Kinematic analysis of lumbar and hip motion while rising from a forward, flexed position in patients with and without a history of low back pain.

STUDY DESIGN: This study analyzed two groups of individuals during return to an upright position (extension) from a forward, bent position. Group 1 (n = 12) included individuals with no history of low back pain who were currently asymptomatic, and group 2 (n = 12) included individuals with no history of low back pain. OBJECTIVES: To determine the amount and pattern of lumbar spine and hip motion that occur as an individual rises from a forward, flexed position, to determine if differences exist in this measurement between individuals with and without a history of low back pain, and to determine if hamstring length is related to the pattern of motion. SUMMARY OF BACKGROUND DATA: Reports of interaction between lumbar spine and hip movement vary for forward bending and extension. Differences may be a result of variations in measurement methods, loading conditions, or the pathology present, such as low back pain. METHODS: A three-dimensional optoelectric motion analysis system was used to measure the amount and velocity of lumbar spine and hip motion during extension. Each participant in the study performed three trials of a complete flexion-extension cycle at a self-selected speed. The data for the extension portion of the cycle were averaged and used for statistical analysis. Hamstring length also was determined using two clinical tests, the passive straight-leg raise and the active knee-extension tests. RESULTS: The pattern of movement was described by calculating lumbar to hip extension ratios for each 25% interval of total extension. Individuals with a history of low back pain tended to move from the lumbar spine earlier than those with no history of low back pain, especially in the initial 25% of the extension motion. For all participants, mean lumbar to hip extension ratios were 0.26 for 0-25% of extension, 0.61 for 25-50%, 0.81 for 50-75%, and 2.3 for 75-100%. The lumbar to hip ratios were different in each 25% interval, demonstrating that the hips had a greater contribution to early extension, with the lumbar spine contribution increasing in the middle intervals and becoming the primary source of motion in the final interval. When lumbar to hip extension ratios were compared with corresponding intervals of flexion, three of four were positively correlated to flexion ratios, demonstrating a reversible lumbopelvic rhythm. Although participants with a history of low back pain had significantly tighter hamstrings than participants with no history of low back pain, hamstring length was not correlated with any of the kinematic characteristics during extension. CONCLUSIONS: Participants who were currently asymptomatic but had a history of low back pain moved in a manner similar to that of participants with no history of low back pain except that they demonstrated greater lumbar motion and velocity during the initial phase of extension. This may have been the result of low back pain or a contributing factor in recurrent low back pain.

Analysis of lumbar spine and hip motion during forward bending in subjects with and without a history of low back pain.

STUDY DESIGN: This study analyzed two groups of subjects during forward bending. Group 1 (n = 20) contained subjects with a history of low back pain and Group 2 (n = 21) included subjects without a history of low back pain. OBJECTIVE: The purposes of this study were to establish the amount and pattern of lumbar spine and hip motion during forward bending, and determine differences in motion in subjects with and without a history of low back pain. SUMMARY OF BACKGROUND DATA: Reported values for lumbar spine motion during forward bending vary from 23.9 degrees to 60 degrees and hip motion during forward bending ranges from 26 degrees to 66 degrees. There has been no direct study of both lumbar spine and hip motion during forward bending in subjects with and without a history of low back pain to establish differences in total amounts or pattern of lumbar spine and hip motion during forward bending. METHODS: A three-dimensional optoelectric motion analysis system was used to measure the amount and velocity of lumbar spine and hip motion during forward bending. Each subject performed three trials of forward bending that were averaged and used for statistical analysis. Hamstring flexibility was also assessed by two clinical tests, the passive straight leg raising and active knee extension tests. RESULTS: Mean total forward bending for all subjects was 111 degrees: 41.6 degrees from the lumbar spine and 69.4 degrees from the hips. There were no group differences for total amounts of lumbar spine and hip motion or velocity during forward bending. The pattern of motion was described by calculating lumbar-to-hip flexion ratios for early (0-30 degrees), middle (30-60 degrees), and late (60-90 degrees) forward bending. For all subjects, mean lumbar-to-hip ratios for early, middle, and late forward bending were 1.9, 0.9, and 0.4, respectively. Therefore, the lumbar spine had a greater contribution to early forward bending, the lumbar spine and hips contributed almost equally to middle forward bending, and the hips had a greater contribution to late forward bending. A t test revealed a difference between groups for the pattern of motion. Group 1 tended to move more at their lumbar spine during early forward bending and had a significantly lower lumbar-to-hip flexion ratio during middle forward bending (P < 0.01). Hamstring flexibility was strongly correlated to motion in subjects with a history of low back pain, but not in healthy subjects. CONCLUSIONS: The results provide quantitative data to guide clinical assessment of forward bending motion. Results also suggest that although people with a history of low back pain have amounts of lumbar spine and hip motion during forward bending similar to those of healthy subjects, the pattern of motion is different. It may be desirable to teach patients with a history of low back pain to use more hip motion during early forward bending, and hamstring stretching may be helpful for encouraging earlier hip motion.