Intro : Work-related Musculoskeletal Disorders (WMSD)



Work related musculoskeletal disorders are a group of painful conditions can affect bones, muscles, nerves, tendons and joints. The common WMSD’s seen include carpal tunnel syndrome, thoracic outlet syndrome and tension neck syndrome.

The U.S. Department of Labour defines WMSDs, as injuries or disorders of the muscles, nerves, tendons, joints, cartilage, and spinal discs associated with exposure to risk factors in the workplace.

WMSDs include :-

  • sprains,
  • strains,
  • tears,
  • swelling,
  • fractures,
  • compression,
  • misalignment,
  • disc herniation
  • excessive, repetitive movements that affect the musculoskeletal, connective, or nervous system

This can be due to activities which require :

  • lifting
  • bending
  • climbing
  • crawling
  • reaching
  • twisting
  • pushing
  • pulling
  • poor postural alignment
  • psychological stress
  • overexertion
  • repetition

WMSDs do not include disorders caused by slips, trips, falls, motor vehicle accidents, or other traumatic injuries.

Most jobs requires the use of hands ,and arms. As a result majority of the WMSD incidences affect the neck , shoulder, arms, elbows and wrists. Certain occupations require prolonged walking or standing leading to WMSD of the hips , thighs, ankles, knees and feet. In addition repetitive activities can also lead to back disorders.

Risk factors for WMSD

  1. Physical and Biomechanical Risk Factors
    – Repetitive movement when working
    – Forceful movements
    – Repetitive forceful tasks
    – Fixed position while working
    – Awkward and unnatural body positions
    – Using vibrating equipment
    – Extreme temperature
    – High altitude
  2. Psychosocial Risk Factors
    – Increased stress or demands
    – Poor job satisfaction
    – Unstable job security
    – Low decision control
    – Low salary and poor benefits
    – Bad relationships with supervisors
    – Poor support at workplace
  3. Individual Predisposing Risk Factors
    – Genetic make up
    – Co-morbid medical conditions
    – Sedentary lifestyle
    – Physical and psychosocial coping behaviors
    – Personality issues
    – Obesity
    – Ageing
    – Female gender
    – Life goals and family responsibilities

Figure 1 : Physical and Biomechanical Risk Factors


How do WMSD’s Occur

Muscle Injury

When we use our muscles , its uses energy from food and it will produce certain toxic-products. One of the common products is lactic acid. A muscle that is contracted for a long time will lead to less blood flow to the muscle. Therefore it takes time for the lactic acid to clear. This leads to additional time for the muscle to remove the acid from the body causing pain and irritation to the muscle.

Figure 2 : Muscle size and blood flow


Tendon Injury
Tendons are fibres that join muscles to bones. Diseases of the tendon can happen when we use our arms and legs repeatedly and also working in awkward position. Tendons are usually present in the hands, wrists, shoulder , elbow and forearm. In the hand , the tendon moves in sliding manner surrounded by the covering or sheaths.

Figure 3 – Tendons around fingers and their sheaths


Figure 4 – Tendon and muscle

Due to repetitive work and awkward position , the tendon can get swollen which then makes movement difficult inside the sheath leading to pain and swelling.

Figure 5 : swollen tendon


Nerve Injury

Figure 6 : Carpal tunnel sydrome

Nerves carry instructions from brain for muscles to work. They carry detailed information of touch, sensation, temperature , vibration and pain. Many nerves are surrounded bu muscles, tendons , bones and ligaments. When one has to perform repetitive jobs at awkward positions, the tissues around the nerves become swollen. Swelling around the nerves will press and squeeze the nervous tissue.

Figure 7 : Thickening of tendon sheath pressing upon nerve

Features of WMSD

The most common symptom is pain. Many people will also have redness, stiffness, tightness and swelling in the particular area. Employees also complain of change in skin color, less sweating in palms and pin and needle sensation.

Stages of WMSD

i. Fatigue , feeling uncomfortable, localised pain which is worse while working and better after rest

ii. Continuous , intense pain with numbness and burning sensation. It is worse with work and daily activities . It decreases productivity.

Iii. Continuous , intense pain which is partially relieved by rest. It is linked to reduced muscle strength, swelling, numbness. He or she is less productive or unable to work

iv. Severe continuous pain with suffering . He or she is unable to do any work at all

How to recognize WMSD

1. History of pain

Characterize the symptoms and history
Ꝋ Onset (date; circumstance; abrupt vs. gradual, etc.)
Ꝋ How long do you have pain. How frequent do you have pain
Ꝋ Quality (pain; tingling; numbness; swelling; tenderness, etc.)
Ꝋ Severity of pain (mild; moderate; severe)
Ꝋ Where is the location of the pain
Ꝋ Is the pain spreading elsewhere
Ꝋ Relieving and aggravating factors of pain ( during work and when not working)
Ꝋ Prior treatment

2. Other important considerations

Demographics (e.g., age; gender; hand dominance)
Previous history of any injury of illness of the affected area )
Recreational activities, hobbies, household activities
Occupational history with emphasis on the:
i. job the employee was performing when the symptoms first seen
ii. prior job if the employee recently changed jobs,
iii. amount of time spent on that job,
iv. whether the employee was working elsewhere or part-time jobs

3. Job characterization
4. Medical examination
5. Assessment and diagnosis


Restricting Movement
One of the main approaches to treat WMSD is to stop activities leading to injury. This needs work restrictions. In certain instances, the employee may need to be transferred to a different job or task. Splint is also useful to reduce movements or immobilze an injured area.

Splints are used mainly for two reasons
a. To support a joint mechanically where excessive load is expected
b. To decrease movement of the injured joint

Applying heat or cold compression
Heat or cold compression can relief pain and fasten the healing process
Cold decreases pain and swelling and is beneficial for injuries and inflammation i.e. parts that are swollen, red and warm. Using ice is not common for muscle pain as cold conditions leads to increase in muscle contraction, therefore delaying recovery.

Warm compression is useful to alleviate muscle pain. Heat accelerates the blood flow which in turn decrease the amount of lactic acid accumulated in muscle. Gradually as the lactic acid amount diminishes, muscle pain also improves.


Stretching is a common exercise as it enhances blood circulation and decreases muscle tension. Therefore , people who commonly suffer from WMSD should opt for exercise on a regular basis. This approach should be conducted under the guidance of trained staff (e.g., ergonomist, physical and occupational therapists).

Painkillers are vital to reduce the symptoms via their analgesic and anti-inflammatory effects.. Despite this, painkillers are only used on a need-to-use basis and not routinely. Certain conditions refractory to conventional treatment, local injection of a corticosteroid might be indicated. Adding an anesthetic agent can provide valuable diagnostic information.


An efficient ergonomics and medical management program, hardly warrants surgical intervention . Surgery should be used when medical treatment does not offer improvement.. While certain indications for urgent surgical interventions may still be present (e.g., ulnar artery thrombosis), it is reserved for severe cases (e.g., severe pain leading to functional limitations) not responding to an adequate trial of conservative therapy.


1.Sufficient training for workers, supervisors and managers in prevention principles including health promotion e.g. proper body mechanics, engineering controls, and early anticipation of the features of WMSDs

2. Requirements for employers to institute engineering controls whenever feasible through proactive changes in work and tool design to reduce or eliminate potentially hazardous conditions;

3. Changing work practices and management policies to decrease hazardous situations.

4. Suitable medical management to diagnose and manage WMSDs

5. Appropriate health,medical and hazard surveillance


References :
KARWOWSKI, W. (Ed)., 2001, International Encyclopedia of Ergonomics and Human Factors. (London: Taylor & Francis)



As the name implies, Return to Work (RTW) program is a plan created by a business to aide and
integrate injured workers back to their workplace. The aim is to return employees to their respective
workplace as soon as they are medically and physically fit. A well maintained RTW program provides
benefits to both the employer as well as the employee.

We Provide RTW Services :

Objective of RTW program

  • To aide injured personnel with illnesses or diseases to return to work in a quick and safe manner
  • To perform an employer's social responsibility towards an employee
  • To maintain a supportive and positive working atmosphere by communicating and aiding employees
    with disabilities
  • To decrease the likelihood of repetitive accidents occurring at workplace
  • To decrease the period of disability
  • To accelerate the productivity of employees with disabilities via total replenishment of income
  • Types of plans under RTW
  • Pain management
  • Limb therapy, sensory, speech therapy
  • Physiotherapy , Occupational therapy
  • Work place therapy
  • Job placement
  • Counseling
  • Health education and employee safety
  • Workplace assessment
  • Skills training
  • Employee aide devices and assistance


Hierarchy of RTW
The duration of each person involved in RTW is on case by case basis. Monitoring and coordination i s
usually over a 6 month period to ensure that the affected individual is able to perform the tasks and
maintain the job. Therefore the success of an RTW program is based on the following hierarchy:

  • same job same employer
  • similar job same employer
  • different job same employer
  • same job different employer
  • similar job different employer
  • different job different employer
  • self-employed

Advantages of Return to work program

  1. Advantages to Employer :
    – Maintain experienced workers
    Injured employees that stay at home for a long period of time can become demotivated and
    subsequently resign from their job. Hence employees can keep their valuable staff by motivating them
    to return to work when they are physically able to do so.
    – Decreased turnover
    In certain industries where injuries and accident are common, staff turnover could lead to disruption of
    daily work activities. By supporting and welcoming injured workers to workplace soon enough,
    employers will avoid the cost of recruiting and re-training temporary or permanent new staff.
    – Harmonious relations
    A well planned return to work program implies that the employer as well as the top management show
    empathy and concern regarding its workers and their immediate welfare
    – Improved productivity
    Upon developing an injury or illness, the total workforce of a company will be reduced. On the other
    hand , any company with a successful RTW program will encourage it's workers to return to work
    despite being unable to work at full capacity. This in in contrast to employees who would opt to rest at
    – Keeping costs low
    Employees who return to work after any injury may work full time or part time. This will lead to
    decreased disability benefits as compared to being temporarily unemployed. On the other hand, an
    effective RTW program will lower the worker & compensation costs.
  2. Advantages to Employee :
    – Maintain social relations
    By return to work as soon as their condition permits, a worker can prevent the feeling of social
    deprivation. As soon as they are able to work, they gradually develop a sense of purpose in their daily
    tasks at work.
    – Financial Security
    By implementing a proper RTW program, this enables an injured employee to keep his position in
    the company. This in turn maintains his income, enabling him to fulfill his/ her financial obligations
    – Skill Retention
    Any skill developed at workplace needs to be applied consistently to maintain its worthiness. Similarly,
    an RTW program helps the injured worker retain his/her skills always.
    – Higher self esteem
    Workers develop higher morale regarding the job position and financial security when they are aware
    that their immediate employer will play an important role to enable them to return to work after
    developing an occupational injury.

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