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Background and Aim:Whole body vibration (WBV) has been regarded as an exercise training method and as a non-pharmacological supportive treatment option appearing to be efficient for chronic disease conditions, such as bone disorders and cardio-respiratory fitness. Since, data on the safety and efficacy of vibration on plasma parameters are lacking, therefore, the purpose of this study was to assess the effects of WBV on the plasma parameters in adult male Wistar rat model.

Materials and Methods: Male Wistar rats weighing 140-180 g were divided into control and the vibration group. Vibration training consisted of vertical sinusoidal whole body vibration for 8 weeks, followed by blood collection.

Results: The vibrated rats weighed more than the control group (approximately 14 % more). Plasma CK, E2 and IL-6 levels were significantly higher in the vibration group compared with the controls. The mean of Vit. D level was 15% higher hsCRP level was 11% lower and IL-6 level was 32% higher in the vibration group. No difference was observed for other selected plasma parameters.

 Conclusion: The potential effects of physiological responses of WBV on several physiological systems are without deteriorations in plasma parameters.

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Background and Aim: In studies of the spinal circuits, change of Renshaw cell activity is measured by H´ response. For recording H' response, new electrical stimulation device was designed and built and the first recorded H' response in Iran was done. The purpose of this study was to investigate the intersession and intra-session reliability of peak amplitude of H´ response and its related intensity detected of new device.
Materials and Methods: Soleus muscles of dominant extremity in 6 subjects were tested in 3 sessions and 2 times in each session that intra-session interval was 20 minutes and intersession interval was 1 week.
Results: Peak amplitude and its related intensity exhibited intra-session and intersession reliability 0.92, 0.98, 0.86 and 0.9 respectively. Standard Error of Measurement was 0.37 and 0.47 for intrasession and 0.44 and 1.06 for inter session respectively.
Conclusion: Peak amplitude and its related intensity exhibited very high intra-session and intersession reliability.

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Abstract

Background and Aim: The Action Observation stimulates mirror neurons. It is the effective acquisition of skills, motor learning and memory formation and this feature can be used to treat injuries such as stroke. The aim of this study was to investigate the effect of action observation on the symmetry of weight distribution in lower limbs and stability indices in semi-dynamic stability.

Materials and Methods: This study was conducted in 91 healthy male and female non-athletes aged 20 to 45 years. Data were collected through questionnaires and clinical examinations. Subjects were randomly assigned to men and women with and without film observation. A 3-minute short film was preapared to stimulate mirror neurons in the standing position on the symmetry weight measurement system and Biodex platform system. In film observation group, before and after viewing the film, distribution of weigh bearing on the right and left sides, and dynamic stability indices in two stability levels of 5 and 8 were measured and calculated indices of total, anterior - posterior and medio- lateral indices were obtained. In without film observation group, measurements were performed at the similar time as a film observation group.

Results: Percentage weight distribution showed no significant difference between the two groups. The comparison of percentage changes between two groups showed that observation of the film improved significantly total index (p <0.002) and anterior – posterior index (p <0.018) in the stability level of 5. Analysis of the results in the separately men and women groups, showed the significant improvement of these parameters only in women group after film observation regardless of film observation, the percentage changes of stability indices showed no significant differences in men groups.

Conclusion: Action Observation (by activating the mirror neurons) can be effective methods to improve the balance standing of healthy people on the stable and unstable surfaces. Significant improvement stability indices in women after viewing the film, may suggest the greater sensitivity of women's mirror neurons related to men.

Keywords: Mirror Neurons, Action Observation, Symmetry of Weight Distribution, Dynamic Stability, Stability

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Background and Aim: The normal response of H-reflex depression (HD) was reduced in chronic spinal cord injury (SCI) patients. The reduction of this normal response can lead to increase the muscle tone and spasticity. The purpose of this study is to investigate the effect of tripolar cathodal stimulation on HD in SCI patients.

 

Materials and Methods: This study was conducted in 10 volunteered SCI patients and 13 healthy male and female aged 28.91 ± 5.78 years. H-reflexes were elicited at 0.2, 5 and 0.2 Hz and intensity of 65-70 percent of the maximum H-reflex amplitude, before and after tripolar cathodal electrical stimulation of the spinal cord at T₁₁ level.

 

Results : Before trioplar stimulation, H-reflex amplitude decreased with increasing stimulation frequency only in healthy group. H-reflex amplitude decreased from 2.60 ± 1.48 to 1.34 ± 1.30 by 5Hz frequency (P=0.000). After trioplar stimulation in SCI patients group, HD increased with increasing stimulation frequency and H-reflex amplitude decreased significantly from 2.21 ± 1.98 by 0.2 Hz frequency to 1.29 ± 1.50 by 5Hz frequency(P=0.014).

Conclusion: Application of one session of cathodal trioplar stimulation can result the returning of normal HD in SCI patients. Cathodal trioplar stimulation is a non-invasive, without side effects, and an inexpensive method that may be a valuable tool to return the normal inhibition and modulating behavior of the spinal cord circuits.

  

Keywords: Spinal cord injury , Tripolar stimulation, H-reflex depression, Soleus muscle

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Background and Aim: Despite the widespread use of whole body vibration (WBV),especiallyin recent years, its neurophysiological mechanism is still unclear and the results about the facilitatory or inhibitory effects of WBV widely vary in different studies. The aim of this study was to compare between immediate (one session) and short term (12 sessions) effects of WBV on the spinal motor neurons excitability in healthy young men.

  

Materials and Methods: Ten voluntary non-athlete healthy young-men (mean age:26.1±2.23) were participated in this study.In the sham sessions subjects stood on the turned off vibration plate while were maintaining the semi-squat position and then after 2 weeks wash-out, vibration training sessions were done on the same position with frequency of 30 HZ and peak to peak amplitude of 3 mm training sessions (sham & vibration) consisted of 12 sessions (3 sessions per week) and 4 set in each of them, weekly one set added to the training protocol. H reflex recruitment curve of soleus muscle was recorded before and after first and also 12th sessions in both sham and vibration training protocol. Ascending slope of recruitment curve, threshold and peak amplitudes and related intensities, amplitude of Mh and Hmax/Mmax ratio were determined.

  

Results: Immediate effects of vibration training 12th session caused a significant decrease of threshold amplitude and an increase of peak intensity (p=0.05 and p=0.05 respectively). Short term WBV training significantly decreased the threshold intensity of soleus recruitment curve (p=0.01).

  

Conclusion: The results suggest the inhibitory effect of acute WBV training on the spinal motor neurons excitability. It seems that short term WBV training may be effective to facilitate the motor neurons excitability or increase the muscle spindle sensitivity.

  

Key Words: Whole body vibration, H reflex recruitment curve, Soleus muscle, Short term training

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Background and Aim: According to the further tendency of osteoporotic people to use the hip strategy to maintain stability, in present study, the relationship between hip, ankle and back extensor muscles strength and functional balance in healthy and osteoporotic postmenopausal women were evaluated.

  

Materials and Methods: Forty-five volunteer postmenopausal women were divided into two normal and osteoporosis groups according to their bone mineral density. Maximal isometric strength of hip, ankle, and back extensor muscles were assessed by a hand-held digital dynamometer. Functional balance was assessed by Near Tandem Stand (NTS), Star excursion (SE) and Figure of 8 walking (F8W) tests.

  

Results: In osteoporosis group, all muscle groups were significantly weaker than the normal group (P<0.05), and the time of F8W test was significantly more than normal group (P=0.031). Also, in osteoporosis group, hip adductors and extensors showed a significant correlation with three functional balance tests (P<0.05).

  

Conclusion: Regarding to decrease of muscle strength in osteoporotic women and its relationship to declining of functional balance in ADL, strengthening of hip and ankle muscle groups should be considered in their rehabilitation programs.

 

Keywords: Muscle strength, Functional balance, Postmenopausal women, Osteoporosis.

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Background and Aim: There are many disputes concerning the role of skin receptors on excitability of spinal motoneurons. The purpose of the present study is to evaluate the motoneuron excitability and H-reflex recovery curve of Soleus and Gastrocnemius muscles after application of local anesthesia on the skin of vertebral column.

Materials and Methods: Thirty healthy non-athlete female volunteers with a mean age of 27.20 ± 3.11 years old, were tested in two separated sessions. The H-reflex recovery curve of Soleus and Gastrocnemius were recorded before intervention and 15 minutes after the application of anesthesia (lidocaine 10%) or placebo anesthesia (water), with two excitation intensity of 30% and 100% of Hmax and interval interpulses of 1-202 ms. After extraction the amplitude of H1 and H2 response and fitting the recovery curve their amplitude and interval of the peak, area under the curve and, thresholds of the early and secondary facilitation were calculated and analyzed.

Results: After application of lidocaine, the sensory threshold of the vertebral column skin increased significantly. Due to a significant increase in H1 amplitude, peak, and area under the curve of the early facilitation showed a significant decrease (p<0.05). Threshold of the secondary facilitation showed a significant decrease in the Gastrocnemius and Soleus muscles (p<0.05).

Conclusion: The results suggest that decrease of skin receptors activity after anesthesia can facilitate motoneurons excitability and H-reflex recovery. It seems that using the method of paired stimulation and H-reflex recovery curve may be useful to investigate the effect of physical therapy modalities on the fast and slow motoneuron excitability.

Keywords: H-reflex recovery curve, Local anesthesia, Cooling, Motoneuron excitability.