Sitting Biomechanics Laboratory

Part of the
Sensory Motor Performance Program
Room 1340, Rehabilitation Institute of Chicago

Occupational Low Back Pain

 

Pressure Distribution of a regular sitting posture and the WO-BPS posture

Upper row:interface pressure between the backrest and the back.

Lower row: interface pressure between the seat cushion and the buttock-thighs.

Left column: interface pressure recorded in Normal sitting posture.

Right column: interface pressure recorded in the WO-BPS sitting posture.

Finding highlight: WO-BPS posture shifts sitting load from rear part of buttocks to thighs and the upper back, decreasing sitting load on lumbar spine.

Back Muscle Activity
In a one-hour sitting, posture changes induced muscle activity changes. Recordings made at T5, T8, L2, and L8

N — Normal posture; W — WO-BPS posture;

R—Right side; L—Left side.

Finding highlight: WO-BPS posture reduces back muscle activities in lumbar region.

Radiographic Evaluation of Lumbar Spine Alignment
Representative lateral radiographs from one subject in the

Standing (A)

Normal (B)

and WO-BPS (C) postures

Measurement of the sacral inclination (a) and the lumbar lordosis are shown. Finding highlight:
  • WO-BPS posture restores lumbar lordosis close to that of standing.
  • WO-BPS posture opens ventral side of lumbar spine.

Last updated May 25, 2008 by Makhsous.
Send EMAIL if there are questions or problems.