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Background and Aim: Sports such as baseball, volleyball, and racquet sports demand skills that place substantial load upon the athlete's shoulder when his or her arm is in an overhead or abducted position. Athletes who participate in these sports are consequently at higher risk for overuse injuries of the shoulder. Infraspinatus syndrome is defined as a condition of frequently painless atrophy of the infraspinatus muscle caused by suprascapular nerve neuropathy. The syndrome typically causes symptoms that mimic those of rotator cuff tendinopathy, and the diagnosis is often overlooked until the condition fails to respond to a traditional rotator cuff treatment program.

In this study muscle timing and activities of shoulder rotator cuff compared between normal athletics and volleyball players with infraspinatus syndrome.

Materials and Methods: Thirty voluntary male professional volleyball players (20 healthy and 10 patient) in the range of 20 -30 years contributed in this study. Patients group in base of electroneurography had injury of suprascapular nerve at right side. Subjects lied prone on table and their shoulder were 90 degree of abduction and medial rotation with 90 degree of flexion in elbow with vertically position of forearm at the lateral side of table. Electromyographic activities of maximum voluntary contraction of infraspinatus, middle trapezius and teres minor . Muscles were recorded three times with monitoring of dynamometer for normalization of dynamic activities. Activities (RMS) of above muscles were recorded during three dynamic motions similar to spark skill and onsets of their activities determined by external synchronized apparatus.

Results: There was significant difference between normalized RMS of infraspinatus,. and middle trapezius of patients in dynamic motion (p<0.05). Whereas healthy subjects showed significant difference between infraspinatus. and two other muscles (p<0.05). Comparison of normalized RMS indicated different in all three muscles between two groups (p<0.05).  

The sequence of onset three muscle activities were different between two groups significantly (p<0.05). This sequence in patients was middle trapezius, teres minor and infraspinatus whereas in healthy subjects was middle trapezius, infraspinatus and teres minor. Duration of above muscle activities were different in two groups (P<0.05). In patients infraspinatus were active less than other two muscles.       

Conclusion: Professional volleyball players are candidate of suprascapular nerve and infraspinatus muscle weakness. Synergic and stabilizer muscles after this condition with more activities contribute and caused reduce of accuracy of motion and early muscle fatigue.

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Background and aim: Ankle plantar flexor is one of the most susceptible muscles to plasticity and contracture after acquired brain injury. The application of thermal agents was introduced before muscle stretch or active exercises in spastic patients for their relaxation effects. The main aim of the present study was to compare the short-term effect of the ultrasound (US) and infrared (IR) on patients with plantar flexor muscle spasticity.

Materials and Methods: 21 patients were randomly allocated placed to either US(n=11)or IR(n=10)groups. The main outcome measures were, H _max / M _max  ratio, Original Ashworth Scale(OAS), active and passive range of motion (ROM).These tests  performed before, immediately after and 15 minutes after the intervention.

Results: There were no significant changes in H _max / M _max ratio and OAS after the intervention in both groups. The significant changes of the H _max / M _max were observed 15 minutes after intervention in the US group .The change in OAS was also statistical significant in IR group in this period. The changes in active and passive ankle dorsiflexion ROM after the intervention were statistically significant in US group. These changes show the significant changes for ankle passive ROM after15 minutes of  the intervention in IR group.

Conclusion: Our findings demonstrate that one session application of the ultrasound and infrared are not effective in the treatment of muscle spasticity. The ultrasound improved the ankle active and passive ROM. Further research is needed.

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Background and aim: Human knee joints experience very large loads and motions during regular daily, occupational and sport activities. Consequently, they are at high risk of being exposed to injuries and degeneration. Osteoarthritis and ligament injuries often inflict knee joints causing considerable pain and loss of productivity involving thus significant human and economic costs. Hence, biomechanics of human knee joints has been the focus of many investigations with the primary aim to improve understanding of joint function in normal and perturbed conditions. The existing prevention and treatment programs have been based on such studies.
Material and Methods: Due to inherent costs, limitations, difficulties and ethical concerns associated with in vivo and in vitro cadaveric studies, finite element model studies have been developed as effective, powerful and complementary tools to investigate knee joint biomechanics subject to internal and external mechanical conditions affecting its normal function.
Results: The advantage of finite element method in study of joint biomechanics lies in its robustness to incorporate complex 3D joint geometry, intricate boundary and loading conditions and materials with nonhomogeneous and nonlinear properties.
Conclusion:This article reviews important model studies, presents their relevant results and discusses some of the promising future directions.

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Background and Aim: Work related injury (WRI) can cause problems such as change or loss in job, fatigue and burnout. Injury prevalence has increased from 10.2% to 13.5% in the U.S. therapists since 2004 to 2006. At least 3,700 physiotherapists and 900 occupational therapists membership in Iranian Medical Council and developments of occupational therapy and physical therapy domains are involved in our country and the growing trend of student admissions in these fields and also limited researches in work-related problems of therapists, there would be a challenge in research studies. The overall goal of this systematic review was to survey the prevalence of work-related problems, predisposing factors and causes of these problems among therapists and finally predict problems of Iranian occupational therapy and physiotherapy population. 
Materials and Methods: By performing the five stages of an evidence based systematic review with regard to the selection criteria obtained from related articles, looking for articles were done through using internet databases, reference books and Citation review. At first, 50 articles were obtained. Finally, this study reviewed 25 articles in the last two decades in different parts of Iran and the world (1990-2010)
Conclusion: It was clarified that muscular injuries were of the most common types of damages caused by these works. Injuries were seen in most particularly in public, orthopedic and acute settings. Low back pain was remarkably reported. Age under30 years, inexperience and heavy work were some of the risk factors. Improper handling was determined as the main cause of injuries in therapists. Besides musculoskeletal injuries, common psychosocial problems were depression, anger and job frustration. Finally, considering culture and job characteristics of the Iranian therapists, the data and results were compared and discussed to predict different aspects of WRI in Iranian therapists.

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 Background and Aim:  Because of high incidence of hand injuries and the need for a quantitative method that provides measures of patient improvement in treatment period, a precise and easy-to-apply quantitative procedure is necessary. As a first step in validating of such a method, the intersession repeatability of quantified measures was assessed in this study. 

Materials and Methods: Measurement of hand drawing skills by drawing circle shape in two speeds (preferred and maximum) and spiral shape just in a preferred voluntary speed with two repetitions for each subject was assessed in 15 subjects. Digital data was recorded by a Tablet PC using special software with average sampling rate of 120 Hz.

Results: The quantified variables computed for circle and spiral drawing tests with preferred speed were reliable (0.55 < ICC < 0.85), so they can be used for drawing quantifications. Results of drawing circles with maximum speed were not reliable (ICC<0.5).

 Conclusion: Repeatability analysis revealed that measures based on drawing circles with maximum speed are not repeatable and cannot be used for progress monitoring. This may be due to large variation in providing maximum drawing speed during test time. On the other hand, spiral and circle drawing parameters with preferred speed had a better repeatability and can be used for quantification of hand drawings in researches. 

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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: Leg stiffness has recognized as a parameter related to sports performance and injury risk. The aim of the present study was to compare of leg stiffness during hopping test between female and male athletes.

 

Materials and Methods: Thirteen females and 12 males of the best Iranian racket-players participated in this study and<span style="font-family:;" dir="RTL" new="" b="" fa;="" mitra";="" roman";="" "times="" roman";"="" 12pt;=""> performed the bilateral hopping test at a frequency of 2.2 Hz. The subjects' leg stiffness was measured and was normalized through dividing by their body weights. Independent samples t-test was used to compare the mean of research variables between the female and male groups.

 

Results: Leg stiffness in the females was significantly lower than the males (p< 0.001), however the body mass-normalized leg stiffness was not significantly different between two groups (p = 0.290).

 

Conclusion: The lower leg stiffness observed in the female athletes may be a factor justifying their weakness in speed-based performances during horizontal movements. Furthermore, non-significant difference in normalized leg stiffness between two groups may indicate using a risky strategy by the females in vertical movement to compensate for the less inherent stiffness of their tendinous and muscular structures. Choosing the proper training programs to change the leg stiffness, may be an effective method to enhance the performance and to decrease the injury risk.

 

Keywords: Leg stiffness, Female and male athletes, Sports performance, Injury risk