplace behavior. Ergonomics and human factors at work A brief guide Introduction This leaflet is aimed at employers, managers and others and will help you understand ergonomics and human factors in the workplace. To set everything up in an ergonomic fashion, there needs to be the following equipment, depending on the employee: Keyboard; Desk; Chair Ergonomics Definition. factors” and “ergonomics” The terms human factors and ergonomics (as it is sometimes called) are used to describe interactions between three interrelated aspects: individuals at work, the task at hand and the workplace itself. Jun 01, 2020 · The goal of this ergonomics self-assessment is to help you set up your workstation for optimal comfort and performance. The National Institute for Occupational Safety and Health (NIOSH) and the Centers for Disease Control and Prevention (CDC) study ergonomics in the office. Those of us who work in an office are familiar with the toll that aches and pains of repetitive tasks and bad posture can take. Ergonomics, an applied science, can be defined as fitting the job to the worker. By taking into account people’s capabilities and limitations, an ergonomically designed workplace design strives to be effective in fulfilling the functional requirements of users. Ergonomics doesn’t have to be costly and can even save you money. Dynamic Ergonomics in AutomotiveVideo analysis ’ Software 2. Ergonomics is the science of the sort of work you do, the setting in which you work, and the instruments you use to do it. digital sustainable mobility ERGONOMICS IS THE SCIENCE THAT STUDIES THE MAN-MACHINE INTERFACE The purpose… Ergonomics is the study of how to improve the fit between the physical demands of the workplace and the employees who perform the work. It is important for workers to know how to adjust their office workstations to suit their individual needs. The purpose of office ergonomics is to design your workplace to be comfortable for you and your work. The purpose of ergonomics is to reduce or eliminate injuries and illnesses that can result from stress on muscles, nerves, and joints. Take the example of an office space for instance. Ergonomics is the study of how to improve the fit between the physical demands of the workplace and the employees who perform the work. In other words, ergonomics tries to make your job fit you, rather than making you fit your job. What is an Ergonomic Assessment? An ergonomic assessment is crucial for the fitness of the workforce in an organization. Ergonomics provides the guiding principles and specifications according to which tools, machines, work procedures and workplaces are designed for safe . It involves designing workstations, work processes, equipment and tools to fit the employee. Two . My mousing hand and arm feels good, without aches or pains. 1 Purpose The purpose of these procedures is to prevent ergonomic injuries. Training is an essential element of a successful workplace ergonomics implementation program. Designers should put themselves in the shoe of the end consumer in order to achieve empathic design. Use a footrest to support your feet as needed. Step 4: Fix Hazards. Jun 17, 2015 · Principles of Ergonomics: Designing with User Comfort in Mind. digital sustainable mobility ERGONOMICS IS THE SCIENCE THAT STUDIES THE MAN-MACHINE INTERFACE The purpose… J Ergonomics 4: 130. The first one is the cost. They cover identifying, evaluating, and mitigating ergonomic risks. Jan 14, 2015 · 1. That means considering the variability in human capabilities when selecting, designing, or modifying equipment, tools, work tasks, and the work environment. The purpose of this policy is to reduce the risk of musculoskeletal disorders associated with ergonomic arrangements and work design in schools. 2 Procedures • Blink often on purpose • Look across the room often, or out the window, to change your focal point 8. It ensures that workers are aware of ergonomics and its benefits, become informed . What is the purpose of ergonomics?. Principle 1. Boosts circulation. The purpose/goals of workplace ergonomics applications include: Occupational injury and illness reduction Jan 14, 2015 · 1. This is often accomplished by ergonomistic (information about people (height, weight, their ability to handle information and make decisions, their ability to see and hear and their ability to work in extremes of temperature) with individual risk factors to make the workplace . Ergonomics (or human factors) is the scientific discipline concerned with the understanding of the interactions among humans and other elements of a system, and the profession that applies theoretical principles, data and methods to design in order to optimise human wellbeing and overall system performance (International Ergonomics Association, 2000). Summary The Occupational Health and Safety (OHS) Act 2004 (Vic) requires the Department to provide or maintain systems of work and a working environment that is, so far as is reasonably practicable . A surprising number of people work in the office with physical complaints of pain. unc. The purpose of an ergonomic evaluation is to identify occupational injury risk factors and make appropriate recommendations based on current The basics of ergonomics do not need to be hard. Aug 24, 2018 · Working in the construction sector is one of the most physically taxing occupations that one can undertake. Work in Neutral Postures. The fundamental purpose of ergonomics is to create a safe, comfortable, and stress-free . The article summarized conclusions about handle design expressed by Kyle Ver Steeg, M. what is the purpose of ergonomics