"Accommodation: any modification or adjustment to a work environment that enables an operator to perform essential job functions.
Administrative controls: procedures and methods, set up by the employer, that significantly reduce exposure to risk factors by altering the way in which work is performed. Examples include job rotation and adjustment of work pace.
Anthropometry: the science of studying human body dimensions. It is used to design ergonomic standards, assembly procedures and workstations. The goal of anthropometry is to minimize design incompatibility and maximize human performance.
Awkward posture: deviation from the ideal working posture of elbows at the side of the torso, with the wrists neutral. It is associated with an increased risk for injury. Awkward postures typically include reaching behind, twisting, forward or backward bending, pinching and squatting.
Biomechanics: a field of study that uses the laws of physics and engineering concepts to describe the motions of body parts and the forces acting upon them during normal daily activities.
Boundary values: a guideline used to design for the 5th to 95th percentile, which means designing for about 90 percent of a given population. The range of sizes dictates the range of flexibility necessary for new workstations, material handling equipment or assembly tools in order to accommodate the full range of employees. Usually, boundary values are obtained from large existing databases.
Carpal tunnel syndrome: a wrist disorder often associated with repetitive hand work. Symptoms include burning, itching, prickling or tingling feelings in the wrist or first three fingers and thumb. Carpal tunnel syndrome is more prevalent in women than in men. It is one example of a cumulative trauma disorder.
Chronobiology: the science of investigating and objectively quantifying phenomena and mechanisms of the biologic time structure, such as circadian rhythms. It is a new and rapidly developing specialty.
Cumulative trauma disorder (CTD): premature wear and tear damage to specific body structures. CTD injuries are mostly caused by low intensity forces applied over a long period of time, with motions repeated over and over concentrated on specific muscles and joints. Common examples of CTD include carpal tunnel syndrome and tendinitis. Cumulative trauma disorder is also called “repetitive motion injury.”
DeQuervain’s disease: an inflammation of the tendon sheath of the thumb attributed to excessive friction between two thumb tendons and their common sheath. It is usually caused by twisting and forceful gripping motions with the hands. The disorder is named after a French doctor who first described it.
Duration: the length of exposure to a risk factor. It can be measured as the minutes or hours per day that an operator is exposed to a risk. Typically, the greater the duration of exposure to a risk factor, the greater the degree of risk.
Engineering controls: physical changes to a job that reduce musculoskeletal disorders. Examples of engineering controls include changing or redesigning workstations, tools, equipment or processes.
Ergonomics: the scientific study of human work. It is derived from the Greek words ergon (work) and nomos (laws). Ergonomics considers the physical and mental capabilities and limits of the worker as he or she interacts with tools, equipment, work methods, tasks and the working environment.
Ergonomist: an individual who analyzes work environments and recommends administrative, engineering and work practice controls. Ergonomists attempt to remove barriers to quality, productivity and safe human performance by fitting products, tasks and environments to people.
Exposure: a concept used to describe the particular risk factor experienced by a worker, with a profile of modifying factors, such as intensity, time characteristics and duration.
Fatigue: a condition that results when the human body cannot provide enough energy for the muscles to perform a task. There is a reduction in the ability to exert force in response to voluntary effort.
Force: the amount of muscular effort required to perform a task. Generally, the greater the force, the greater the degree of risk. High force has been associated with work-related musculoskeletal disorders at the shoulder, neck, forearm, wrist, hand and lower back.
Frequency: the number of cycles occurring per time unit.
Global boundaries: the working population used to generate boundary values. If global boundaries are not considered, data can easily be misrepresented. For instance, a 95th percentile male at an auto parts assembly plant in Michigan will be different in height and arm length from individuals working at similar plants in China and Mexico.
Human factors: a branch of ergonomics that focuses on cognitive performance of humans." (Continued via ASSEMBLY, Austin Weber) [Ergonomics Resources]