A mathematical model of the impact response of the seated subject.

A model of the lumbar spine, pelvis and buttocks is developed, based on linear horizontal and vertical systems along with a rotational subsystem. The model can mimic qualitatively different experimental observations of transmission of vibrations from the seat to L3 in the sitting posture. It is concluded that while the model lacks detailed sophistication, it adds to our qualitative understanding of the biomechanics of seated vibrations by pointing to those subsystems responsible for the observed transfer functions.