RESUMEN
BACKGROUND: Limited research exists on lumbar spine and lower extremity movement during functional tasks in people with and without low back pain (LBP). OBJECTIVE: To determine differences in lumbar spine and lower extremity kinematics in people with and without LBP during the down phase of a pick up task. DESIGN: Cross-sectional, observational study. METHOD: 35 people (14 M, 21 F, 26.9 ± 10.9 years, 24.8 ± 3.2 kg/m2); 18 with and 17 without LBP were matched based on age, gender and BMI. Kinematics of the lumbar spine and lower extremities were measured using 3D motion capture, while subjects picked up an object off the floor. People with LBP were examined and assigned to movement-based LBP subgroups. Repeated measures ANOVA tests were conducted to determine the effect of group and region on lumbar spine and lower extremity kinematics. A secondary analysis was conducted to examine the effect of LBP subgroup on lumbar spine kinematics. RESULTS: Compared to controls, subjects with LBP displayed greater upper and less lower lumbar flexion (P < 0.05), and more lumbar flexion during the first 25% of the pick up task (P < 0.01). There were no group differences in frontal or axial plane lumbar spine kinematics. Subjects with LBP displayed more frontal plane movement at the knee than control subjects (P < 0.01). There were no significant effects of movement-based LBP subgroup on kinematics (P > 0.05). CONCLUSIONS: When evaluating movement during a functional task, the clinician should consider regional differences in the lumbar spine, pattern of movement, and lower extremity movement.