Glossary : NS Labour and Advanced Education, Ergonomics

The following terms are often used with reference to ergonomics and/or musculoskeletal injuries (soft tissue injuries). If there are other terms you'd like to see explained, contact us.

Anti-Fatigue Mats:

Mats placed on the floor where workers stand to work. They are designed to reduce musculoskeletal fatigue associated with static standing. Cushioned insoles for shoes can be viewed as 'portable anti-fatigue mats', to some degree.


The study and measurement of human physical dimensions.

Awkward Posture:

Any fixed or constrained body position that overloads muscles and tendons or loads joints in an uneven or asymmetrical manner.


The study of the effects of internal and external forces on the human body in movement and at rest. Biomechanical models calculate physical stresses occurring at various body joints, including the vertebral joints in the low back. The stresses are compared with accepted limits for compressive and/or shear forces.


Bursae are lubricating pads separating tendons from bones in some joints of the body. Bursitis is the result of the inflammation of a bursae. The inflammation may be caused by repetitive or forceful exertions at that joint.

Carpal Tunnel Syndrome:

A specific musculoskeletal injury (soft-tissue injury) resulting from compression on the median nerve, which travels through the carpal tunnel in the wrist. Symptoms can include tingling and numbness in the hand, and loss of dexterity and strength in the hand.

Contact stress:

Exposure of a body part to a hard or sharp surface/edge at a workstation or by using a tool, e.g. leaning forearms against a sharp table edge. Contact stress has been associated with the development of some musculoskeletal injuries.


See musculoskeletal injury.


Movement of a body part away from the neutral position for that joint/limb. Typically used to describe wrist positions. For example, ulnar deviation of the wrist describes the movement of the wrist away from a straight position towards the baby finger. Deviation of a limb towards the end of a joint's range of motion is considered a risk factor for musculoskeletal injury.


The continuous time a task is performed without a rest period.


A discipline dealing with the interaction between the worker and the work environment. Also called human factors. See About Ergonomics.

Ergonomic hazards:

Workplace conditions that place workers at increased risk of developing a musculoskeletal injury or which otherwise increase the likelihood of other work performance problems.

Ergonomics Program:

Systematic application of ergonomics principles to day-to-day business decisions and operations. Typically employed to prevent musculoskeletal injuries and/or improve work performance. Program components include health and risk factor surveillance, workplace analysis and design, training and medical management.


The joint between the 5th lumbar (L5) and 1st sacral (S1) vertebrae of the spinal column. Many low-back disc injuries occur at this joint.


Fibrous structures that connect bones to bones within the body, providing support while allowing flexibility and movement.


Manual Materials Handling (MMH) refers to any handling task involving the human body as the "power source". MMH includes lifting, lowering, pushing, pulling, carrying, and holding.

Median Nerve:

The nerve that travels through the carpal tunnel of the wrist and services the thumb and first three fingers of the hand. Compression of the median nerve results in carpal tunnel syndrome.

Musculoskeletal Injury:

Chronic muscle, tendon, and nerve disorders caused by repetitive exertions, rapid motions, high forces, contact stresses, extreme postures, vibration, and/or low temperatures.

Also referred to as: cumulative trauma disorders (CTDs), repetitive strain injuries (RSI), work-related musculoskeletal disorders (WMSDs), or soft-tissue injuries (STIs).

Neutral Posture:

A body position that minimizes stresses on that part of the body. Typically the neutral posture will be near the mid-range of any joint's range of motion.

NIOSH Equation:

The National Institute of Occupational Safety and Health (NIOSH) Revised (1991) Equation for the Design and Evaluation of Manual Lifting Tasks. The equation incorporates data from actual manual lifting tasks and provides a method for computing a weight limit for that lift. The objective of the equation is to prevent or reduce the occurrence of lifting-related low back pain.


Deals with the relationship between human sensation and their physical stimuli. The psychophysical approach used in the study of manual materials handling (MMH) tasks requires the worker to adjust the weight, force or frequency in a handling situation until they feel it represents their maximum acceptable weight or force.

Risk Factors:

Job and/or workplace requirements or conditions that pose stress on the body, resulting in the development of musculoskeletal injuries. The predominant risk factors known to contribute to musculoskeletal injuries are repetitive exertions, rapid motions, high forces, contact stresses, extreme postures, vibration, and low temperatures.


A workstation that enables the worker to alternate between standing and sitting while performing his/her tasks. A sit/stand set-up is recommended over dedicated sitting or standing workstation set-ups.


A joint injury in which the supporting ligaments are partially or sometimes fully torn.

Static Load:

Stress placed on the body due to body parts remaining immobile for extended periods of time. Localized muscle fatigue can result.


An injury in which muscle fibers are torn, often due to working against a heavy load.


Tendons connect muscles to bones, and 'itis' means inflammation. Tendonitis is the generic term for inflammation of a tendon. The specific type of tendonitis is named after the affected body part, e.g. lateral epicondylitis, or tennis elbow, is inflammation of the forearm extensor muscles' tendon where it attaches to the elbow.


Swelling and inflammation of the sheath that surrounds certain tendons. The sheath protects, guides, and lubricates the tendon in places where there is a great deal of movement or potential friction.

Trigger Finger:

The partial or complete entrapment of a tendon within its sheath. Often the index, or trigger, finger is affected due to squeezing a tool that causes pressure on the palm of the hand while there is stretching and pulling upon the tendon. The tendon and its sheath become inflamed. When repeated over time, changes to the tendon and sheath make it difficult for the tendon to move smoothly along its course. A popping or crackling sound can often be heard when the finger is re-extended.

Vibration White Finger:

A condition where the small blood vessels in the hand constrict, resulting in decreased blood flow and subsequent blanching of the hands. The small nerves of the hand may also be damaged. This disease is associated with the long-term use of vibrating tools (or, in general, exposure to vibration).

Vertebral Disc:

Discs separate the bones (vertebrae) that make up the spinal column. They are fibrous structures filled with a pulpy, gelatinous matter. They function as shock absorbers for the spine. Disc-related injuries to the back can be associated with deformation of the discs, including bulging and rupturing of the discs.


The entire work area accessed by a worker when performing a specific task or job cycle.

FAQs | Glossary | Links | Publications