| چکیده انگلیسی مقاله |
Background and Aim: Several studies have investigated the effects of angular velocity on mechanical and physiological variables such as joint net torque, muscle force and myoelectrical activity, but so far its effects on the control of the pattern of synergist muscle activation during isokinetic movements have not been studied. In this experiment, a computational method of identifying and analyzing muscle synergies were used which is based on the framework of the uncontrolled manifold hypothesis to determine the variability of muscle synergies following movement velocity alteration. Materials and Methods: Twelve healthy females without any known neurological or motor disorders participated in the experiment. The participants were positioned on a Biodex dynamometer. They were asked to perform ten continuous knee extension and flexion motions with maximal strength at 45˚/s or 300˚/s. Electromyographic activity of the vastus medialis (VM), vastus lateralis (VL) and rectus femoris (RF) were recorded and variance within the UCM (VUCM) and orthogonal to the UCM (VORT) with respect to an appropriate Jacobian matrix was computed. An independent t-test was used to compare VUCM between two velocities. Results: Across subjects, VUCM was significantly higher than VORT (VUCM>VORT) in both tasks. There was no significant difference in VUCM between two velocities (p>0.05). Conclusion: Our findings suggest that angular velocity is not an important parameter when a controller of a multi-element system wants to stabilize a particular value of a performance variable. Keywords: Variability, Angular velocity, Muscle synergie, Externsor muscle. |
| نویسندگان مقاله |
فهیمه خالقی | fahimeh khaleghi
msc student, department of physiotherapy, school of rehabilitation, tehran university of medical sciences, tehran, iran
دانشجوی کارشناسی ارشد فیزیوتراپی، دانشکده توانبخشی، دانشگاه علوم پزشکی تهران، تهران، ایران
سازمان اصلی تایید شده: دانشگاه علوم پزشکی تهران (Tehran university of medical sciences)
غلامرضا علیایی | gholam reza olyaei
full professor, department of physiotherapy, school of rehabilitation, tehran university of medical sciences, tehran, iran.
استاد گروه آموزشی فیزیوتراپی، دانشکده توانبخشی، دانشگاه علوم پزشکی تهران، تهران، ایران
سازمان اصلی تایید شده: دانشگاه علوم پزشکی تهران (Tehran university of medical sciences)
سعید طالبیان مقدم | saeid talebian moghadam
full professor, department of physiotherapy, school of rehabilitation, tehran university of medical sciences, tehran, iran.
استاد گروه آموزشی فیزیوتراپی، دانشکده توانبخشی، دانشگاه علوم پزشکی تهران، تهران، ایران
سازمان اصلی تایید شده: دانشگاه علوم پزشکی تهران (Tehran university of medical sciences)
کاظم مالمیر | kazem malmir
assistant professor, department of physiotherapy, school of rehabilitation, tehran university of medical sciences, tehran, iran.
استادیار گروه آموزشی فیزیوتراپی، دانشکده توانبخشی، دانشگاه علوم پزشکی تهران، تهران، ایران
سازمان اصلی تایید شده: دانشگاه علوم پزشکی تهران (Tehran university of medical sciences)
حسین باقری | hossein bagheri
full professor, department of physiotherapy, school of rehabilitation, tehran university of medical sciences, tehran, iran.
استاد گروه آموزشی فیزیوتراپی، دانشکده توانبخشی، دانشگاه علوم پزشکی تهران، تهران، ایران
سازمان اصلی تایید شده: دانشگاه علوم پزشکی تهران (Tehran university of medical sciences)
نورالدین نخستین انصاری | noredin nakhostin ansari
full professor, department of physiotherapy, school of rehabilitation, tehran university of medical sciences, tehran, iran.
استاد گروه آموزشی فیزیوتراپی، دانشکده توانبخشی، دانشگاه علوم پزشکی تهران، تهران، ایران
سازمان اصلی تایید شده: دانشگاه علوم پزشکی تهران (Tehran university of medical sciences)
شهره جلایی | shohreh jalaei
associate professor, department of physiotherapy, school of rehabilitation, tehran university of medical sciences, tehran, iran.
دانشیار گروه فیزیوتراپی، دانشکده توانبخشی، دانشگاه علوم پزشکی تهران
سازمان اصلی تایید شده: دانشگاه علوم پزشکی تهران (Tehran university of medical sciences)
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