The purpose of this study was to determine whether stretching the hamstring muscles affects extensibility, as indicated by straight leg raising (SLR), lumbopelvic posture, and the relative amounts of lumbar and hip motion during forward bending. Thirty-nine subjects without known musculoskeletal impairments of their spine or lower extremities and with tight hamstring muscles (ie, SLR of ≤70�) were randomly assigned to either a stretching group or a control group. A three-dimensional digitizer was used to measure lumbar, pelvic, and hip positions while subjects were in a standing position and during partial and full forward bending. Straight leg raising and hip motion during late and total forward bending were increased after stretching. No changes occurred in standing posture or lumbar motion during forward bending. The results of this study suggest that there is no relationship between hamstring muscle length and lumbopelvic posture. There was some indication, however, that stretching the hamstring muscles may affect motion during forward bending.