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Practice in Motion: Part II - 6 Components of Posture

Course Number: 554

Science Behind Sitting

History has shown that transitioning from a standing to a sitting position has traded one set of physical aches and pains for another, with many careers ending far too early from severe low back pain and other musculoskeletal disorders. To minimize the detrimental effects of static sitting we must turn to the science underlying both the principles of sitting and the surfaces on which we sit.

Science Behind Sitting: Disc Pressures, Lumbar Lordosis, and Ischial Contact Pressure

As discussed in Practice in Motion: Part I, disc pressures in sitting far exceed those in standing.15

An increase in the spinal load from sitting causes an increase in disc pressure, reduces the disc heights and decreases the lumbar lordosis, contributing to pain and disc degeneration.16,17 The decreased lumbar lordosis associated with sitting as compared to standing16,18 has been associated with low back pain18,19 and degenerative disc disease at the L5 S1 segment.20

Increasing the lumbar lordosis can be accomplished in three ways. First, clinicians can actively rotate their pelvis forward by raising the tailbone up. Second, a lumbar support that supports them into a lordotic curve, like that in standing, will work. Finally, tilting the angle of the seat downward will rotate the pelvis forward and create more lordosis in the lumbar spine.