- The chair height
- The shape of the seat surface
- The depth of the seat surface
- The chair back
The height of the chair is critical. Many people sit too low, which will create a bias into a flexed lumbar, slumped position – particularly if you have tight hamstrings and gluteal muscles. Some people – those who are vertically challenged – may find that most chairs are too high, and their feet cannot rest on the ground. This is also a problem because it means that their weight cannot be distributed into the ground and their legs become long levers, pulling on the hips and lumbar spine. The appropriate height of the seat is, generally, the height at which you feel you have the most equal mobility between slouching and sitting up tall. This will enable you to find a comfortable, middle position, where there is minimal tension on your lower back and hips. You should have an open hip angle, meaning your hips are slightly higher than your knees. If you are one of those people whose feet dangle and can’t reach the ground, find something to use as a foot support. Reams of paper work are great because you can adjust the height by removing paper until it supports your feet at just the right height.
- Is there a space between the seating surface and the chair back? If there is, you need to fill this in. Use a towel, or if the gap is so large that towel will fall through to the ground, you may need to use a sheet to put over the entire chair so that any support you use in to fill in that space will not fall to the ground. This may seem extreme, but this space between the seat surface and chair back is the primary reason that people end up slouching for prolonged periods while sitting, which is terrible for lumbar discs.
- Is the chair back flat and vertical? Or is it undulating to accommodate the natural curves of the spine? Notice I said ‘the spine’, because your chair was not designed solely with you in mind. Everybody’s natural curve of their spine is unique. You need to adapt your chair back to you – don’t try to adapt to your chair back. This will require that you use a towel or free article of clothing to support any open spaces between your body and the chair back,so that you are supported in a comfortable position.
Hopefully this information will help as a starting point for improving yoursitting posture. Next we will look at how you can better position yourself in anunsupported position.