October 24, 2007: How to Sit in a Chair

Hi everyone,

I have been having this problem for almost a year - upper back and shoulder tension after sitting for 30 minutes or so. It is not so painful but it does makes me feel uncomfortable. I always end up going for massage when it becomes unbearable. (shhh, isn't that a good excuse to be pamphered by 1 hour body massage? )

Lately I have been reading and collecting facts of why's and how's, the do's and the don't regarding 'how to sit in a chair'!

Do you know that when we sit it is harder on back then standing? This is because when we stand the spine is in a state called 'lordosis' - with pressure evenly distributed along the 24 vertebrae of our backbone. Blood flow along the spine is free and unobstructed. When we bend our body at a right angle in sitting, we flatten the lumbar (lower section) of our back. This causes a state called kyphosis, or uneven pressure on the disks in our back. This state strains the muscles in that area and causes lower back pain.

Most people think our backbone supports our body. It doesn't. Our body actually supports our backbone. Our back's 24 vertebrae and its jelly-like disks offer us flexibility, but not much strength.

The less we move while sitting, the less our bodies are able to supply parts of our bodies with vital nutrients. When our lumbar area is nutrient-deprived, those fluids-filled disks harden. As they become less flexible, our body is more vulnerable to injuries caused by motion. And sitting incorrectly, essentially crunching our lumbar area, will gradually erode the disks in our back over time.

The best bet for our bodies is to maintain lordosis, which helps make sure that nutrients can reach vital areas of our spine. Sitting for just 20 minutes can so reduce the flow of nutrients to our disks that they begin to harden (errrrrr, Honey .... from now on we must take 5 minutes break after 20 minutes webcam session ). So, if our chair is too soft and fluffy, our body doesn't really move much. It's almost like being encased in a foam-rubber body cast. No movement. No nutrients. And our disks pay the price.

So, the goal is to continually allow our muscles and bones to find the most stable, most healthy position as easily as possible.

Below are tips from Neutral Posture Ergonomics, work for just about anyone. An ounce of "adjustment consciousness" can protect our body from long term stress injuries.

I hope you find it useful!

Love - Larra

If you experience this problem	Caused by:	Try this:
Neck tension, tightness, upper back and shoulders tension.	Head too far forward while you type or view your monitor	Elevate your monitor so your head and trunk relationship is more vertical.
	Hands and arms not supported while keyboarding.	Adjust the chair's armrests. Note: ideally ergonomic professionals suggest not resting arms while keyboarding. However in the "real world" we recognize this is often done.
	Head is too far back during monitor viewing.	Tilt the seat and backrest forward so as to keep the head and trunk relationship more vertical.
Hand, wrist and lower arm discomfort	The wrist is deviated (turned) in an unnatural position.	Set the keyboard or calculator to produce a neutral (straight) position.
	Excessive application of force to the keys	Train yourself to reduce excessive keystroke force. Excessive force is not needed or efficient.
Lower back pain discomfort.	Lumbar curvature is not being maintained or supported.	Bring your chair's backrest in closer to your back, tilt it forward, or change your lumbar support by increasing or decreasing the air pressure on the chair's air lumbar support (if you have this.). The backrest should be placed just above the pelvis to provide lower back region support.
	The major thigh muscle is pulling on the spine because your feet are dangling or unsupported.	Lower your chair and or use a footrest so that the feet support both their own weight and the weight of the lower legs only.
	Increased disc pressure because vertebrae do not have equidistance spacing. This results in stretching the muscle, tendon and ligament system.	Open up trunk/thigh angle towards the neutral position.
Buttock discomfort	Sitting too far forward in the seat pan and not using the footrest.	Sit deeper in the chair. It may be necessary to adjust the backrest by tilting the angle.
	Pressure is too great on the buttock/ischial tuberosities (the bony parts of the pelvis where we sit on.	Raise the chair height and increase the pressure naturally for the thigh. Back of the thighs should touch the seat pan.
Thigh discomfort	Too much pressure on the thigh because the chair is too high and legs are dangling	Lower chair height so the feet support themselves and the lower legs only.
	Too much pressure on the popliteal area (the soft tissue area behind the knee) from the seat pan.	Sit further forward in the seat pan and adjust backrest further forward.
Lower leg/foot discomfort	Too much pressure in the popliteal area (soft tissue behind the knee) from the seat pan so that circulation is restricted to the lower leg and feet. This puts pressure on the nerves to the lower legs and feet.	Sit further forward in the seat pan and adjust the backrest further forward.
	Infrequent posture changes in the feet and lower legs.	Utilize a well designed footrest to promote movement and frequent posture changes.