[Test- retest reliability of coordination and movement pattern stability measures during repetitive trunk bending in healthy and non specific low back pain groups]

To define the dynamic organization of the neuromuscular system, we need useful tools that allow for the expression of the neuromuscular system in low dimensional term [i.e one variable], so it seems that relative phase provides a better measure of organization of the neuromuscular system. Besides, selection of a measure for research or clinical use should be motivated by several factors, including the measure reliability. To our knowledge there seems to exist no study that have ever investigated the reliability of the relative phase and deviation phase in healthy or Low back pain subjects in dynamic movement tasks. Twelve healthy volunteers and 12 low back pain patients performed repeated trunk bending motion in eight different conditions of high and low speed, in symmetric and asymmetric planes, with or without external load. All measurements were repeated on a second session, 7-10 days later. Mean absolute relative phase and deviation phase of lumbar-thorax and pelvis-lumbar were used to calculate coordination pattern and variability. Relative reliability was assessed using intra class correlation coefficient [ICC] and absolute reliability was assessed using standard error measurement, minimum detectable change and coefficient of variation. Results in healthy subjects revealed that relative phase and deviation phase showed good to excellent reliability, with ICC range of 5.3-8.4 and in low back pain group ICC range was0 /52-0/85 except in three asymmetric test conditions and one symmetric test condition. SEM values range for healthy subjects were 0/92-4/8 and for low back patients were 1/2-5/8. Relative phase and deviation phase are suggested as good parameter to use for evaluating coordination and variability in dynamic situations such as lifting and complex trunk movement and also for discrimination low back pain patients from healthy subjects.

[Variability of anticipatory postural adjustments after performing stabilization exercises in recurrent nonspecific low back pain patients]

The theraputic exercise is regarded as one of the most important theraputic interventions in the chronic low back pain patients. Stabilization exercise is among the most significant practical ones in these patients. The study of the effects of these exercises on the variability of trunk muscles postural strategies and the ability in normalizing these strategies are among the uncertainties that have remained unknown up to the present time. The purpose of this research is the study of the effect of stabilization exercises on the variability of postural control strategies in these patients. The study was performed on 21 [14 males, 7 females] recurrent non-specific low back pain patients. The electromyographic activity of Deltoid, Transverse Abdominis/Internal Oblique, External Oblique and Erector Spinae muscles of each person was recorded in 75 rapid arm flexion with maximum acceleration. Then, 14 individuals were placed in the experimental group and 7 in the control group randomly. The experimental group performed isolated abdominal hollowing and bracing exercises using pressure biofeedback with the supervision of a physiotherapist in different positions including supine, sitting on a chair, standing still and standing with rapid arm raises with maximum acceleration once a day, for 20 sessions. The variables studied in this research were evaluated in both experimental and control groups after the training sessions. The standard deviation of the trunk muscles onset latencies relative to deltoid muscle was statistically analyzed by a dependent t-test in both groups. The results revealed that performing the stabilization exercises increases the variability of the timing of anticipatory postural adjustments in TrA/IO in the experimental group [P=.037], while there were no significant changes in the variability of EO [P=.0346] and ES [P=.673] muscles in these patients. The variability of the timing of the anticipatory postural adjustment in TrA/IO [P=.199], EO [P=.702] and ES [P=.465] muscles did not show any significant changes in the control group. The study of the results showed that the reduction in the variability of postural control system in recurrent non-specific low back pain patients as a factor that causes the continuity of back pain can be improved by goal-directed stabilization exercises

effects of consecutive supervised stabilitytraining on postural balance in patients with chronic low back pain

To examine the effects of consecutive supervised stability training on postural control of Chronic Low Back Pain [CLBP] population. Thirty-eight subjects with Chronic Low Back Pain [CLBP] were randomly assigned to one of two groups: Concise Supervised Stability Training [CSST] group [n=20] and electrotherapy [E] group [n=18]. Bilateral and unilateral stance ability with eyes open or closed was assessed by using Biodex Balance System. Postural indices including overall, anterior/posterior, medial/lateral stability indices and limit of stability parameters as time to complete and functional performance of subjects were recorded. Qualitative and quantitative variables were not significant between groups before treatment. Most postural indices showed significant decrease after stability training comparing with E group. CSST may improve postural balance in patients with Chronic Low Back Pain [CLBP] because of facilitating feed forward mechanism, proprioception and postural strategies. Nevertheless, more investigations are needed to evaluate the effects of CSST in Chronic Low Back Pain [CLBP] patients

Reliability of postural balance evaluation using the biodex balance system in subjects with and without low back pain

The purpose of this study was to evaluate the reliability of dynamic standing balance in individuals with and without low back pain [LBP] using Biodex Balance System [BBS]. Twenty three patients with LBP and 20 age-matched healthy subjects participated in this study. Bilateral and unilateral stance both with eyes open and eyes closed with the BBS over a period of 20s was assessed. The subjects were assigned to two groups [with and without LBP] by an independent observer. The tester was unaware of the group assignment and completed balance test using BBS. Two days after the first measurement session, the tester retested the subjects in the second measurement session in a random order, different from the first measurement session. The results of this study showed that the intra-class correlation coefficient in normal subjects and those with LBP was between [0.91-0.95] and [0.88-0.96] respectively. The results showed that BBS is reliable for evaluating dynamic postural balance in subjects with and without LBP. A significant difference was found in Medial-Lateral Stability Index [MLSI] and Overall Stability Index [OSI] between subjects with and without LBP. The findings of this study showed high reliability for BBS to evaluate dynamic postural balance in subjects with and without LBP

Evaluation of postural balance using the biodex balance system in subjects with and without low back pain

To evaluate the reliabiity of dynamic standing balance in individuals with and without low back pain [LBP] using Biodex Balance System [BBS] and to compare the balance indices between two groups. Across-sectional non-experimental design. Biomechanics Laboratory and Saba spine specific physical therapy clinic, University of social welfare and rehabilitation sciences, Tehran, Iran. Twenty three male patients with LBP [mean age: 30.4 +/- 6.5 years] and twenty age-matched healthy male subjects [mean age: 29.8 +/- 6.4 years] participated in this study. Medial-Lateral stability index [MLSI], Anterior-posterior stability index [APSI] and an Overall stability index [OSI] were measured in two measurement sessions using the BBS. Balance was measured in four conditions; bilateral and unilateral stance with eyes open and eyes closed; over a period of 20s. The results showed that ICC in healthy subjects and those with LBP was between [0.91-0.95] and [0.88-0.96] respectively. The Bland-Altman plot of agreement in balance scores between tests and retests demonstrated good agreement. A significant difference was found in MLSI and OSI between subjects with and without LBP. However, no significant difference was detected in APSI between two groups. The findings of this study showed high reliability for BBS to evaluate dynamic postural balance in subjects with and without LBP. It seems that MLSI and 051 significantly differ between subjects with and without LBP