Comparison of Lumbopelvic and Hip Movement Patterns During Passive Hip External Rotation in Two Groups of Low Back Pain Patients with and without Rotational Demand Activities.

BACKGROUND Because different groups of people with low back pain (LBP) engage in different tasks, their lumbopelvic-hip complex may move in different ways in those groups. The purpose of this study was to quantify the differences in lumbopelvic movement pattern during the passive hip external rotation (PHER) test in LBP patients with and without rotational demand activities (RDA). MATERIAL AND METHODS A total of 30 subjects with LBP, including 15 patients with-RDA and 15 patients without-RDA were enrolled. A passive hip external rotation test was performed. Pelvic and hip rotation over the full range of the test, timing of hip and pelvic motion, and pelvic rotation in the first half of the movement were measured using a 3-D motion analysis system. RESULTS Passive pelvic rotation during the test in the group with RDA was significantly greater than in the other group. However, there was no significant difference between the groups in other kinematic variables, including hip external rotation, timing of hip and pelvic motion and pelvic rotation in the first half of the movement (p > 0.05). CONCLUSIONS 1. A greater lumbopelvic rotation ROM during the PHER existed in LBP patients who regularly participated in RDA. 2. Different groups of patients with LBP who engage in different specific activities may have a specific lumbopelvic movement pattern impairment. Therefore, each group of LBP patients in regard to their specific activities may need a different, specific plan of treatment

Stability analysis in patients with neurological and musculoskeletal disorders using linear and non-linear approaches

Standing stability is controlled by musculoskeletal and neurological systems. Various methods have been used to evaluate the performance of subjects during standing including linear and non-linear methods. It is not clear which method has more sensitivity to represent the stability of subjects with various musculoskeletal disorders. Therefore, the aim of this study was to investigate the stability of the subjects with various musculoskeletal disorders by use of linear and non-linear methods. About 65 subjects including, normal and those with flatfoot, Parkinson and Perthes were recruited into this study. A Kistler forceplate was used to evaluate the stability. The difference between the linear (center of pressure excursion, velocity and path length) and non-linear (approximate entropy) parameters were evaluated using the independent t-test. The mean values of stability parameters (linear and non-linear) of flat arch subjects were more than that of normal subjects. Although there was no difference between linear stability parameters of normal and those with Parkinson disease, their mean value of non-linear parameter was less than that of normal subject (p-< 0.05). The results of stability analysis based on both linear and non-linear approaches showed that the subjects with Perthes disease were more unstable than normal subjects. It seems that non-linear method is more sensitive to represent the difference between stability of subjects with flatfoot, Parkinson and Perthes. However, if a combination of various parameters, based on linear method, is used to measure stability, the difference between stability can be enhanced. Depending on the disease condition increasing and decreasing the value of approximate entropy represent the unstability situations