نوع مقاله : مقاله پژوهشی
نویسندگان
1 دانشجوی دکتری رفتار حرکتی، دانشگاه تهران
2 دانشیار رفتار حرکتی و روانشناسی ورزشی، دانشگاه تهران
3 استادیار بیومکانیک ورزشی، پژوهشگاه علوم ورزشی
چکیده
در مطالعات متفاوتی برتری کانون توجه بیرونی نسبت به کانون توجه درونی با استفاده از معیارهای نسبتاً ساده توصیف شده است.این پژوهش با هدف آزمون فرضیة عمل محدودشدة کانون توجه ازطریق بررسی مکانیسمهای زیربنایی نوروفیزیولوژیک عضلات اندام تحتانی در پرش عمودی تحتتأثیر کانون توجه انجام شد. بدینمنظور، 12 والیبالیست ماهر مرد (میانگین سنی92/1 ±24 سال، میانگین وزنی 8/7 ±5/73 کیلوگرم)که بهصورت داوطلبانه در این پژوهش شرکت کرده بودند، حرکت پرش عمودی را روی صفحة نیروسنج در دو وضعیت کانون توجه بیرونی و درونی اجرا کردند. در طول پرش، سیگنالهای الکترومایوگرافی سطحی عضلات اندام تحتانی با استفاده از دستگاه الکترومایوگرافی که با دستگاه صفحة نیروسنج از نظر زمانی همسان شده بود، ثبت شد. نتایج آزمون تی همبسته نشان داد که ارتفاع پرش در وضعیت کانون توجه بیرونی از وضعیت کانون توجه درونی بیشتر بود. همچنین، نتایج آزمون تحلیل واریانس مرکب نشان داد که تفاوت معناداری در زمان شروع و پایان فعالیت عضلانی در دو وضعیت کانون توجه بیرونی و درونی وجود نداشت (زمان شروع: (0.85 = P)، زمان پایان: (0.08 =P ). بین فعالیت الکتریکی عضلات در فاز درونگرای پرش عمودی در دو وضعیت کانون توجه بیرونی و درونی تفاوت معنادار وجود داشت (0.005 = P)، اما در فاز برونگرا تفاوت معنادار مشاهده نشد (0.069 =P ). این نتایج حاکی از این است که هماهنگی برونعضلانی تحتتأثیر نوع کانون توجه قرار نمیگیرد، اما هماهنگی درونعضلانی تحتتأثیر کانون توجه بیرونی افزایش مییابد و کانون توجه بیرونی موجب توسعة خودکاری بیشتر در کنترل حرکات میشود که این موضوع با فرضیة عمل محدودشده همراستاست.
کلیدواژهها
موضوعات
عنوان مقاله [English]
The Effect of External and Internal Focus of Attention on Electromyography of the Lower Extremity Muscles in Different Phases of Vertical Jump
نویسندگان [English]
- Fardin Qeysari 1
- Mehdi Shahbazi 2
- Shahzad Tahmasebi Boroujeni 2
- Ali Sharifnejad 3
1 PhD Student in Motor Behavior, University of Teheran
2 Associate Professor of Motor Behavior and Sport Psychology, University of Teheran
3 Assistant Professor of Sport Biomechanics, Sport Science Research Institute
چکیده [English]
Different studies have shown the advantage of the external focus of attention using relatively simple variables. The aim of this study was to investigate the constrained action hypothesis by underlying neurophysiological mechanisms tests of the lower extremity muscle in vertical jump under the impression of Focus of Attention Types. For this purpose, 12 male professional volleyball players (mean age: 24±1.92, mean weight: 73.5±8.7) performed a vertical jump on the force plate under two conditions in a counterbalanced order: external focus and internal focus. EMG activity of the lower extremity muscle was measured during jumps by using EMG device that coupled with force plate. Paired t-test results showed height of jump under the external focus was greater than that of the internal focus, while there were no significant differences in onset and offset times of the muscles activity between attentional focus conditions (onset times:(P=0.085), offset times:(P=0.08)). Also, the results show significant increases in EMG of the lower extremity with internal focus during concentric phase (P=0.005). However, there was no significant difference in EMG of these muscles between the internal and external focus in the eccentric phase (P=0.069). These results suggest that the intermuscular of coordination are not affected by the focus conditions but the intermuscular coordination is enhanced by the external focus of attention and the external focus of attention increase develop more automation of motor control.
کلیدواژهها [English]
- Vertical Jump
- Timing Muscles
- EMG Activity
- Focus of Attention
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