Ergonomics - gravity economics (my definition)
or.. How to Sit!

There couldn't be a week long event of computer workshops without a bit of training in how to SIT behind (that is in front of) the computer. If only to make it possible to sustain MORE hours in this symbiotic machine relation!

This list of rules and suggestions that follows might seem complicated and a bit cramped but it all makes sense if you keep in mind some basic knowledge about gravity. If you were to pile a stack of wooden blocks (or books as in our example here at the ITC carnival), in order to make the pile more stable you would intuitively put the books neatly on top of each other so that the lower ones would support the ones on top. (If you wouldn't do this, the books on top would slide off the pile to either side.)

Our body works by the same principle, where the main task is to support the heavy head. This is a tricky one, specially when typing and staring onto the screen and we have to pay attention to how to position the spine in order to support the head without too much effort. And whatever ergonomic gadgets like split keyboards, palm rests or mouse pens there are available for work relief, the best prevention is to have a correct posture and typing technique and good work habits.

Sit Bones
A correct posture starts with a good sitting base, that is
to be evenly positioned on top of the two sit bones in the
pelvis. No more left than right or in front or behind.
Roll a bit to the sides to find a good balance. The only
way to sit rightly on top of the sit bones is to have both
feet on the ground, with the knees in a slightly more than
90 degrees position. Notice the difference if you put the
feet backwards under the chair (you roll in front of the
sit bones) or stretch the legs out (you lean somewhere
behind the sit bones). If you don't reach down (and your
legs therefore hang towards the back) you can put
something to put your feet on.

Lower back
To keep the spine on top of this base you have just
established, you need to work slightly with your lower
back and belly muscles. This can seem hard at first,
especially if you are not used to this posture, but you
gain enough strength pretty quickly if you practice the
posture every day. It is not a matter if sitting with a
fully contracted belly, that would be exhausting and is
also not very healthy. There should be only a slight
tension in the lower muscles of the belly. For the back,
you find the muscles you need to hold yourself with by
raising your (bent) arms to the sides (elbows straight out
from the body, shoulder level and hands up). Notice which
back muscles you are using. Now lower the arms slowly
(still bent with hands up) until the arms hang but keep
the tension in those back muscles. This is how you should
hold yourself straight up from now on!

Shoulders
Most physical complains from computer work establish
themselves as stiffness or pains in the shoulders. If your
spine is not supported from the base and by the muscles
mentioned above, the shoulders have to do all the work of
holding the head. This is where the tension comes from.
But if your spine is already supported from below, your
shoulders can relax in a position vertically on top of the
spine and fall (relax) with the gravity that pulls them down.

Head
Now you have created a pillar on which the head could
rest. To find the perfect position for your head, place
your fist under the chin. It should be neither squeezed
nor have to much space, just perfectly fit under the chin.
That way the head is not hanging forward or putting
pressure on the spine to the back. To keep your head in
this position while working, you need to put the screen at
a hight where you don't have to look down (like on a
laptop) or up on it. A solution for the laptop is to put
it on a box of sufficient hight and use an external
keyboard and mouse. It is also useful to learn to type
without having to look at the keys, then you don't need to
look down all the time.

Tongue
Most of us keep the tongue pressed towards the top of the
mouth. This is unnecessary work. If you can train yourself
to keep the tongue leaning on the bottom of the mouth,
this is a much more relaxed state and releases tension in
the face and neck. (This might require some time of being
conscious about where the tongue is but eventually it will
change position automatically.)

Arms
The most natural position for the arms is to fall down to
the earth. The least effort for the shoulders is to
maintain this as much possible, thus you need to work in a
way where you don't raise your arms or shoulders but just
bend the elbows, in a straight angle. (Adjust the table
hight if necessary and possible.)

Hands & Wrists
With the elbows bent, you should be able to reach your
keyboard. Thus, you need to sit close enough where you
don't need to bend forward with the whole body. (If you do
need to bend forward, you should do that using the belly
and the back muscles, not by bending the shoulders.) The
keyboard should be a little lower than your wrists so you
can type with your fingers downwards, avoiding bending the
wrist in any direction. Many desktop computers have
keyboards that are higher in the back, but this easily
forces the wrist bending upwards, which blocks blood
circulation to the hand. Also leaning the wrists on the
table results in this awkward bend and should be avoided.
Best is to hold the hands in the air and type downwards
(requires some muscles in the arms but this is easily
built up over time). If the table is too high to permit
this, you may do better to put the keyboard in your lap.
To hit different keys, your arms should move your hands
around instead of stretching the fingers.

There is no point in trying to sit in this posture if it becomes a cramped and hated exercise. Take it easy in the beginning and allow the muscles to develop at their own pace...but don't give up and remember the gravity. It may seem and feel as if the slouching position we generally and too easily fall back into is the more relaxing one. But actually, when any part of our upper body falls off "the pillar", it will automatically be weighed down by gravity and the body has to work hard and compensate with other muscles only to keep you from falling. If you then start working in this already tense and stretched condition, you easily over-stress your muscles (which is when people get permanent muscle damage and pains). To sit in the pillar shape, with straight back and head, is the position that requires the least effort to maintain.

Anything that creates awkward angles in the body will create similar problems. For example to sit in the typical position with one leg over the other creates an in-balance to the side which needs to be compensated and can cause long-term problems. Best is to work with everything as evenly as possible, for example put the mouse in front of you instead of to the sides so you can keep and move both arms in a straight position in front.

Please note that even a "perfect" posture may result in problems if it is held rigidly for long periods of time: relax, MOVE and shift positions frequently. A muscle that has worked for 2 hours needs something like 45 minutes to relax back to its original resting level, because the tension from working has reached deeper. If you relax your muscles more often, the relaxing period can be shortened. Recommended is to take lots of micro breaks (say 10 seconds every 5 minutes) and some longer breaks in between (15 minutes every hour or 30 minutes every two hours).

A break is something where you do something different with your muscles. Meaning, you do not necessarily need to stop working, just do some other tasks for a while...move around or look at some papers, talk to a colleague, get a coffee or something. This is also a good moment to relax your eyes, by looking at a different distance than the screen. (Gaze towards the furthest upper corner of the room from time to time.) A minimum is to move the hands away from the keyboard, let them hang for a bit!

Exercises
You can also use the breaks to do some stretching exercises.
A number of exercises and other practical suggestions can
be found on the R.S.I. page

R.S.I. stands for Repetitive Strain Injury which is a condition you can end up with if you don't follow the suggestions above and continue to work in various painful and constraining ways. There are lots of information about R.S.I. and how to avoid it on the internet.