Musculoskeletal Disorders in the Workplace. What are the Risk Factors?
It is generally assumed that MSDs such as low back pain, knee, and upper extremity disorders can be attributed to workplace exposures including physical and ergonomic risk factors such as poor body mechanics, repetitive work and use of excessive force, often referred to as “job risk”. Little attention has been paid to the individual or personal risk lifestyle; often referred to as “life risk”. The effect of these life and job risks are not independent of each other, yet they are often handled in the workplace by 2 independent parallel paths, workplace health promotion targeting life risks and occupational health and safety, targeting job risks.
Job risks involve the design and organization of the workplace and include physical risk factors, as well as factors involving work design, like overtime, shift length, etc. There are three primary job risk factors:
- High task repetition. Many work tasks and cycles are repetitive in nature and are frequently controlled by hourly or daily production targets and work processes. High task repetition, when combined with other risks factors such as high force and/or awkward postures, can contribute to the formation of MSD. A job is considered highly repetitive if the cycle time is 30 seconds or less.
- Forceful exertions. Many work tasks require high force loads on the human body. Muscle effort increases in response to high force requirements, increasing associated fatigue which can lead to MSD.
- Repetitive or sustained awkward postures. Awkward postures place excessive force on joints and overload the muscles and tendons around the affected joint. Joints of the body are most efficient when they operate closest to the mid-range motion of the joint. Risk of MSD is increased when joints are worked outside of this mid-range repetitively or for sustained periods of time without adequate rest.
Life risk factors include health-related behaviors both inside and outside the workplace – diet and sleep patterns. Exercise; anxiety levels as well as behavior at work – lifting patterns, hours of computer use, reaching patterns, etc. There are four primary life risk factors:
- Poor work practices. Workers who use poor work practices, body mechanics and lifting techniques are introducing unnecessary risk factors that can contribute to MSDs. Workers who fail to heed the early signs of an MSD (usually mild discomfort) may increase their risk.
- Poor overall health habits. Workers who smoke, are inactive, obese, or exhibit other poor health habits are putting themselves at risk for MSDs and other health issues.
- Poor rest and recovery. MSDs develop when fatigue and discomfort are not matched by rest and recovery. Breaks, task rotation, adequate balancing of home and work activities, adequate sleep – all are helpful in preventing MSDs.
- Poor nutrition, fitness, and hydration. Poor diet and exercise habits put workers at a higher risk of developing musculoskeletal and chronic health problems.
To lessen the burden of MSDs in the workplace, an integrated approach addressing both job and life risks must be implemented.