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Background and Objectives: Measuring the H-reflex latency (Tp) is an electrophysiologic test to evaluate the S1 root lesions This reflex traverses a relatively long course and its sensitivity to diagnose mild S1 root lesions is low, so investigators have tried to shorten this pathway Evaluation of the central loop of the H-reflex (Tc) is one of these efforts and may be more sensitive in diagnosing S1 radiculopathy (Compared to standard H-reflex latency). We have tried to determine its influencing factors and find the related regression equation. Materials and Methods: Forty volunteers were investigated with their informed consent. Their history, physical examination and a brief electrophysiologic study were normal. H-reflex latencies (Peripheral- central) of right gastrocnemius-soleus muscle as described in literature, right leg length and age were recorded. Results: This group consisted of 26 males (65%) and 14 female (35%). Mean latencies (And SDs) of peripheral and central H-reflexes were 28.8 (SD: 1.66) and 6.78 (SD: 0.3) milliseconds respectively. The correlation between Tc and leg length was significant (P<0.05). There was no significant correlation between Tc and age (P<0.05). Tc and Tp were correlated. These regression equations were found: Tc=0.04L+5.28, Tc=0.05Tp+4.56, Tp=0.04A+0.3L+16.13 (L: leg length in centimeters, A: age in years, Tc and Tp in milliseconds). Discussion: The results of this study, regarding mean and SD of Tc are in line with the previous studies, and regarding the influence of age on Tc are in contrast with only one study and in line with another study. Conclusion: The correlation between Tc and leg length was significant (P<0.05). There was no significant correlation between Tc and age (P<0.05). These regression equations were found. Tc=0.04L+5.28, Tcx=0.07Tp+4.56, Tp=0.04A+0.3L+16.13 (L: Leg length in centimeters, A: Age in years, Tc and Tp in milliseconds). We concluded that it is wise to use leg length for calculating normal Tc and limiting the normal values. On the other hand, the authors believe that more research on specificity and sensitivity of this test (To diagnose S1 radiculopathy) and comparing it with other diagnostic tools is needed.

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Background&Objective: Low back pain (LBP) is common in youth, although `associated with chronic pain in adults. The purpose of this study was to determine the prevalence and risk factors of LBP in school children age 11-14. Materials&Methods: A cross sectional study was carried out on school children aged 11-14 in north of Iran. Using random multistage sampling 5000 children were selected. Demographic, mechanical and lifestyle data as well as the prevalence and LBP characteristics were collected by a questionnaire. Data analysis was carried out using SPSS (version11) software. Results: Of the original sample, 4813 (96.2%) children returned the questionnaire. Point, last month, last 6 months and annual prevalence were 15%, 14.4%, 15.6%, and 17.4%, respectively. LBP was significantly correlated with age (p<0.05), lifting (p<0.05), position and duration of watching TV, doing homework and duration of exercise (p<0.05). Conclusion: The results indicated that the prevalence of LBP in school children is relatively high. Further studies evaluating the effect of different preventive strategies to reduce the prevalence of LBP in school children is strongly recommended.

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Low back pain (LBP) is a common and complicated disorder which is influenced by a number of factors, among them is the lack of spinal stability provided by muscle contraction. One of the most important muscles which has a role in spinal stability is musculus transversus abdominis. A literature search for the period of 2000-11 was performed in PubMed, ProQuest, Science Direct, Thomson, EMBASE, OVID, CINAHL and MEDLINE databases using musculus Transversus Abdominis, ultrasonography, chronic nonspecific low back pain as keywords. Nineteen articles were selected according to the inclusion criteria of the study. Evidences demonstrated that thickness of transversus abdominis reduces in patients with chronic nonspecific low back pain (LBP) and ultrasonography seemed to be a valid and highly reliable instrument for measuring thickness of transversus abdominis in patients with LBP and healthy subjects on different positions and states. Studies demonstrated that there are adequate evidences to confirm the merit of ultrasonography in the assessment of musculus transversus abdominis in patients with chronic LBP and healthy subjects.

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Background and Objective: Low back pain is a common musculoskeletal disorder. Core stability exercises have been recommended to improve neuromuscular skeletal system function in order to increase the protection of vertebral column and improve functional activities. This study was done to evaluate the effect of core stability and general exercise on functional activity in non- specific low back pain patients.

Methods: In this clinical trail study, sixty patients with chronic low back pain were randomly divided into general exercise (n=30) and core stability (n=30) groups. The protocol of intervention included 4 weeks (3 sessions in week) of designed exercise for each group. The functional activities were measured before and after intervention.

Results: Functional activity indicators were significantly increased in core stability exercise compared to general exercise (P<0.05).

Conclusion: Core stability exercise is more effective than general exercise to improve functional activities in patients with non-specific low back pain.

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Background and Objective: Lower back pain is one of the common discomforts of the occupational-musculoskeletal system, and the scope of motion measurement is important for assessing the effectiveness of therapeutic interventions. This study was carried out to evaluate the reproducibility of the modified-modified Shober's technique (MMST) in measuring the range of motion of lumbar in patients with non-specific chronic low back pain.
Methods: In this descriptive-analytic study, the range of motion of lumbar (flexion and extension) of 15 patients with non-specific chronic low back pain was measured in three times with modified – modified Shober's technique by two physiotherapists. To achieve this, the correlation coefficient (ICC) was used. Two measurements with an interval of one hour and one week were run to evaluate the reproducibility within-days and between-day, respectively.
Results: Flexion and extension were measured by the first assessor in within-day that showed a high reproducibility for flexion (ICC=0.88) and extension (ICC=0.71), findings also revealed an acceptable ICC for flexion (ICC=0.85) and extension (ICC=0.68) in between-days. The second assessor measurements of flexion and extension in whiten-day also presented high reproducibility for flexion (ICC=0.85) and extension (ICC=0.76); moreover, in between-days evaluation, correlation was found for flexion (ICC=0.81) and for extension (ICC=0.71).
Conclusion: This study showed that the modified-modified Shober's technique is applicable for measuring the reproducibility of range of lumbar motion in patients with non-specific chronic lumbar pain.

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Background and Objective: Vitamin deficiency is common in patients with chronic low back pain and is one of the most important risk factors for chronic kidney disease. The aim of this study was to evaluate the effect of one course of core stabilization exercise and vitamin D intake on some of renal function biomarkers in patients with chronic back pain.
Methods: This single-blind clinical trial study was done on 48 women with chronic low back pain with random assignment in 4 groups of 12 people including control, exercise, vitamin D and combined groups. The exercise and combined groups performed 8 weeks of core stabilizing exercises with different levels. The vitamin D and combined groups received 50,000 IU vitamin D/week. Creatinine, urea and uric acid levels were measured before and after the interventions.
Results: The results showed that 74.26% and 25.64% of the patients had deficiency and insufficiency of vitamin D, respectively. After 8 weeks, significant reduction was observed in creatinine, urea and uric acid indicators of the exercise, vitamin D and combined groups (P˂0.05). In addition, combined intervention induced more reduction in mean of urea, and uric acid levels in compared to the two other interventions but the effect of exercise on the reduction of uric acid was more than vitamin D intake (P˂0.05).
Conclusion: Both core stabilization exercises and vitamin D intake intervention can be effective in improving renal function in chronic low back pain patients having abnormal low vitamin D levels. On the other hand the combined intervention seems to have more effectiveness.

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Background and Objective: Back pain is a common orthopedic disease that affects up to 80% of the population at some point in life. Brace is one of the tools that used to reduce pain. The relationship between brace application and gait parameters in people with low back pain is not well understood. This study was done to determine the effects of simple and sensor thoracolumbosacral braces on gait kinetics in patients with low back pain.
Methods: This quasi-experimental study was performed on 15 men and women with low back pain in the biomechanics laboratory of Mohaghegh Ardabili University Health Center in nort-west of Iran during 2020. Each participant performed three gait conditions including without brace, with sensory brace and with simple brace. Ground reaction forces were recorded and compared by a force plate while walking.
Results: The average walking speed during no brace, simple brace and sensor braces were not significant different. Also, results did not demonstrate any significant effect of simple or sensor braces on ground reaction force amplitudes, their time to peak, and free moment values.
Conclusion: Simple and sensory thoracolumbosacral brace did not effect on gait kinetics in low back patients.

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Background and Objective: The scientific evidence related to the effectiveness of rehabilitation on electromyographical activity of trunk muscles is limited. This study was performed to determine the effect of movement-pattern training on frequency of selected trunk muscles during single-leg landing in individuals with non-specific chronic low back pain.
Methods: In this clinical trial study, 28 patients with non-specific chronic low back pain were randomly divided into intervention and control groups. The control group did not receive treatment. The intervention group performed treatment as a movement-pattern training. Subjects performed single leg landing from 30 cm height. Trunk muscle activity was assessed using an 8-chanel EMG system. The assessments were completed in pre-test and after six weeks.
Results: Frequency content of right rectus abdominus and right lumbar erector spinae in intervention group were lower than control group (P<0.05). In other muscles ant there was not any significant significant differences between interventional and control groups.
Conclusion: The movement-pattern training can be used in rehabilitation of individuals with non-specific chronic low back pain.