1.
When seated your hips should be higher than your
knees, or at a right angle to your hip.
2.
Your low back (think waist) should be supported
(a small rolled towel can be placed here) if your chair does not provide back
support
3.
You should be able to feel equal weight across
your sitting bones when seated.
Avoid 'bucket seats', here is why:
Buckets,
position your knees higher than your hips. This throws all your upper body
weight back onto your gluteus maximus and piriformis muscles through which--and
this is the important part--the Sciatic nerve runs. Sit on that nerve often
enough and long enough, and you will probably end up with shooting pains down
one or both legs.
Human
beings were designed to sit on their pelvic bones, or ischium, those hard bones
you sometimes feel when you first sit down on a hard chair. Sitting on those
bones automatically gives us a natural arch in the small of our backs. When we
sit this way, the Sciatic nerve, Sacroilliac joints, lumbar vertebrae and hips
are unencumbered and unstressed.