FAQs about MSDsAnswers to the most frequently asked questions about musculoskeletal disorders.
Musculoskeletal disorders (MSDs) are injuries of the muscles, nerves, tendons, ligaments, joints, cartilage, or spinal discs. MSDs are not typically the result of any instantaneous or acute event (such as a slip, trip, or fall) but reflect a more gradual or chronic development.
Medical terms used to describe MSDs to various parts of the body include low back pain, tendinitis, bursitis, carpal tunnel syndrome, epicondylitis, trigger finger, thoracic outlet syndrome, carpet layers' knee, and degenerative disc disease.
The following are recognized as important risk factors, especially when they occur at high levels and in combination.
Force is the amount of effort required to perform a task or job. The amount of force one can exert depends on one's posture and the number of exertions performed. The more force that is exerted, the greater the stress on the body. Lifting, pushing, pulling, and gripping a tool are examples of activities that require exerting force or muscle effort.
Movements performed over and over are described as repetitive movements. But a repetitive movement can also be an awkward posture held for long periods of time. These movements can be of risk to the worker because of continual stress placed on one body part without sufficient muscle recovery time. Nailing a deck, screwing drywall, and tying rebar are examples of repetitive tasks.
Postures are the positions of body parts. Unnatural positions or awkward postures are those in which joints are held or moved away from the body's natural position. The closer the joint is to its end of range of motion (for instance, bending the back forward as far as possible), the greater the stress placed on the soft tissues of that joint, such as muscles, nerves, and tendons.
Chance of injury increases when two or more MSD risk factors combine in one job. One factor alone is unlikely to cause a high risk of injury. For example, performing a forceful lift once places a worker at less risk than performing a forceful lift several times an hour.
Two approaches are widely accepted for controlling workplace ergonomic hazards.
These are measures taken to modify the forcefulness, repetitiveness, awkwardness, vibration levels, physical pressures, or environmental extremes connected with a particular job. Engineering controls are the preferred approach in preventing MSDs. Examples include modifications of 1) the workstation layout, 2) selection and use of tools, 3) work materials, and 4) work methods.
Administrative controls are management-directed work practices and policies. Administrative control strategies include 1) changes in job rules and procedures such as scheduling more rest breaks, 2) rotating workers through jobs that are physically tiring, and 3) training workers to recognize ergonomic risk factors and to learn techniques for reducing stress and strain while performing their job. Although engineering controls are preferred, administrative controls can be helpful as temporary measures until engineering controls can be implemented or when engineering controls are not technically feasible. Since administrative controls do not eliminate hazards, the necessary precautions and safeguards must be followed. Interventions to control MSDs can range from the simple to the elaborate. Modifications to existing design can be costly, but in many circumstances the interventions can save time and money.
The following are examples of engineering and administrative controls aimed at reducing MSDs in construction.
Manual handling of tools and material
