Work-related musculoskeletal disorders (WRMSDs) affect the lives of many New Zealanders. They contribute to high numbers of injuries in our workplaces.

Defining the nature of musculoskeletal health risk is essential. This will help to guide how, as the health and safety regulator, we might act to reduce harm to New Zealanders.

Here we present our definitions for musculoskeletal disorders (MSDs) and work-related musculoskeletal disorders (WRMSDs). We recommend these definitions for use by WorkSafe New Zealand and the work health and safety sector.

For more information on how we developed these definitions, see the research report: Work-related musculoskeletal disorders definitions review 

Musculoskeletal disorders (MSDs) definition

MSDs are injuries and conditions affecting the muscles, ligaments, bones, tendons, blood vessels, and nerves. MSDs may also include inflammatory conditions (for example, rheumatoid arthritis, gout), degenerative conditions (for example, osteoarthritis), bone density conditions (for example, osteoporosis) and pain conditions (for example, fibromyalgia).

The term MSDs is appropriate to use when referring to general conditions of the musculoskeletal system.

Work-related musculoskeletal disorders (WRMSDs) definition

WRMSDs are injuries and conditions affecting the muscles, ligaments, bones, tendons, blood vessels, and nerves. WRMSDs occur when work demands lead or contribute to pain, discomfort, or injury.

The term WRMSDs should be used when referring to conditions of the musculoskeletal system that occur when work demands lead or contribute to them.

Multiple work factors usually cause the injury or condition. Risk factors often work in combination including physical and biomechanical, organisational, psychosocial, environmental, and individual factors. Both manual and sedentary work have risk factors that may lead to WRMSDs. Non-work factors may also contribute to injury risks (for example, mountain biking after work might add to forearm muscle loading from the workday).

Work risk factors that contribute to injury include:

• biomechanical and physical
  • forces/loads (for example, weight of loads, forces to move objects, sudden force)
  • task duration/repetition (for example, repetitive, sustained)
  • workplace layout (for example, workstation design)
  • vibration (for example, hand/arm or whole body vibration)
  • awkward postures (for example, sit, stand, overhead reach, stoop, kneel, constrained)
• work organisation (for example, workplace/plant design, task/equipment, shifts, training/education)
• environment (for example, temperature, humidity, lighting, noise
• individual (for example, age, body size, previous injuries/fitness, fatigue/mental state)
• psychosocial (for example, job demands, workload, control and support, job satisfaction).

Most WRMSDs develop over time. They can also occur suddenly from a specific event or series of events. WRMSDs may be injuries from a work-related incident or accident.

WRMSDs vary in severity. They may start as mild aches and pains but can develop into a serious condition. Symptoms may include pain or discomfort, and loss of strength, sensation, dexterity, or function. They can be recurring and long lasting. In many cases, WRMSDs impact the ability to work and do other daily activities.

WRMSDs in New Zealand have been called sprains and strains, repetitive strain injury, occupational overuse syndrome or discomfort, pain, and injury among other things. For public use, other terms can be used.

WorkSafe preferred term. WRMSDs is preferred for use within the work health and safety regulatory and professional context.

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