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Study of myoeletric activity in isometric exercise with different contractions

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Author(s):
Emanuele Moraes Mello
Total Authors: 1
Document type: Master's Dissertation
Press: São Carlos.
Institution: Universidade de São Paulo (USP). Escola de Engenharia de São Carlos (EESC/SBD)
Defense date:
Examining board members:
Orivaldo Lopes da Silva; José Angelo Barela; Carlos Dias Maciel
Advisor: Neri Alves
Abstract

There are few studies about isometric activity at the literature that approaches the context of his variation in function of the muscle contraction. The aim of the present study is an evaluation of isometric exercises in different ways, analyzing variations at mioelectric activity. In the exercise named dissipative, the voluntary contraction pulls an inextensible wire, whereas in the exercise named conservative the same load is pulled by lifting weights. This study showed experimentally that the electromyography signals are different in function of the two kind of isometric exercises. The results show that the differences among the dissipative and conservative exercises depend on the level of force used, being larger in high levels. These results may be related to the different pattern of muscular activation and the muscular fiber type. The dissipative exercises show a larger muscular activation and larger activation of fibers of slow contraction, whereas the conservative have smaller muscular activation and larger activation of fast contraction fibers. The obtained differences were confirmed by the visualization techniques denominated parallel coordinates and Viz3D. These kind of analyses presented great potentiality for the study of these signals, making possible to include the parameters of subjects and muscles differences as exercises attributes, possibly a global evaluation. The conclusion of this work is that these two isometric exercises present different characteristics. (AU)