Our ability to work – in any way – is completely dependent on our physical health. When we feel unease, discomfort, pain or numbness, we may be able to ignore the body’s warning signals and still perform work, but the body will perform slower; with less power, quality and precision; with more errors; and at worst, resulting in serious accidents. A very real problem that is faced by all productio industry is when the limit has been passed for what a human body can tolerate, resulting in a worke needing to go on sick leave, i.e. be absent from work to recover from physical disability. If the disability affects the worker’s physical ability to move and handle loading, then the worker is said to be suffering from a work-related musculo-skeletal disorder (abbreviated either as WMSD or just MSD). MSDs are defined as a heterogeneous group of disorders caused by a multitude of potential (physical) factors. Pain, discomfort and fatigue are considered common first symptoms, while more obvious signs of the presence of an MSD include loss of function, limited movement range and loss of muscle power.
1. The costs of a worker taking sick leave can balloon to huge proportions: not only does the employer in many cases need to cover the worker’s sick leave compensation and rehabilitation costs, but there are also the costs of recruitment, training of new personnel and losses of productivity and quality until a new employee has reached the previous worker’s level of skill, competence and speed . All in all, losing valuable, experienced staff due to an unnecessary physical disability is a terrible waste that can be avoided in two steps:
1. Evaluating ergonomic risks
2. Designing workplaces that lessen the strain on the human body
Some potential causes of musculo-skeletal injuries are related to biological and lifestyle characteristicsof individuals, and are therefore difficult to anticipate or do anything about using design. Biological and lifestyle-related factors influencing MSDs. However, work-related MSD causes are possible for an engineer to avoid and are therefore the most interesting ones to identify quickly. Engineers with knowledge of ergonomics should design work and workplaces to minimize the adverse risks of the following:
• forced working postures
• load weight
• static work
• continuous loading of tissue structures
• repetitive working tasks
• time pressure/lack of recovery time
• working technique
• working attitude
• demotivation, stress
MSDs are the work-related health problem with the highest impact on sickness absenteeism in Europe; they are the cause of half of all absences from work and cost the EU €240 billion each yearin productivity losses (Fit for Work Europe 2013). MSDs are also the work-related health problem with the highest impact on permanent incapacity; 61% of permanent incapacity is due to MSDs (OSHA 2007). Forty-four million workers across the EU have an MSD caused by their work, 30% of those with MSDs also have depression, making it even more difficult for them to stay in or return to work (Bevan 2013). Typically the back tends to be the most commonly affected area of thebody ( Figure 2.1); 80% of all adults have back pain some time in their working life and 30% of sickleave cases in Sweden are due to back pain (many young people) (Palmer, 2000). Blue-collar workers are at the highest risk for contracting an MSD, with almost 20 times as many employees experiencing an MSD compared to white-collar employees. Of these workers, those involved in manual labour such as trade workers, plant and machine operators and assemblers, are at the highest risk (OSHA 2007).