Abstract
BACKGROUND/OBJECTIVES: Sedentary office workers (SOWs) often adopt prolonged sitting postures, which potentially disrupt the lumbar-pelvic rhythm (LPR) and contribute to lower back pain (LBP). This study aimed to clarify the group differences in LPR and related physical factors between SOWs with and without LBP. METHODS: Sixty-three SOWs were divided into LBP (n = 30) and non-LBP (n = 33) groups. The lumbar flexion angle (LF) and lumbar-hip angle difference (LHD), which are indicators of LPR, were measured using inertial sensors during trunk flexion. Hip flexion muscle strength (HFMS) and hip-extension muscle strength (HEMS) were assessed using handheld dynamometry. Hip joint range of motion (ROM) was measured using a goniometer. Lumbar proprioception was evaluated via active joint repositioning, and pain and perception were assessed using the Visual Analog Scale, Oswestry Disability Index, and Fremantle Back Awareness Questionnaire. RESULTS: Multiple regression analysis showed significantly greater LF (estimated regression coefficient [ERC]: -2.9, p < 0.05) and LHD (ERC: -5.5, p < 0.05) during early trunk flexion (ETF) in the LBP group. In the LBP group, LHD during ETF and late trunk flexion were positively correlated with HFMS, and HFMS was correlated with HEMS. CONCLUSIONS: HFMS may contribute to an altered LPR in SOWs with LBP.