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mrj 2016, 9 - : 88-93 Back to browse issues page
Effects of angular velocity alteration on the motor variability of knee externsor muscle synergies during isokinetic movements
Fahimeh Khaleghi1, Gholam Reza Olyaei 2, Saeid Talebian Moghadam3, Kazem Malmir4, Hossein Bagheri3, Noredin Nakhostin Ansari3, Shohreh Jalaei5
1- MSc Student, Department of Physiotherapy, School of Rehabilitation, Tehran University of Medical Sciences, Tehran, Iran
2- Full Professor, Department of Physiotherapy, School of Rehabilitation, Tehran University of Medical Sciences, Tehran, Iran. , olyaeigh@sina.tums.ac.ir
3- Full Professor, Department of Physiotherapy, School of Rehabilitation, Tehran University of Medical Sciences, Tehran, Iran.
4- Assistant Professor, Department of Physiotherapy, School of Rehabilitation, Tehran University of Medical Sciences, Tehran, Iran.
5- Associate Professor, Department of Physiotherapy, School of Rehabilitation, Tehran University of Medical Sciences, Tehran, Iran.
Abstract:   (2336 Views)

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.

Keywords: Variability, Angular velocity, Muscle synergie, Externsor muscle.
Full-Text [PDF 146 kb]   (673 Downloads)    
Type of Study: Research | Subject: Physiotherapy
Received: 2016/01/6 | Accepted: 2016/01/6 | Published: 2016/01/6
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Khaleghi F, Olyaei G R, Talebian Moghadam S, Malmir K, Bagheri H, Nakhostin Ansari N et al . Effects of angular velocity alteration on the motor variability of knee externsor muscle synergies during isokinetic movements. mrj. 2016; 9 (S1) :88-93
URL: http://mrj.tums.ac.ir/article-1-5387-en.html
Volume 9 - Back to browse issues page
فصلنامه توانبخشی نوین Journal of Modern Rehabilitation
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