Changes in the range of lumbar flexion during cyclic stooping

Abstract

Previously, responses to stooping or static upper body flexion have been evaluated by quantifying the changes in the range of lumbar flexion after a bout of stooping with restricted and controlled posture conditions. The current study was aimed to confirm the same with unrestricted posture conditions that resembled work-related postures. Twenty two subjects performed stooping work tasks for 6 minutes with intermediate short breaks, followed by a 6-min upright standing recovery period. Time-dependent changes in the range of lumbar flexion were evaluated by measuring peak lumbar flexion angle in full flexion trials and stooping postures before, during and after the stooping period. Results found a significant increase (p<0.05) in the peak lumbar flexion angle after stooping, and the increased range of lumbar flexion did not return to its pre-stooping level after the recovery period. Short breaks during stooping moderated the increase in the flexion range, resulting in a smaller increase in the flexion range compared to what static and controlled full flexion postures have produced in previous research.