The objective of this study was to conduct gender- and time-based comparisons of postural and discomfort responses during prolonged simulated driving. Prolonged driving has been linked with low back disorders (LBD), however underlying mechanisms of pain or injury are not well understood despite many efforts to delineate the biomechanics of automobile seating. Twelve males and 12 females were exposed to one hour of simulated automobile driving. Body postures, body-seat pressure distributions, and ratings of perceived discomfort were documented and gender- and time-based comparisons were performed. Females exhibited approximately 10° greater changes in lumbo-pelvic orientation when upright standing postures were compared to those in automobile seating. Attributed to gender-based differences in body size was the finding that males experienced significantly greater body-seat interface pressures. Many of the postural, pressure, and discomfort measures varied significantly over 30 to 45 minutes, and these variations were mostly consistent between genders. Many variables examined varied as a function of gender and duration of driving. Future biomechanical investigations of automobile seating design for more effective LBD prevention should consider these potential effects in order to gain further insight into potential low back pain- or injury-generating mechanisms.

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Understanding factors that influence preferred sitting postures is considered important to prevent low-back pain (LBP) associated with seated exposures. The purpose of this study was to examine the influence of gender and flexibility (hip, hamstring, and low-back) on lumbo-pelvic postures adopted when performing laboratory-simulated computer work and automobile driving. Ten female and 9 male volunteers were exposed to 10 minutes each of the abovementioned sitting conditions. Sagittal lumbo-pelvic kinematics were recorded during each sitting condition. Correlation analyses were performed between lumbo-pelvic postures and various measures of hip, hamstring, and low-back flexibility. When driving, females exhibited 9.8 degrees more posterior pelvic tilt (p = 0.0329) and 10.5 degrees more lumbar flexion (p = 0.0116) than males with respect to their lumbo-pelvic alignments in upright standing. When performing seated computer work, it was males who experienced greater posterior pelvic tilt (p = 0.0048). Individuals with greater hip flexibility, typically females, adopted lumbar flexion postures closer to their voluntary end-range while driving (r = 0.5709; p = 0.0107). Individuals who exhibited greater posterior pelvic tilt in office chair sitting, typically males, were those with less hip (r = -0.5484; p = 0.0150) and hamstring (r = -0.4690; p = 0.0496) flexibility. Given that differences exist between males and females with respect to various indices of hip, hamstring, and low-back flexibility, it is possible that gender-based differences in seated postures are related to inherent differences in flexibility between the sexes. These findings suggest that strategies to prevent LBP associated with sitting may depend on both individual flexibility characteristics and the type of seated exposure.