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:: Volume 3, Issue 1 And 2 (27 2009) ::
mrj 2009, 3(1 And 2): 21-27 Back to browse issues page
Movement pattern & motor output during resisted trunk three dimensional motion
Mehdi Sadeghi 1, Azadeh Shadmehr, Hossein Bagheri, Saeid Talebian, Gholam Olyaei, Shohreh Jalaei, Vahid Samadi
Abstract:   (7069 Views)

Background and aim: Asymmetric motions of trunk, external forces and other occupational factors such as frequent bending and twisting, lifting and forceful movement contribute to low back disorders. However, the dynamic and three-Dimensional motions of trunk at varying exertion levels were not addressed in literature. Hence, the aim of this study was to investigate the movement pattern and motor output during resisted trunk three-dimensional motion. 

Materials and Methods: Thirty healthy male subjects randomly performed dynamic asymmetric trunk motion at four resistance levels (nominal resistance, 25%, 50%, and 75% maximal voluntary contraction (MVC) torque) while positioned in standing with the L5-S1 interspinous space aligned with the flexion / extension axis of isostation B200. Under each resistance condition, movement patterns (range of motion), motor output (maximum torque) of the trunk were measured.

Results: In general, with increasing resistance from nominal to 75% MVC torque, the maximum torque of trunk in different directions of motion (flexion, extension, right & left lateral flexion, right & left rotation) increased significantly (p= 0.000). With increasing resistance from nominal to 50%  MVC torque, the range of motion of the trunk decreased significant (p<0.0083), but no significant change was found in this variable between resistance conditions of 50% and 75% MVC torque (p>0.0083).

Conclusion: When the resistance level is increased , the created external forces  must be balanced by internal forces generated by trunk muscles. Because the muscles have short lever arms compared with the external forces, they must generate large amounts of forces, placing compressive and shear loads on the structures of the spine. Under these conditions, spine injuries may be enhanced.

Keywords: Motor Control, Surface Electromyography, Resistance, Spinal Column
Full-Text [PDF 398 kb]   (1415 Downloads)    
Type of Study: Research | Subject: General
Received: 2009/05/2 | Accepted: 2009/07/7 | Published: 2013/08/6
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Sadeghi M, Shadmehr A, Bagheri H, Talebian S, Olyaei G, Jalaei S et al . Movement pattern & motor output during resisted trunk three dimensional motion. mrj. 2009; 3 (1 and 2) :21-27
URL: http://mrj.tums.ac.ir/article-1-120-en.html

Volume 3, Issue 1 And 2 (27 2009) Back to browse issues page
فصلنامه توانبخشی نوین Journal of Modern Rehabilitation
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