From a physical point of view, having a basic understanding of the human body’s strengths, abilities, and limitations is an important basis for making well thought-out tweaks to the design of the workplace, in order to build work systems that are not a risk to huma health or performance. Knowing how your muscles, bones and joints work may seem like a far cry from your engineering work, but it will significantly help your understanding in later chapters where physical loading and methods of ergonomics evaluation are discussed. Another thing this chapter does, is to provide a limited description of anatomy and physiology; it will not go into as much detail as an anatomy book, but provides the level of detail needed to understand some of the methods that will be explained later.
If you as an engineer start using ergonomics evaluation methods without first gaining the knowledge in this chapter, the reasoning that those methods are based on would probably remain a mystery. You could still use them, but if you were questioned about their limitations or why you were Using them, you would probably not be able to explain their validity, or reason about unexpected results. Knowing about the human body and its strongest and weakest positions can also encourage even an engineer to adopt more healthy movement, posture, loading and sitting behaviours in their everyday life – and that awareness is the best basis for becoming a great workplace designer.
WHICH ROLES BENEFIT FROM THIS KNOWLEDGE?
The engineer who acts as system performance improver or work environment/ safety specialist is likely to observe and analyze actual physical work being performed, before making a recommendation or a design proposal. With knowledge of how the human body functions optimally and how it is limited in strength, stamina and injury recovery, the engineer can avoid building potential risks for MSDs (musculo-skeletal disorders) into the work system.
These roles may also interact with workers who complain in an imprecise manner about pain or discomfort, or with medical or health personnel who are not trained in using ergonomics evaluation methods to evaluate risks. With basic knowledge of anatomy and physiology, the engineer can communicate Effectively with these stakeholders about risks and possible solutions.
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 production industry is when the limit has been passed for what a human body can tolerate, resulting in a worker 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.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 (see chapter 11). 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
• Descriptions of how the different structures of the musculo-skeletal system are shaped (anatomy)
and how they work and respond to loading (physiology).
• A description of current injury statistics regarding musculo-skeletal disorders and how big the
problem is for production industry.