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Background and aim: The shoulder area is the most complex region of the body and inherently unstable that motions are produced and controlled by sequenced activation of muscles in force couple patterns. It seems that investigating of shoulder muscle activation pattern is essential in the various tasks in healthy subjects due to the unstable structure of the shoulder and vital role of muscles in the stability. In order to evaluate motor control changes in the various movement, designing the therapeutic programs suitable to the shoulder pain and to evaluate effects of physiotherapy and preventing of side effects, this study was conducted. Up to now, it has not been evaluated in the D1flex & D1ext patterns yet.

Materials and methods: Thirteen female healthy volunteers participated in the experiment. Dependent variables of muscle activation such as onset and offset as well as sequencing of muscles (upper trapezius, lower trapezius, serratus anterior, pectoralis major, anterior deltoid and posterior deltoid) of dominant side were calculated during D1flex & D1ext patterns by surface EMG and Data log software in the standing position with speed movement of 25 degree/second.

Results: Special patterns of muscle activation were observed during D1flex & D1ext. Sequencing of muscle activation was different in the both movement patterns. Also, significant differences were found in the latency time of all muscles (p<0.05) except upper fibers of trapezius related to flex/ext goniometer (p=0.33) between both movement patterns.

Conclusion: This study demonstrated that there are special patterns of activation of muscles around the scapulohumeral articulation in the normal subjects. Rehabilitation and conditioning programs should be designed to restore and optimize the activation sequences and task specific functions of these muscles.

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Background and aim: Altered muscle activity in the scapulothoracic and glenohumeral muscles is commonly believed to be a factor contributing to shoulder impingement syndrome (SIS), then, the aim of the study was to determine and compare the activity pattern of the shoulder muscles in subjects with and without SIS.
Materials & Methods: In this case-control study, 9 female subjects with shoulder impingement syndrome and 13 matched healthy female subjects were participated voluntarily by simple random sampling. Surface electromyography of serratus anterior, pectoralis major, upper trapezium, lower trapezium, posterior deltoid, anterior deltoid muscles of dominant side were recorded during D1ext and D1flex movement. Muscle activities were processed and compared in subjects with and without SIS. Non parametric test (Mann-Whitney Test)) was used for data analysis
Results: In both movement patterns, all muscles of the patient showed a greater normalized RMS than healthy group but this increase was statistically significant in anterior deltoid (p=0/003, p=0/04), pectoralis major (p=0/01, p=0/02), serratus anterior (p=0/01) and posterior deltoid (p=0/01) during D1ext and in lower trapezium (p=0/005,p=0/006) and pectoralis major (p=0/01) during D1flex.
Conclusion: The results of this study indicate that patients with impingement symptoms show abnormal muscle activity. The findings support the theory that shoulders impingement may be related to altered muscle activity in the scapulothoracic and glenohumeral muscles.

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Background: Flexible flat foot is a congenital common deformity in lower extremity associated with ligamentus laxity. This deformity may cause hammer toe, heel spur, inflammation of achille tendon, early muscle fatigue during sport, foot imbalance and pain in leg, knee and hip. The use of insole with medial arch support considered as one of the common treatments for patients. The purpose of this study was to determine the effect of a composite insole, Ethyl Vinyl Acetate (EVA) with Poron layer on ground reaction force on subjects with flexible flat foot in comparison with common EVA insole.

Materials and Methods: Fifty two subjects (14 Male and 38 female) between 18-40 years of age with flexible flat foot participated in this study. Twenty six subjects received Poron insole (EVA with Poron layer) and 26 subjects received common EVA insole. After assessment each subject asked to walk with normal speed across two force plate in two conditions, walking with insole and shoe and walking without insole. Then each subject asked to use insole for forty hours during two weeks. Vertical ground reaction force in the first session and after two weeks was assessed.

Results: Impact force and first peak of vertical ground reaction force (F₁) with Poron insole in comparison with shoe significantly increased in second session (P<0.05). The second peak (F₃) with common insole in comparison with shoe significantly increased in second session (P<0.05). Significant reduction was noted in first peak (F1) with common insole in second session in comparison with first session (P<0.05). There was no observable significant difference in two groups before and after intervention.

Conclusion: The results of this preliminary study show that both insoles change vertical ground reaction force in comparison with shoe alone. But using a composite Poron Layer on EVA insole has not demonstrated a significant difference with common arch support insoles. Therefore application of Poron Silicon layer on EVA insole by itself can not show a significant reduction of ground reaction force.