Backset-stationary and during car driving.
OBJECTIVE
The aim of the study was to measure and analyze backset, defined as the horizontal distance between the back of the occupant's head and a point located on the ventral/top aspect of the sewn rim of the head restraint, with the car stationary and during driving, in the driver's position in a modern car.


METHODS
A population of 65 subjects, 35 males and 30 females, was studied in a Volvo V70 car, model year 2007. The subjects were studied in the driver's position, in a self-selected posture. Stationary backset was measured with the technique described by Jonsson et al. (2007) and backset during driving with video analysis. Descriptive data were calculated, and variability and correlation analyses were performed. A t-test was used to test differences of means. Significance level was set to 0.05.


RESULTS
In comparison to stationary backset, mean backset during driving was 43 mm greater in males and 41 mm greater in females. Driving backset was 44 mm larger in males than in females. Driving backset was moderately correlated (0.37-0.43) to stature, seated height, and seat back angle in males and moderately correlated (0.44-0.52) to hip width, waist circumference, and weight in females. The overall intraclass correlation coefficient for backset during driving was 0.81 (CI: 0.75-0.86).


CONCLUSIONS
These results may be of use in designing future updates of test protocols/routines for geometric backset, such as RCAR and RCAR-IIWPG.
Jonsson
Bertil
B
Department of Surgical and Preoperative Sciences, Division of Surgery, Umeå University, Umeå, Sweden. bertil.jonsson@mail.se
Stenlund
Hans
H
Björnstig
Ulf
U
D000328:Adult; D001334:Automobile Driving; D001336:Automobiles; D001696:Biomechanical Phenomena; D049628:Body Size; D004867:Equipment Design; D006804:Ergonomics; D005260:Female; D006260:Head Protective Devices; D006801:Humans; D008297:Male; D008875:Middle Aged; D011187:Posture; D012737:Sex Factors