any good links for how to adjust posture? Like, I've got a fancy "ergonomic" chair, but I know I'm not sitting in it right, because the front of the desk rests on my stomach and I'm pretty much resting my chin on my chest, recliner style. Also, I don't understand your comment about chair height and the 90 degree elbow angle. So, I'm supposed to be at a height where my elbow IS greater than 90 degrees? And my wrist, if anything, should bend what, downwards towards the mouse to keep my tendons from scratching on my bones?
While you ought to
try other postures, etc. the main goal is to sit in the manner that is most comfortable
to you for the longest periods of time.
There are
studies that show that sitting back at around 135 degrees is optimal, rather than up straight. It puts less strain on your spine. Still, look at the guy's neck. That can't be comfortable, so it's going also depend on the chair, and whether other parts of your body are comfortable as well.
I believe that the most ergonomic and proper way to sit is the way that produces the least strain for as many parts of your body as possible. Many "proper" postures, etc. assume a certain set of conditions. Many of those conditions are outdated.
The traditional typing posture, for example, was established in different times. Think about the equipment people were using in when the proper posture for typing was established: hard straight-back chairs without armrests; keyboards that were elevated inches above the surface of the table; transcribing from papers on the desk, rather than other sources. The keyboards, or rather typewriters, were mechanical devices; electric typewriters weren't developed until later. Having your hands raised above the keyboard would give you more ability to use your
arm to push the keys, not your
wrist, reducing strain. It made sense that "proper" posture was important--for that technology.
It's not the 1950s anymore. We've got other options, better equipment, and don't use the same techniques for our technology. For example, nowadays you're supposed to have the keyboard at around waist level, instead of above on your desk. This saves you the effort of elevating your arms, reducing strain. This is possible because you're not requiring to put much force into your typing, and now you've got computer monitors to work with.
The same kind of thing occurs with slouching. My friend works on his computer (laptop) in much the same way you describe, with his back almost completely on the chair, chin to chest, and his legs outwards. Because my friend only uses the laptop, he doesn't need to move his head around, which would require straining his neck. It's comfortable for him because all parts of his body are supported by the chair so he's relaxed.
This may be different for a different situation. To go back to the traditional typing posture, many of those typists were concentrating on transcribing documents. Having a straight back to look down on papers on your desk would be important. These days, however, transcribing is rarely done. Your head is level with your monitor, and it is more important to keep your head level with your screen, not perched above your desk.
I started thinking about this with chairs in general. This was after my legs would fall asleep on longer flights. What makes a chair comfortable to sit on for long periods of time? The answer came to me: evenly distributed pressure. Distributing the pressure ensures that individual parts of your sitting body (butt, lower thighs, back, neck, etc.) don't individually have their circulation cut off and start hurting. When typing, it's not so much important to have your knees bent at 90 degrees, but rather finding that balance that prevents your legs from cutting off circulation, while also not causing too much angled pressure on your lower legs.
All this will depend quite a bit on what your furniture can do for you as well. If you have a chair that can support your lower back while slouched, as well as your neck, maybe 135 degrees is the best angle. If you're in some chair that doesn't support your back, you'll need to sit up straight.
We've got so many ergonomic technologies at our disposal. Rather than be forced into some posture, why not adapt your furniture to suit the way you work? There's no one-true-way to sitting comfortably. The important thing is that you're aware of what makes you comfortable, and can make adjustments to
become comfortable.
