کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4065075 1266239 2011 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Time course of stretching-induced changes in mechanomyogram and force characteristics
موضوعات مرتبط
علوم پزشکی و سلامت پزشکی و دندانپزشکی ارتوپدی، پزشکی ورزشی و توانبخشی
پیش نمایش صفحه اول مقاله
Time course of stretching-induced changes in mechanomyogram and force characteristics
چکیده انگلیسی

To evaluate the time-course of stretching-induced changes in mechanical properties of the muscle-tendon unit (MTU), 11 participants (age 22 ± 1 yr; body mass 77 ± 5 kg; stature 1.78 ± 0.05 m; mean ± SD) underwent tetanic electrical stimulations of the medial gastrocnemius muscle before and after (up to 2 h) stretching administration. During contractions, surface electromyogram (EMG), mechanomyogram (MMG) and force were recorded simultaneously. From MMG, peak-to-peak (p–p) and root mean square (RMS) were calculated during the on-phase and plateau phase of tetanic contraction, respectively. After stretching: (i) no differences were found in EMG parameters; (ii) MMG p–p and slope decreased (−16% and −10%, respectively; P < 0.05) and remained depressed for the entire recovery period; (iii) MMG RMS increased (+20%; P < 0.05), returning to pre-stretching values within 15 min; and (iv) peak force (pF), with its first (dF/dt) and second (d2F/dt2) derivative, decreased significantly by 32%, 35% and 54%, respectively, and remained depressed for the entire recovery period. The lack of MMG p–p and pF recovery could be ascribable to a reduced muscle force generating capacity due to persisting changes in viscoelastic characteristics of series elastic components. The early return of MMG RMS to pre-stretching values suggests that changes in viscoelastic parallel components recovered after few minutes.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Electromyography and Kinesiology - Volume 21, Issue 5, October 2011, Pages 795–802
نویسندگان
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