From The Ergoweb® Learning Center

Ergonomics Glossary of Terms

Administrative Control – 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 employee rotation, job task enlargement, and adjustment of work pace.

ANSI – American National Standards Institute. A private, non-profit membership organization that coordinates voluntary standards activities. ANSI assists with standards-developers and standards users from the private sector and government to reach agreement on the need for standards and establish priorities.

Anthropometry – Anthropometry is the branch of the human sciences that deals with body measurements.

Awkward Posture – Posture is the position of the body while performing work activities. Awkward posture is associated with an increased risk for injury. It is generally considered that the more a joint deviates from the neutral (natural) position, the greater the risk of injury.

Specific postures have been associated with injury. For example:


  • Flexion/extension (bending up and down)
  • Ulnar/radial deviation (side bending)


  • Abduction/flexion (upper arm positioned out to the side or above shoulder level)
  • Hands at or above shoulder height

Neck (cervical spine)

  • flexion/extension or bending the neck forward and to the back
  • side bending as when holding a telephone receiver on the shoulder

Low back

  • Bending at the waist, twisting

Cumulative Trauma Disorders (CTDs) – Term used for injuries that occur over a period because of repeated trauma or exposure to a specific body part, such as the back, hand, wrist and forearm. Muscles and joints are stressed, tendons are inflamed, nerves pinched or the flow of blood is restricted. Common occupational induced disorders in this class include carpal tunnel syndrome, epicondylitis (tennis elbow), tendinitis, tenosynovitis, synovitis, stenosing tenosynovitis of the finger, DeQuervian’s Syndrome, and low back pain.

Duration – Duration is the length of exposure to a risk factor. It can be measured as the minutes or hours per day the worker is exposed to a risk. Duration can also be viewed as the years of exposure to a risk factor. In general, the greater the duration of exposure to a risk factor, the greater the degree of risk. However, specific duration guidelines have not been established for risk factors such as force, posture and repetition.

Engineering Control – Physical changes to jobs that control exposure to risk. Engineering controls act on the source of the hazard and control employee exposure to the hazard without relying on the employee to take self-protective action or intervention. Examples include: changing the handle angle of a tool, using a lighter weight part, and providing a chair that has adjustability.

Ergonomics – According to Ergoweb: The science of work. Ergonomics removes barriers to quality, productivity, and safe human performance by fitting products, tasks and environments to people.

Ergonomic program – A systematic process for anticipating, identifying, analyzing and controlling ergonomic risk factors.</>

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, the low back and the forearm/wrist/hand.

Human Factors – A term synonymous with ‘ergonomics’, is the branch of this science that began in the US and focuses on cognitive performance of humans.

Lighting – The level of illumination in the workplace. Poor lighting can lead to visual symptoms of eyestrain, eye focusing breakdown, eye coordination abnormalities, and eye fatigue while performing select activities such as video display terminal tasks.

Manual Material Handling – Lifting, carrying, and moving materials without mechanical aide.

Motion: Velocity/Acceleration – Velocity/ acceleration is the speed of body part motion and the rate of change of speed of body part motion, respectively. It is generally regarded that increased acceleration leads to increased risk of injury.

Musculoskeletal Disorders (MSD) – Injuries and disorders of the muscles, nerves, tendons, ligaments, joints, cartilage and spinal disc; examples include carpal tunnel syndrome, rotator cuff tendonitis, and tension neck syndrome.

NIOSH – National Institute of Occupational Safety and Health. NIOSH is the institution that provides scientific data upon which OSHA makes recommendations.

Occupational Biomechanics – Occupational Biomechanics is a science concerned with the mechanical behavior of muscuskeletal tissues when physical work is performed.

RSI – Repetitive Strain Injury

RMI – Repetitive Motion Injury

UECTD – Upper Extremity Cumulative Trauma Disorders

WRULD – Work Related Upper Limb Disorder

Occupational Illness – Any abnormal condition or disorder, other than one resulting from an occupational injury caused by exposure to factors associated with employment. It includes acute and chronic illnesses or disease which may be caused by inhalation, absorption, ingestion or direct contact. The broad categories of occupational illnesses are skin diseases and disorders, dust diseases of the lungs, respiratory condition due to toxic agents, poisoning (systemic effects of toxic materials), disorders due to physical agents other than toxic materials, and disorders from repeated trauma.

Occupational Injury – Any injury such as a cut, fracture, sprain, amputation, etc., which results from a work-related event or from a single instantaneous exposure in the work environment. Examples of injuries or disorders that can be work related include:

  • Carpal tunnel syndrome (CTS)
  • Rotator cuff syndrome
  • De Quervain’s disease
  • Trigger finger
  • Tarsal tunnel syndrome
  • Sciatica
  • Epicondylitis
  • Tendinitis
  • Raynaud’s phenomenon
  • Carpet layers knee
  • Herniated spinal disc
  • Low back pain

OSHA – Occupational Safety and Health Administration. The mission of the Occupational Safety and Health Administration (OSHA) is to save lives, prevent injuries and protect the health of America’s workers. To accomplish this, federal and state governments must work in partnership with the more than 100 million working men and women and their six and a half million employers who are covered by the Occupational Safety and Health Act of 1970.

OSHA 300 Log – An OSHA-required form for employers to record and classify occupational injuries and illnesses, and note the extent of each case.

Recovery Time – Recovery time is the length of rest between exertions. Short work pauses can reduce discomfort. Inadequate rest periods between exertions can decrease performance. As the duration of the uninterrupted work increases, so does the amount of recovery time needed.

Repetition – Repetition is the number of a similar exertions performed during a task. A warehouse worker may lift three boxes per minute from the floor to a countertop; an assembly worker may make 20 units per hour. Repetitive motion has been associated with injury and worker discomfort.

Generally, the greater the number of repetitions, the greater the degree of risk. However, there is no specific repetition limit or threshold value (cycles/unit of time, movements/unit of time) associated with injury.

Risk Factor – Actions in the workplace, workplace conditions, or a combination thereof, that may cause or aggravate a Work Related Musculoskeletal Disorders; examples include forceful exertion, awkward postures, repetitive exertion, and environmental factors such as temperature.

Segmental Vibration (Hand-Arm Vibration) – Vibration applied to the hand/arms through a tool or piece of equipment. This can cause a reduction in blood flow to the hands/fingers (Raynaud’s disease or vibration white finger). Also, it can interfere with sensory receptor feedback leading to increased handgrip force to hold the tool. Further, a strong association has been reported between carpal tunnel syndrome and segmental vibration.

Whole Body Vibration – Exposure of the whole body to vibration (usually through the feet/buttocks when riding in a vehicle). Whole body vibration may increase the risk for injury, including low back pain and internal organ disruption.

Work Related Musculoskeletal Disorders (WMSD, WRMSD) – Injuries and disorders of the muscles, nerves, tendons, ligaments, joints, cartilage and spinal disc due to physical work activities or workplace conditions in the job. Examples include: carpal tunnel syndrome related to long term computer data entry, rotator cuff tendinitis from repeat overhead reaching, and tension neck syndrome associated with long term cervical spine flexion.

Work Related Musculoskeletal Disorder Hazard – Workplace conditions or physical work activities that cause or are reasonably likely to cause or contribute to a work related musculoskeletal disorder.