Poor posture often gets the blame for causing lower back pain. While it probably gets the blame more often than it deserves, it is a common cause of back pain, and one that is easily treatable!
What Causes It?
Poor posture can lead to back pain by placing too much load through certain structures in the back. When your back is in a neutral posture the load going through it is distributed evenly throughout each joint. When you're in an end-range posture that same load is only taken by a small portion of each joint. This can cause you to feel pain without necessarily damaging your back, similar to how bending your finger back and holding it there will cause pain in your finger which will settle once your return your finger to it's normal position.
Obviously lots of other things can cause back pain, so what do you look for to see if your back pain is postural, or if posture is contributing to your back pain?
What Makes Your Pain Worse?
If your back pain is coming from posture then that posture should aggravate your pain, and the longer you spend in that posture the more pain you'll feel. So your pain might be coming from your sitting posture if you start to feel pain after you've been sitting for a while and the pain gets progressively worse. If your standing posture is causing your pain then you should find prolonged standing will cause you pain, while sitting will relieve your pain. (Suprisingly pain with lying on your back and / or your stomach can be associated with pain from a poor standing posture too).
What Makes Your Pain Better?
Unsurprisingly getting out of the aggravating posture will ease your pain. If your pain is aggravated by sitting then getting up and going for a walk should ease your pain, if your pain is aggravated by standing then sitting down should ease your pain.
Improving your posture will help, but it's not as easy as just thinking "sit up straight"
How Do You Improve Your Posture?
Seeing as you don't have time to be thinking about your posture all day, good posture has to be maintained without using your conscious brain. To do this you rely on two things:
Good proprioceptive awareness of your lower back and pelvis
Maintaining resting tone in postural muscles which support the lower back and pelvis.
Both these things can improve with targeted exercises. Most people don't have very good proprioceptive awareness of this region, but you have nerve pathways in place that can be developed with specific exercises.
There are also braces and tapings which can improve posture. It's better to use these as a temporary measure for pain relief while your muscle tone and proprioception improve.
What Benefits are There to Improving My Posture?
We're generally designed to work with our backs in a neutral posture. This means that as well as preventing postural back pain, having good sitting or standing posture reduces your risk of upper back, neck and shoulder pain, as well as making your lungs and muscles work more efficiently.