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Background and Aim: Multifidus muscle is one of the short and deep posterior Paraspinal muscles, which gives stability to the spine during various activities. Studies have shown that in people with neck pain, weakness and atrophy of neck muscles are major factors in the incidence of neck pain. Measurement of muscle's dimensions by ultrasonography provides an opportunity to be able to objectively assess muscle atrophy or hypertrophy. This study aimed to assess symmetry of cervical multifidus muscle size in females with chronic non-specific neck pain and healthy by ultrasonography apparatus.

Materials & Methods: Twenty five women with unilateral chronic nonspecific neck pain and 25 healthy women were participated in this study. All subjects were employed and more than 4 hours working with computers or paying office in a day. Imaging of the cervical multifidus muscles were done bilaterally in the level of the fourth vertebra. Anterior-Posterior Dimension(APD), Lateral Dimension(LD), Cross-Sectional Area (multiplied of two diameters(APD&LD)) and the Shape ratio (Lateral diameter divided by the Anterior-Posterior diameter(LD/APD)) of the muscle were measured and recorded. 

Results: Multifidus muscle size in patients group was smaller than the healthy group. In patients group, size of multifidus muscle in the painful side was smaller than the opposite side. Asymmetry of muscle size between the two sides, in the patient group was higher than the control group (P < 0.05). The ratio of smaller size to the larger size of the muscle, in the healthy group was higher than the ratio in the patient group (P < 0.05).

Conclusion: In patients group, asymmetry of the muscle size between two sides, also smaller size of the muscle in the painful side, showed that muscle atrophy has happened in the involved side.

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Background and Aim: One of the risk factors in sports injuries is inappropriate flexibility of muscles, which leads to pain, decrease range of motion and functional limitation in sport or daily activities and affects the athletes’ quality of life. The aim of this study was to investigate the relationship between flexibility of calf muscles and functional status of athletes with ankle injuries.
Materials and Methods: Thirty male athletes with ankle injuries (mean age ± SD, 22.63 ± 3.94 range: 18-40 years) participated in this study. Ankle dorsiflexion of affected and non-affected sides were measured with a goniometer. FAOS (Foot and Ankle Outcome Score) questionnaire was used to evaluate the functional status of ankle.
Results: The relationship between flexibility of calf muscles in the affected extremity, and total score of the functional questionnaire, was not statistically significant (P>0.05). While the relationship between the flexibility of muscles and functional questionnaire's total score in the non injured extremity was significant (P = 0.004, r = 0.51).
Conclusion: This study revealed that although the athletes who have more flexibility of calf muscles, show better functional status of ankle but there is not necessarily a relationship between inflexibility of the muscles and lowered functional status.

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  Background and Aim: Since many of people in their functional activities mostly place their knee joint in flexed position, the hamstring muscles tend to be shortened. On the other hand, shortness of these muscles affect the knee joint directly and the ankle and hip joints indirectly. It predisposes the individual to musculo-skeletal injuries. Thus, by early diagnosing and treatment of it, the tension may be decreased, the relaxation increased and the development of injuries can be prevented. In order to achieve this goal, various stretching techniques are used. The purpose of this study is to compare the effects of static and PNF stretching on shortness of hamstring muscles in 18-30 years young women.

  

  Materials and Methods: Thirty 18-30 years old nonathletic women without any history of pathology in hip, knee or back were selected. They were divided into three groups with 10 women in each group(static stretch, PNF stretch and control). The two stretch groups were received stretching program five days every week for three weeks, while the control group was not.

  Results: The range of knee extension of both groups of static and PNF stretching increased (p<0/05). However there was no significant difference between these two groups (p>0/05).

  

  Conclusion: Employing of both methods (static and PNF stretching) increase the hamstring muscles flexibility. However there was no significant difference between two groups in increasing rang of knee extension.

  

  Key words: Hamstring muscles, static stretching, PNF stretching

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Background and Aim: Sacroiliac joint (SIJ) is one of the most important elements in normal musculoskeletal function during gait cycle and serve as a shock absorber during heel strike and load transfer from lower limbs to trunk. Its stabilizing is the product of osseous, ligamentus and muscular elements which muscle activity of these muscles (Gluteus Maximus, Biceps Femoris, Multifidus, Erector Spinea, and Latissimus Dorsi) is important in load transfer through SIJ. It seems that the function of the given muscles in sacroiliac joint pain subjects is interrupted. So, the aim of the present study is to compare muscle activity during different events of stance phase of gait cycle during preferred and slow speed between sacroiliac joint pain and healthy subjects.

  

Methods and Materials: Thirteen SIJ pain subjects (12 females, 1 male) and thirteen healthy subjects (11 females, 2 male) participated in this study. Muscle activity based on RMS from selected muscles was recorded during different events of stance phase of gait either preferred or slow speed by EMG Data-link Biometrics and normalized according to muscle activity during a 500 ms period in rest position before starting walking called Baseline Correction.

  

Results: Significant statistical differences were found between two groups in muscle activity based RMS during different events of stance (p=0/006), but there was no significant difference in effect of speed on RMS between two groups (p=0/37). Significant Statistical differences were also seen between selected muscles in each group separately during slow speed of walking (p=0/003) but no significant statistical difference during preferred speed in SIJ pain group (p=0/14).

  

Conclusion: SIJ subjects have showed increased levels of muscle activity during different events of stance phase of gait with preferred and slow speeds. These increased levels can be interpreted as a mechanism to control trunk movements effectively, provide sufficient support and transfer load to lumbar area efficiently.

  

Key words: Muscle activity, Sacroiliac joint, Gait, Trunk muscle, Lower limb muscles

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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: Genu varum and genu valgum are two most common deformities of the knee joint in children and adults. In these deformities knee muscles function maybe affected by the alteration in mechanical axis of lower limb. The aim of this survey was to provide some basic knowledge about the function of knee muscles in patients with genu varum and genu valgum deformities.

  

Materials and Methods: Studies were identified by searching in the Pub-Med, Science Direct, Google Scholar databases and authoritative references available on the internet and library for articles and books published after 1990,with the key words such as genu varum, genu valgum, knee muscles, bow leg, knock knee and knee frontal angle.

  

Results: Among 102 papers and 10 books resulted from the first search, only 30 papers and 5 books were related to this literature review and just10 papers and 2 books among them were about changes in knee muscles.

  

Conclusion: The results of this survey indicated that patients with genu varum and genu valgum deformities have architectural and functional alteration in their knee muscles. According to the results most of these studies have noticed the basic changes in quadriceps muscle function and architecture. It is necessary to study more about the function of other knee muscles.

  

Key words: Genu varum, Genu valgum, Bow leg, Knock knee, Knee muscles.

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Background and Aim: Muscle fascicle length and pennation angle can be non-invasively studied by applying methods like ultrasonography. The aim of this study was to introduce fascicle length and fascicle angle for the estimation of the strength of skeletal muscle by using ultrasonography.

  

Materials and Methods: The data of this study have been driven from pubmed and authoritative references available on the internet and in libraries. In all fifteen full text articles and 30 abstracts have been collected and reviewed. Keywords such as: muscle, fascicle, pennation angle, force and ultrasonography were searched to fulfill the purpose of this study.

  

Results : Detailed information about the angles of pennation and fascicles length are important to predict muscle force. It has been suggested that changes in muscle pennation angles are positively correlated to the length of fascicle in a muscle contraction. While muscle thickness may in some case be remained constant in this relation.

  

Conclusion: Real-time ultrasonography is a noninvasive procedure to monitor the architecture of the living muscle at rest and during static and dynamic sets. It is a valuable measurement tool to estimate muscle force by measuring the muscle architecture parameters such as angle of pennation and fascicle length.

 

Keywords : Muscle, Fascicle, Pennation angle, Force, Ultrasonography

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Background and Aim : The aim of this study was to determine the effects of fatigue due to plyometric training on vertical jump ability and activity pattern of rectus femoris of dominant leg of high jump of active girls .

 

Materials and Methods : Seventeen females , mean age (21.5 ± 0.76 years ) were randomly assigned to two experimental (n = 10 ) and control ( n = 7) groups. Experimental group performed plyometric training and control group had no activity. Before and after training , vertical jump test using Ergo jump and electrical activity of rectus femoris muscle of dominant leg using electromyography were tested . The results of vertical jump test showed a decrease in performance (p: 0.04, F: 4.5) and fatigue process was confirmed . The raw EMG signal based on deep jump phases was divided in three phases and only 2 phases of the first were analyzed . In every phase, the maximum activity , amplitude and total time were obtained .respectively. M ultivariate analysis of variance (2×2) was used to compare of post-test of two groups.

 

Results : After one session training , rectus femoris maximum activity of the experimental group showed a significant decrease in pre-activation phase of motor program .

 

Conclusion : This study showed that neural fatigue due to plyometric training can occur in motor program (especially in pre-activation phase of motor program ).

  

Keywords : Deep jump, Plyometric training, Vertical jump, Electromyography, Rectus femoris muscle.

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Background and Aim : Hemiplegic shoulder pain is a common problem that its prevalence varies from 48% to 84%. This disorder limits the patient’s ability to achieve the optimal function. The objective of study was to assess the relationship between hemiplegic shoulder pain with neuromusculoskeletal disorders in post stroke hemiparesis

  

Materials and Methods: This study was an observational-analytic that fullfilled on fifty patients with acute stroke. The post stroke period was 28 days. The following items were evaluated:shoulder subluxation with X-ray, shoulder spasticity with Modified Modified Ashworth Scale (MMAS), soft tissue injury with orthopaedic tests and RSD with clinical features.

 

Results: Hemiplegic shoulder pain was present in 28 patients(56%). Seventeen patients (85%) showed shoulder subluxation, 18 patients (72%) had supraspinatus tendonitis ,13 patients (65%) had biceps tendinits, 4 patients (14/2%) had ACJ involvement, 3 patients (10/7%) had elbow flexor spasticity, 2 patients (7/1%) had shoulder adductor spasticity ,2 patients (7/1%)had shoulder internal rotators spsticity , 4 (14/2%) patients had RSD.

  

Conclusion: Results from this study show that one factor does not play role in causing hemiplegic shoulder pain and this disorder is multifactorial. Prevention of shoulder pain and performing appropriate physiotherapy can play a role in improving stroke patients’ function.

 

Keywords: Stroke, Shoulder pain, Sublxation, Muscle tone, Shoulder –Hand syndrone

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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: Low back pain (LBP) is the most common and expensive musculoskeletal problem in industrialized societies. One in ten people suffers from LBP once in his life. It is self-limited up to 90%, but it is common to repeat. By the way, sacroiliac joint (SIJ) is the origin of low back and pelvic pain in many cases and one of the most important elements in normal musculoskeletal function during gait cycle. Muscles are important to stabilize this joint plus to bones and ligaments. Some of the muscles (Gluteus Maximus, Biceps Femoris, Multi Fidus, Erector Spinae) contributing in gait cycle are important to transfer load through SIJ. The aim of this present study is to compare muscle activity timing during initial and mid stance phase of gait cycle.

  

Methods and Materials: Sixteen low back pain cases and fifteen healthy subjects participated in this study. A footswitch is placed beneath foot at the suffered side in LBP cases and dominant foot in control group. Two markers were on the 5^th metatarsal bone and lateral maleolus. Electrodes are placed on selected muscles according to SENIAM. Digital camera and EMG Datalink were turned on simultaneously and subject started to walk with his own favorite speed in a specific direction and path. Onset and time to peak of selected muscles were recorded during gait by Datalink and processed by its software.

  

Results: Low back pain cases showed delayed muscle onset, although it was not significant (P=0.4). Time to peak of all selected muscles in loading response event in LBP group was longer and significant (P=0.01). There was also significant difference in time to peak of all selected muscles during mid-stance event (P= 0.005) except biceps femoris muscle.

  

Conclusion: Delayed onset and longer time to peak during initial and mid stance phase of gait can be interpreted as a compensatory strategy to control trunk movements effectively, provide sufficient stability and transfer load to lumbar area efficiently.

  

Key words: Muscle activity, Low back pain, Gait, Trunk muscles, Lower Limb Muscles

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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

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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: Low back pain (LBP) is the most common and expensive musculoskeletal problem in industrialized societies. One in ten people suffers from LBP once in his life. It is self-limited up to 90%, but it is common to repeat. By the way, sacroiliac joint (SIJ) is the origin of low back and pelvic pain in many cases and one of the most important elements in normal musculoskeletal function during gait cycle. Muscles are important to stabilize this joint plus to bones and ligaments. Some of the muscles (Gluteus Maximus, Biceps Femoris, Multi Fidus, Erector Spinae) contributing in gait cycle are important to transfer load through SIJ. The aim of this present study is to compare muscle activity timing during initial and mid stance phase of gait cycle.

  

Methods and Materials: Sixteen low back pain cases and fifteen healthy subjects participated in this study. A footswitch is placed beneath foot at the suffered side in LBP cases and dominant foot in control group. Two markers were on the 5^th metatarsal bone and lateral maleolus. Electrodes are placed on selected muscles according to SENIAM. Digital camera and EMG Datalink were turned on simultaneously and subject started to walk with his own favorite speed in a specific direction and path. Onset and time to peak of selected muscles were recorded during gait by Datalink and processed by its software.

  

Results: Low back pain cases showed delayed muscle onset, although it was not significant (P=0.4). Time to peak of all selected muscles in loading response event in LBP group was longer and significant (P=0.01). There was also significant difference in time to peak of all selected muscles during mid-stance event (P= 0.005) except biceps femoris muscle.

  

Conclusion: Delayed onset and longer time to peak during initial and mid stance phase of gait can be interpreted as a compensatory strategy to control trunk movements effectively, provide sufficient stability and transfer load to lumbar area efficiently.

  

Key words: Muscle activity, Low back pain, Gait, Trunk muscles, Lower Limb Muscles

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Background and Aim: Postural control is the ability of maintaining of the body posture in space. Peripheral and central factors have important role in muscle fatigue. Repetitive muscle contraction leads to muscle fatigue. If strength is educed up to 30% of maximum contraction can be disturbed stance control of subjects. The objective of the present study was to compare the effect of lumbar muscle fatigue on postural control in athlete and non-athlete subjects.

  

Materials and Methods: Fifteen men as athlete subjects and other fifteen matched men as non- athlete subjects participated in this study. Trunk extensor muscle fatigue was produced by dynamometer. Stance postural sways were evaluated by force platform device in bipedal stance with open eye.

  

Results: In pre-fatigue state there is no significant difference between two groups. Fatigue had significantly effect on postural sways in both group after Lumbar muscle fatigue specially in non-athlete group (P ≥ 0.05) .

  

Conclusion: The postural control of athletes after muscle fatigue was better than non athlete subjects probably due to better proprioception in athlete subjects.

  

Keywords: Muscle fatigue, Postural control, Force plattform.

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Background and Aim: Reliability or unreliability of the results achieved from recording of surface electromyography of muscles has always been questioned. The aim of present study was to  measure the reliability of the delayed reaction time of muscle electromyography of the knee joints on the exposure of unexpected rotary turbulence in the transverse plane from the area of supporting surface.

Materials and Methods: Twenty healthy women from 19 to 30 years old and free from any clear deformities in the lower extremities were participated in the present study. Surface electromyography of the six knee musculature was carried out for every subject separately in 4 situations including: External Rotation (Ext Rot) from plantar area on the transverse plane with bent and straight knee, Internal Rotation (Int. Rot) with the same conditions, Single Leg Stance situation in 4 stages, and repeatability of Intra Session through intra-class correlation coefficients when the muscles are in action on the exposure of turbulence in four applied forms were analyzed.

Result: The results from 24 analyzed forms showed that 18 forms of muscles at the time of action had moderate to high repeatability (Monroe Classification)

Conclusion: Regarding reliability, the muscles indicated different amounts in onset latency time, on the exposure of rotary turbulence, according to joint angle and the direction of applying rotation on the transverse plane. In respect to direction of rotation, most of the muscles indicated more reliability on the exposure of external rotation turbulence (clockwise) in relation to internal rotation (anti-clockwise) and also regarding the joint angle in turbulences with straight knee in relation to turbulences with bent knee. 

Keyword: Knee muscles, Surface electromyography, Reliability, Rotational turbulence

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Background and Aim: The main cause of Myofascial pain syndrome is trigger point. The purpose of this study was to compare muscle energy technique (MET) with dry needling (DN) on latent trigger point of upper trapezius.

Materials and Methods: Fourty females, with diagnosis of latent trigger point of upper trapezius after adopting the inclusion and exclusion criteria were equally and randomly allocated into either the muscle energy technique or dry needling groups. Each patient received one treatment to the upper trapezius muscle. Outcome measures (visual analogue scale (VAS), pressure pain threshold (PPT), and range of active contra lateral flexion (CLF) measured before and 48 hours after treatment.

Results: Two techniques which used in this study were effective for treating latent trigger point of upper trapezius (P<0/001) but no significant differences were found between the two groups in terms of the above variables (p>0/05).

Conclusion: This study demonstrated that muscle energy technique was as effective as dry needling in improvement of VAS, PPT and ROM in subjects with latent trigger point of upper trapezius muscle. But since muscle energy technique is safe and non-invasive method, therefore, if you want to select one of these two techniques, muscle energy technique is recommended.

Keywords: Dry needling, Muscle energy technique, Trigger points

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Background and Aim: Shoulder injury is one of the most common injuries in overhead sports. Impingement syndrome is most frequent cause of these injures. Scapular has important biomechanical role in normal shoulder function .Muscle imbalance changes normal scapular arthrokinematic and as a result the risk of injury is high. One of the treatment methods which is used in athletes with impingement syndrome is kinesio taping. Goals of this study was to investigate the effects of kinesio taping of trapezius muscles on pain , functional movements of shouhder joint and lateral scapular slide in athletes with impingement syndrome.

Materials and Methods: Fifteen athletes with a mean age of 30.53±3.56 with impingement syndrome participated in this study. Pain with visual analog scale , functional movements and lateral scapular slide test in 3 positions was  assessed . Then kinesio taping was used for trapezius muscles .Repeated evaluation was performed in 3 different periods of : 20 minutes , 72 hours , 6 days  after first session.

Results: Mean of  pain was reduced in 72 hours and 6 days after kinesio taping (p=0.003) .  Ext.rot + abd movement after kinesio taping was improved and the most improvement was 6 days after kinesio taping (p=0.004). Int.rot+add movement after kinesio taping was improved and the most improvement was 6 days after kinesio taping (p=0.001). Lateral scapular slide test in first position and second position improved significantly. In third position test did not change significantly after kinesiotaping.

Conclusion: Kinesio taping of trapezius muscles in athletes with impingement syndrome has effects on pain reduction, improvement of functional movement of shoulder and improvement of scapular kinematic. Therefore kinesio taping can be used as a treatment in athletes with impingement syndrome.

Keywords: Kinesio taping, Trapezius muscles, Impingement syndrome.

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Background and Aim: Several studies have investigated the effects of angular velocity on mechanical and physiological variables such as joint net torque, muscle force and myoelectrical activity, but so far its effects on the control of the pattern of synergist muscle activation during isokinetic movements have not been studied. In this experiment, a computational method of identifying and analyzing muscle synergies were used which is based on the framework of the uncontrolled manifold hypothesis to determine the variability of muscle synergies following movement velocity alteration.

 

Materials and Methods: Twelve healthy females without any known neurological or motor disorders participated in the experiment. The participants were positioned on a Biodex dynamometer. They were asked to perform ten continuous knee extension and flexion motions with maximal strength at 45˚/s or 300˚/s. Electromyographic activity of the vastus medialis (VM), vastus lateralis (VL) and rectus femoris (RF) were recorded and variance within the UCM (VUCM) and orthogonal to the UCM (VORT) with respect to an appropriate Jacobian matrix was computed. An independent t-test was used to compare VUCM between two velocities.

 

Results: Across subjects, VUCM was significantly higher than VORT (VUCM>VORT) in both tasks. There was no significant difference in VUCM between two velocities (p>0.05).

 

Conclusion: Our findings suggest that angular velocity is not an important parameter when a controller of a multi-element system wants to stabilize a particular value of a performance variable.

 

Keywords: Variability, Angular velocity, Muscle synergie, Externsor muscle.

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Background and Aim:: Muscular shortness is one of the most common musculoskeletal impairments. It may occur as a result of trauma or even a sedentary life style and cause clinical symptoms. Hamstring muscle, due to its functional roles, is prone to injuries during physical activities. Research has shown that decreased hamstring muscle flexibility may lead to lower extremity injury. The goal of this study is to compare the effects of myofascial release (MFR) and muscle energy technique (MET) effects on hamstring muscle flexibility. 

Materials and Methods: Twenty four non-athlete healthy subjects (means ± SD= 26/12 ± 5.4 Years) were randomly assigned to two groups; myofascial release group and muscle energy technique group. Passive range of motion (ROM) of knee extension was measured using a digital goniometer before and immediately after the intervention.

Results: There was a significant increase in the knee passive range of motion immediately after both interventions (in MFR group p=0.000 and in MET Group p=0.000).The amount of knee extension increase was greater in myofascial release group (p=0.023).

Conclusion: Both MFR and MET can increase hamstring muscle flexibility; however, in this study MFR has shown to be more effective than MET.

Keywords: Flexibility, Muscle energy technique,  Myofascial release technique,  Hamstring muscle