Analysis of possible lower lumbar strains caused by the structural properties of automobile seats: a review of some recent technical literature.
BACKGROUND
Epidemiologic studies on low back pain (LBP) persistently point to a strong correlation with whole-body vibration from motor vehicle driving. Vehicle vibration enters the driver's body through the seat. Therefore, the analysis of the vibrational properties of automobile seats is a necessary prerequisite to understanding the correlation between LBP and driving.


OBJECTIVE
To examine structural properties of automobile seats that might be a source of LBP for the passenger, to modify the seat design accordingly, and to have it tested by drivers who have LBP.


METHODS
Recent studies of the vibrational properties of automobile seats published in automotive technical journals not readily accessible to a medical audience are summarized and further analyzed from a biomechanical point of view.


CONCLUSIONS
Because of the strong coupling between the seat backrest and the vehicle floor, a differential motion between backrest and seat cushion occurs when one is driving. It inevitably induces continuous strains in the lower lumbar spine of the seat occupant and is therefore a possible source of LBP. Vibrational measurements performed on a prototype automobile seat with a vertically moving backrest show that, compared with a standard seat with fixed backrest, the differential motion is strongly reduced. The resulting relief of LBP is confirmed by drivers who used this type of seat.
Johnson
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Department of Mechanical Engineering, Université Catholique de Louvain, Louvain-la-Neuve, Belgium.
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D001334:Automobile Driving; D001696:Biomechanical Phenomena; D004867:Equipment Design; D006801:Humans; D017116:Low Back Pain / Q000209:etiology* / Q000517:prevention & control*; D018986:Motor Vehicles; D014732:Vibration / Q000009:adverse effects*