Gender Responses to Automobile and Office Sitting - Influence of Hip, Hamstring, and Low-Back Flexibility on Seated Postures

Abstract

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 per- formed 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 fe- males, adopted lumbar flexion postures closer to their voluntary end-range while driving (r = 0.5709; p = 0.0107). Indi- viduals 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 differ- ences 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.