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Background and Aim: In this study, we investigated : 1) The effect of diferent lengths of Abd. policis brevis muscle on variations EMG frequency spectrum. 2) The effect of muscle contractions on frequency spectrum and 3) The effect of different lengths of muscle on local muscle fatigue.

Material and Method: 20 normal subjects participated in this study. (with range of 20 - 34 years old). Each test carried out in four steps. Every person performed 3 minutes of isometric contraction in Abd. policis brevis muscle and EMG signals were saved for 5 seconds before and after the test. Then the  same procedure was performed while individual did 6 minutes free dynamic contraction and 6 minutes high speed dynamic contraction and 6 minutes forceful dynamic contraction respectively.

Results:This study showed that when the individual performed muscle contraction in short length, median and mean frequency increased (P = % 0) and fatigue test caused a decrease in frequency charactristics that was more in dynamic contractions in compare with isometric contraction (it was more obvious in forceful dynamic contraction). These parameters didn't change in different lengths (P = %9, P = %4, P= %3 for 0 - 45, 0 -90 and 45 - 90 degrees respectively).

Conclusion and discussion:This study showed that different muscle lengths and muscle contractions affect on frequency spectrum and it also showed the effect of different muscle lengths and muscle contractions on local muscle fatigue.

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Background and aim: Since 1998, the effect of traction on the H- reflex has been investigated by Hiraoka and the other researchers. Some of them have been done on lower extremity and the other on the upper extremity. The effect of traction was assessed by H reflex amplitude. Different results have been achieved. The new method which has been used since 2000, the effect of cervical traction on the H reflex was carried out by measuring H reflex slope .In this experiment the effect of manual cervical traction has been studied on the H slope of the upper extremity. Now we have sought to extend this work by examining the effects of cervical traction with 3 kg force on the H slope of the lower extremity 

Materials and Methods: This study was administered to sixteen healthy men with a mean age 23.12 of years and SD=2.55. The parameters of H reflex were recorded before and after of cervical traction .All data were analyzed with SPSS (V: 11.5).    

Results: The results showed that, there were no significant differences between before and after the application of cervical traction in H reflex parameters, ratio of H max/M max amplitude and M slope. But H slope and ratio of H slope /M slope were increased significantly after the application of traction (P<0.001).

Conclusion: The present study showed that traction with 3 Kg force can increase motor neuron excitability of soleus muscle and this result is against the previous study. This could be due to the application of the new method (H slope), which is more precise.

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Background and aim: Neck muscles contract dynamically in the majority of daily activities. Athletes, agricultures and industrial labors are predisposed to muscular fatigue. Aim: The aim of the present study was to compare the effect of dynamic fatigue on power and frequency domains of EMG spectrum.
Material and methods: In this study 20 healthy young men contracted neck muscles dynamically, until muscular fatigue occurs. Surface electromyography was recorded of levator scapula, neck paraspinals and upper trapezius, as neck extensors. The effects of dynamic contraction on frequency (Median Frequency) and Power domains(RMS) were compared before and after fatigue.
Results: The results of the present study indicated that MedF decreases following dynamic fatigue (P<0.05). After dynamic fatigue, RMS of levator scapula and upper trapezius increased significantly (P<0.05). Regarding to significant decrease of RMS and increase of MedF, paraspinals encountered with force reduction .
Conclusion: Changes of MedF and RMS indicated that a continuous dynamic contraction tends to exhaust levator scapula and upper trapezius but decreases paraspinals force.

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Background and Aim: The purpose of this study was to compare the effect of different types of isokinetic contractions on hemodynamic parameters in men.
Materials and Methods: Ten healthy male subjects (age, 26.1±3.4 years) in three separate sessions performed three exercise protocols included Concentric/Concentric (C/C), Eccentric/Eccentric (E/E) and Concentric/Eccentric (C/E) contractions (flexion and extension) in the knee joint. In each session subjects performed 4 sets, 10 repetitions, at the speed of 60 degree per second. Hemodynamic parameters (heart rate, systolic blood pressure, diastolic blood pressure, mean arterial blood pressure and rate of pressure product) were measured before exercise, immediately after exercise and after 30 min recovery. Data were analyzed using two- way repeated measures of ANOVA.
Results: Statistical analysis of data showed significant increases in heart rate, systolic blood pressure (P<0.001), mean arterial blood pressure (P=0.053) and rate of pressure product (P<0.001) during exercise and significant reductions in these parameters in recovery period. Rate of perceived exertion (RPE) was significantly different among the contraction protocols (F2,34=15.5) and post-hoc test showed that RPE was lower in E/E protocol than the other two protocols.
Conclusion: Hemodynamic parameters change in response to different muscular contractions, though these changes are not related to contraction type.

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Background and Aim: Osteoarthritis is the most common joint disease in adults around the world and plays a great role in inducing disability in elderly. Patients suffering from severe knee osteoarthritis usually complain of pain and severe functional disability. For these patients, conservative treatments are often induces least remedy for pain and improvement of functional ability. This study evaluates the effects of knee mechanical traction on pain, edema, range of movement and functional ability in patients with severe knee osteoarthritis.

Materials and Methods: In this clinical trial, forty women with severe knee OA (grade 3 & 4 on the Kellgren-Lawrence grading scale) were recruited and randomly divided into two groups with different treatment protocols (common physiotherapy treatment and common physiotherapy treatment accompanied by knee traction). Functional capacity and level of pain were assessed by 6-minute walking test and visual analog scale respectively. A goniometer was used to measure knee range of movement and edema was also evaluated by use of measuring tape.

 Results: Common physiotherapy treatment accompanied by knee traction compared to common physiotherapy treatment leads to significant decrease in pain (P<0.01) and increase in functional capacity (P<0.05).

Conclusion: Common physiotherapy treatment accompanied by knee traction is a more effective treatment than common physiotherapy procedure in patients with severe knee osteoarthritis.

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Background and Aim: Osteoarthrosis is a common condition in the cervical region due to the high mobility of this region. Despite the clinical popularity of traction that is often prescribed for patients with neck pain, there is no agreement on the effectiveness of traction. Due to the high controversy and the lack of experimental documents in the efficiency of the pneumatic traction device in reducing symptoms of neck pain, present study was conducted to evaluate the efficacy of the pneumatic traction device in reducing pain and amount of drug use, and improving disability level in patients with neck osteoarthrosis compared to the control group.

Materials and Methods: Twenty-six patients with neck pain aroused by osteoarthrosis were randomly assigned into two groups of control or experimental. The control group received hot pack, TENS, US, exercise therapy and ergonomic training as their usual physical therapy care. Patients in the experimental group also benefited from the sustained traction via the pneumatic traction device too. All participants were treated for 10 sessions. Pain (NPRS), the level of disability (NDI), the number of sedative drugs and NSAIDs were evaluated in the beginning of the first session and at the end of the last session.

Results: A significant decrease in the levels of the pain and disability in both groups were found (P<0.05). The decrease of pain and disability in the experimental group was significantly higher (P<0.05) than the control group. There was no significant difference in terms of the sedatives and NSAIDs within and between the groups at the end of the last session (P>0.05).

Conclusion: Although physical therapy and ergonomic trainings may lead to a significant improvement in neck pain and related disability in the osteoarthrosis patients, the use of pneumatic traction device can increase the rate of improvement.

Key words: Spondylosis, Neck pain, Traction, Air neck traction device