فعاليت الكترومايوگرافي عضلات منتخب در پسران 10 تا 12 سال داراي عارضه سر به جلو طي دويدن

Electromyography Activity of Selected Muscles during Running in Boys (Aged Range between 10-12 Years) with Forward Head Posture during Running

عارضه سر به جلو يكي از شايع ترين وضعيت ­هاي قامتي ضعيف است كه مي ­تواند باعث آسيب در ناحيه گردن ­شود. هدف اين مطالعه بررسي فعاليت الكتريكي عضلات منتخب طي دويدن در كودكان داراي عارضه سر به جلو در مقايسه با همتايان سالم مي­ باشد. روش بررسي: 28 پسر با ميانگين سني برابر 1/3± 11/8 سال داوطلب شركت در پژوهش شدند. آزمودني­ ها در دو گروه شاهد (تعداد=16 نفر) و سر به جلو (تعداد=12 نفر) قرار گرفتند. يك سيستم الكترومايوگرافي 16 كاناله بي­ سيم جهت ثبت فعاليت عضلات دندانه­­اي قدامي، راست­ كننده ستون فقرات (ناحيه گردني)، جناغي چنبري پستاني، و ذوزنقه فوقاني و تحتاني در دو سمت بدن طي دويدن با پاي برهنه استفاده شد. جهت تحليل الكترومايوگرافي، مقادير دامنه فعاليت هر عضله طي دويدن توسط بيشينه مقدار دامنه در حداكثر انقباض ارادي ايزومتريك همسان ­سازي شد. از آزمون آماري تي مستقل جهت مقايسه بين­ گروهي استفاده شد. سطح معناداري براي تمام تحليل ­ها برابر 0/05>p قرار گرفت. يافته ­ها: نتايج نشان داد كه سرعت دويدن در پسران داراي عارضه سر به جلو (0/09±2/70 متر بر ثانيه) در مقايسه با گروه كنترل (0/14±2/91 متر بر ثانيه) كمتر مي ­باشد (0/001>p). سطح فعاليت عضلات منتخب به لحاظ آماري بين دو گروه تفاوت معناداري را نشان نداد (0/05

Purpose: Forward head posture is one of the most prevalent poor postures that cause neck injuries. The objective of this study was to investigate the electrical activity of selected muscles during running in an able-bodied control group and in boys with forward head posture. Methods: Twenty eight boys were volunteered to participate in this study. The subjects divided into a healthy control group (n=16) and a group of boys with forward head posture (n=12). A portable EMG system was used to record the electrical activity of the bilateral seratus anterior, erector spinae (cervical part), sternocleidomastoid, and upper and lower trapezius muscles during barefoot running. For EMG analysis, the average root mean square (RMS) values of the three trials were calculated and then normalized based on the peak RMS obtained by the maximum isometric voluntary contraction. Independent sample t-test was used for between group comparisons. The significance level was set at p<0.05 for all analyses. Results: The findings indicated that running speed in boys with forward head (2.70±0.09 m/s) was smaller than that in control group (2.91±0.14 m/s) (p<0.001). The activity level of all selected muscles were not statistically different between both groups (p>0.05). However, asymmetry index of electrical activity of sternocleidomastoid muscle in control group was greater than that in forward head posture group by 8.3±1.5% (p=0.045). Conclusion: In boys with forward head posture the running speed was reduced and the muscle activity was similar with respect to those in control group. This altered running speed and muscle activity is suggestive of a lower mechanical efficiency of running in boys with forward head posture that is consistent with literature.