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Musculoskeletal disorders

What is a musculoskeletal disorder?

Back pain, shoulder pain, tendinitis, bursitis, epicondylitis, lumbar sprain and herniated disc are some of the musculoskeletal disorders (MSDs) that workers can develop while doing their work.

Musculoskeletal disorders include all musculoskeletal injuries that affect joints, muscles, tendons, ligaments, cartilage and sometimes nerves. These injuries are usually caused by excessive strain on soft tissues, when the demands of the work exceed the tissues’ ability to adapt.

Musculoskeletal injuries are the most common type of injury in all workplaces. The hands, wrists, elbows, shoulders, neck and back are the most commonly affected parts of the body.

Signs of a musculoskeletal disorder

  • Joint pain (during movement and at rest)
  • Joint discomfort
  • Joint stiffness
  • Localized fatigue (decreased endurance and muscle strength)
  • Reduction in range of motion to the point of inability to move
  • Swelling
  • Numbness
  • Increased tenderness

Musculoskeletal disorders can develop suddenly or gradually. The frequency, intensity and duration of exposure to hazardous work situations influence the significance of the effects of the work on the worker. Early signs of a musculoskeletal disorder must be responded to promptly. Otherwise, the problem may get worse and the worker reduces their chances of achieving a full recovery.

The 3 stages of musculoskeletal disorders
Stage 1  Stage 2 Stage 3 
  • Pain and fatigue during work hours 
  • No symptoms in the evening and after work 
  • Symptoms during work hours 
  • Symptoms persist after work hours 
  • Symptoms persist even at rest 
  • Pain is felt even without making repetitive movements 
  • Pain disturbs sleep 

This condition can last for weeks. It is a reversible condition, that is, the inflammation can resolve completely. 

Pain may wake the worker up at night. This condition can last for months. It is preferable to consult a health professional before reaching stage 3. 

At this stage, musculoskeletal disorders can be irreversible and there is no guaranteed treatment. There is a risk that the pain will become chronic, which is why it is important to consult a health professional as soon as the symptoms are confirmed, that is, in stage 2. 
Prevention of musculoskeletal disorders in the workplace

To prevent the risk of workers’ developing musculoskeletal disorders, employers and those responsible for occupational health and safety must remain vigilant with respect to working conditions. It is important to have effective management in the workplace.

Identify the causes

The first step is to identify the causes of musculoskeletal disorders. To clearly identify the problem to be solved, it is necessary to:

  • recognize the signals the body sends (stiffness, pain, numbness, frequency and severity of symptoms, etc.)
  • make the connection between the discomfort and the work (which task triggers pain, what might be causing the discomfort)
  • determine the constraints imposed by the task (heavy load, rapid pace, vibration, etc.)
  • identify elements that can be modified (share work to reduce intensity, lighten the weight of equipment and loads, rearrange the workplace to shorten reach distances, etc.)

Correct the situation

The second step is to take concrete action to correct situations that involve risks. To do this, it is necessary to:

  • test the solution
  • assess the outcome and make adjustments as necessary

A technical solution (for example, an ergonomic layout) may be combined with administrative measures (for example, alternating tasks appropriately) to achieve the objective.

Control the risk

Controlling means preventing the risk from reappearing. Once the risk has been eliminated or the situation has been corrected, control measures are intended to ensure that the problem is resolved in the long term. Adjustments are made based on the knowledge gained at the correction stage. For example, the employer can:

  • develop a purchasing policy that includes recommendations on the tools or equipment to be purchased
  • update worker training
  • carry out inspections and apply monitoring and control measures
  • regularly check whether the measures used are effective
  • set up an MSD monitoring system

It is important to ensure the corrective measures taken are permanent.

Main risk factors for musculoskeletal disorders

When a job involves a risk of musculoskeletal disorders, the worker or supervisor must be aware of the risk in order to be able to prevent it. Each risk factor can contribute to a greater or lesser extent. Risk factors for musculoskeletal disorders are often combined.

Excessive physical effort

The force applied is one of the main risk factors for musculoskeletal disorders. It is the force deployed by the body to, for example, lift, use or carry an object. Physical force is often required to perform a task, such as open a door, operate a tool or push a cart. Sometimes, significant force is required and the effort becomes excessive. Excessive physical effort is an effort that exceeds the worker's physical capabilities. Lifting, pushing, pulling or carrying a heavy, bulky or unstable load can lead to excessive effort.

Ways to reduce risk

The most effective solution is to eliminate the source of the risk by designing the task better, for example by mechanizing a loading activity that was done manually. When this is not possible, a preferred solution is to use the appropriate material handling equipment for the task and to follow recommendations for safe use to reduce the effort whenever the situation allows.

Unnatural postures

The body position required to perform a task can put excessive strain on joints. Every joint has a neutral or natural posture, where it feels the least amount of strain. It also has an end range of motion or a position where it feels the greatest amount of strain. An awkward posture is therefore a significant risk factor for musculoskeletal disorders.

Often, an unnatural posture is combined with the use of force. In this work situation, 2 risk factors are present (an awkward posture and the use of force) and interact, increasing the strain on the joint.

Ways to reduce risk

The ideal solution lies in the design and organization of the workstation, where possible. Ergonomic workspaces allow workers to perform their tasks in the most natural position possible. This type of solution is even more important when workers have to apply force.

Repetitive movements

Some tasks involve repeating the same movements, which puts significant strain on the parts of the body and the tissues concerned. When the tissues fail to recover, this is referred to as overuse. Repetitive movement, combined with one or more other risk factors, increases the risk of developing a musculoskeletal disorder.

Ways to reduce risk

The most effective solution to this problem lies in the design of the task. Whenever the situation allows, the tasks should be designed or corrected so that the parts of the body used have time to recover.

Exposure to vibration, shock or impact

Workers who use vibrating tools, such as drills, sandblasters, jackhammers and other tools that emit vibrations may be uncomfortable and even develop musculoskeletal disorders, such as hand-arm vibration syndrome. The sensitivity of their hands may also be affected.

Workers who regularly drive a car, truck, tractor or off-road vehicle are also exposed to vibrations that can affect the whole body in the long term. There are seats that neutralize vibration from the vehicle and protect workers.

Ways to reduce risk

The best way to protect yourself is to minimize exposure. • Use well-designed, balanced and well-maintained tools that emit less vibration • Adjust the tool to reduce vibration at the source. • Use a vibration-absorbing handle. • Avoid gripping the handle too tightly. • Wear anti-vibration gloves.
Compression of a body region

Some tasks may expose workers to mechanical compression of soft tissues by a hard object. For example, the sharp edges and right angles of some tools can compress or crush the palm of the hand, the base of the thumb or fingers, and cause injury. The risk increases if they are used repeatedly and if force is applied.

Ways to reduce risk

The solution is to use well-designed tools that do not compress a small area of the hand or body. Tools with padded and rounded handles or those designed to minimize the force that has to be applied are preferable.

Insufficient recovery periods

Some work situations involve long work hours with short rest periods. These recovery periods are not always long enough to allow the tissues involved to recover. Especially if workers are exposed to other risk factors, such as repetitive movements, excessive effort or an unnatural position.

Ways to reduce risk

It is important that these periods of intensive work are brief so that the body has the opportunity to recover. Breaks proportional to the effort should be included to allow recovery. They can last a few seconds in a short repetitive work cycle or several consecutive days in other work situations.

Working in the cold

Working in a refrigerated area such as a meat cutting room, a perishable warehouse, or working outdoors in winter, exposes the body to cold. This exposure can create muscle tension because the body tends to become tense when it is cold. Combined with other risk factors, working in the cold can lead to musculoskeletal injuries.

Ways to reduce risk

To avoid the effects of working in the cold, workers should avoid prolonged exposure, dress warmly and take frequent breaks in heated areas. Workers should replace clothing or gloves that become wet during the workday because humidity conducts cold