HCI VISTAS, VOLUME-II, 2005-2006

  

Human and Computer in Traction: The Grand Challenge of Posture Design

Dr. Dinesh S. Katre

Article IRN-5./Nov. 2005
   

 
The Human and Computer:
That day, though I was having slight cold and fever, I was about to leave for office and suddenly I sneezed with the force of supersonic jet. The jolt of sneeze gave me acute pain in my back and before I could realize what had happened, I collapsed on floor. I was deeply in pain and not in position to get up. The waist mussels had become stiff and were in severe spasm. Finally, my wife and neighbors had to carry me to an orthopedic hospital. The doctor immediately guessed what had happened to me the moment I told him that I work in Information Technology (IT). My vertebral column had crumbled due to extended hours of working on computer for the past 13 years. IT is also flourishing orthopedic doctors by creating patients like me with back problems. I suspect whether the developed countries are outsourcing their Back Pain or Business Processes?
 
  
           So is it Back Pain Outsourcing or Business Process Outsourcing (BPO)?
  
The Traction:
The doctor kept me on a slanting bed. The traction belts were tied to my waist with 25kg of weight. I was asked to be on traction for at least one week. I was given several injections alternately in my both hands, pain killer tablets, Short Wave Diathermy (SWD) repeatedly. On the third day, they took me for MRI scanning. The doctor studied my MRI Scan Reports and told me with a serious face that I am sitting on a bomb! He said that the disc between L4 and L5 had slipped and desiccated. The lumber lordosis (the curved shape of vertebral column in the waist area) had lost its original shape due to sitting in front of computer. The doctor gave me a prolonged sermon on how drastically I needed to change my lifestyle and working habits.
 
The Physical Posture:
The gravity of problem forced me study designs of various chairs I used in the house, office, airports and the seating arrangement in the car. The slipped disk taught me the real meaning of physiological ergonomics. I began to introspect about what was wrong with my working habits. The computer activity involves four key elements such as human (user), physical posture (sitting in chair), supporting structure (furniture like chair and table) and the object of task (computer). 
  
I realized that the design of computer system (the typical tabletop monitor and CPU cabinet) presupposes that the user would be sitting in chair, which is at the root of problem. If one is expected to work with a gadget like computer for 8 to 12 hours every day, what kind of physical posture or more precisely "Aasan" (in Sanskrit language) should you recommend? Isn't it obvious that the vertebral column in lumber area would crumble as it has to take the load of upper body and keep itself erect against the force of gravity.
 
The Sanganak (Computer) Aasan:
Therefore, my proposal is that Yogic and Ergonomic experts should first identify the Sanganak Aasan (I can help you with it as the sufferer knows where the chair pinches!) and then the suitable furniture and computer system could be designed to suit the posture. The 'chair sitting posture' seems to be the default preference of westerners for all kinds of activities. Even the dining and toilet activities are performed in the chair sitting posture. Their knowledge of physical postures seems to be confined to sitting, sleeping and standing. Whereas, ancient Indians have thoughtfully designed different postures for different tasks and objectives. One can study the innumerable physical postures introduced in Yoga, Kaamsutra, Bharatnatyam, Suryanamaskara and Religious rituals.
 
The Grand Challenge:
All chair designers and ergonomic experts can appreciate that the real problem is the 'sitting posture' of computer users and not the design of chair. In my personal assessment, chair sitting is suitable for short duration (2/3 hours with some intervals) but completely hazardous for longer duration (8/10 hours or more). The waist mussels are unable to bear the load on lumber vertebrae for long duration and as a result one starts bending forward. So-called ergonomic chairs, which I have seen so far, provide cushions and supports for the back. Providing supports to strengthen the sitting posture is like the 'Bamboo' supports given to a crumbling old building. It is bound to crumble sooner or later.
 
Therefore the real design issues are in the following serial order:
  
1. Physical posture (Sanganak Aasan) that does not strain the vertebral column even after working for 8 to 10 hours.
2. Supporting structure (Furniture) that can take load of the body and reduce the tension on mussels.
3. Object of task (Computer System) that can suit with the Sanganak Aasan and Furniture.
   
Sanganak Aasan is an original idea conceived by the author of this article. If interested in developing it further pls. write to the author. 
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Perspectives
Hope you are doing better - just read your article today. Back problems are really bad - you should take care.

Some comments on your article:

I am not sure if the problem is of the Asana or the posture. I would rather pin the blame on the extended duration of holding the same position for many hours at a stretch. Add to it the element of Repetitive Micro-movements, and the problem is compounded. I have previously thought that the typical position utilized by the astronauts would be perfect for the Workstation design (as well as in any journey that extends beyond 2 to 3 hours. Undoubtedly, this would work to an extent. There is no other position that takes the weight off the vertebral column - every other position will always exert a component of the gravitational force on the vertebral column. With micro-movements, what happens is this - the discs between the vertebrae are meant to take the friction between two vertebrae. When we sit in front of the PC, or any desk job, the vertebrae do not move that much - they keep moving in very tiny movements at the same place - this gives a grinding effect, rather than a distributed friction. Hence, the discs tend to degenerate.

This is more pronounced in long drives (especially over bumpy roads) - vibration enhances the Grinding effect and bumps at a force to the grinding. So, essentially one is grinding the inter-vertebral discs thinning them, or deforming them in the same places - slowly and surely. The result is predictable. This will happen, no matter what position you adopt (other than the astronaut position, in which one is really lying on one's back, thereby relieving the back of all stress) Therefore, it makes sense to keep changing one's position all the time - unless the boss configures an astronaut workstation (whether PC or similar desk job. The IT angle to this problem is, again, redundant! There are very few new, original problems - its all the same stuff in new packaging) for you, with the monitor towards the ceiling, keyboard placed almost vertically. The main problem with the astronaut position is, of course, its very easy to fall asleep, especially after a nice lunch :) Productivity would plummet, while back-aches would reduce. Hmmm...no - I  don't think the IT world is going to take to Astronaut chairs anytime soon.

I'd say - the sanganak-Asana would simply consist of sitting as you like in a chair with lumbar support, but constantly changing the position of the spine as you work - added to getting up every 20 minutes, and moving around. Especially, the neck must be continually moved around, since the neck gets more Repetitive Micromovements while looking at a monitor.

Pankaj Sapkal (Industrial Designer, Remote 3D)