Ergonomics and my home ergonomic chair


Today, I decided to do something on the chair that I have been using for about 6 years now (circa 2014 when I retired from government service at age 65) in my house whenever I do computer work.   I have been occupying the room of my son for my homework table as he has been out of the house because of his study and work at the University of the Philippines College of Medicine and lately, Philippine General Hospital. I have been using what commercial store call ” Office Chair Desk Ergonomic Swivel Executive Adjustable Task Computer High Back Chair.”  Initially, for so many years, I could adjust the height of the chair.  Lately, for the past one to two years, I couldn’t anymore.  It got stuck up to a low height.  I have been noticing discomfort and stiffness on my legs and knees since then whenever I would get off from the chair.  I tried remedying the situation by getting off the chair every hour and not staying sitting down for 2 hours or more.  Since I have been having a hard time making a break (standing up) after each hour of computering, I decided last week to change my chair.  I got hold of an old wooden chair with a good height.  However, I could not move freely as there is no swivel (rotation); there are no wheels on the chair; and there is no soft sitting cushion and back rest.

Today, I decided to make another try at my old “Office Chair Desk Ergonomic Swivel Executive Adjustable Task Computer High Back Chair.”  With some maneuvers, trial and error, I was fortunate and happy at that to see the chair being able to be moved to a higher height again.  However, when I sit on it, it goes down to a low height.  I decided to find an improvised way of putting a wedge to prevent the chair from going down to a lower height.  Fortunately, I was able to find and use two pieces of high-density polyethylene tubes for the wedge.  These tubes were remnants of the project which our friend, May Lim, tried to make an improvised wheelchair for our dog, Jhun-Jhun Bato, who passed away last April 18, 2019.

This is the improved chair that I will be using from hereon.  Hope I will be able to use it for the next 5 years or more. (ROJoson@70to75 – 2019to2024).

It is now an “ergonomic” chair for me.

In the process of fixing my chair, I learned these things today:

Ergonomics (or human factors) is the scientific discipline concerned with the understanding of interactions among humans and other elements of a system, and the profession that applies theory, principles, data and methods to design in order to optimize human well-being and overall system performance.

The word ergonomics comes from the Greek word “ergon” which means work and “nomos” which means laws. It’s essentially the “laws of work” or “science of work”. Good ergonomic design removes incompatibilities between the work and the worker and creates the optimal work environment.

How do I adjust a chair for my height?


  • Stand in front of the chair. Adjust the height so the highest point of the seat, (when in the horizontal position), is just below the knee cap.


  • Sit on the chair and keep your feet flat on the floor.
  • Check that the clearance between the front edge of the seat and the lower part of the legs (your calves) fits a clenched fist (about 5 cm or 2 inches).


  • Adjust the back rest forwards and backwards as well as up and down so that it fits the hollow in your lower back.
  • Sit upright with your arms hanging loosely by your sides. Bend your elbows at about a right angle (90 degrees) and adjust the armrest(s) height until they barely touch the undersides of the elbows.
  • Remove the armrests from the chair if this level can not be achieved or if armrests, in their lowest adjustment, elevate your elbows even slightly.


  • Tilt the seat itself forwards or backwards if you prefer.


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