Many of us spend hours sitting at a desk each day. If we have the wrong posture this can put a lot of pressure on our spine. Here are a couple of videos to show the correct sitting posture.
This first one is a short - 39 sec - simple video showing the correct, relaxed sitting posture.
This second one is by an Alexander Technique teacher, who demonstrates with a a model skeleton, so you can see what your bones are doing. This is a longer 9 minute video.
Postural dysfunction can occur anytime good sitting posture is ignored. When we sit in a position that can be considered "poor", then ligaments in the lower back can get stretched out and weak. It may also cause a distortion of the lumbar discs between your vertebrae.
Good sitting posture can be described as:
1. Your head should be directly in line with your neck. Having your chin tucked in slightly. Keep the ears over the shoulders.
2. Both shoulders should be level.
3. The middle of your back should be straight.
4. The hips should be in line with the shoulders and the ankles should be in line with the hips.
5. When sitting the hips and knees should both be at 90 degree angles.
6. Maintain a natural curve in the low back (referred to as your lordosis).
At first, trying to maintain a proper sitting posture can seem like quite a bit of work. But if practiced regularly for about six weeks, you will notice improved endurance and greater ease in sitting.
I would add to good sitting posture that your gluts should be slightly higher than your knees. Whenever your gluts are lower than your knees, it increases the lordotic curve in your lumbar spine and it also creates a shortening to the hip flexors. The combination of those two things results in lower back pain. The more lordotic your lumbar curve is, the more likely it is that you will have a forward head, rounded shoulders and thoracic or middle back pain. It is ideal if you can change the configurations of your chair to accommodate your body shape and size.
I must respectfully disagree with Martin. As your lordosis increases, it is more likely that your shoulders and head will be thrust backwards, and not forward. A slumped posture might actually cause a forward head and/or rounded shoulders. Just look at the first video above entitled "sitting posture" and you will see this is the case.
And I am not so sure having your glutes lower than your knees will bring you into a greater lordosis either? It is likely that if your glutes are lower than your knees that the pelvis will be tilted backwards, like that of spinal flexion.
It seems to me, sitting with and maintaining your natural lordosis during prolonged sitting postures is essential for good spinal health.
Not looking to be disagreeable but Martin's advice is probably not sound advice.
Tommy, I did look at the video above, but it does not address the issue I was bringing up. My point was that when a seating surface creates a scenario in which the gluts are lower than your knees, that is not good sitting posture. I stand corrected in that your lordotic curve does not increase, rather its your thoracic spine that becomes more rounded. I disagree with you in that if you are siitting in a a seat or sofa that is soft and it makes your knees higher than your gluts, your shoulders and head will not thrust backwards. The oppostie will happen, your shoulders will round and your posture becomes very poor. I highly doubt that you would recommend to a patient to sit in a low chair, sofa or toilet. My point in all this is that if you can control the surface you are sitting in, make sure it is supportive and promotes good spinal posture. I beliieve that is sound advice.
"The more lordotic your lumbar curve is, the more likely it is that you will have a forward head, rounded shoulders and thoracic or middle back pain."
That is an incorrect statement and so I felt compelled to bring your attention to it. Your position was that if your glutes were higher than your knees your lordosis would increase and thus create pain. That is not true.
And I think up until now, we were all talking about a standard sitting posture where your hips and knees are at 90/90. Your point was: "that when a seating surface creates a scenario" that changes this 90/90 position at the hips and knees, the person assumes a "slumped" posture.
I did not realize you were trying to explain the dynamics of what happens to the lumbar spine during poor seated positions or using the wrong choice of chair (too low).
You are right, I would not recommend someone sit on a toilet (for other than bathroom purposes) or a chair that does not allow a 90/90 at the hips and knees for any extended period of time. Including a couch. Especially as back pain is present.
And you are right, as you are talking about a "slumped" sitting position, then the whole spine will be placed into flexion.
The point is, we want our patients to avoid slumped positions. Bringing your lower back into a proper lordosis will improve sitting posture no matter where you sit. It just becomes that much more difficult on a poor choice of sitting surface (low chair or toilet).
It has been my experience that while maintaining a proper lordosis during sitting postures the head and neck are forced back into proper alignment. That is proper sitting posture with the hip and knees creating 90 degree angles.
As the patient is in a "slumped" posture, as you describe where the lordosis is lost, and the thoracic spine is increased, then indeed, back pain will follow.
We were just describing two totally different things.