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Background and aim: The presence of the flexion relaxation phenomenon (FRP) during trunk flexion represents myoelectric  silence consistent with increased load sharing of the posterior discoligamentous passive structures. A number of studies have shown differences in the FRP between patients with chronic low back pain and healthy individuals, Persistent activation of the lumbar erector spinae musculature among patients with back pain may represent the body's attempt to stabilize injured spinal structures via reflexogenic ligamentomuscular activation for protecting them from further injury and avoiding pain.

Materials and methods: Two groups of female subjects ((20 - 40 years old) were participated in this study. First group consisted of 10 subjects with chronic low back pain (CLBP) and second group consisted of 10 healthy ones as control group. Both groups have performed 5 cycles of trunk flexion - extension . The speed of the movement repetition controlled by an electronic metronome . The EMG signals recorded from T12 and L3 paravertebral muscles and bisepse femoris on the right side. The lumbar flexion motion degree has been measured by the digital flexible goniometry.  All subjects have done Sorenson Back Endurance test in prone laying position. The subjects have extended their trunk up to the horizontal position and sustained in this position up to fatigue level .The subjects leave the table and asked to do 5 more cycle of trunk flexion - extension.

Results:  In patients group there is an increment and significant differences in lumbar flexion degree at the time of muscle EMG off  in comparison with healthy subjects after fatigue test (p<0.05). In both groups, the myoelectric silence period showed a significant change with respect to the pre- fatigue (p<0.05). The median frequencies shifted to lower frequencies after fatigue protocol (p<0.05).

Conclusion: Muscle reflexive responses would change following fatigue protocol. Therefore, the muscle activity will increase after the fatigue period. In the other hand, in patient group the role of the muscles as a stabilizer seems to be increased to enhance the stability at the injured segment after fatigue protocol .This protects the segment against pain and disability.

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Background and aim: Proprioception is a main component of somatosensory system that plays a protective role in acute injuries through reflex muscular splinting. Proprioception reduction could be a source of deficits in reaction time, postural control and postural stability. In chronic low back pain  patients (CLBP) the proprioception is decreased and leads to dysfunction in motor control and increased the risk of injury. Evaluation the repositioning of lumbar region could be an indication to measure the lumbar proprioception . The purpose of this study was to compare the lumbar repositioning in CLBP and healthy females. 

Material and Methods: Eighteen CLBP (22.83 ± 2.93 years) and 18 healthy females (23.33 ± 2.19 years) participated in this study. Lumbar repositioning error in 30% and 60% of lumbar full flexion and neutral position with closed eye in standing was evaluated with electrogoniometer. Absolute and constant error for 3 repositioning points were obtained and analyzed.

Results: Absolute error in patients with low back pain was significantly higher than control subjects in all 3 position points (P<0.05). Constant error did not show significant difference between two groups. (P>0.05)

Conclusion: Increased in absolute error of females with CLBP in lumbar repositioning implies that some aspects of proprioception may lose in patients with CLBP.

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Background and Aim: Regarding to high prevalence of low back pain (LBP) in athletes and its effect on their athletic function, an accurate evaluation before planning the rehabilitation program seems necessary in athletes with LBP. It should be considered that human movements are like as a kinetic chain. It means that any problems in every parts of this chain can cause dysfunction in the other parts of the chain. Not taking attention to the relationships between different parts of this chain may result in suboptimal rehabilitation. Therefore, focusing treatment on the entire parts of the kinetic chain besides the injured part, may prevent recurrenceof the dysfunction. Since in the kinetic chain hip muscles act as a link between lower extremities and trunk, the purpose of the present study was to evaluate and compare muscles strength of hip joint in female athletes with and without non-specific chronic LBP.

  

Materials and Methods: Fifteen healthy female athletes and 15 female athletes with non-specific chronic LBP participated in this study. Their age was between 18-30 years. Hip extension, abduction and external rotation strength in all participants were measured. A hand-held dynamometer (HHD) was used to measure muscle strength. Since fixing HHD by examiner’s hand is fraught with error, it is fixed by a stable frame.

  

Results: The maximum strength value of hip extension and abduction in female athletes with LBP were significantly lower than these measures in healthy group (P < 0.05). No significant differences were seen in the maximum value of hip external rotation strength between two groups (P > 0.05).

  

Conclusion: The results of the present study show that hip extension and abduction strength in female athletes with LBP were lower than these measures in healthy group. Therefore, hip strength measurements besides the examination of the spinal column seem to be necessary in evaluation and rehabilitation of the patients with LBP.

  

Key Words: Non-Specific Chronic Low Back Pain, Hip Muscles Strength, Athlete