“Fitting the Person to the Task Not the Task to the Person”

This could be considered to be the “tagline” of ergonomics.  What the science of ergonomics aims to do is to make sure that the work that people do is changed to fit them, not the other way around.  The most effective way to do this is to make sure that everything that can be adjustable, is adjustable.  Take for instance, an office worker:

  • The office chair needs to be adjustable in height, depth, amount of back support, angle, and more (see previous posts);
  • The keyboard and mouse heights need to be adjustable to accommodate 90 degrees of flexion at the elbows;
  • The monitor height needs to be adjustable to accommodate proper height;
  • The hard copy needs to have an adjustable height to avoid neck flexion and rotation.

And for an assembly line worker:

  • The conveyor belt or other surface needs to be height adjustable to accommodate workers of all heights to reduce awkward postures in the neck, shoulders and back;
  • The tools needs to have proper sized grips to accommodate all hand sizes to reduce hand, wrist and arm awkward postures;
  • The tasks need to be rotated throughout the line so that the same types of tasks are not performed all day resulting in repetition and overuse;
  • Any heavier lifting needs to be assisted with a lift or table or an alternate way to transport must be found.

If workers are made to fit into a workstation or work area without any opportunity to adjust it to fit their bodies, discomfort and injuries are likely to ensue.  The worker is the most important part of the process – their comfort and abilities must be considered first.

Advertisements

Ergonomics and Feng Shui

This is a question I was asked recently:  how is ergonomics different from feng shui?  There is quite a difference as I will explain below.

Wikipedia defines feng shui as “an ancient Chinese system of aesthetics believed to use the laws of both Heaven and Earth to help improve one’s life by receiving positive qi”.  Western feng shui has come to be associated with designing one’s home and/or office to block negative energy and allow qi to flow for balance and harmony.  For example, some feng shui tips state that one’s desk should not be facing the door, and that water should be represented to promote energy flow.

Ergonomics comes from two Greek words:  ergos meaning work, and nomos meaning natural laws.  It is the science of ensuring the worker fits to his/her tasks and tools with minimum biomechanical and physiological stress.  For example, ensuring workers have fully adjustable chairs to fit their bodies, ensuring workers have lightweight, adjustable tools for assembly work, ensuring workers do not experience heat stress working in hot environments for too long, and changing work practices to reduce risk factors such as repetition and force.

In a nutshell, Feng shui uses the elements, colors, and furniture placement to improve the workplace, where ergonomics uses a change in equipment, tools, and work practices to improve the workplace.  Feng shui may help people increase harmony and balance in their lives, but it has not been scientifically proven.  Ergonomics has been scientifically proven to reduce the risk of injury.

Essential Office Chair Features – Part VII

13.  Lumbar support

  • Many chair backrests do not have lumbar support.  Lumbar support is found in the lower part of the backrest and is usually a small rounded-out area in the padding.
  • When there is no lumbar support, the natural curve of the spine straightens when in a seated position.  Prolonged sitting with a straight lumbar spine affects the proper alignment of the vertebrae and discs and in turn can possibly cause discomfort and strain.
  • The backrest should have adequate padding to provide lumbar support.

14.  Lumbar support adjustment

  • Many lumbar supports cannot be raised or lowered and/or the amount of padding cannot be increased or decreased.
  • When the lumbar support can’t be adjusted, it is difficult to achieve the proper natural curve of the spine because each person requires differing amounts of support.
  • The backrest should raise and lower, and the amount of lumbar support should be adjustable either with a crank mechanism or an air pocket system.

Essential Office Chair Features – Part VI

11.  Arm rest height adjustment

  • Some chairs do not have height adjustable arm rests, and if they do, the arm rests rarely lower enough.
  • If the arm rests do not lower, or do not lower enough, the arm rests block the employee from pulling their chair all the way into the desk when using a keyboard tray.  As a result, the employees sit forward in their chair in a “perched” position and do not use their back rest for support.
  • Additionally if the arm rests do not lower enough, the employee tends to rest their elbows/forearms on the arm rests too frequently.  Pressure placed on the forearm and elbow can result in compression discomfort and possibly injury.
  • The arm rests must lower to at least 5” above the seat pan.

12.  Arm rest width adjustment

  • Many chairs do not have width adjustable arm rests.
  • If the arm rests do not widen enough, the employee tends to rest their elbows/forearms on the arm rests too frequently (see above)
  • The arm rests must widen up to 2” out from the seat pan.

Essential Office Chair Features – Part V

9.   Backrest height adjustment

  • Many chairs have backrests that are fixed and do not raise or lower.
  • When the backrest is not height adjustable, the lumbar support cannot be placed at the proper height on the employee’s back.  Without lumbar support, the vertebrae and discs of the back do not stack properly on top of each other, increasing risk for stress and strain of tissues.
  • The backrest must be fully adjustable in height within a range of at least 5”.

10.  Backrest height adjustment with proper lock

  • Some chairs have height adjustment that is supposed to lock the backrest in place, but the mechanism is faulty and the backrest slides down (e.g. chairs where you lift the backrest up and it is supposed to stay up on its own)
  • When the backrest does not lock properly, the lumbar support cannot be placed at the proper height on the employee’s back resulting in problems as described above.
  • The backrest must have a locking lever (a knob can be substituted, but it requires extra force to tighten and can loosen with wear).